diff mbox

[v4,1/2] dma: at_xdmac: creation of the atmel eXtended DMA Controller driver

Message ID 1410792622-22621-2-git-send-email-ludovic.desroches@atmel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ludovic Desroches Sept. 15, 2014, 2:50 p.m. UTC
New atmel DMA controller known as XDMAC, introduced with SAMA5D4
devices.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/dma/Kconfig            |    7 +
 drivers/dma/Makefile           |    1 +
 drivers/dma/at_xdmac.c         | 1210 ++++++++++++++++++++++++++++++++++++++++
 drivers/dma/at_xdmac.h         |  307 ++++++++++
 include/dt-bindings/dma/at91.h |   25 +
 5 files changed, 1550 insertions(+)
 create mode 100644 drivers/dma/at_xdmac.c
 create mode 100644 drivers/dma/at_xdmac.h

Comments

Arnd Bergmann Sept. 15, 2014, 4:47 p.m. UTC | #1
On Monday 15 September 2014, Ludovic Desroches wrote:
>  
> +config AT_XDMAC
> +	tristate "Atmel XDMA support"
> +	depends on ARCH_AT91
> +	select DMA_ENGINE
> +	help
> +	  Support the Atmel XDMA controller.

This should depend on (ARCH_AT91 || COMPILE_TEST) and built on x86 to
get into the usual automated build checkers.

> +static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
> +				       struct of_dma *of_dma)
> +{
> +	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
> +	struct at_xdmac_chan	*atchan;
> +	struct dma_chan		*chan;
> +	struct device		*dev = atxdmac->dma.dev;
> +	dma_cap_mask_t 		mask;
> +
> +	if (dma_spec->args_count != 2) {
> +		dev_err(dev, "dma phandler args: bad number of args\n");
> +		return NULL;
> +	}
> +
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_SLAVE, mask);

The mask is unused, just remove it.

> +	chan = dma_get_any_slave_channel(&atxdmac->dma);
> +	if (!chan) {
> +		dev_err(dev, "can't get a dma channel\n");
> +		return NULL;
> +	}
> +
> +	atchan = to_at_xdmac_chan(chan);
> +	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
> +	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
> +	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[1]);
> +	dev_info(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
> +		 atchan->memif, atchan->perif, atchan->perid);

Maybe dev_dbg instead of dev_info?

I think having three cells would be nicer here, so you can get rid of the
macros.
> diff --git a/drivers/dma/at_xdmac.h b/drivers/dma/at_xdmac.h
> new file mode 100644
> index 0000000..5f4d898
> --- /dev/null
> +++ b/drivers/dma/at_xdmac.h

The header is only used in one file, so just move the contents into that file.

> +
> +static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
> +{
> +	return (void __iomem *)(atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40));
> +}

That type cast should not be needed. Is atxdmac->regs not already a void __iomem *

> +#define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
> +#define at_xdmac_write(atxdmac, reg, value) \
> +	writel_relaxed((value), (atxdmac)->regs + (reg))
> +
> +#define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
> +#define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))

Is writel_relaxed the right accessor here? I haven't reviewed all uses of this,
but you have to ensure that every use that needs synchronization against the
actual DMA has explicit barriers here.
(0x2 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* single AHB access */
>  
> +
> +/* ---------- XDMAC ---------- */
> +#define AT91_XDMAC_DT_MEM_IF_MASK	(0x1)
> +#define AT91_XDMAC_DT_MEM_IF_OFFSET	(16)
> +#define AT91_XDMAC_DT_MEM_IF(mem_if)	(((mem_if) & AT91_XDMAC_DT_MEM_IF_MASK) \
> +					<< AT91_XDMAC_DT_MEM_IF_OFFSET)
> +#define AT91_XDMAC_DT_GET_MEM_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_MEM_IF_OFFSET) \
> +					& AT91_XDMAC_DT_MEM_IF_MASK)
> +
> +#define AT91_XDMAC_DT_PER_IF_MASK	(0x1)
> +#define AT91_XDMAC_DT_PER_IF_OFFSET	(0)
> +#define AT91_XDMAC_DT_PER_IF(per_if)	(((per_if) & AT91_XDMAC_DT_PER_IF_MASK) \
> +					<< AT91_XDMAC_DT_PER_IF_OFFSET)
> +#define AT91_XDMAC_DT_GET_PER_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_PER_IF_OFFSET) \
> +					& AT91_XDMAC_DT_PER_IF_MASK)
> +
> +#define AT91_XDMAC_DT_PERID_MASK	(0x7f)
> +#define AT91_XDMAC_DT_PERID_OFFSET	(24)
> +#define AT91_XDMAC_DT_PERID(perid)	(((perid) & AT91_XDMAC_DT_PERID_MASK) \
> +					<< AT91_XDMAC_DT_PERID_OFFSET)
> +#define AT91_XDMAC_DT_GET_PERID(cfg)	(((cfg) >> AT91_XDMAC_DT_PERID_OFFSET) \
> +					& AT91_XDMAC_DT_PERID_MASK)

As mentioned, I think it would be much better to keep the macros inside of the
driver and not visible to the binding, so you can use simple numbers in DT.

	Arnd
Ludovic Desroches Sept. 16, 2014, 9:34 a.m. UTC | #2
On Mon, Sep 15, 2014 at 06:47:22PM +0200, Arnd Bergmann wrote:
> On Monday 15 September 2014, Ludovic Desroches wrote:
> >  
> > +config AT_XDMAC
> > +	tristate "Atmel XDMA support"
> > +	depends on ARCH_AT91
> > +	select DMA_ENGINE
> > +	help
> > +	  Support the Atmel XDMA controller.
> 
> This should depend on (ARCH_AT91 || COMPILE_TEST) and built on x86 to
> get into the usual automated build checkers.
>

Ok
 
> > +static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
> > +				       struct of_dma *of_dma)
> > +{
> > +	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
> > +	struct at_xdmac_chan	*atchan;
> > +	struct dma_chan		*chan;
> > +	struct device		*dev = atxdmac->dma.dev;
> > +	dma_cap_mask_t 		mask;
> > +
> > +	if (dma_spec->args_count != 2) {
> > +		dev_err(dev, "dma phandler args: bad number of args\n");
> > +		return NULL;
> > +	}
> > +
> > +	dma_cap_zero(mask);
> > +	dma_cap_set(DMA_SLAVE, mask);
> 
> The mask is unused, just remove it.
> 

Ok

> > +	chan = dma_get_any_slave_channel(&atxdmac->dma);
> > +	if (!chan) {
> > +		dev_err(dev, "can't get a dma channel\n");
> > +		return NULL;
> > +	}
> > +
> > +	atchan = to_at_xdmac_chan(chan);
> > +	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
> > +	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
> > +	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[1]);
> > +	dev_info(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
> > +		 atchan->memif, atchan->perif, atchan->perid);
> 
> Maybe dev_dbg instead of dev_info?
> 
> I think having three cells would be nicer here, so you can get rid of the
> macros.

I can split the memory and peripheral interface in two cells. But I
would like to keep the macro for the third cell which is in fact the
channel configuration register. The idea is to not have to change the
bindings if one day we need to setup an extra field from this register.
We had this case with the hdma controller: we didn't planned to exhibit
the fifo configuration but we had to do it to allow dma use with usart.

> > diff --git a/drivers/dma/at_xdmac.h b/drivers/dma/at_xdmac.h
> > new file mode 100644
> > index 0000000..5f4d898
> > --- /dev/null
> > +++ b/drivers/dma/at_xdmac.h
> 
> The header is only used in one file, so just move the contents into that file.
> 

I'll merge the two files.

> > +
> > +static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
> > +{
> > +	return (void __iomem *)(atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40));
> > +}
> 
> That type cast should not be needed. Is atxdmac->regs not already a void __iomem *
> 

Right.

> > +#define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
> > +#define at_xdmac_write(atxdmac, reg, value) \
> > +	writel_relaxed((value), (atxdmac)->regs + (reg))
> > +
> > +#define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
> > +#define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
> 
> Is writel_relaxed the right accessor here? I haven't reviewed all uses of this,
> but you have to ensure that every use that needs synchronization against the
> actual DMA has explicit barriers here.

I'll try to check if relaxed ordering can cause some issues. 

> (0x2 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* single AHB access */
> >  
> > +
> > +/* ---------- XDMAC ---------- */
> > +#define AT91_XDMAC_DT_MEM_IF_MASK	(0x1)
> > +#define AT91_XDMAC_DT_MEM_IF_OFFSET	(16)
> > +#define AT91_XDMAC_DT_MEM_IF(mem_if)	(((mem_if) & AT91_XDMAC_DT_MEM_IF_MASK) \
> > +					<< AT91_XDMAC_DT_MEM_IF_OFFSET)
> > +#define AT91_XDMAC_DT_GET_MEM_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_MEM_IF_OFFSET) \
> > +					& AT91_XDMAC_DT_MEM_IF_MASK)
> > +
> > +#define AT91_XDMAC_DT_PER_IF_MASK	(0x1)
> > +#define AT91_XDMAC_DT_PER_IF_OFFSET	(0)
> > +#define AT91_XDMAC_DT_PER_IF(per_if)	(((per_if) & AT91_XDMAC_DT_PER_IF_MASK) \
> > +					<< AT91_XDMAC_DT_PER_IF_OFFSET)
> > +#define AT91_XDMAC_DT_GET_PER_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_PER_IF_OFFSET) \
> > +					& AT91_XDMAC_DT_PER_IF_MASK)
> > +
> > +#define AT91_XDMAC_DT_PERID_MASK	(0x7f)
> > +#define AT91_XDMAC_DT_PERID_OFFSET	(24)
> > +#define AT91_XDMAC_DT_PERID(perid)	(((perid) & AT91_XDMAC_DT_PERID_MASK) \
> > +					<< AT91_XDMAC_DT_PERID_OFFSET)
> > +#define AT91_XDMAC_DT_GET_PERID(cfg)	(((cfg) >> AT91_XDMAC_DT_PERID_OFFSET) \
> > +					& AT91_XDMAC_DT_PERID_MASK)
> 
> As mentioned, I think it would be much better to keep the macros inside of the
> driver and not visible to the binding, so you can use simple numbers in DT.
> 
> 	Arnd
Nicolas Ferre Sept. 17, 2014, 12:10 p.m. UTC | #3
On 15/09/2014 16:50, Ludovic Desroches :
> New atmel DMA controller known as XDMAC, introduced with SAMA5D4
> devices.
> 
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> ---
>  drivers/dma/Kconfig            |    7 +
>  drivers/dma/Makefile           |    1 +
>  drivers/dma/at_xdmac.c         | 1210 ++++++++++++++++++++++++++++++++++++++++
>  drivers/dma/at_xdmac.h         |  307 ++++++++++
>  include/dt-bindings/dma/at91.h |   25 +
>  5 files changed, 1550 insertions(+)
>  create mode 100644 drivers/dma/at_xdmac.c
>  create mode 100644 drivers/dma/at_xdmac.h
> 
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 9b1ea0e..d04e79a 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -107,6 +107,13 @@ config AT_HDMAC
>  	help
>  	  Support the Atmel AHB DMA controller.
>  
> +config AT_XDMAC
> +	tristate "Atmel XDMA support"
> +	depends on ARCH_AT91
> +	select DMA_ENGINE
> +	help
> +	  Support the Atmel XDMA controller.
> +
>  config FSL_DMA
>  	tristate "Freescale Elo series DMA support"
>  	depends on FSL_SOC
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index c6adb92..f32bfe1 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
>  obj-$(CONFIG_MV_XOR) += mv_xor.o
>  obj-$(CONFIG_DW_DMAC_CORE) += dw/
>  obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
> +obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
>  obj-$(CONFIG_MX3_IPU) += ipu/
>  obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
>  obj-$(CONFIG_SH_DMAE_BASE) += sh/
> diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
> new file mode 100644
> index 0000000..9c7af22
> --- /dev/null
> +++ b/drivers/dma/at_xdmac.c
> @@ -0,0 +1,1210 @@
> +/*
> + * Driver for the Atmel Extensible DMA Controller (aka XDMAC on AT91 systems)
> + *
> + * Copyright (C) 2014 Atmel Corporation
> + *
> + * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <dt-bindings/dma/at91.h>
> +#include <linux/clk.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dmapool.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm.h>
> +
> +#include "dmaengine.h"
> +#include "at_xdmac.h"
> +
> +static unsigned int init_nr_desc_per_channel = 64;
> +module_param(init_nr_desc_per_channel, uint, 0644);
> +MODULE_PARM_DESC(init_nr_desc_per_channel,
> +		 "initial descriptors per channel (default: 64)");
> +
> +
> +static bool at_xdmac_chan_is_enabled(struct at_xdmac_chan *atchan)
> +{
> +	return at_xdmac_chan_read(atchan, AT_XDMAC_GS) & atchan->mask;
> +}
> +
> +static void at_xdmac_off(struct at_xdmac *atxdmac)
> +{
> +	at_xdmac_write(atxdmac, AT_XDMAC_GD, -1L);
> +
> +	/* Wait that all chans are disabled. */
> +	while (at_xdmac_read(atxdmac, AT_XDMAC_GS))
> +		cpu_relax();
> +	at_xdmac_write(atxdmac, AT_XDMAC_GID, -1L);
> +}
> +
> +/* Call with lock hold. */
> +static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
> +				struct at_xdmac_desc *first)
> +{
> +	struct at_xdmac	*atxdmac = to_at_xdmac(atchan->chan.device);
> +	u32		reg;
> +
> +	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);
> +
> +	if (at_xdmac_chan_is_enabled(atchan))
> +		return;
> +
> +	/* Set transfer as active to not try to start it again. */
> +	first->active_xfer = true;
> +
> +	/* Tell xdmac where to get the first descriptor. */
> +	reg = AT_XDMAC_CNDA_NDA(first->tx_dma_desc.phys)
> +	      | AT_XDMAC_CNDA_NDAIF(atchan->memif);
> +	at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, reg);
> +
> +	/*
> +	 * When doing memory to memory transfer we need to use the next
> +	 * descriptor view 2 since some fields of the configuration register
> +	 * depend on transfer size and src/dest addresses.
> +	 */
> +	if (atchan->cfg & AT_XDMAC_CC_TYPE_PER_TRAN) {
> +		reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
> +		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->cfg);
> +	} else

Style: we need {} even in the alternative.

> +		reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
> +
> +	reg |= AT_XDMAC_CNDC_NDDUP
> +	       | AT_XDMAC_CNDC_NDSUP
> +	       | AT_XDMAC_CNDC_NDE;
> +	at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, reg);
> +
> +	dev_vdbg(chan2dev(&atchan->chan),
> +		 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, XDMAC_CNDC=0x%08x, "
> +		 "XDMAC_CSA=0x%08x, XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
> +		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
> +
> +	/*
> +	 * There is no end of list when doing cyclic dma, we need to get
> +	 * an interrupt after each periods.
> +	 */
> +	if (at_xdmac_chan_is_cyclic(atchan))
> +		at_xdmac_chan_write(atchan, AT_XDMAC_CIE, AT_XDMAC_CIE_BIE);
> +	else
> +		at_xdmac_chan_write(atchan, AT_XDMAC_CIE, AT_XDMAC_CIE_LIE);
> +	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
> +	dev_vdbg(chan2dev(&atchan->chan),
> +		 "%s: enable channel (0x%08x)\n", __func__, atchan->mask);

After having read the remark from Arnd and as we discussed together, a
write memory barrier seems needed here.

