diff mbox series

[v8,5/9] dmaengine: dw: dmamux: Introduce RZN1 DMA router support

Message ID 20220406161856.1669069-6-miquel.raynal@bootlin.com (mailing list archive)
State Superseded
Headers show
Series RZN1 DMA support | expand

Commit Message

Miquel Raynal April 6, 2022, 4:18 p.m. UTC
The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
dmamux register located in the system control area which can take up to
32 requests (16 per DMA controller). Each DMA channel can be wired to
two different peripherals.

We need two additional information from the 'dmas' property: the channel
(bit in the dmamux register) that must be accessed and the value of the
mux for this channel.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw/Kconfig       |   9 ++
 drivers/dma/dw/Makefile      |   2 +
 drivers/dma/dw/rzn1-dmamux.c | 157 +++++++++++++++++++++++++++++++++++
 3 files changed, 168 insertions(+)
 create mode 100644 drivers/dma/dw/rzn1-dmamux.c

Comments

Ilpo Järvinen April 8, 2022, 9:55 a.m. UTC | #1
On Wed, 6 Apr 2022, Miquel Raynal wrote:

> The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
> dmamux register located in the system control area which can take up to
> 32 requests (16 per DMA controller). Each DMA channel can be wired to
> two different peripherals.
> 
> We need two additional information from the 'dmas' property: the channel
> (bit in the dmamux register) that must be accessed and the value of the
> mux for this channel.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---

> +static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
> +					struct of_dma *ofdma)
> +{
> +	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
> +	struct rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
> +	struct rzn1_dmamux_map *map;
> +	unsigned int dmac_idx, chan, val;
> +	u32 mask;
> +	int ret;
> +
> +	if (dma_spec->args_count != 6)
> +		return ERR_PTR(-EINVAL);
> +
> +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> +	if (!map)
> +		return ERR_PTR(-ENOMEM);
> +
> +	chan = dma_spec->args[0];
> +	map->req_idx = dma_spec->args[4];
> +	val = dma_spec->args[5];
> +	dma_spec->args_count -= 2;
> +
> +	if (chan >= RZN1_DMAMUX_MAX_LINES) {
> +		dev_err(&pdev->dev, "Invalid DMA request line: %u\n", chan);
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	if (map->req_idx >= RZN1_DMAMUX_LINES ||
> +	    (map->req_idx % RZN1_DMAMUX_MAX_LINES) != chan) {
> +		dev_err(&pdev->dev, "Invalid MUX request line: %u\n", map->req_idx);
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	dmac_idx = map->req_idx >= RZN1_DMAMUX_MAX_LINES ? 1 : 0;
> +	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", dmac_idx);
> +	if (!dma_spec->np) {
> +		dev_err(&pdev->dev, "Can't get DMA master\n");
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
> +		map->req_idx, dmac_idx, chan);
> +
> +	mask = BIT(map->req_idx);
> +	mutex_lock(&dmamux->lock);
> +	dmamux->used_chans |= mask;
> +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> +	if (ret)
> +		goto release_chan_and_unlock;
> +
> +	mutex_unlock(&dmamux->lock);
> +
> +	return map;
> +
> +release_chan_and_unlock:
> +	dmamux->used_chans &= ~mask;

Now that I check this again, I'm not sure why dmamux->used_chans |= mask; 
couldn't be done after r9a06g032_sysctrl_set_dmamux() call so this 
rollback of it wouldn't be necessary.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Andy Shevchenko April 8, 2022, 11:45 a.m. UTC | #2
On Fri, Apr 08, 2022 at 12:55:47PM +0300, Ilpo Järvinen wrote:
> On Wed, 6 Apr 2022, Miquel Raynal wrote:
> 
> > The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
> > dmamux register located in the system control area which can take up to
> > 32 requests (16 per DMA controller). Each DMA channel can be wired to
> > two different peripherals.
> > 
> > We need two additional information from the 'dmas' property: the channel
> > (bit in the dmamux register) that must be accessed and the value of the
> > mux for this channel.