> +	at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
> +
> +	dev_vdbg(chan2dev(&atchan->chan),
> +		 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, XDMAC_CNDC=0x%08x, "
> +		 "XDMAC_CSA=0x%08x, XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
> +		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
> +		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
> +
> +}
> +
> +static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
> +{
> +	struct at_xdmac_desc	*desc = txd_to_at_desc(tx);
> +	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(tx->chan);
> +	dma_cookie_t		cookie;
> +	unsigned long		flags;
> +
> +	spin_lock_irqsave(&atchan->lock, flags);
> +	cookie = dma_cookie_assign(tx);
> +
> +	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
> +		 __func__, atchan, desc);
> +	list_add_tail(&desc->xfer_node, &atchan->xfers_list);
> +	if (list_is_singular(&atchan->xfers_list))
> +		at_xdmac_start_xfer(atchan, desc);
> +
> +	spin_unlock_irqrestore(&atchan->lock, flags);
> +	return cookie;
> +}
> +
> +static struct at_xdmac_desc *at_xdmac_alloc_desc(struct dma_chan *chan,
> +						 gfp_t gfp_flags)
> +{
> +	struct at_xdmac_desc	*desc;
> +	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
> +	dma_addr_t		phys;
> +
> +	desc = dma_pool_alloc(atxdmac->at_xdmac_desc_pool, gfp_flags, &phys);
> +	if (desc) {
> +		memset(desc, 0, sizeof(*desc));
> +		INIT_LIST_HEAD(&desc->descs_list);
> +		dma_async_tx_descriptor_init(&desc->tx_dma_desc, chan);
> +		desc->tx_dma_desc.tx_submit = at_xdmac_tx_submit;
> +		desc->tx_dma_desc.phys = phys;
> +	}
> +
> +	return desc;
> +}
> +
> +/* Call must be protected by lock. */
> +static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
> +{
> +	struct at_xdmac_desc *desc;
> +
> +	if (list_empty(&atchan->free_descs_list)) {
> +		desc = at_xdmac_alloc_desc(&atchan->chan, GFP_NOWAIT);
> +	} else {
> +		desc = list_first_entry(&atchan->free_descs_list,
> +					struct at_xdmac_desc, desc_node);
> +		list_del(&desc->desc_node);
> +	}
> +
> +	return desc;
> +}
> +
> +static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
> +				       struct of_dma *of_dma)
> +{
> +	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
> +	struct at_xdmac_chan	*atchan;
> +	struct dma_chan		*chan;
> +	struct device		*dev = atxdmac->dma.dev;
> +	dma_cap_mask_t 		mask;
> +
> +	if (dma_spec->args_count != 2) {
> +		dev_err(dev, "dma phandler args: bad number of args\n");
> +		return NULL;
> +	}
> +
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_SLAVE, mask);
> +	chan = dma_get_any_slave_channel(&atxdmac->dma);
> +	if (!chan) {
> +		dev_err(dev, "can't get a dma channel\n");
> +		return NULL;
> +	}
> +
> +	atchan = to_at_xdmac_chan(chan);
> +	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
> +	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
> +	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[1]);
> +	dev_info(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
> +		 atchan->memif, atchan->perif, atchan->perid);
> +
> +	return chan;
> +}
> +
> +static int at_xdmac_set_slave_config(struct dma_chan *chan,
> +				      struct dma_slave_config *sconfig)
> +{
> +	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
> +
> +	atchan->cfg = AT91_XDMAC_DT_PERID(atchan->perid)
> +		      |	AT_XDMAC_CC_SWREQ_HWR_CONNECTED
> +		      | AT_XDMAC_CC_MBSIZE_SIXTEEN
> +		      | AT_XDMAC_CC_TYPE_PER_TRAN;
> +
> +	if (sconfig->direction == DMA_DEV_TO_MEM) {
> +		atchan->cfg |= AT_XDMAC_CC_DAM_INCREMENTED_AM
> +			       | AT_XDMAC_CC_SAM_FIXED_AM
> +			       | AT_XDMAC_CC_DIF(atchan->memif)
> +			       | AT_XDMAC_CC_SIF(atchan->perif)
> +			       | AT_XDMAC_CC_DSYNC_PER2MEM;
> +		atchan->dwidth = ffs(sconfig->src_addr_width) - 1;
> +		atchan->cfg |= AT_XDMAC_CC_DWIDTH(atchan->dwidth);
> +		atchan->cfg |= at_xdmac_csize(sconfig->src_maxburst);
> +	} else if (sconfig->direction == DMA_MEM_TO_DEV) {
> +		atchan->cfg |= AT_XDMAC_CC_DAM_FIXED_AM
> +			       | AT_XDMAC_CC_SAM_INCREMENTED_AM
> +			       | AT_XDMAC_CC_DIF(atchan->perif)
> +			       | AT_XDMAC_CC_SIF(atchan->memif)
> +			       | AT_XDMAC_CC_DSYNC_MEM2PER;
> +		atchan->dwidth = ffs(sconfig->dst_addr_width) - 1;
> +		atchan->cfg |= AT_XDMAC_CC_DWIDTH(atchan->dwidth);
> +		atchan->cfg |= at_xdmac_csize(sconfig->dst_maxburst);
> +	} else

Style: {} missing.

> +		return -EINVAL;
> +
> +	/*
> +	 * Src address and dest addr are needed to configure the link list
> +	 * descriptor so keep the slave configuration.
> +	 */
> +	memcpy(&atchan->dma_sconfig, sconfig, sizeof(struct dma_slave_config));
> +
> +	dev_dbg(chan2dev(chan), "%s: atchan->cfg=0x%08x\n", __func__, atchan->cfg);
> +
> +	return 0;
> +}
> +
> +static struct dma_async_tx_descriptor *
> +at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> +		       unsigned int sg_len, enum dma_transfer_direction direction,
> +		       unsigned long flags, void *context)
> +{
> +	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
> +	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
> +	struct at_xdmac_desc	*first = NULL, *prev = NULL;
> +	struct scatterlist	*sg;
> +	int 			i;
> +
> +	if (!sgl)
> +		return NULL;
> +
> +	if (!is_slave_direction(direction)) {
> +		dev_err(chan2dev(chan), "invalid DMA direction\n");
> +		return NULL;
> +	}
> +
> +	dev_dbg(chan2dev(chan), "%s: sg_len=%d, dir=%s, flags=0x%lx\n",
> +		 __func__, sg_len,
> +		 direction == DMA_MEM_TO_DEV ? "to device" : "from device",
> +		 flags);
> +
> +	/* Protect dma_sconfig field that can be modified by set_slave_conf. */
> +	spin_lock(&atchan->lock);
> +
> +	/* Prepare descriptors. */
> +	for_each_sg(sgl, sg, sg_len, i) {
> +		struct at_xdmac_desc	*desc = NULL;
> +		u32			len, mem;
> +
> +		len = sg_dma_len(sg);
> +		mem = sg_dma_address(sg);
> +		if (unlikely(!len)) {
> +			dev_err(chan2dev(chan), "sg data length is zero\n");
> +			spin_unlock(&atchan->lock);
> +			return NULL;
> +		}
> +		dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
> +			 __func__, i, len, mem);
> +
> +		desc = at_xdmac_get_desc(atchan);
> +		if (!desc) {
> +			dev_err(chan2dev(chan), "can't get descriptor\n");
> +			if (first)
> +				list_splice_init(&first->descs_list, &atchan->free_descs_list);
> +			spin_unlock(&atchan->lock);
> +			return NULL;
> +		}
> +
> +		/* Linked list descriptor setup. */
> +		if (direction == DMA_DEV_TO_MEM) {
> +			desc->lld.mbr_sa = sconfig->src_addr;
> +			desc->lld.mbr_da = mem;
> +		} else {
> +			desc->lld.mbr_sa = mem;
> +			desc->lld.mbr_da = sconfig->dst_addr;
> +		}
> +		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1		/* next descriptor view */
> +			| AT_XDMAC_MBR_UBC_NDEN				/* next descriptor dst parameter update */
> +			| AT_XDMAC_MBR_UBC_NSEN				/* next descriptor src parameter update */
> +			| (i == sg_len - 1 ? 0 : AT_XDMAC_MBR_UBC_NDE)	/* descriptor fetch */
> +			| len / (1 << atchan->dwidth);			/* microblock length */
> +		dev_dbg(chan2dev(chan),
> +			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x\n",
> +			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc);
> +
> +		/* Chain lld. */
> +		if (prev) {
> +			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
> +			dev_dbg(chan2dev(chan),
> +				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
> +				 __func__, prev, prev->lld.mbr_nda);
> +		}
> +
> +		prev = desc;
> +		if (!first)
> +			first = desc;
> +
> +		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
> +			 __func__, desc, first);
> +		list_add_tail(&desc->desc_node, &first->descs_list);
> +	}
> +
> +	spin_unlock(&atchan->lock);
> +
> +	first->tx_dma_desc.cookie = -EBUSY;
> +	first->tx_dma_desc.flags = flags;
> +	first->xfer_size = sg_len;
> +
> +	return &first->tx_dma_desc;
> +}
> +
> +static struct dma_async_tx_descriptor *
> +at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
> +			 size_t buf_len, size_t period_len,
> +			 enum dma_transfer_direction direction,
> +			 unsigned long flags)
> +{
> +	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
> +	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
> +	struct at_xdmac_desc	*first = NULL, *prev = NULL;
> +	unsigned int		periods = buf_len / period_len;
> +	unsigned long		lock_flags;
> +	int 			i;
> +
> +	dev_dbg(chan2dev(chan), "%s: buf_addr=0x%08x, buf_len=%d, period_len=%d, "
> +		"dir=%s, flags=0x%lx\n",
> +		__func__, buf_addr, buf_len, period_len,
> +		direction == DMA_MEM_TO_DEV ? "mem2per" : "per2mem", flags);
> +
> +	if (!is_slave_direction(direction)) {
> +		dev_err(chan2dev(chan), "invalid DMA direction\n");
> +		return NULL;
> +	}
> +
> +	if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
> +		dev_err(chan2dev(chan), "channel currently used\n");
> +		return NULL;
> +	}
> +
> +	for (i = 0; i < periods; i++) {
> +		struct at_xdmac_desc	*desc = NULL;
> +
> +		spin_lock_irqsave(&atchan->lock, lock_flags);
> +		desc = at_xdmac_get_desc(atchan);
> +		spin_unlock_irqrestore(&atchan->lock, lock_flags);
> +		if (!desc) {
> +			dev_err(chan2dev(chan), "can't get descriptor\n");
> +			if (first)
> +				list_splice_init(&first->descs_list, &atchan->free_descs_list);
> +			return NULL;
> +		}
> +		dev_dbg(chan2dev(chan),
> +			"%s: desc=0x%p, tx_dma_desc.phys=0x%08x\n",
> +			__func__, desc, desc->tx_dma_desc.phys);
> +
> +		if (direction == DMA_DEV_TO_MEM) {
> +			desc->lld.mbr_sa = sconfig->src_addr;
> +			desc->lld.mbr_da = buf_addr + i * period_len;
> +		} else {
> +			desc->lld.mbr_sa = buf_addr + i * period_len;
> +			desc->lld.mbr_da = sconfig->dst_addr;
> +		};
> +		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
> +			| AT_XDMAC_MBR_UBC_NDEN
> +			| AT_XDMAC_MBR_UBC_NSEN
> +			| AT_XDMAC_MBR_UBC_NDE
> +			| period_len / (1 << atchan->dwidth);
> +
> +		dev_dbg(chan2dev(chan),
> +			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x\n",
> +			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc);
> +
> +		/* Chain lld. */
> +		if (prev) {
> +			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
> +			dev_dbg(chan2dev(chan),
> +				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
> +				 __func__, prev, prev->lld.mbr_nda);
> +		}
> +
> +		prev = desc;
> +		if (!first)
> +			first = desc;
> +
> +		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
> +			 __func__, desc, first);
> +		list_add_tail(&desc->desc_node, &first->descs_list);
> +	}
> +
> +	prev->lld.mbr_nda = first->tx_dma_desc.phys;
> +	dev_dbg(chan2dev(chan),
> +		"%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
> +		__func__, prev, prev->lld.mbr_nda);
> +	first->tx_dma_desc.cookie = -EBUSY;
> +	first->tx_dma_desc.flags = flags;
> +	first->xfer_size = buf_len;
> +
> +	return &first->tx_dma_desc;
> +}
> +
> +static struct dma_async_tx_descriptor *
> +at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> +			 size_t len, unsigned long flags)
> +{
> +	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
> +	struct at_xdmac_desc	*first = NULL, *prev = NULL;
> +	size_t			remaining_size = len, xfer_size = 0, ublen;
> +	dma_addr_t		src_addr = src, dst_addr = dest;
> +	u32			dwidth;
> +	/*
> +	 * WARNING: The channel configuration is set here since there is no
> +	 * dmaengine_slave_config call in this case. Moreover we don't know the
> +	 * direction, it involves we can't dynamically set the source and dest
> +	 * interface so we have to use the same one. Only interface 0 allows EBI
> +	 * access. Hopefully we can access DDR through both ports (at least on
> +	 * SAMA5D4x), so we can use the same interface for source and dest,
> +	 * that solves the fact we don't know the direction.
> +	 */
> +	u32			chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM
> +					| AT_XDMAC_CC_SAM_INCREMENTED_AM
> +					| AT_XDMAC_CC_DIF(0)
> +					| AT_XDMAC_CC_SIF(0)
> +					| AT_XDMAC_CC_MBSIZE_SIXTEEN
> +					| AT_XDMAC_CC_TYPE_MEM_TRAN;
> +
> +	dev_dbg(chan2dev(chan), "%s: src=0x%08x, dest=0x%08x, len=%d, flags=0x%lx\n",
> +		__func__, src, dest, len, flags);
> +
> +	if (unlikely(!len))
> +		return NULL;
> +
> +	/* Check address alignment to select the greater data width we can use.

Style: "/*" alone on the line ;-)

> +	 * Some XDMAC implementations don't provide dword transfer, in this
> +	 * case selecting dword has the same behavior as selecting word transfers.
> +	 */
> +	if (!((src_addr | dst_addr) & 7)) {
> +		dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
> +		dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
> +	} else if (!((src_addr | dst_addr)  & 3)) {
> +		dwidth = AT_XDMAC_CC_DWIDTH_WORD;
> +		dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
> +	} else if (!((src_addr | dst_addr) & 1)) {
> +		dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
> +		dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
> +	} else {
> +		dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
> +		dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
> +	}
> +
> +	atchan->cfg = chan_cc | AT_XDMAC_CC_DWIDTH(dwidth);
> +
> +	/* Prepare descriptors. */
> +	while (remaining_size) {
> +		struct at_xdmac_desc	*desc = NULL;
> +
> +		dev_dbg(chan2dev(chan), "%s: remaining_size=%u\n", __func__, remaining_size);
> +
> +		spin_lock_irqsave(&atchan->lock, flags);
> +		desc = at_xdmac_get_desc(atchan);
> +		spin_unlock_irqrestore(&atchan->lock, flags);
> +		if (!desc) {
> +			dev_err(chan2dev(chan), "can't get descriptor\n");
> +			if (first)
> +				list_splice_init(&first->descs_list, &atchan->free_descs_list);
> +			return NULL;
> +		}
> +
> +		/* Update src and dest addresses. */
> +		src_addr += xfer_size;
> +		dst_addr += xfer_size;
> +
> +		if (remaining_size >= AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)
> +			xfer_size = AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth;
> +		else
> +			xfer_size = remaining_size;
> +
> +		dev_dbg(chan2dev(chan), "%s: xfer_size=%u\n", __func__, xfer_size);
> +
> +		/* Check remaining length and change data width if needed. */
> +		if (!((src_addr | dst_addr | xfer_size) & 7)) {
> +			dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
> +			dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
> +		} else if (!((src_addr | dst_addr | xfer_size)  & 3)) {
> +			dwidth = AT_XDMAC_CC_DWIDTH_WORD;
> +			dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
> +		} else if (!((src_addr | dst_addr | xfer_size) & 1)) {
> +			dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
> +			dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
> +		} else if ((src_addr | dst_addr | xfer_size) & 1) {
> +			dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
> +			dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
> +		}
> +		chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
> +
> +		ublen = xfer_size >> dwidth;
> +		remaining_size -= xfer_size;
> +
> +		desc->lld.mbr_sa = src_addr;
> +		desc->lld.mbr_da = dst_addr;
> +		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
> +			| AT_XDMAC_MBR_UBC_NDEN
> +			| AT_XDMAC_MBR_UBC_NSEN
> +			| (remaining_size ? 0 : AT_XDMAC_MBR_UBC_NDE)
> +			| ublen;
> +		desc->lld.mbr_cfg = chan_cc;
> +
> +		dev_dbg(chan2dev(chan),
> +			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
> +			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
> +
> +		/* Chain lld. */
> +		if (prev) {
> +			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
> +			dev_dbg(chan2dev(chan),
> +				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
> +				 __func__, prev, prev->lld.mbr_nda);
> +		}
> +
> +		prev = desc;
> +		if (!first)
> +			first = desc;
> +
> +		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
> +			 __func__, desc, first);
> +		list_add_tail(&desc->desc_node, &first->descs_list);
> +	}
> +
> +	first->tx_dma_desc.cookie = -EBUSY;
> +	first->tx_dma_desc.flags = flags;
> +	first->xfer_size = len;
> +
> +	return &first->tx_dma_desc;
> +}
> +
> +static enum dma_status
> +at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
> +		struct dma_tx_state *txstate)
> +{
> +	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
> +	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
> +	struct at_xdmac_desc	*desc, *_desc;
> +	unsigned long		flags;
> +	enum dma_status		ret;
> +	int			residue;
> +	u32			cur_nda;
> +
> +	ret = dma_cookie_status(chan, cookie, txstate);
> +	if (ret == DMA_COMPLETE)
> +		return ret;
> +
> +	if (!txstate)
> +		return ret;
> +
> +	spin_lock_irqsave(&atchan->lock, flags);
> +
> +	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
> +
> +	/*
> +	 * If the transfer has not been started yet, don't need to compute the
> +	 * residue, it's the transfer length.
> +	 */
> +	if (!desc->active_xfer) {
> +		dma_set_residue(txstate, desc->xfer_size);
> +		return ret;
> +	}
> +
> +	residue = desc->xfer_size;
> +	/* Flush FIFO. */
> +	at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);
> +	while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS));
> +		cpu_relax();
> +
> +	cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
> +	/*
> +	 * Remove size of all microblocks already transferred and the current
> +	 * one. Then add the remaining size to transfer of the current
> +	 * microblock.
> +	 */
> +	list_for_each_entry_safe(desc, _desc, &desc->descs_list, desc_node) {
> +		residue -= (desc->lld.mbr_ubc & 0xffffff) << atchan->dwidth;
> +		if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
> +			break;
> +	}
> +	residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << atchan->dwidth;
> +
> +	spin_unlock_irqrestore(&atchan->lock, flags);
> +
> +	dma_set_residue(txstate, residue);
> +
> +	dev_dbg(chan2dev(chan),
> +		 "%s: desc=0x%p, tx_dma_desc.phys=0x%08x, tx_status=%d, cookie=%d, residue=%d\n",
> +		 __func__, desc, desc->tx_dma_desc.phys, ret, cookie, residue);
> +
> +	return ret;
> +}
> +
> +static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan,
> +				    struct at_xdmac_desc *desc)
> +{
> +	dev_dbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
> +
> +	/*
> +	 * Remove the transfer from the transfer list then move the transfer
> +	 * descriptors into the free descriptors list.
> +	 */
> +	list_del(&desc->xfer_node);
> +	list_splice_init(&desc->descs_list, &atchan->free_descs_list);
> +}
> +
> +static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
> +{
> +	struct at_xdmac_desc	*desc;
> +	unsigned long		flags;
> +
> +	spin_lock_irqsave(&atchan->lock, flags);
> +
> +	/*
> +	 * If channel is enabled, do nothing, advance_work will be triggered
> +	 * after the interruption.
> +	 */
> +	if (!at_xdmac_chan_is_enabled(atchan) && !list_empty(&atchan->xfers_list)) {
> +		desc = list_first_entry(&atchan->xfers_list,
> +					struct at_xdmac_desc,
> +					xfer_node);
> +		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
> +		if (!desc->active_xfer)
> +			at_xdmac_start_xfer(atchan, desc);
> +	}
> +
> +	spin_unlock_irqrestore(&atchan->lock, flags);
> +}
> +
> +static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
> +{
> +	struct at_xdmac_desc		*desc;
> +	struct dma_async_tx_descriptor	*txd;
> +
> +	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
> +	txd = &desc->tx_dma_desc;
> +
> +	if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
> +		txd->callback(txd->callback_param);
> +}
> +
> +static void at_xdmac_tasklet(unsigned long data)
> +{
> +	struct at_xdmac_chan	*atchan = (struct at_xdmac_chan *)data;
> +	struct at_xdmac_desc	*desc;
> +	u32			error_mask;
> +
> +	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08lx\n",
> +		 __func__, atchan->status);
> +
> +	error_mask = AT_XDMAC_CIS_RBEIS
> +		     | AT_XDMAC_CIS_WBEIS
> +		     | AT_XDMAC_CIS_ROIS;
> +
> +	if (at_xdmac_chan_is_cyclic(atchan)) {
> +		at_xdmac_handle_cyclic(atchan);
> +	} else if ((atchan->status & AT_XDMAC_CIS_LIS)
> +		   || (atchan->status & error_mask)) {
> +		struct dma_async_tx_descriptor  *txd;
> +
> +		if (atchan->status & AT_XDMAC_CIS_RBEIS)
> +			dev_err(chan2dev(&atchan->chan), "read bus error!!!");
> +		else if (atchan->status & AT_XDMAC_CIS_WBEIS)
> +			dev_err(chan2dev(&atchan->chan), "write bus error!!!");
> +		else if (atchan->status & AT_XDMAC_CIS_ROIS)
> +			dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
> +
> +		desc = list_first_entry(&atchan->xfers_list,
> +					struct at_xdmac_desc,
> +					xfer_node);
> +		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
> +		BUG_ON(!desc->active_xfer);
> +
> +		txd = &desc->tx_dma_desc;
> +
> +		at_xdmac_remove_xfer(atchan, desc);
> +
> +		if (!at_xdmac_chan_is_cyclic(atchan)) {
> +			dma_cookie_complete(txd);
> +			if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
> +				txd->callback(txd->callback_param);
> +		}
> +
> +		dma_run_dependencies(txd);
> +
> +		at_xdmac_advance_work(atchan);
> +	}
> +}
> +
> +static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
> +{
> +	struct at_xdmac		*atxdmac = (struct at_xdmac *)dev_id;
> +	struct at_xdmac_chan	*atchan;
> +	u32 			imr, status, pending;
> +	u32			chan_imr, chan_status;
> +	int			i, ret = IRQ_NONE;
> +
> +	do {
> +		imr = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
> +		status = at_xdmac_read(atxdmac, AT_XDMAC_GIS);
> +		pending = status & imr;
> +
> +		dev_vdbg(atxdmac->dma.dev,
> +			 "%s: status=0x%08x, imr=0x%08x, pending=0x%08x\n",
> +			 __func__, status, imr, pending);
> +
> +		if (!pending)
> +			break;
> +
> +		/* We have to find which channel has generated the interrupt. */
> +		for (i = 0; i < atxdmac->dma.chancnt; i++) {
> +			if (!((1 << i) & pending))
> +				continue;
> +
> +			atchan = &atxdmac->chan[i];
> +			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
> +			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);
> +			atchan->status = chan_status & chan_imr;
> +			dev_vdbg(atxdmac->dma.dev,
> +				 "%s: chan%d: imr=0x%x, status=0x%x\n",
> +				 __func__, i, chan_imr, chan_status);
> +			dev_vdbg(chan2dev(&atchan->chan),
> +				 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, "
> +				 "XDMAC_CNDC=0x%08x, XDMAC_CSA=0x%08x, "
> +				 "XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
> +				 __func__,
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CC),
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
> +				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
> +
> +			if (atchan->status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
> +				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
> +
> +			tasklet_schedule(&atchan->tasklet);
> +			ret = IRQ_HANDLED;
> +		}
> +
> +	} while (pending);
> +
> +	return ret;
> +}
> +
> +static void at_xdmac_issue_pending(struct dma_chan *chan)
> +{
> +	struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
> +
> +	dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
> +
> +	if (!at_xdmac_chan_is_cyclic(atchan))
> +		at_xdmac_advance_work(atchan);
> +
> +	return;
> +}
> +
> +static int at_xdmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> +			    unsigned long arg)
> +{
> +	struct at_xdmac_desc	*desc, *_desc;
> +	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
> +	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
> +	unsigned long		flags;
> +	int			ret = 0;
> +
> +	dev_dbg(chan2dev(chan), "%s: cmd=%d\n", __func__, cmd);
> +
> +	spin_lock_irqsave(&atchan->lock, flags);
> +
> +	switch (cmd) {
> +	case DMA_PAUSE:
> +		at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask);
> +		set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
> +		break;
> +
> +	case DMA_RESUME:
> +		if (!at_xdmac_chan_is_paused(atchan))
> +			break;
> +
> +		at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask);
> +		clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
> +		break;
> +
> +	case DMA_TERMINATE_ALL:
> +		at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);

This is not needed, is it?

> +		at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
> +		while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
> +			cpu_relax();
> +
> +		/* Cancel all pending transfers. */
> +		list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node)
> +			at_xdmac_remove_xfer(atchan, desc);
> +
> +		clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
> +		break;
> +
> +	case DMA_SLAVE_CONFIG:
> +		ret = at_xdmac_set_slave_config(chan,
> +				(struct dma_slave_config *)arg);
> +		break;
> +
> +	default:
> +		dev_err(chan2dev(chan),
> +			"unmanaged or unknown dma control cmd: %d\n", cmd);
> +		ret = -ENXIO;
> +	}
> +
> +	spin_unlock_irqrestore(&atchan->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
> +{
> +	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
> +	struct at_xdmac_desc	*desc;
> +	unsigned long		flags;
> +	int			i;
> +
> +	spin_lock_irqsave(&atchan->lock, flags);
> +
> +	if (at_xdmac_chan_is_enabled(atchan)) {
> +		dev_err(chan2dev(chan),
> +			"can't allocate channel resources (channel enabled)\n");
> +		i = -EIO;
> +		goto spin_unlock;
> +	}
> +
> +	if (!list_empty(&atchan->free_descs_list)) {
> +		dev_err(chan2dev(chan),
> +			"can't allocate channel resources (channel not free from a previous use)\n");
> +		i = -EIO;
> +		goto spin_unlock;
> +	}
> +
> +	for (i = 0; i < init_nr_desc_per_channel; i++) {
> +		desc = at_xdmac_alloc_desc(chan, GFP_ATOMIC);
> +		if (!desc) {
> +			dev_warn(chan2dev(chan),
> +				"only %d descriptors have been allocated\n", i);
> +			break;
> +		}
> +		list_add_tail(&desc->desc_node, &atchan->free_descs_list);
> +	}
> +
> +	dma_cookie_init(chan);
> +
> +	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
> +
> +spin_unlock:
> +	spin_unlock_irqrestore(&atchan->lock, flags);
> +	return i;
> +}
> +
> +static void at_xdmac_free_chan_resources(struct dma_chan *chan)
> +{
> +	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
> +	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
> +	struct at_xdmac_desc	*desc, *_desc;
> +
> +	list_for_each_entry_safe(desc, _desc, &atchan->free_descs_list, desc_node) {
> +		dev_dbg(chan2dev(chan), "%s: freeing descriptor %p\n", __func__, desc);
> +		list_del(&desc->desc_node);
> +		dma_pool_free(atxdmac->at_xdmac_desc_pool, desc, desc->tx_dma_desc.phys);
> +	}
> +
> +	return;
> +}
> +
> +#define AT_XDMAC_DMA_BUSWIDTHS\
> +	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
> +        BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
> +        BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
> +        BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
> +        BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
> +
> +static int at_xdmac_device_slave_caps(struct dma_chan *dchan,
> +				      struct dma_slave_caps *caps)
> +{
> +
> +	caps->src_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
> +	caps->dstn_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
> +	caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
> +	caps->cmd_pause = true;
> +	caps->cmd_terminate = true;
> +	caps->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int atmel_xdmac_prepare(struct device *dev)

For this funtion, maybe CONFIG_PM is the directive that you should use.

> +{
> +	struct platform_device	*pdev = to_platform_device(dev);
> +	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
> +	struct dma_chan		*chan, *_chan;
> +
> +	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
> +		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
> +
> +		/* Wait for transfer completion, except in cyclic case. */
> +		if (at_xdmac_chan_is_enabled(atchan) && !at_xdmac_chan_is_cyclic(atchan))
> +			return -EAGAIN;
> +	}
> +	return 0;
> +}
> +
> +static int atmel_xdmac_suspend(struct device *dev)
> +{
> +	struct platform_device	*pdev = to_platform_device(dev);
> +	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
> +	struct dma_chan		*chan, *_chan;
> +
> +	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
> +		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
> +
> +		if (at_xdmac_chan_is_cyclic(atchan)) {
> +			if (!at_xdmac_chan_is_paused(atchan))
> +				at_xdmac_control(chan, DMA_PAUSE, 0);
> +			atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
> +			atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA);
> +			atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC);
> +		}
> +	}
> +	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
> +
> +	at_xdmac_off(atxdmac);
> +	clk_disable_unprepare(atxdmac->clk);
> +	return 0;
> +}
> +
> +static int atmel_xdmac_resume(struct device *dev)
> +{
> +	struct platform_device	*pdev = to_platform_device(dev);
> +	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
> +	struct at_xdmac_chan	*atchan;
> +	struct dma_chan		*chan, *_chan;
> +	int			i;
> +
> +	clk_prepare_enable(atxdmac->clk);
> +
> +	/* Clear pending interrupts. */
> +	for (i = 0; i < atxdmac->dma.chancnt; i++) {
> +		atchan = &atxdmac->chan[i];
> +		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
> +			cpu_relax();
> +	}
> +
> +	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atxdmac->save_gim);
> +	at_xdmac_write(atxdmac, AT_XDMAC_GE, atxdmac->save_gs);
> +	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
> +		atchan = to_at_xdmac_chan(chan);
> +		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->cfg);
> +		if (at_xdmac_chan_is_cyclic(atchan)) {
> +			at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
> +			at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
> +			at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);

As realized together, a write memory barried seems needed here.

> +			at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
> +		}
> +	}
> +	return 0;
> +}
> +#else
> +#	define atmel_xdmac_prepare NULL
> +#endif /* CONFIG_PM_SLEEP */
> +
> +static int at_xdmac_probe(struct platform_device *pdev)
> +{
> +	struct resource	*res;
> +	struct at_xdmac	*atxdmac;
> +	int		irq, size, nr_channels, i, ret;
> +	void __iomem	*base;
> +	u32		reg;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -EINVAL;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	/*
> +	 * Read number of xdmac channels, read helper function can't be used
> +	 * since atxdmac is not yet allocated and we need to know the number
> +	 * of channels to do the allocation.
> +	 */
> +	reg = readl_relaxed(base + AT_XDMAC_GTYPE);
> +	nr_channels = AT_XDMAC_NB_CH(reg);
> +	if (nr_channels > AT_XDMAC_MAX_CHAN) {
> +		dev_err(&pdev->dev, "invalid number of channels (%u)\n",
> +			nr_channels);
> +		return -EINVAL;
> +	}
> +
> +	size = sizeof(*atxdmac);
> +	size += nr_channels * sizeof(struct at_xdmac_chan);
> +	atxdmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
> +	if (!atxdmac) {
> +		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
> +		return -ENOMEM;
> +	}
> +
> +	atxdmac->regs = base;
> +	atxdmac->irq = irq;
> +
> +	atxdmac->clk = devm_clk_get(&pdev->dev, "dma_clk");
> +	if (IS_ERR(atxdmac->clk)) {
> +		dev_err(&pdev->dev, "can't get dma_clk\n");
> +		return PTR_ERR(atxdmac->clk);
> +	}
> +
> +	/* Do not use dev res to prevent races with tasklet */
> +	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
> +	if (ret) {
> +		dev_err(&pdev->dev, "can't request irq\n");
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(atxdmac->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "can't prepare or enable clock\n");
> +		goto err_free_irq;
> +	}
> +
> +	atxdmac->at_xdmac_desc_pool =
> +		dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
> +				sizeof(struct at_xdmac_desc), 4, 0);
> +	if (!atxdmac->at_xdmac_desc_pool) {
> +		dev_err(&pdev->dev, "no memory for descriptors dma pool\n");
> +		ret = -ENOMEM;
> +		goto err_clk_disable;
> +	}
> +
> +	dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
> +	dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
> +	dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
> +	atxdmac->dma.dev				= &pdev->dev;
> +	atxdmac->dma.device_alloc_chan_resources	= at_xdmac_alloc_chan_resources;
> +	atxdmac->dma.device_free_chan_resources		= at_xdmac_free_chan_resources;
> +	atxdmac->dma.device_tx_status			= at_xdmac_tx_status;
> +	atxdmac->dma.device_issue_pending		= at_xdmac_issue_pending;
> +	atxdmac->dma.device_prep_dma_cyclic		= at_xdmac_prep_dma_cyclic;
> +	atxdmac->dma.device_prep_dma_memcpy		= at_xdmac_prep_dma_memcpy;
> +	atxdmac->dma.device_prep_slave_sg		= at_xdmac_prep_slave_sg;
> +	atxdmac->dma.device_control			= at_xdmac_control;
> +	atxdmac->dma.chancnt				= nr_channels;
> +	atxdmac->dma.device_slave_caps			= at_xdmac_device_slave_caps;
> +
> +	/* Disable all chans and interrupts. */
> +	at_xdmac_off(atxdmac);
> +
> +	/* Init channels. */
> +	INIT_LIST_HEAD(&atxdmac->dma.channels);
> +	for (i = 0; i < nr_channels; i++) {
> +		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
> +
> +		atchan->chan.device = &atxdmac->dma;
> +		list_add_tail(&atchan->chan.device_node,
> +			      &atxdmac->dma.channels);
> +
> +		atchan->ch_regs = at_xdmac_chan_reg_base(atxdmac, i);
> +		atchan->mask = 1 << i;
> +
> +		spin_lock_init(&atchan->lock);
> +		INIT_LIST_HEAD(&atchan->xfers_list);
> +		INIT_LIST_HEAD(&atchan->free_descs_list);
> +		tasklet_init(&atchan->tasklet, at_xdmac_tasklet,
> +			     (unsigned long)atchan);
> +
> +		/* Clear pending interrupts. */
> +		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
> +			cpu_relax();
> +	}
> +	platform_set_drvdata(pdev, atxdmac);
> +
> +	ret = dma_async_device_register(&atxdmac->dma);
> +	if (ret) {
> +		dev_err(&pdev->dev, "fail to register DMA engine device\n");
> +		goto err_clk_disable;
> +	}
> +
> +	ret = of_dma_controller_register(pdev->dev.of_node,
> +					 at_xdmac_xlate, atxdmac);
> +	if (ret) {
> +		dev_err(&pdev->dev, "could not register of dma controller\n");
> +		goto err_dma_unregister;
> +	}
> +
> +	dev_info(&pdev->dev, "%d channels, mapped at 0x%p\n",
> +		 nr_channels, atxdmac->regs);
> +
> +	return 0;
> +
> +err_dma_unregister:
> +	dma_async_device_unregister(&atxdmac->dma);
> +err_clk_disable:
> +	clk_disable_unprepare(atxdmac->clk);
> +err_free_irq:
> +	free_irq(atxdmac->irq, atxdmac->dma.dev);
> +	return ret;
> +}
> +
> +static int at_xdmac_remove(struct platform_device *pdev)
> +{
> +	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
> +	int		i;
> +
> +	at_xdmac_off(atxdmac);
> +	of_dma_controller_free(pdev->dev.of_node);
> +	dma_async_device_unregister(&atxdmac->dma);
> +	clk_disable_unprepare(atxdmac->clk);
> +
> +	synchronize_irq(atxdmac->irq);
> +
> +	free_irq(atxdmac->irq, atxdmac->dma.dev);
> +
> +	for (i = 0; i < atxdmac->dma.chancnt; i++) {
> +		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
> +
> +		tasklet_kill(&atchan->tasklet);
> +		at_xdmac_free_chan_resources(&atchan->chan);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops atmel_xdmac_dev_pm_ops = {
> +	.prepare	= atmel_xdmac_prepare,
> +	SET_LATE_SYSTEM_SLEEP_PM_OPS(atmel_xdmac_suspend, atmel_xdmac_resume)
> +};
> +
> +static const struct of_device_id atmel_xdmac_dt_ids[] = {
> +	{
> +		.compatible = "atmel,sama5d4-dma",
> +	}, {
> +		/* sentinel */
> +	}
> +};
> +MODULE_DEVICE_TABLE(of, atmel_xdmac_dt_ids);
> +
> +static struct platform_driver at_xdmac_driver = {
> +	.probe		= at_xdmac_probe,
> +	.remove		= at_xdmac_remove,
> +	.driver = {
> +		.name		= "at_xdmac",
> +		.owner		= THIS_MODULE,
> +		.of_match_table	= of_match_ptr(atmel_xdmac_dt_ids),
> +		.pm		= &atmel_xdmac_dev_pm_ops,
> +	}
> +};
> +
> +static int __init at_xdmac_init(void)
> +{
> +	return platform_driver_probe(&at_xdmac_driver, at_xdmac_probe);
> +}
> +subsys_initcall(at_xdmac_init);
> +
> +MODULE_DESCRIPTION("Atmel Extended DMA Controller driver");
> +MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/dma/at_xdmac.h b/drivers/dma/at_xdmac.h
> new file mode 100644
> index 0000000..5f4d898
> --- /dev/null
> +++ b/drivers/dma/at_xdmac.h
> @@ -0,0 +1,307 @@
> +/*
> + * Copyright (C) 2014 Atmel Corporation
> + *
> + * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __AT_XDMAC_H__
> +#define __AT_XDMAC_H__
> +
> +#include <linux/clk.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dmapool.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of_dma.h>
> +#include <linux/platform_device.h>
> +
> +#include "dmaengine.h"
> +
> +/* Global registers */
> +#define AT_XDMAC_GTYPE		0x00	/* Global Type Register */
> +#define		AT_XDMAC_NB_CH(i)	(((i) & 0x1F) + 1)		/* Number of Channels Minus One */
> +#define		AT_XDMAC_FIFO_SZ(i)	(((i) >> 5) & 0x7FF)		/* Number of Bytes */
> +#define		AT_XDMAC_NB_REQ(i)	((((i) >> 16) & 0x3F) + 1)	/* Number of Peripheral Requests Minus One */
> +#define AT_XDMAC_GCFG		0x04	/* Global Configuration Register */
> +#define AT_XDMAC_GWAC		0x08	/* Global Weighted Arbiter Configuration Register */
> +#define AT_XDMAC_GIE		0x0C	/* Global Interrupt Enable Register */
> +#define AT_XDMAC_GID		0x10	/* Global Interrupt Disable Register */
> +#define AT_XDMAC_GIM		0x14	/* Global Interrupt Mask Register */
> +#define AT_XDMAC_GIS		0x18	/* Global Interrupt Status Register */
> +#define AT_XDMAC_GE		0x1C	/* Global Channel Enable Register */
> +#define AT_XDMAC_GD		0x20	/* Global Channel Disable Register */
> +#define AT_XDMAC_GS		0x24	/* Global Channel Status Register */
> +#define AT_XDMAC_GRS		0x28	/* Global Channel Read Suspend Register */
> +#define AT_XDMAC_GWS		0x2C	/* Global Write Suspend Register */
> +#define AT_XDMAC_GRWS		0x30	/* Global Channel Read Write Suspend Register */
> +#define AT_XDMAC_GRWR		0x34	/* Global Channel Read Write Resume Register */
> +#define AT_XDMAC_GSWR		0x38	/* Global Channel Software Request Register */
> +#define AT_XDMAC_GSWS		0x3C	/* Global channel Software Request Status Register */
> +#define AT_XDMAC_GSWF		0x40	/* Global Channel Software Flush Request Register */
> +#define AT_XDMAC_VERSION	0xFFC	/* XDMAC Version Register */
> +
> +/* Channel relative registers offsets */
> +#define AT_XDMAC_CIE		0x00	/* Channel Interrupt Enable Register */
> +#define		AT_XDMAC_CIE_BIE	BIT(0)	/* End of Block Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_LIE	BIT(1)	/* End of Linked List Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_DIE	BIT(2)	/* End of Disable Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_FIE	BIT(3)	/* End of Flush Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_RBEIE	BIT(4)	/* Read Bus Error Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_WBEIE	BIT(5)	/* Write Bus Error Interrupt Enable Bit */
> +#define		AT_XDMAC_CIE_ROIE	BIT(6)	/* Request Overflow Interrupt Enable Bit */
> +#define AT_XDMAC_CID		0x04	/* Channel Interrupt Disable Register */
> +#define		AT_XDMAC_CID_BID	BIT(0)	/* End of Block Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_LID	BIT(1)	/* End of Linked List Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_DID	BIT(2)	/* End of Disable Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_FID	BIT(3)	/* End of Flush Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_RBEID	BIT(4)	/* Read Bus Error Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_WBEID	BIT(5)	/* Write Bus Error Interrupt Disable Bit */
> +#define		AT_XDMAC_CID_ROID	BIT(6)	/* Request Overflow Interrupt Disable Bit */
> +#define AT_XDMAC_CIM		0x08	/* Channel Interrupt Mask Register */
> +#define		AT_XDMAC_CIM_BIM	BIT(0)	/* End of Block Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_LIM	BIT(1)	/* End of Linked List Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_DIM	BIT(2)	/* End of Disable Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_FIM	BIT(3)	/* End of Flush Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_RBEIM	BIT(4)	/* Read Bus Error Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_WBEIM	BIT(5)	/* Write Bus Error Interrupt Mask Bit */
> +#define		AT_XDMAC_CIM_ROIM	BIT(6)	/* Request Overflow Interrupt Mask Bit */
> +#define AT_XDMAC_CIS		0x0C	/* Channel Interrupt Status Register */
> +#define		AT_XDMAC_CIS_BIS	BIT(0)	/* End of Block Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_LIS	BIT(1)	/* End of Linked List Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_DIS	BIT(2)	/* End of Disable Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_FIS	BIT(3)	/* End of Flush Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_RBEIS	BIT(4)	/* Read Bus Error Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_WBEIS	BIT(5)	/* Write Bus Error Interrupt Status Bit */
> +#define		AT_XDMAC_CIS_ROIS	BIT(6)	/* Request Overflow Interrupt Status Bit */
> +#define AT_XDMAC_CSA		0x10	/* Channel Source Address Register */
> +#define AT_XDMAC_CDA		0x14	/* Channel Destination Address Register */
> +#define AT_XDMAC_CNDA		0x18	/* Channel Next Descriptor Address Register */
> +#define 	AT_XDMAC_CNDA_NDAIF(i)	((i) & 0x1)			/* Channel x Next Descriptor Interface */
> +#define		AT_XDMAC_CNDA_NDA(i)	((i) & 0xfffffffc)		/* Channel x Next Descriptor Address */
> +#define AT_XDMAC_CNDC		0x1C	/* Channel Next Descriptor Control Register */
> +#define		AT_XDMAC_CNDC_NDE		(0x1 << 0)		/* Channel x Next Descriptor Enable */
> +#define		AT_XDMAC_CNDC_NDSUP		(0x1 << 1)		/* Channel x Next Descriptor Source Update */
> +#define		AT_XDMAC_CNDC_NDDUP		(0x1 << 2)		/* Channel x Next Descriptor Destination Update */
> +#define		AT_XDMAC_CNDC_NDVIEW_NDV0	(0x0 << 3)		/* Channel x Next Descriptor View 0 */
> +#define		AT_XDMAC_CNDC_NDVIEW_NDV1	(0x1 << 3)		/* Channel x Next Descriptor View 1 */
> +#define		AT_XDMAC_CNDC_NDVIEW_NDV2	(0x2 << 3)		/* Channel x Next Descriptor View 2 */
> +#define		AT_XDMAC_CNDC_NDVIEW_NDV3	(0x3 << 3)		/* Channel x Next Descriptor View 3 */
> +#define AT_XDMAC_CUBC		0x20	/* Channel Microblock Control Register */
> +#define AT_XDMAC_CBC		0x24	/* Channel Block Control Register */
> +#define AT_XDMAC_CC		0x28	/* Channel Configuration Register */
> +#define		AT_XDMAC_CC_TYPE	(0x1 << 0)	/* Channel Transfer Type */
> +#define			AT_XDMAC_CC_TYPE_MEM_TRAN	(0x0 << 0)	/* Memory to Memory Transfer */
> +#define			AT_XDMAC_CC_TYPE_PER_TRAN	(0x1 << 0)	/* Peripheral to Memory or Memory to Peripheral Transfer */
> +#define		AT_XDMAC_CC_MBSIZE_MASK	(0x3 << 1)
> +#define			AT_XDMAC_CC_MBSIZE_SINGLE	(0x0 << 1)
> +#define			AT_XDMAC_CC_MBSIZE_FOUR		(0x1 << 1)
> +#define			AT_XDMAC_CC_MBSIZE_EIGHT	(0x2 << 1)
> +#define			AT_XDMAC_CC_MBSIZE_SIXTEEN	(0x3 << 1)
> +#define		AT_XDMAC_CC_DSYNC	(0x1 << 4)	/* Channel Synchronization */
> +#define			AT_XDMAC_CC_DSYNC_PER2MEM	(0x0 << 4)
> +#define			AT_XDMAC_CC_DSYNC_MEM2PER	(0x1 << 4)
> +#define		AT_XDMAC_CC_PROT	(0x1 << 5)	/* Channel Protection */
> +#define			AT_XDMAC_CC_PROT_SEC		(0x0 << 5)
> +#define			AT_XDMAC_CC_PROT_UNSEC		(0x1 << 5)
> +#define		AT_XDMAC_CC_SWREQ	(0x1 << 6)	/* Channel Software Request Trigger */
> +#define			AT_XDMAC_CC_SWREQ_HWR_CONNECTED	(0x0 << 6)
> +#define			AT_XDMAC_CC_SWREQ_SWR_CONNECTED	(0x1 << 6)
> +#define		AT_XDMAC_CC_MEMSET	(0x1 << 7)	/* Channel Fill Block of memory */
> +#define			AT_XDMAC_CC_MEMSET_NORMAL_MODE	(0x0 << 7)
> +#define			AT_XDMAC_CC_MEMSET_HW_MODE	(0x1 << 7)
> +#define		AT_XDMAC_CC_CSIZE_MASK	(0x7 << 8)	/* Channel Chunk Size */
> +#define			AT_XDMAC_CC_CSIZE_CHK_1		(0x0 << 8)
> +#define			AT_XDMAC_CC_CSIZE_CHK_2		(0x1 << 8)
> +#define			AT_XDMAC_CC_CSIZE_CHK_4		(0x2 << 8)
> +#define			AT_XDMAC_CC_CSIZE_CHK_8		(0x3 << 8)
> +#define			AT_XDMAC_CC_CSIZE_CHK_16	(0x4 << 8)
> +#define		AT_XDMAC_CC_DWIDTH(i)	((i) << 11)	/* Channel Data Width */
> +#define			AT_XDMAC_CC_DWIDTH_BYTE		0x0
> +#define			AT_XDMAC_CC_DWIDTH_HALFWORD	0x1
> +#define			AT_XDMAC_CC_DWIDTH_WORD		0x2
> +#define			AT_XDMAC_CC_DWIDTH_DWORD	0x3
> +#define		AT_XDMAC_CC_SIF(i)	((0x1 & (i)) << 13)	/* Channel Source Interface Identifier */
> +#define		AT_XDMAC_CC_DIF(i)	((0x1 & (i)) << 14)	/* Channel Destination Interface Identifier */
> +#define		AT_XDMAC_CC_SAM_MASK	(0x3 << 16)	/* Channel Source Addressing Mode */
> +#define			AT_XDMAC_CC_SAM_FIXED_AM	(0x0 << 16)
> +#define			AT_XDMAC_CC_SAM_INCREMENTED_AM	(0x1 << 16)
> +#define			AT_XDMAC_CC_SAM_UBS_AM		(0x2 << 16)
> +#define			AT_XDMAC_CC_SAM_UBS_DS_AM	(0x3 << 16)
> +#define		AT_XDMAC_CC_DAM_MASK	(0x3 << 18)	/* Channel Source Addressing Mode */
> +#define			AT_XDMAC_CC_DAM_FIXED_AM	(0x0 << 18)
> +#define			AT_XDMAC_CC_DAM_INCREMENTED_AM	(0x1 << 18)
> +#define			AT_XDMAC_CC_DAM_UBS_AM		(0x2 << 18)
> +#define			AT_XDMAC_CC_DAM_UBS_DS_AM	(0x3 << 18)
> +#define		AT_XDMAC_CC_INITD	(0x1 << 21)	/* Channel Initialization Terminated (read only) */
> +#define			AT_XDMAC_CC_INITD_TERMINATED	(0x0 << 21)
> +#define			AT_XDMAC_CC_INITD_IN_PROGRESS	(0x1 << 21)
> +#define		AT_XDMAC_CC_RDIP	(0x1 << 22)	/* Read in Progress (read only) */
> +#define			AT_XDMAC_CC_RDIP_DONE		(0x0 << 22)
> +#define			AT_XDMAC_CC_RDIP_IN_PROGRESS	(0x1 << 22)
> +#define		AT_XDMAC_CC_WDIP	(0x1 << 23)	/* Write in Progress (read only) */
> +#define			AT_XDMAC_CC_WDIP_DONE		(0x0 << 23)
> +#define			AT_XDMAC_CC_WDIP_IN_PROGRESS	(0x1 << 23)
> +#define		AT_XDMAC_CC_PERID(i)	(0x7f & (h) << 24)	/* Channel Peripheral Identifier */
> +#define AT_XDMAC_CDS_MSP	0x2C	/* Channel Data Stride Memory Set Pattern */
> +#define AT_XDMAC_CSUS		0x30	/* Channel Source Microblock Stride */
> +#define AT_XDMAC_CDUS		0x34	/* Channel Destination Microblock Stride */
> +
> +#define AT_XDMAC_CHAN_REG_BASE	0x50	/* Channel registers base address */
> +
> +/* Microblock control members */
> +#define AT_XDMAC_MBR_UBC_UBLEN_MAX	0xFFFFFFUL	/* Maximum Microblock Length */
> +#define AT_XDMAC_MBR_UBC_NDE		(0x1 << 24)	/* Next Descriptor Enable */
> +#define AT_XDMAC_MBR_UBC_NSEN		(0x1 << 25)	/* Next Descriptor Source Update */
> +#define AT_XDMAC_MBR_UBC_NDEN		(0x1 << 26)	/* Next Descriptor Destination Update */
> +#define AT_XDMAC_MBR_UBC_NDV0		(0x0 << 27)	/* Next Descriptor View 0 */
> +#define AT_XDMAC_MBR_UBC_NDV1		(0x1 << 27)	/* Next Descriptor View 1 */
> +#define AT_XDMAC_MBR_UBC_NDV2		(0x2 << 27)	/* Next Descriptor View 2 */
> +#define AT_XDMAC_MBR_UBC_NDV3		(0x3 << 27)	/* Next Descriptor View 3 */
> +
> +#define AT_XDMAC_MAX_CHAN	0x20
> +
> +enum atc_status {
> +	AT_XDMAC_CHAN_IS_CYCLIC = 0,
> +	AT_XDMAC_CHAN_IS_PAUSED,
> +};
> +
> +/* ----- Channels ----- */
> +struct at_xdmac_chan {
> +	struct dma_chan		chan;
> +	void __iomem		*ch_regs;
> +	u32			mask;		/* Channel Mask */
> +	u32			cfg;		/* Channel Configuration Register */
> +	u8			perid;		/* Peripheral ID */
> +	u8			dwidth;		/* Data Width */
> +	u8			perif;		/* Peripheral Interface */
> +	u8			memif;		/* Memory Interface */
> +	u32			save_cim;
> +	u32			save_cnda;
> +	u32			save_cndc;
> +	unsigned long		status;
> +	struct tasklet_struct	tasklet;
> +	struct dma_slave_config	dma_sconfig;
> +
> +	spinlock_t		lock;
> +
> +	struct list_head	xfers_list;
> +	struct list_head	free_descs_list;
> +};
> +
> +
> +/* ----- Controller ----- */
> +struct at_xdmac {
> +	struct dma_device	dma;
> +	void __iomem		*regs;
> +	int			irq;
> +	struct clk		*clk;
> +	u32			save_gim;
> +	u32			save_gs;
> +	struct dma_pool		*at_xdmac_desc_pool;
> +	struct at_xdmac_chan	chan[0];
> +};
> +
> +
> +/* ----- Descriptors ----- */
> +
> +/* Linked List Descriptor */
> +struct at_xdmac_lld {
> +	dma_addr_t	mbr_nda;	/* Next Descriptor Member */
> +	u32		mbr_ubc;	/* Microblock Control Member */
> +	dma_addr_t	mbr_sa;		/* Source Address Member */
> +	dma_addr_t	mbr_da;		/* Destination Address Member */
> +	u32		mbr_cfg;	/* Configuration Register */
> +};
> +
> +
> +struct at_xdmac_desc {
> +	struct at_xdmac_lld		lld;
> +	enum dma_transfer_direction	direction;
> +	struct dma_async_tx_descriptor	tx_dma_desc;
> +	struct list_head		desc_node;
> +	/* Following members are only used by the first descriptor */
> +	bool				active_xfer;
> +	unsigned int			xfer_size;
> +	struct list_head		descs_list;
> +	struct list_head		xfer_node;
> +};
> +
> +static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
> +{
> +	return (void __iomem *)(atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40));
> +}
> +
> +#define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
> +#define at_xdmac_write(atxdmac, reg, value) \
> +	writel_relaxed((value), (atxdmac)->regs + (reg))
> +
> +#define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
> +#define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
> +
> +static inline struct at_xdmac_chan *to_at_xdmac_chan(struct dma_chan *dchan)
> +{
> +	return container_of(dchan, struct at_xdmac_chan, chan);
> +}
> +
> +static struct device *chan2dev(struct dma_chan *chan)
> +{
> +	return &chan->dev->device;
> +}
> +
> +static inline struct at_xdmac *to_at_xdmac(struct dma_device *ddev)
> +{
> +	return container_of(ddev, struct at_xdmac, dma);
> +}
> +
> +static inline struct at_xdmac_desc *txd_to_at_desc(struct dma_async_tx_descriptor *txd)
> +{
> +	return container_of(txd, struct at_xdmac_desc, tx_dma_desc);
> +}
> +
> +static inline int at_xdmac_chan_is_cyclic(struct at_xdmac_chan *atchan)
> +{
> +	return test_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
> +}
> +
> +static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan)
> +{
> +	return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
> +}
> +
> +static inline u32 at_xdmac_csize(u32 maxburst)
> +{
> +	u32 csize;
> +
> +	switch (ffs(maxburst) - 1) {
> +	case 1:
> +		csize = AT_XDMAC_CC_CSIZE_CHK_2;
> +		break;
> +	case 2:
> +		csize = AT_XDMAC_CC_CSIZE_CHK_4;
> +		break;
> +	case 3:
> +		csize = AT_XDMAC_CC_CSIZE_CHK_8;
> +		break;
> +	case 4:
> +		csize = AT_XDMAC_CC_CSIZE_CHK_16;
> +	default:
> +		csize = AT_XDMAC_CC_CSIZE_CHK_1;
> +	}
> +
> +	return csize;
> +};
> +#endif /* __AT_XDMAC_H__ */
> diff --git a/include/dt-bindings/dma/at91.h b/include/dt-bindings/dma/at91.h
> index e835037..4875a50 100644
> --- a/include/dt-bindings/dma/at91.h
> +++ b/include/dt-bindings/dma/at91.h
> @@ -9,6 +9,8 @@
>  #ifndef __DT_BINDINGS_AT91_DMA_H__
>  #define __DT_BINDINGS_AT91_DMA_H__
>  
> +/* ---------- HDMAC ---------- */
> +
>  /*
>   * Source and/or destination peripheral ID
>   */
> @@ -24,4 +26,27 @@
>  #define AT91_DMA_CFG_FIFOCFG_ALAP	(0x1 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* largest defined AHB burst */
>  #define AT91_DMA_CFG_FIFOCFG_ASAP	(0x2 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* single AHB access */
>  
> +
> +/* ---------- XDMAC ---------- */
> +#define AT91_XDMAC_DT_MEM_IF_MASK	(0x1)
> +#define AT91_XDMAC_DT_MEM_IF_OFFSET	(16)
> +#define AT91_XDMAC_DT_MEM_IF(mem_if)	(((mem_if) & AT91_XDMAC_DT_MEM_IF_MASK) \
> +					<< AT91_XDMAC_DT_MEM_IF_OFFSET)
> +#define AT91_XDMAC_DT_GET_MEM_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_MEM_IF_OFFSET) \
> +					& AT91_XDMAC_DT_MEM_IF_MASK)
> +
> +#define AT91_XDMAC_DT_PER_IF_MASK	(0x1)
> +#define AT91_XDMAC_DT_PER_IF_OFFSET	(0)
> +#define AT91_XDMAC_DT_PER_IF(per_if)	(((per_if) & AT91_XDMAC_DT_PER_IF_MASK) \
> +					<< AT91_XDMAC_DT_PER_IF_OFFSET)
> +#define AT91_XDMAC_DT_GET_PER_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_PER_IF_OFFSET) \
> +					& AT91_XDMAC_DT_PER_IF_MASK)
> +
> +#define AT91_XDMAC_DT_PERID_MASK	(0x7f)
> +#define AT91_XDMAC_DT_PERID_OFFSET	(24)
> +#define AT91_XDMAC_DT_PERID(perid)	(((perid) & AT91_XDMAC_DT_PERID_MASK) \
> +					<< AT91_XDMAC_DT_PERID_OFFSET)
> +#define AT91_XDMAC_DT_GET_PERID(cfg)	(((cfg) >> AT91_XDMAC_DT_PERID_OFFSET) \
> +					& AT91_XDMAC_DT_PERID_MASK)
> +
>  #endif /* __DT_BINDINGS_AT91_DMA_H__ */
>
diff mbox

Patch

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 9b1ea0e..d04e79a 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -107,6 +107,13 @@  config AT_HDMAC
 	help
 	  Support the Atmel AHB DMA controller.
 
+config AT_XDMAC
+	tristate "Atmel XDMA support"
+	depends on ARCH_AT91
+	select DMA_ENGINE
+	help
+	  Support the Atmel XDMA controller.
+
 config FSL_DMA
 	tristate "Freescale Elo series DMA support"
 	depends on FSL_SOC
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index c6adb92..f32bfe1 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -17,6 +17,7 @@  obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
 obj-$(CONFIG_MV_XOR) += mv_xor.o
 obj-$(CONFIG_DW_DMAC_CORE) += dw/
 obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
+obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
 obj-$(CONFIG_MX3_IPU) += ipu/
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
 obj-$(CONFIG_SH_DMAE_BASE) += sh/
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
new file mode 100644
index 0000000..9c7af22
--- /dev/null
+++ b/drivers/dma/at_xdmac.c
@@ -0,0 +1,1210 @@ 
+/*
+ * Driver for the Atmel Extensible DMA Controller (aka XDMAC on AT91 systems)
+ *
+ * Copyright (C) 2014 Atmel Corporation
+ *
+ * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <dt-bindings/dma/at91.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+
+#include "dmaengine.h"
+#include "at_xdmac.h"
+
+static unsigned int init_nr_desc_per_channel = 64;
+module_param(init_nr_desc_per_channel, uint, 0644);
+MODULE_PARM_DESC(init_nr_desc_per_channel,
+		 "initial descriptors per channel (default: 64)");
+
+
+static bool at_xdmac_chan_is_enabled(struct at_xdmac_chan *atchan)
+{
+	return at_xdmac_chan_read(atchan, AT_XDMAC_GS) & atchan->mask;
+}
+
+static void at_xdmac_off(struct at_xdmac *atxdmac)
+{
+	at_xdmac_write(atxdmac, AT_XDMAC_GD, -1L);
+
+	/* Wait that all chans are disabled. */
+	while (at_xdmac_read(atxdmac, AT_XDMAC_GS))
+		cpu_relax();
+
+	at_xdmac_write(atxdmac, AT_XDMAC_GID, -1L);
+}
+
+/* Call with lock hold. */
+static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
+				struct at_xdmac_desc *first)
+{
+	struct at_xdmac	*atxdmac = to_at_xdmac(atchan->chan.device);
+	u32		reg;
+
+	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);
+
+	if (at_xdmac_chan_is_enabled(atchan))
+		return;
+
+	/* Set transfer as active to not try to start it again. */
+	first->active_xfer = true;
+
+	/* Tell xdmac where to get the first descriptor. */
+	reg = AT_XDMAC_CNDA_NDA(first->tx_dma_desc.phys)
+	      | AT_XDMAC_CNDA_NDAIF(atchan->memif);
+	at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, reg);
+
+	/*
+	 * When doing memory to memory transfer we need to use the next
+	 * descriptor view 2 since some fields of the configuration register
+	 * depend on transfer size and src/dest addresses.
+	 */
+	if (atchan->cfg & AT_XDMAC_CC_TYPE_PER_TRAN) {
+		reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
+		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->cfg);
+	} else
+		reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
+
+	reg |= AT_XDMAC_CNDC_NDDUP
+	       | AT_XDMAC_CNDC_NDSUP
+	       | AT_XDMAC_CNDC_NDE;
+	at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, reg);
+
+	dev_vdbg(chan2dev(&atchan->chan),
+		 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, XDMAC_CNDC=0x%08x, "
+		 "XDMAC_CSA=0x%08x, XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
+		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
+
+	/*
+	 * There is no end of list when doing cyclic dma, we need to get
+	 * an interrupt after each periods.
+	 */
+	if (at_xdmac_chan_is_cyclic(atchan))
+		at_xdmac_chan_write(atchan, AT_XDMAC_CIE, AT_XDMAC_CIE_BIE);
+	else
+		at_xdmac_chan_write(atchan, AT_XDMAC_CIE, AT_XDMAC_CIE_LIE);
+	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
+	dev_vdbg(chan2dev(&atchan->chan),
+		 "%s: enable channel (0x%08x)\n", __func__, atchan->mask);
+	at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
+
+	dev_vdbg(chan2dev(&atchan->chan),
+		 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, XDMAC_CNDC=0x%08x, "
+		 "XDMAC_CSA=0x%08x, XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
+		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
+		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
+
+}
+
+static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct at_xdmac_desc	*desc = txd_to_at_desc(tx);
+	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(tx->chan);
+	dma_cookie_t		cookie;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&atchan->lock, flags);
+	cookie = dma_cookie_assign(tx);
+
+	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
+		 __func__, atchan, desc);
+	list_add_tail(&desc->xfer_node, &atchan->xfers_list);
+	if (list_is_singular(&atchan->xfers_list))
+		at_xdmac_start_xfer(atchan, desc);
+
+	spin_unlock_irqrestore(&atchan->lock, flags);
+	return cookie;
+}
+
+static struct at_xdmac_desc *at_xdmac_alloc_desc(struct dma_chan *chan,
+						 gfp_t gfp_flags)
+{
+	struct at_xdmac_desc	*desc;
+	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
+	dma_addr_t		phys;
+
+	desc = dma_pool_alloc(atxdmac->at_xdmac_desc_pool, gfp_flags, &phys);
+	if (desc) {
+		memset(desc, 0, sizeof(*desc));
+		INIT_LIST_HEAD(&desc->descs_list);
+		dma_async_tx_descriptor_init(&desc->tx_dma_desc, chan);
+		desc->tx_dma_desc.tx_submit = at_xdmac_tx_submit;
+		desc->tx_dma_desc.phys = phys;
+	}
+
+	return desc;
+}
+
+/* Call must be protected by lock. */
+static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
+{
+	struct at_xdmac_desc *desc;
+
+	if (list_empty(&atchan->free_descs_list)) {
+		desc = at_xdmac_alloc_desc(&atchan->chan, GFP_NOWAIT);
+	} else {
+		desc = list_first_entry(&atchan->free_descs_list,
+					struct at_xdmac_desc, desc_node);
+		list_del(&desc->desc_node);
+	}
+
+	return desc;
+}
+
+static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
+				       struct of_dma *of_dma)
+{
+	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
+	struct at_xdmac_chan	*atchan;
+	struct dma_chan		*chan;
+	struct device		*dev = atxdmac->dma.dev;
+	dma_cap_mask_t 		mask;
+
+	if (dma_spec->args_count != 2) {
+		dev_err(dev, "dma phandler args: bad number of args\n");
+		return NULL;
+	}
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	chan = dma_get_any_slave_channel(&atxdmac->dma);
+	if (!chan) {
+		dev_err(dev, "can't get a dma channel\n");
+		return NULL;
+	}
+
+	atchan = to_at_xdmac_chan(chan);
+	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
+	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
+	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[1]);
+	dev_info(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
+		 atchan->memif, atchan->perif, atchan->perid);
+
+	return chan;
+}
+
+static int at_xdmac_set_slave_config(struct dma_chan *chan,
+				      struct dma_slave_config *sconfig)
+{
+	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
+
+	atchan->cfg = AT91_XDMAC_DT_PERID(atchan->perid)
+		      |	AT_XDMAC_CC_SWREQ_HWR_CONNECTED
+		      | AT_XDMAC_CC_MBSIZE_SIXTEEN
+		      | AT_XDMAC_CC_TYPE_PER_TRAN;
+
+	if (sconfig->direction == DMA_DEV_TO_MEM) {
+		atchan->cfg |= AT_XDMAC_CC_DAM_INCREMENTED_AM
+			       | AT_XDMAC_CC_SAM_FIXED_AM
+			       | AT_XDMAC_CC_DIF(atchan->memif)
+			       | AT_XDMAC_CC_SIF(atchan->perif)
+			       | AT_XDMAC_CC_DSYNC_PER2MEM;
+		atchan->dwidth = ffs(sconfig->src_addr_width) - 1;
+		atchan->cfg |= AT_XDMAC_CC_DWIDTH(atchan->dwidth);
+		atchan->cfg |= at_xdmac_csize(sconfig->src_maxburst);
+	} else if (sconfig->direction == DMA_MEM_TO_DEV) {
+		atchan->cfg |= AT_XDMAC_CC_DAM_FIXED_AM
+			       | AT_XDMAC_CC_SAM_INCREMENTED_AM
+			       | AT_XDMAC_CC_DIF(atchan->perif)
+			       | AT_XDMAC_CC_SIF(atchan->memif)
+			       | AT_XDMAC_CC_DSYNC_MEM2PER;
+		atchan->dwidth = ffs(sconfig->dst_addr_width) - 1;
+		atchan->cfg |= AT_XDMAC_CC_DWIDTH(atchan->dwidth);
+		atchan->cfg |= at_xdmac_csize(sconfig->dst_maxburst);
+	} else
+		return -EINVAL;
+
+	/*
+	 * Src address and dest addr are needed to configure the link list
+	 * descriptor so keep the slave configuration.
+	 */
+	memcpy(&atchan->dma_sconfig, sconfig, sizeof(struct dma_slave_config));
+
+	dev_dbg(chan2dev(chan), "%s: atchan->cfg=0x%08x\n", __func__, atchan->cfg);
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		       unsigned int sg_len, enum dma_transfer_direction direction,
+		       unsigned long flags, void *context)
+{
+	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
+	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
+	struct at_xdmac_desc	*first = NULL, *prev = NULL;
+	struct scatterlist	*sg;
+	int 			i;
+
+	if (!sgl)
+		return NULL;
+
+	if (!is_slave_direction(direction)) {
+		dev_err(chan2dev(chan), "invalid DMA direction\n");
+		return NULL;
+	}
+
+	dev_dbg(chan2dev(chan), "%s: sg_len=%d, dir=%s, flags=0x%lx\n",
+		 __func__, sg_len,
+		 direction == DMA_MEM_TO_DEV ? "to device" : "from device",
+		 flags);
+
+	/* Protect dma_sconfig field that can be modified by set_slave_conf. */
+	spin_lock(&atchan->lock);
+
+	/* Prepare descriptors. */
+	for_each_sg(sgl, sg, sg_len, i) {
+		struct at_xdmac_desc	*desc = NULL;
+		u32			len, mem;
+
+		len = sg_dma_len(sg);
+		mem = sg_dma_address(sg);
+		if (unlikely(!len)) {
+			dev_err(chan2dev(chan), "sg data length is zero\n");
+			spin_unlock(&atchan->lock);
+			return NULL;
+		}
+		dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
+			 __func__, i, len, mem);
+
+		desc = at_xdmac_get_desc(atchan);
+		if (!desc) {
+			dev_err(chan2dev(chan), "can't get descriptor\n");
+			if (first)
+				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+			spin_unlock(&atchan->lock);
+			return NULL;
+		}
+
+		/* Linked list descriptor setup. */
+		if (direction == DMA_DEV_TO_MEM) {
+			desc->lld.mbr_sa = sconfig->src_addr;
+			desc->lld.mbr_da = mem;
+		} else {
+			desc->lld.mbr_sa = mem;
+			desc->lld.mbr_da = sconfig->dst_addr;
+		}
+		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1		/* next descriptor view */
+			| AT_XDMAC_MBR_UBC_NDEN				/* next descriptor dst parameter update */
+			| AT_XDMAC_MBR_UBC_NSEN				/* next descriptor src parameter update */
+			| (i == sg_len - 1 ? 0 : AT_XDMAC_MBR_UBC_NDE)	/* descriptor fetch */
+			| len / (1 << atchan->dwidth);			/* microblock length */
+		dev_dbg(chan2dev(chan),
+			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x\n",
+			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc);
+
+		/* Chain lld. */
+		if (prev) {
+			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
+			dev_dbg(chan2dev(chan),
+				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
+				 __func__, prev, prev->lld.mbr_nda);
+		}
+
+		prev = desc;
+		if (!first)
+			first = desc;
+
+		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
+			 __func__, desc, first);
+		list_add_tail(&desc->desc_node, &first->descs_list);
+	}
+
+	spin_unlock(&atchan->lock);
+
+	first->tx_dma_desc.cookie = -EBUSY;
+	first->tx_dma_desc.flags = flags;
+	first->xfer_size = sg_len;
+
+	return &first->tx_dma_desc;
+}
+
+static struct dma_async_tx_descriptor *
+at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
+			 size_t buf_len, size_t period_len,
+			 enum dma_transfer_direction direction,
+			 unsigned long flags)
+{
+	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
+	struct dma_slave_config	*sconfig = &atchan->dma_sconfig;
+	struct at_xdmac_desc	*first = NULL, *prev = NULL;
+	unsigned int		periods = buf_len / period_len;
+	unsigned long		lock_flags;
+	int 			i;
+
+	dev_dbg(chan2dev(chan), "%s: buf_addr=0x%08x, buf_len=%d, period_len=%d, "
+		"dir=%s, flags=0x%lx\n",
+		__func__, buf_addr, buf_len, period_len,
+		direction == DMA_MEM_TO_DEV ? "mem2per" : "per2mem", flags);
+
+	if (!is_slave_direction(direction)) {
+		dev_err(chan2dev(chan), "invalid DMA direction\n");
+		return NULL;
+	}
+
+	if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
+		dev_err(chan2dev(chan), "channel currently used\n");
+		return NULL;
+	}
+
+	for (i = 0; i < periods; i++) {
+		struct at_xdmac_desc	*desc = NULL;
+
+		spin_lock_irqsave(&atchan->lock, lock_flags);
+		desc = at_xdmac_get_desc(atchan);
+		spin_unlock_irqrestore(&atchan->lock, lock_flags);
+		if (!desc) {
+			dev_err(chan2dev(chan), "can't get descriptor\n");
+			if (first)
+				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+			return NULL;
+		}
+		dev_dbg(chan2dev(chan),
+			"%s: desc=0x%p, tx_dma_desc.phys=0x%08x\n",
+			__func__, desc, desc->tx_dma_desc.phys);
+
+		if (direction == DMA_DEV_TO_MEM) {
+			desc->lld.mbr_sa = sconfig->src_addr;
+			desc->lld.mbr_da = buf_addr + i * period_len;
+		} else {
+			desc->lld.mbr_sa = buf_addr + i * period_len;
+			desc->lld.mbr_da = sconfig->dst_addr;
+		};
+		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
+			| AT_XDMAC_MBR_UBC_NDEN
+			| AT_XDMAC_MBR_UBC_NSEN
+			| AT_XDMAC_MBR_UBC_NDE
+			| period_len / (1 << atchan->dwidth);
+
+		dev_dbg(chan2dev(chan),
+			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x\n",
+			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc);
+
+		/* Chain lld. */
+		if (prev) {
+			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
+			dev_dbg(chan2dev(chan),
+				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
+				 __func__, prev, prev->lld.mbr_nda);
+		}
+
+		prev = desc;
+		if (!first)
+			first = desc;
+
+		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
+			 __func__, desc, first);
+		list_add_tail(&desc->desc_node, &first->descs_list);
+	}
+
+	prev->lld.mbr_nda = first->tx_dma_desc.phys;
+	dev_dbg(chan2dev(chan),
+		"%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
+		__func__, prev, prev->lld.mbr_nda);
+	first->tx_dma_desc.cookie = -EBUSY;
+	first->tx_dma_desc.flags = flags;
+	first->xfer_size = buf_len;
+
+	return &first->tx_dma_desc;
+}
+
+static struct dma_async_tx_descriptor *
+at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+			 size_t len, unsigned long flags)
+{
+	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
+	struct at_xdmac_desc	*first = NULL, *prev = NULL;
+	size_t			remaining_size = len, xfer_size = 0, ublen;
+	dma_addr_t		src_addr = src, dst_addr = dest;
+	u32			dwidth;
+	/*
+	 * WARNING: The channel configuration is set here since there is no
+	 * dmaengine_slave_config call in this case. Moreover we don't know the
+	 * direction, it involves we can't dynamically set the source and dest
+	 * interface so we have to use the same one. Only interface 0 allows EBI
+	 * access. Hopefully we can access DDR through both ports (at least on
+	 * SAMA5D4x), so we can use the same interface for source and dest,
+	 * that solves the fact we don't know the direction.
+	 */
+	u32			chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM
+					| AT_XDMAC_CC_SAM_INCREMENTED_AM
+					| AT_XDMAC_CC_DIF(0)
+					| AT_XDMAC_CC_SIF(0)
+					| AT_XDMAC_CC_MBSIZE_SIXTEEN
+					| AT_XDMAC_CC_TYPE_MEM_TRAN;
+
+	dev_dbg(chan2dev(chan), "%s: src=0x%08x, dest=0x%08x, len=%d, flags=0x%lx\n",
+		__func__, src, dest, len, flags);
+
+	if (unlikely(!len))
+		return NULL;
+
+	/* Check address alignment to select the greater data width we can use.
+	 * Some XDMAC implementations don't provide dword transfer, in this
+	 * case selecting dword has the same behavior as selecting word transfers.
+	 */
+	if (!((src_addr | dst_addr) & 7)) {
+		dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
+		dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
+	} else if (!((src_addr | dst_addr)  & 3)) {
+		dwidth = AT_XDMAC_CC_DWIDTH_WORD;
+		dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
+	} else if (!((src_addr | dst_addr) & 1)) {
+		dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
+		dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
+	} else {
+		dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
+		dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
+	}
+
+	atchan->cfg = chan_cc | AT_XDMAC_CC_DWIDTH(dwidth);
+
+	/* Prepare descriptors. */
+	while (remaining_size) {
+		struct at_xdmac_desc	*desc = NULL;
+
+		dev_dbg(chan2dev(chan), "%s: remaining_size=%u\n", __func__, remaining_size);
+
+		spin_lock_irqsave(&atchan->lock, flags);
+		desc = at_xdmac_get_desc(atchan);
+		spin_unlock_irqrestore(&atchan->lock, flags);
+		if (!desc) {
+			dev_err(chan2dev(chan), "can't get descriptor\n");
+			if (first)
+				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+			return NULL;
+		}
+
+		/* Update src and dest addresses. */
+		src_addr += xfer_size;
+		dst_addr += xfer_size;
+
+		if (remaining_size >= AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)
+			xfer_size = AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth;
+		else
+			xfer_size = remaining_size;
+
+		dev_dbg(chan2dev(chan), "%s: xfer_size=%u\n", __func__, xfer_size);
+
+		/* Check remaining length and change data width if needed. */
+		if (!((src_addr | dst_addr | xfer_size) & 7)) {
+			dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
+			dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
+		} else if (!((src_addr | dst_addr | xfer_size)  & 3)) {
+			dwidth = AT_XDMAC_CC_DWIDTH_WORD;
+			dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
+		} else if (!((src_addr | dst_addr | xfer_size) & 1)) {
+			dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
+			dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
+		} else if ((src_addr | dst_addr | xfer_size) & 1) {
+			dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
+			dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
+		}
+		chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
+
+		ublen = xfer_size >> dwidth;
+		remaining_size -= xfer_size;
+
+		desc->lld.mbr_sa = src_addr;
+		desc->lld.mbr_da = dst_addr;
+		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
+			| AT_XDMAC_MBR_UBC_NDEN
+			| AT_XDMAC_MBR_UBC_NSEN
+			| (remaining_size ? 0 : AT_XDMAC_MBR_UBC_NDE)
+			| ublen;
+		desc->lld.mbr_cfg = chan_cc;
+
+		dev_dbg(chan2dev(chan),
+			 "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
+			 __func__, desc->lld.mbr_sa, desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
+
+		/* Chain lld. */
+		if (prev) {
+			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
+			dev_dbg(chan2dev(chan),
+				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
+				 __func__, prev, prev->lld.mbr_nda);
+		}
+
+		prev = desc;
+		if (!first)
+			first = desc;
+
+		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
+			 __func__, desc, first);
+		list_add_tail(&desc->desc_node, &first->descs_list);
+	}
+
+	first->tx_dma_desc.cookie = -EBUSY;
+	first->tx_dma_desc.flags = flags;
+	first->xfer_size = len;
+
+	return &first->tx_dma_desc;
+}
+
+static enum dma_status
+at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
+		struct dma_tx_state *txstate)
+{
+	struct at_xdmac_chan 	*atchan = to_at_xdmac_chan(chan);
+	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
+	struct at_xdmac_desc	*desc, *_desc;
+	unsigned long		flags;
+	enum dma_status		ret;
+	int			residue;
+	u32			cur_nda;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	if (!txstate)
+		return ret;
+
+	spin_lock_irqsave(&atchan->lock, flags);
+
+	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
+
+	/*
+	 * If the transfer has not been started yet, don't need to compute the
+	 * residue, it's the transfer length.
+	 */
+	if (!desc->active_xfer) {
+		dma_set_residue(txstate, desc->xfer_size);
+		return ret;
+	}
+
+	residue = desc->xfer_size;
+	/* Flush FIFO. */
+	at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);
+	while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS));
+		cpu_relax();
+
+	cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
+	/*
+	 * Remove size of all microblocks already transferred and the current
+	 * one. Then add the remaining size to transfer of the current
+	 * microblock.
+	 */
+	list_for_each_entry_safe(desc, _desc, &desc->descs_list, desc_node) {
+		residue -= (desc->lld.mbr_ubc & 0xffffff) << atchan->dwidth;
+		if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
+			break;
+	}
+	residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << atchan->dwidth;
+
+	spin_unlock_irqrestore(&atchan->lock, flags);
+
+	dma_set_residue(txstate, residue);
+
+	dev_dbg(chan2dev(chan),
+		 "%s: desc=0x%p, tx_dma_desc.phys=0x%08x, tx_status=%d, cookie=%d, residue=%d\n",
+		 __func__, desc, desc->tx_dma_desc.phys, ret, cookie, residue);
+
+	return ret;
+}
+
+static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan,
+				    struct at_xdmac_desc *desc)
+{
+	dev_dbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
+
+	/*
+	 * Remove the transfer from the transfer list then move the transfer
+	 * descriptors into the free descriptors list.
+	 */
+	list_del(&desc->xfer_node);
+	list_splice_init(&desc->descs_list, &atchan->free_descs_list);
+}
+
+static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
+{
+	struct at_xdmac_desc	*desc;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&atchan->lock, flags);
+
+	/*
+	 * If channel is enabled, do nothing, advance_work will be triggered
+	 * after the interruption.
+	 */
+	if (!at_xdmac_chan_is_enabled(atchan) && !list_empty(&atchan->xfers_list)) {
+		desc = list_first_entry(&atchan->xfers_list,
+					struct at_xdmac_desc,
+					xfer_node);
+		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
+		if (!desc->active_xfer)
+			at_xdmac_start_xfer(atchan, desc);
+	}
+
+	spin_unlock_irqrestore(&atchan->lock, flags);
+}
+
+static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
+{
+	struct at_xdmac_desc		*desc;
+	struct dma_async_tx_descriptor	*txd;
+
+	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
+	txd = &desc->tx_dma_desc;
+
+	if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
+		txd->callback(txd->callback_param);
+}
+
+static void at_xdmac_tasklet(unsigned long data)
+{
+	struct at_xdmac_chan	*atchan = (struct at_xdmac_chan *)data;
+	struct at_xdmac_desc	*desc;
+	u32			error_mask;
+
+	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08lx\n",
+		 __func__, atchan->status);
+
+	error_mask = AT_XDMAC_CIS_RBEIS
+		     | AT_XDMAC_CIS_WBEIS
+		     | AT_XDMAC_CIS_ROIS;
+
+	if (at_xdmac_chan_is_cyclic(atchan)) {
+		at_xdmac_handle_cyclic(atchan);
+	} else if ((atchan->status & AT_XDMAC_CIS_LIS)
+		   || (atchan->status & error_mask)) {
+		struct dma_async_tx_descriptor  *txd;
+
+		if (atchan->status & AT_XDMAC_CIS_RBEIS)
+			dev_err(chan2dev(&atchan->chan), "read bus error!!!");
+		else if (atchan->status & AT_XDMAC_CIS_WBEIS)
+			dev_err(chan2dev(&atchan->chan), "write bus error!!!");
+		else if (atchan->status & AT_XDMAC_CIS_ROIS)
+			dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
+
+		desc = list_first_entry(&atchan->xfers_list,
+					struct at_xdmac_desc,
+					xfer_node);
+		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
+		BUG_ON(!desc->active_xfer);
+
+		txd = &desc->tx_dma_desc;
+
+		at_xdmac_remove_xfer(atchan, desc);
+
+		if (!at_xdmac_chan_is_cyclic(atchan)) {
+			dma_cookie_complete(txd);
+			if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
+				txd->callback(txd->callback_param);
+		}
+
+		dma_run_dependencies(txd);
+
+		at_xdmac_advance_work(atchan);
+	}
+}
+
+static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
+{
+	struct at_xdmac		*atxdmac = (struct at_xdmac *)dev_id;
+	struct at_xdmac_chan	*atchan;
+	u32 			imr, status, pending;
+	u32			chan_imr, chan_status;
+	int			i, ret = IRQ_NONE;
+
+	do {
+		imr = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
+		status = at_xdmac_read(atxdmac, AT_XDMAC_GIS);
+		pending = status & imr;
+
+		dev_vdbg(atxdmac->dma.dev,
+			 "%s: status=0x%08x, imr=0x%08x, pending=0x%08x\n",
+			 __func__, status, imr, pending);
+
+		if (!pending)
+			break;
+
+		/* We have to find which channel has generated the interrupt. */
+		for (i = 0; i < atxdmac->dma.chancnt; i++) {
+			if (!((1 << i) & pending))
+				continue;
+
+			atchan = &atxdmac->chan[i];
+			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
+			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);
+			atchan->status = chan_status & chan_imr;
+			dev_vdbg(atxdmac->dma.dev,
+				 "%s: chan%d: imr=0x%x, status=0x%x\n",
+				 __func__, i, chan_imr, chan_status);
+			dev_vdbg(chan2dev(&atchan->chan),
+				 "%s: XDMAC_CC=0x%08x XDMAC_CNDA=0x%08x, "
+				 "XDMAC_CNDC=0x%08x, XDMAC_CSA=0x%08x, "
+				 "XDMAC_CDA=0x%08x, XDMAC_CUBC=0x%08x\n",
+				 __func__,
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CC),
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
+				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
+
+			if (atchan->status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
+				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
+
+			tasklet_schedule(&atchan->tasklet);
+			ret = IRQ_HANDLED;
+		}
+
+	} while (pending);
+
+	return ret;
+}
+
+static void at_xdmac_issue_pending(struct dma_chan *chan)
+{
+	struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
+
+	dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
+
+	if (!at_xdmac_chan_is_cyclic(atchan))
+		at_xdmac_advance_work(atchan);
+
+	return;
+}
+
+static int at_xdmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			    unsigned long arg)
+{
+	struct at_xdmac_desc	*desc, *_desc;
+	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
+	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
+	unsigned long		flags;
+	int			ret = 0;
+
+	dev_dbg(chan2dev(chan), "%s: cmd=%d\n", __func__, cmd);
+
+	spin_lock_irqsave(&atchan->lock, flags);
+
+	switch (cmd) {
+	case DMA_PAUSE:
+		at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask);
+		set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
+		break;
+
+	case DMA_RESUME:
+		if (!at_xdmac_chan_is_paused(atchan))
+			break;
+
+		at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask);
+		clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
+		break;
+
+	case DMA_TERMINATE_ALL:
+		at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
+		at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
+		while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
+			cpu_relax();
+
+		/* Cancel all pending transfers. */
+		list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node)
+			at_xdmac_remove_xfer(atchan, desc);
+
+		clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
+		break;
+
+	case DMA_SLAVE_CONFIG:
+		ret = at_xdmac_set_slave_config(chan,
+				(struct dma_slave_config *)arg);
+		break;
+
+	default:
+		dev_err(chan2dev(chan),
+			"unmanaged or unknown dma control cmd: %d\n", cmd);
+		ret = -ENXIO;
+	}
+
+	spin_unlock_irqrestore(&atchan->lock, flags);
+
+	return ret;
+}
+
+static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
+	struct at_xdmac_desc	*desc;
+	unsigned long		flags;
+	int			i;
+
+	spin_lock_irqsave(&atchan->lock, flags);
+
+	if (at_xdmac_chan_is_enabled(atchan)) {
+		dev_err(chan2dev(chan),
+			"can't allocate channel resources (channel enabled)\n");
+		i = -EIO;
+		goto spin_unlock;
+	}
+
+	if (!list_empty(&atchan->free_descs_list)) {
+		dev_err(chan2dev(chan),
+			"can't allocate channel resources (channel not free from a previous use)\n");
+		i = -EIO;
+		goto spin_unlock;
+	}
+
+	for (i = 0; i < init_nr_desc_per_channel; i++) {
+		desc = at_xdmac_alloc_desc(chan, GFP_ATOMIC);
+		if (!desc) {
+			dev_warn(chan2dev(chan),
+				"only %d descriptors have been allocated\n", i);
+			break;
+		}
+		list_add_tail(&desc->desc_node, &atchan->free_descs_list);
+	}
+
+	dma_cookie_init(chan);
+
+	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
+
+spin_unlock:
+	spin_unlock_irqrestore(&atchan->lock, flags);
+	return i;
+}
+
+static void at_xdmac_free_chan_resources(struct dma_chan *chan)
+{
+	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
+	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
+	struct at_xdmac_desc	*desc, *_desc;
+
+	list_for_each_entry_safe(desc, _desc, &atchan->free_descs_list, desc_node) {
+		dev_dbg(chan2dev(chan), "%s: freeing descriptor %p\n", __func__, desc);
+		list_del(&desc->desc_node);
+		dma_pool_free(atxdmac->at_xdmac_desc_pool, desc, desc->tx_dma_desc.phys);
+	}
+
+	return;
+}
+
+#define AT_XDMAC_DMA_BUSWIDTHS\
+	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
+        BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+        BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+        BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
+        BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
+
+static int at_xdmac_device_slave_caps(struct dma_chan *dchan,
+				      struct dma_slave_caps *caps)
+{
+
+	caps->src_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
+	caps->dstn_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
+	caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	caps->cmd_pause = true;
+	caps->cmd_terminate = true;
+	caps->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int atmel_xdmac_prepare(struct device *dev)
+{
+	struct platform_device	*pdev = to_platform_device(dev);
+	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
+	struct dma_chan		*chan, *_chan;
+
+	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
+		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
+
+		/* Wait for transfer completion, except in cyclic case. */
+		if (at_xdmac_chan_is_enabled(atchan) && !at_xdmac_chan_is_cyclic(atchan))
+			return -EAGAIN;
+	}
+	return 0;
+}
+
+static int atmel_xdmac_suspend(struct device *dev)
+{
+	struct platform_device	*pdev = to_platform_device(dev);
+	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
+	struct dma_chan		*chan, *_chan;
+
+	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
+		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
+
+		if (at_xdmac_chan_is_cyclic(atchan)) {
+			if (!at_xdmac_chan_is_paused(atchan))
+				at_xdmac_control(chan, DMA_PAUSE, 0);
+			atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
+			atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA);
+			atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC);
+		}
+	}
+	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
+
+	at_xdmac_off(atxdmac);
+	clk_disable_unprepare(atxdmac->clk);
+	return 0;
+}
+
+static int atmel_xdmac_resume(struct device *dev)
+{
+	struct platform_device	*pdev = to_platform_device(dev);
+	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
+	struct at_xdmac_chan	*atchan;
+	struct dma_chan		*chan, *_chan;
+	int			i;
+
+	clk_prepare_enable(atxdmac->clk);
+
+	/* Clear pending interrupts. */
+	for (i = 0; i < atxdmac->dma.chancnt; i++) {
+		atchan = &atxdmac->chan[i];
+		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
+			cpu_relax();
+	}
+
+	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atxdmac->save_gim);
+	at_xdmac_write(atxdmac, AT_XDMAC_GE, atxdmac->save_gs);
+	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
+		atchan = to_at_xdmac_chan(chan);
+		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->cfg);
+		if (at_xdmac_chan_is_cyclic(atchan)) {
+			at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
+			at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
+			at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);
+			at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
+		}
+	}
+	return 0;
+}
+#else
+#	define atmel_xdmac_prepare NULL
+#endif /* CONFIG_PM_SLEEP */
+
+static int at_xdmac_probe(struct platform_device *pdev)
+{
+	struct resource	*res;
+	struct at_xdmac	*atxdmac;
+	int		irq, size, nr_channels, i, ret;
+	void __iomem	*base;
+	u32		reg;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	/*
+	 * Read number of xdmac channels, read helper function can't be used
+	 * since atxdmac is not yet allocated and we need to know the number
+	 * of channels to do the allocation.
+	 */
+	reg = readl_relaxed(base + AT_XDMAC_GTYPE);
+	nr_channels = AT_XDMAC_NB_CH(reg);
+	if (nr_channels > AT_XDMAC_MAX_CHAN) {
+		dev_err(&pdev->dev, "invalid number of channels (%u)\n",
+			nr_channels);
+		return -EINVAL;
+	}
+
+	size = sizeof(*atxdmac);
+	size += nr_channels * sizeof(struct at_xdmac_chan);
+	atxdmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+	if (!atxdmac) {
+		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
+		return -ENOMEM;
+	}
+
+	atxdmac->regs = base;
+	atxdmac->irq = irq;
+
+	atxdmac->clk = devm_clk_get(&pdev->dev, "dma_clk");
+	if (IS_ERR(atxdmac->clk)) {
+		dev_err(&pdev->dev, "can't get dma_clk\n");
+		return PTR_ERR(atxdmac->clk);
+	}
+
+	/* Do not use dev res to prevent races with tasklet */
+	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
+	if (ret) {
+		dev_err(&pdev->dev, "can't request irq\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(atxdmac->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "can't prepare or enable clock\n");
+		goto err_free_irq;
+	}
+
+	atxdmac->at_xdmac_desc_pool =
+		dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
+				sizeof(struct at_xdmac_desc), 4, 0);
+	if (!atxdmac->at_xdmac_desc_pool) {
+		dev_err(&pdev->dev, "no memory for descriptors dma pool\n");
+		ret = -ENOMEM;
+		goto err_clk_disable;
+	}
+
+	dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
+	dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
+	dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
+	atxdmac->dma.dev				= &pdev->dev;
+	atxdmac->dma.device_alloc_chan_resources	= at_xdmac_alloc_chan_resources;
+	atxdmac->dma.device_free_chan_resources		= at_xdmac_free_chan_resources;
+	atxdmac->dma.device_tx_status			= at_xdmac_tx_status;
+	atxdmac->dma.device_issue_pending		= at_xdmac_issue_pending;
+	atxdmac->dma.device_prep_dma_cyclic		= at_xdmac_prep_dma_cyclic;
+	atxdmac->dma.device_prep_dma_memcpy		= at_xdmac_prep_dma_memcpy;
+	atxdmac->dma.device_prep_slave_sg		= at_xdmac_prep_slave_sg;
+	atxdmac->dma.device_control			= at_xdmac_control;
+	atxdmac->dma.chancnt				= nr_channels;
+	atxdmac->dma.device_slave_caps			= at_xdmac_device_slave_caps;
+
+	/* Disable all chans and interrupts. */
+	at_xdmac_off(atxdmac);
+
+	/* Init channels. */
+	INIT_LIST_HEAD(&atxdmac->dma.channels);
+	for (i = 0; i < nr_channels; i++) {
+		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
+
+		atchan->chan.device = &atxdmac->dma;
+		list_add_tail(&atchan->chan.device_node,
+			      &atxdmac->dma.channels);
+
+		atchan->ch_regs = at_xdmac_chan_reg_base(atxdmac, i);
+		atchan->mask = 1 << i;
+
+		spin_lock_init(&atchan->lock);
+		INIT_LIST_HEAD(&atchan->xfers_list);
+		INIT_LIST_HEAD(&atchan->free_descs_list);
+		tasklet_init(&atchan->tasklet, at_xdmac_tasklet,
+			     (unsigned long)atchan);
+
+		/* Clear pending interrupts. */
+		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
+			cpu_relax();
+	}
+	platform_set_drvdata(pdev, atxdmac);
+
+	ret = dma_async_device_register(&atxdmac->dma);
+	if (ret) {
+		dev_err(&pdev->dev, "fail to register DMA engine device\n");
+		goto err_clk_disable;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 at_xdmac_xlate, atxdmac);
+	if (ret) {
+		dev_err(&pdev->dev, "could not register of dma controller\n");
+		goto err_dma_unregister;
+	}
+
+	dev_info(&pdev->dev, "%d channels, mapped at 0x%p\n",
+		 nr_channels, atxdmac->regs);
+
+	return 0;
+
+err_dma_unregister:
+	dma_async_device_unregister(&atxdmac->dma);
+err_clk_disable:
+	clk_disable_unprepare(atxdmac->clk);
+err_free_irq:
+	free_irq(atxdmac->irq, atxdmac->dma.dev);
+	return ret;
+}
+
+static int at_xdmac_remove(struct platform_device *pdev)
+{
+	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
+	int		i;
+
+	at_xdmac_off(atxdmac);
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&atxdmac->dma);
+	clk_disable_unprepare(atxdmac->clk);
+
+	synchronize_irq(atxdmac->irq);
+
+	free_irq(atxdmac->irq, atxdmac->dma.dev);
+
+	for (i = 0; i < atxdmac->dma.chancnt; i++) {
+		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
+
+		tasklet_kill(&atchan->tasklet);
+		at_xdmac_free_chan_resources(&atchan->chan);
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops atmel_xdmac_dev_pm_ops = {
+	.prepare	= atmel_xdmac_prepare,
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(atmel_xdmac_suspend, atmel_xdmac_resume)
+};
+
+static const struct of_device_id atmel_xdmac_dt_ids[] = {
+	{
+		.compatible = "atmel,sama5d4-dma",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, atmel_xdmac_dt_ids);
+
+static struct platform_driver at_xdmac_driver = {
+	.probe		= at_xdmac_probe,
+	.remove		= at_xdmac_remove,
+	.driver = {
+		.name		= "at_xdmac",
+		.owner		= THIS_MODULE,
+		.of_match_table	= of_match_ptr(atmel_xdmac_dt_ids),
+		.pm		= &atmel_xdmac_dev_pm_ops,
+	}
+};
+
+static int __init at_xdmac_init(void)
+{
+	return platform_driver_probe(&at_xdmac_driver, at_xdmac_probe);
+}
+subsys_initcall(at_xdmac_init);
+
+MODULE_DESCRIPTION("Atmel Extended DMA Controller driver");
+MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/dma/at_xdmac.h b/drivers/dma/at_xdmac.h
new file mode 100644
index 0000000..5f4d898
--- /dev/null
+++ b/drivers/dma/at_xdmac.h
@@ -0,0 +1,307 @@ 
+/*
+ * Copyright (C) 2014 Atmel Corporation
+ *
+ * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __AT_XDMAC_H__
+#define __AT_XDMAC_H__
+
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+
+#include "dmaengine.h"
+
+/* Global registers */
+#define AT_XDMAC_GTYPE		0x00	/* Global Type Register */
+#define		AT_XDMAC_NB_CH(i)	(((i) & 0x1F) + 1)		/* Number of Channels Minus One */
+#define		AT_XDMAC_FIFO_SZ(i)	(((i) >> 5) & 0x7FF)		/* Number of Bytes */
+#define		AT_XDMAC_NB_REQ(i)	((((i) >> 16) & 0x3F) + 1)	/* Number of Peripheral Requests Minus One */
+#define AT_XDMAC_GCFG		0x04	/* Global Configuration Register */
+#define AT_XDMAC_GWAC		0x08	/* Global Weighted Arbiter Configuration Register */
+#define AT_XDMAC_GIE		0x0C	/* Global Interrupt Enable Register */
+#define AT_XDMAC_GID		0x10	/* Global Interrupt Disable Register */
+#define AT_XDMAC_GIM		0x14	/* Global Interrupt Mask Register */
+#define AT_XDMAC_GIS		0x18	/* Global Interrupt Status Register */
+#define AT_XDMAC_GE		0x1C	/* Global Channel Enable Register */
+#define AT_XDMAC_GD		0x20	/* Global Channel Disable Register */
+#define AT_XDMAC_GS		0x24	/* Global Channel Status Register */
+#define AT_XDMAC_GRS		0x28	/* Global Channel Read Suspend Register */
+#define AT_XDMAC_GWS		0x2C	/* Global Write Suspend Register */
+#define AT_XDMAC_GRWS		0x30	/* Global Channel Read Write Suspend Register */
+#define AT_XDMAC_GRWR		0x34	/* Global Channel Read Write Resume Register */
+#define AT_XDMAC_GSWR		0x38	/* Global Channel Software Request Register */
+#define AT_XDMAC_GSWS		0x3C	/* Global channel Software Request Status Register */
+#define AT_XDMAC_GSWF		0x40	/* Global Channel Software Flush Request Register */
+#define AT_XDMAC_VERSION	0xFFC	/* XDMAC Version Register */
+
+/* Channel relative registers offsets */
+#define AT_XDMAC_CIE		0x00	/* Channel Interrupt Enable Register */
+#define		AT_XDMAC_CIE_BIE	BIT(0)	/* End of Block Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_LIE	BIT(1)	/* End of Linked List Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_DIE	BIT(2)	/* End of Disable Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_FIE	BIT(3)	/* End of Flush Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_RBEIE	BIT(4)	/* Read Bus Error Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_WBEIE	BIT(5)	/* Write Bus Error Interrupt Enable Bit */
+#define		AT_XDMAC_CIE_ROIE	BIT(6)	/* Request Overflow Interrupt Enable Bit */
+#define AT_XDMAC_CID		0x04	/* Channel Interrupt Disable Register */
+#define		AT_XDMAC_CID_BID	BIT(0)	/* End of Block Interrupt Disable Bit */
+#define		AT_XDMAC_CID_LID	BIT(1)	/* End of Linked List Interrupt Disable Bit */
+#define		AT_XDMAC_CID_DID	BIT(2)	/* End of Disable Interrupt Disable Bit */
+#define		AT_XDMAC_CID_FID	BIT(3)	/* End of Flush Interrupt Disable Bit */
+#define		AT_XDMAC_CID_RBEID	BIT(4)	/* Read Bus Error Interrupt Disable Bit */
+#define		AT_XDMAC_CID_WBEID	BIT(5)	/* Write Bus Error Interrupt Disable Bit */
+#define		AT_XDMAC_CID_ROID	BIT(6)	/* Request Overflow Interrupt Disable Bit */
+#define AT_XDMAC_CIM		0x08	/* Channel Interrupt Mask Register */
+#define		AT_XDMAC_CIM_BIM	BIT(0)	/* End of Block Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_LIM	BIT(1)	/* End of Linked List Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_DIM	BIT(2)	/* End of Disable Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_FIM	BIT(3)	/* End of Flush Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_RBEIM	BIT(4)	/* Read Bus Error Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_WBEIM	BIT(5)	/* Write Bus Error Interrupt Mask Bit */
+#define		AT_XDMAC_CIM_ROIM	BIT(6)	/* Request Overflow Interrupt Mask Bit */
+#define AT_XDMAC_CIS		0x0C	/* Channel Interrupt Status Register */
+#define		AT_XDMAC_CIS_BIS	BIT(0)	/* End of Block Interrupt Status Bit */
+#define		AT_XDMAC_CIS_LIS	BIT(1)	/* End of Linked List Interrupt Status Bit */
+#define		AT_XDMAC_CIS_DIS	BIT(2)	/* End of Disable Interrupt Status Bit */
+#define		AT_XDMAC_CIS_FIS	BIT(3)	/* End of Flush Interrupt Status Bit */
+#define		AT_XDMAC_CIS_RBEIS	BIT(4)	/* Read Bus Error Interrupt Status Bit */
+#define		AT_XDMAC_CIS_WBEIS	BIT(5)	/* Write Bus Error Interrupt Status Bit */
+#define		AT_XDMAC_CIS_ROIS	BIT(6)	/* Request Overflow Interrupt Status Bit */
+#define AT_XDMAC_CSA		0x10	/* Channel Source Address Register */
+#define AT_XDMAC_CDA		0x14	/* Channel Destination Address Register */
+#define AT_XDMAC_CNDA		0x18	/* Channel Next Descriptor Address Register */
+#define 	AT_XDMAC_CNDA_NDAIF(i)	((i) & 0x1)			/* Channel x Next Descriptor Interface */
+#define		AT_XDMAC_CNDA_NDA(i)	((i) & 0xfffffffc)		/* Channel x Next Descriptor Address */
+#define AT_XDMAC_CNDC		0x1C	/* Channel Next Descriptor Control Register */
+#define		AT_XDMAC_CNDC_NDE		(0x1 << 0)		/* Channel x Next Descriptor Enable */
+#define		AT_XDMAC_CNDC_NDSUP		(0x1 << 1)		/* Channel x Next Descriptor Source Update */
+#define		AT_XDMAC_CNDC_NDDUP		(0x1 << 2)		/* Channel x Next Descriptor Destination Update */
+#define		AT_XDMAC_CNDC_NDVIEW_NDV0	(0x0 << 3)		/* Channel x Next Descriptor View 0 */
+#define		AT_XDMAC_CNDC_NDVIEW_NDV1	(0x1 << 3)		/* Channel x Next Descriptor View 1 */
+#define		AT_XDMAC_CNDC_NDVIEW_NDV2	(0x2 << 3)		/* Channel x Next Descriptor View 2 */
+#define		AT_XDMAC_CNDC_NDVIEW_NDV3	(0x3 << 3)		/* Channel x Next Descriptor View 3 */
+#define AT_XDMAC_CUBC		0x20	/* Channel Microblock Control Register */
+#define AT_XDMAC_CBC		0x24	/* Channel Block Control Register */
+#define AT_XDMAC_CC		0x28	/* Channel Configuration Register */
+#define		AT_XDMAC_CC_TYPE	(0x1 << 0)	/* Channel Transfer Type */
+#define			AT_XDMAC_CC_TYPE_MEM_TRAN	(0x0 << 0)	/* Memory to Memory Transfer */
+#define			AT_XDMAC_CC_TYPE_PER_TRAN	(0x1 << 0)	/* Peripheral to Memory or Memory to Peripheral Transfer */
+#define		AT_XDMAC_CC_MBSIZE_MASK	(0x3 << 1)
+#define			AT_XDMAC_CC_MBSIZE_SINGLE	(0x0 << 1)
+#define			AT_XDMAC_CC_MBSIZE_FOUR		(0x1 << 1)
+#define			AT_XDMAC_CC_MBSIZE_EIGHT	(0x2 << 1)
+#define			AT_XDMAC_CC_MBSIZE_SIXTEEN	(0x3 << 1)
+#define		AT_XDMAC_CC_DSYNC	(0x1 << 4)	/* Channel Synchronization */
+#define			AT_XDMAC_CC_DSYNC_PER2MEM	(0x0 << 4)
+#define			AT_XDMAC_CC_DSYNC_MEM2PER	(0x1 << 4)
+#define		AT_XDMAC_CC_PROT	(0x1 << 5)	/* Channel Protection */
+#define			AT_XDMAC_CC_PROT_SEC		(0x0 << 5)
+#define			AT_XDMAC_CC_PROT_UNSEC		(0x1 << 5)
+#define		AT_XDMAC_CC_SWREQ	(0x1 << 6)	/* Channel Software Request Trigger */
+#define			AT_XDMAC_CC_SWREQ_HWR_CONNECTED	(0x0 << 6)
+#define			AT_XDMAC_CC_SWREQ_SWR_CONNECTED	(0x1 << 6)
+#define		AT_XDMAC_CC_MEMSET	(0x1 << 7)	/* Channel Fill Block of memory */
+#define			AT_XDMAC_CC_MEMSET_NORMAL_MODE	(0x0 << 7)
+#define			AT_XDMAC_CC_MEMSET_HW_MODE	(0x1 << 7)
+#define		AT_XDMAC_CC_CSIZE_MASK	(0x7 << 8)	/* Channel Chunk Size */
+#define			AT_XDMAC_CC_CSIZE_CHK_1		(0x0 << 8)
+#define			AT_XDMAC_CC_CSIZE_CHK_2		(0x1 << 8)
+#define			AT_XDMAC_CC_CSIZE_CHK_4		(0x2 << 8)
+#define			AT_XDMAC_CC_CSIZE_CHK_8		(0x3 << 8)
+#define			AT_XDMAC_CC_CSIZE_CHK_16	(0x4 << 8)
+#define		AT_XDMAC_CC_DWIDTH(i)	((i) << 11)	/* Channel Data Width */
+#define			AT_XDMAC_CC_DWIDTH_BYTE		0x0
+#define			AT_XDMAC_CC_DWIDTH_HALFWORD	0x1
+#define			AT_XDMAC_CC_DWIDTH_WORD		0x2
+#define			AT_XDMAC_CC_DWIDTH_DWORD	0x3
+#define		AT_XDMAC_CC_SIF(i)	((0x1 & (i)) << 13)	/* Channel Source Interface Identifier */
+#define		AT_XDMAC_CC_DIF(i)	((0x1 & (i)) << 14)	/* Channel Destination Interface Identifier */
+#define		AT_XDMAC_CC_SAM_MASK	(0x3 << 16)	/* Channel Source Addressing Mode */
+#define			AT_XDMAC_CC_SAM_FIXED_AM	(0x0 << 16)
+#define			AT_XDMAC_CC_SAM_INCREMENTED_AM	(0x1 << 16)
+#define			AT_XDMAC_CC_SAM_UBS_AM		(0x2 << 16)
+#define			AT_XDMAC_CC_SAM_UBS_DS_AM	(0x3 << 16)
+#define		AT_XDMAC_CC_DAM_MASK	(0x3 << 18)	/* Channel Source Addressing Mode */
+#define			AT_XDMAC_CC_DAM_FIXED_AM	(0x0 << 18)
+#define			AT_XDMAC_CC_DAM_INCREMENTED_AM	(0x1 << 18)
+#define			AT_XDMAC_CC_DAM_UBS_AM		(0x2 << 18)
+#define			AT_XDMAC_CC_DAM_UBS_DS_AM	(0x3 << 18)
+#define		AT_XDMAC_CC_INITD	(0x1 << 21)	/* Channel Initialization Terminated (read only) */
+#define			AT_XDMAC_CC_INITD_TERMINATED	(0x0 << 21)
+#define			AT_XDMAC_CC_INITD_IN_PROGRESS	(0x1 << 21)
+#define		AT_XDMAC_CC_RDIP	(0x1 << 22)	/* Read in Progress (read only) */
+#define			AT_XDMAC_CC_RDIP_DONE		(0x0 << 22)
+#define			AT_XDMAC_CC_RDIP_IN_PROGRESS	(0x1 << 22)
+#define		AT_XDMAC_CC_WDIP	(0x1 << 23)	/* Write in Progress (read only) */
+#define			AT_XDMAC_CC_WDIP_DONE		(0x0 << 23)
+#define			AT_XDMAC_CC_WDIP_IN_PROGRESS	(0x1 << 23)
+#define		AT_XDMAC_CC_PERID(i)	(0x7f & (h) << 24)	/* Channel Peripheral Identifier */
+#define AT_XDMAC_CDS_MSP	0x2C	/* Channel Data Stride Memory Set Pattern */
+#define AT_XDMAC_CSUS		0x30	/* Channel Source Microblock Stride */
+#define AT_XDMAC_CDUS		0x34	/* Channel Destination Microblock Stride */
+
+#define AT_XDMAC_CHAN_REG_BASE	0x50	/* Channel registers base address */
+
+/* Microblock control members */
+#define AT_XDMAC_MBR_UBC_UBLEN_MAX	0xFFFFFFUL	/* Maximum Microblock Length */
+#define AT_XDMAC_MBR_UBC_NDE		(0x1 << 24)	/* Next Descriptor Enable */
+#define AT_XDMAC_MBR_UBC_NSEN		(0x1 << 25)	/* Next Descriptor Source Update */
+#define AT_XDMAC_MBR_UBC_NDEN		(0x1 << 26)	/* Next Descriptor Destination Update */
+#define AT_XDMAC_MBR_UBC_NDV0		(0x0 << 27)	/* Next Descriptor View 0 */
+#define AT_XDMAC_MBR_UBC_NDV1		(0x1 << 27)	/* Next Descriptor View 1 */
+#define AT_XDMAC_MBR_UBC_NDV2		(0x2 << 27)	/* Next Descriptor View 2 */
+#define AT_XDMAC_MBR_UBC_NDV3		(0x3 << 27)	/* Next Descriptor View 3 */
+
+#define AT_XDMAC_MAX_CHAN	0x20
+
+enum atc_status {
+	AT_XDMAC_CHAN_IS_CYCLIC = 0,
+	AT_XDMAC_CHAN_IS_PAUSED,
+};
+
+/* ----- Channels ----- */
+struct at_xdmac_chan {
+	struct dma_chan		chan;
+	void __iomem		*ch_regs;
+	u32			mask;		/* Channel Mask */
+	u32			cfg;		/* Channel Configuration Register */
+	u8			perid;		/* Peripheral ID */
+	u8			dwidth;		/* Data Width */
+	u8			perif;		/* Peripheral Interface */
+	u8			memif;		/* Memory Interface */
+	u32			save_cim;
+	u32			save_cnda;
+	u32			save_cndc;
+	unsigned long		status;
+	struct tasklet_struct	tasklet;
+	struct dma_slave_config	dma_sconfig;
+
+	spinlock_t		lock;
+
+	struct list_head	xfers_list;
+	struct list_head	free_descs_list;
+};
+
+
+/* ----- Controller ----- */
+struct at_xdmac {
+	struct dma_device	dma;
+	void __iomem		*regs;
+	int			irq;
+	struct clk		*clk;
+	u32			save_gim;
+	u32			save_gs;
+	struct dma_pool		*at_xdmac_desc_pool;
+	struct at_xdmac_chan	chan[0];
+};
+
+
+/* ----- Descriptors ----- */
+
+/* Linked List Descriptor */
+struct at_xdmac_lld {
+	dma_addr_t	mbr_nda;	/* Next Descriptor Member */
+	u32		mbr_ubc;	/* Microblock Control Member */
+	dma_addr_t	mbr_sa;		/* Source Address Member */
+	dma_addr_t	mbr_da;		/* Destination Address Member */
+	u32		mbr_cfg;	/* Configuration Register */
+};
+
+
+struct at_xdmac_desc {
+	struct at_xdmac_lld		lld;
+	enum dma_transfer_direction	direction;
+	struct dma_async_tx_descriptor	tx_dma_desc;
+	struct list_head		desc_node;
+	/* Following members are only used by the first descriptor */
+	bool				active_xfer;
+	unsigned int			xfer_size;
+	struct list_head		descs_list;
+	struct list_head		xfer_node;
+};
+
+static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
+{
+	return (void __iomem *)(atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40));
+}
+
+#define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
+#define at_xdmac_write(atxdmac, reg, value) \
+	writel_relaxed((value), (atxdmac)->regs + (reg))
+
+#define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
+#define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
+
+static inline struct at_xdmac_chan *to_at_xdmac_chan(struct dma_chan *dchan)
+{
+	return container_of(dchan, struct at_xdmac_chan, chan);
+}
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static inline struct at_xdmac *to_at_xdmac(struct dma_device *ddev)
+{
+	return container_of(ddev, struct at_xdmac, dma);
+}
+
+static inline struct at_xdmac_desc *txd_to_at_desc(struct dma_async_tx_descriptor *txd)
+{
+	return container_of(txd, struct at_xdmac_desc, tx_dma_desc);
+}
+
+static inline int at_xdmac_chan_is_cyclic(struct at_xdmac_chan *atchan)
+{
+	return test_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
+}
+
+static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan)
+{
+	return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
+}
+
+static inline u32 at_xdmac_csize(u32 maxburst)
+{
+	u32 csize;
+
+	switch (ffs(maxburst) - 1) {
+	case 1:
+		csize = AT_XDMAC_CC_CSIZE_CHK_2;
+		break;
+	case 2:
+		csize = AT_XDMAC_CC_CSIZE_CHK_4;
+		break;
+	case 3:
+		csize = AT_XDMAC_CC_CSIZE_CHK_8;
+		break;
+	case 4:
+		csize = AT_XDMAC_CC_CSIZE_CHK_16;
+	default:
+		csize = AT_XDMAC_CC_CSIZE_CHK_1;
+	}
+
+	return csize;
+};
+#endif /* __AT_XDMAC_H__ */
diff --git a/include/dt-bindings/dma/at91.h b/include/dt-bindings/dma/at91.h
index e835037..4875a50 100644
--- a/include/dt-bindings/dma/at91.h
+++ b/include/dt-bindings/dma/at91.h
@@ -9,6 +9,8 @@ 
 #ifndef __DT_BINDINGS_AT91_DMA_H__
 #define __DT_BINDINGS_AT91_DMA_H__
 
+/* ---------- HDMAC ---------- */
+
 /*
  * Source and/or destination peripheral ID
  */
@@ -24,4 +26,27 @@ 
 #define AT91_DMA_CFG_FIFOCFG_ALAP	(0x1 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* largest defined AHB burst */
 #define AT91_DMA_CFG_FIFOCFG_ASAP	(0x2 << AT91_DMA_CFG_FIFOCFG_OFFSET)	/* single AHB access */
 
+
+/* ---------- XDMAC ---------- */
+#define AT91_XDMAC_DT_MEM_IF_MASK	(0x1)
+#define AT91_XDMAC_DT_MEM_IF_OFFSET	(16)
+#define AT91_XDMAC_DT_MEM_IF(mem_if)	(((mem_if) & AT91_XDMAC_DT_MEM_IF_MASK) \
+					<< AT91_XDMAC_DT_MEM_IF_OFFSET)
+#define AT91_XDMAC_DT_GET_MEM_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_MEM_IF_OFFSET) \
+					& AT91_XDMAC_DT_MEM_IF_MASK)
+
+#define AT91_XDMAC_DT_PER_IF_MASK	(0x1)
+#define AT91_XDMAC_DT_PER_IF_OFFSET	(0)
+#define AT91_XDMAC_DT_PER_IF(per_if)	(((per_if) & AT91_XDMAC_DT_PER_IF_MASK) \
+					<< AT91_XDMAC_DT_PER_IF_OFFSET)
+#define AT91_XDMAC_DT_GET_PER_IF(cfg)	(((cfg) >> AT91_XDMAC_DT_PER_IF_OFFSET) \
+					& AT91_XDMAC_DT_PER_IF_MASK)
+
+#define AT91_XDMAC_DT_PERID_MASK	(0x7f)
+#define AT91_XDMAC_DT_PERID_OFFSET	(24)
+#define AT91_XDMAC_DT_PERID(perid)	(((perid) & AT91_XDMAC_DT_PERID_MASK) \
+					<< AT91_XDMAC_DT_PERID_OFFSET)
+#define AT91_XDMAC_DT_GET_PERID(cfg)	(((cfg) >> AT91_XDMAC_DT_PERID_OFFSET) \
+					& AT91_XDMAC_DT_PERID_MASK)
+
 #endif /* __DT_BINDINGS_AT91_DMA_H__ */