> > +	mask = BIT(map->req_idx);
> > +	mutex_lock(&dmamux->lock);
> > +	dmamux->used_chans |= mask;
> > +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> > +	if (ret)
> > +		goto release_chan_and_unlock;
> > +
> > +	mutex_unlock(&dmamux->lock);
> > +
> > +	return map;
> > +
> > +release_chan_and_unlock:
> > +	dmamux->used_chans &= ~mask;
> 
> Now that I check this again, I'm not sure why dmamux->used_chans |= mask; 
> couldn't be done after r9a06g032_sysctrl_set_dmamux() call so this 
> rollback of it wouldn't be necessary.

I would still need the mutex unlock which I believe is down path there under
some other label. Hence you are proposing something like

	mask = BIT(map->req_idx);

	mutex_lock(&dmamux->lock);
	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
	if (ret)
		goto err_unlock; // or whatever label is

	dmamux->used_chans |= mask;
	mutex_unlock(&dmamux->lock);

	return map;

Is that correct? If so, I don't see impediments either.

> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Ilpo Järvinen April 8, 2022, 12:38 p.m. UTC | #3
On Fri, 8 Apr 2022, Andy Shevchenko wrote:

> On Fri, Apr 08, 2022 at 12:55:47PM +0300, Ilpo Järvinen wrote:
> > On Wed, 6 Apr 2022, Miquel Raynal wrote:
> > 
> > > The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
> > > dmamux register located in the system control area which can take up to
> > > 32 requests (16 per DMA controller). Each DMA channel can be wired to
> > > two different peripherals.
> > > 
> > > We need two additional information from the 'dmas' property: the channel
> > > (bit in the dmamux register) that must be accessed and the value of the
> > > mux for this channel.
> 
> > > +	mask = BIT(map->req_idx);
> > > +	mutex_lock(&dmamux->lock);
> > > +	dmamux->used_chans |= mask;
> > > +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> > > +	if (ret)
> > > +		goto release_chan_and_unlock;
> > > +
> > > +	mutex_unlock(&dmamux->lock);
> > > +
> > > +	return map;
> > > +
> > > +release_chan_and_unlock:
> > > +	dmamux->used_chans &= ~mask;
> > 
> > Now that I check this again, I'm not sure why dmamux->used_chans |= mask; 
> > couldn't be done after r9a06g032_sysctrl_set_dmamux() call so this 
> > rollback of it wouldn't be necessary.
> 
> I would still need the mutex unlock which I believe is down path there under
> some other label. Hence you are proposing something like
> 
> 	mask = BIT(map->req_idx);
> 
> 	mutex_lock(&dmamux->lock);
> 	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> 	if (ret)
> 		goto err_unlock; // or whatever label is
> 
> 	dmamux->used_chans |= mask;
> 	mutex_unlock(&dmamux->lock);
> 
> 	return map;
> 
> Is that correct? If so, I don't see impediments either.

Yes, and yes, the mutex still has to be unlocked on that error path.

> > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Vinod Koul April 11, 2022, 11:24 a.m. UTC | #4
On 06-04-22, 18:18, Miquel Raynal wrote:
> The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
> dmamux register located in the system control area which can take up to
> 32 requests (16 per DMA controller). Each DMA channel can be wired to
> two different peripherals.
> 
> We need two additional information from the 'dmas' property: the channel
> (bit in the dmamux register) that must be accessed and the value of the
> mux for this channel.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw/Kconfig       |   9 ++
>  drivers/dma/dw/Makefile      |   2 +
>  drivers/dma/dw/rzn1-dmamux.c | 157 +++++++++++++++++++++++++++++++++++
>  3 files changed, 168 insertions(+)
>  create mode 100644 drivers/dma/dw/rzn1-dmamux.c
> 
> diff --git a/drivers/dma/dw/Kconfig b/drivers/dma/dw/Kconfig
> index db25f9b7778c..a9828ddd6d06 100644
> --- a/drivers/dma/dw/Kconfig
> +++ b/drivers/dma/dw/Kconfig
> @@ -16,6 +16,15 @@ config DW_DMAC
>  	  Support the Synopsys DesignWare AHB DMA controller. This
>  	  can be integrated in chips such as the Intel Cherrytrail.
>  
> +config RZN1_DMAMUX
> +	tristate "Renesas RZ/N1 DMAMUX driver"
> +	depends on DW_DMAC
> +	depends on ARCH_RZN1 || COMPILE_TEST
> +	help
> +	  Support the Renesas RZ/N1 DMAMUX which is located in front of
> +	  the Synopsys DesignWare AHB DMA controller located on Renesas
> +	  SoCs.
> +
>  config DW_DMAC_PCI
>  	tristate "Synopsys DesignWare AHB DMA PCI driver"
>  	depends on PCI
> diff --git a/drivers/dma/dw/Makefile b/drivers/dma/dw/Makefile
> index a6f358ad8591..e1796015f213 100644
> --- a/drivers/dma/dw/Makefile
> +++ b/drivers/dma/dw/Makefile
> @@ -9,3 +9,5 @@ dw_dmac-$(CONFIG_OF)		+= of.o
>  
>  obj-$(CONFIG_DW_DMAC_PCI)	+= dw_dmac_pci.o
>  dw_dmac_pci-y			:= pci.o
> +
> +obj-$(CONFIG_RZN1_DMAMUX)	+= rzn1-dmamux.o
> diff --git a/drivers/dma/dw/rzn1-dmamux.c b/drivers/dma/dw/rzn1-dmamux.c
> new file mode 100644
> index 000000000000..5f878a55158f
> --- /dev/null
> +++ b/drivers/dma/dw/rzn1-dmamux.c
> @@ -0,0 +1,157 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022 Schneider-Electric
> + * Author: Miquel Raynal <miquel.raynal@bootlin.com
> + * Based on TI crossbar driver written by Peter Ujfalusi <peter.ujfalusi@ti.com>
> + */
> +#include <linux/of_device.h>
> +#include <linux/of_dma.h>
> +#include <linux/slab.h>
> +#include <linux/soc/renesas/r9a06g032-sysctrl.h>
> +
> +#define RZN1_DMAMUX_LINES 64
> +#define RZN1_DMAMUX_MAX_LINES 16
> +
> +struct rzn1_dmamux_data {
> +	struct dma_router dmarouter;
> +	u32 used_chans;
> +	struct mutex lock;
> +};
> +
> +struct rzn1_dmamux_map {
> +	unsigned int req_idx;
> +};
> +
> +static void rzn1_dmamux_free(struct device *dev, void *route_data)
> +{
> +	struct rzn1_dmamux_data *dmamux = dev_get_drvdata(dev);
> +	struct rzn1_dmamux_map *map = route_data;
> +
> +	dev_dbg(dev, "Unmapping DMAMUX request %u\n", map->req_idx);
> +
> +	mutex_lock(&dmamux->lock);
> +	dmamux->used_chans &= ~BIT(map->req_idx);
> +	mutex_unlock(&dmamux->lock);

Why not use idr or bitmap for this. Hint: former does locking as well

> +
> +	kfree(map);
> +}
> +
> +static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
> +					struct of_dma *ofdma)
> +{
> +	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
> +	struct rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
> +	struct rzn1_dmamux_map *map;
> +	unsigned int dmac_idx, chan, val;
> +	u32 mask;
> +	int ret;
> +
> +	if (dma_spec->args_count != 6)

magic

> +		return ERR_PTR(-EINVAL);
> +
> +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> +	if (!map)
> +		return ERR_PTR(-ENOMEM);
> +
> +	chan = dma_spec->args[0];
> +	map->req_idx = dma_spec->args[4];
> +	val = dma_spec->args[5];
> +	dma_spec->args_count -= 2;
> +
> +	if (chan >= RZN1_DMAMUX_MAX_LINES) {
> +		dev_err(&pdev->dev, "Invalid DMA request line: %u\n", chan);
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	if (map->req_idx >= RZN1_DMAMUX_LINES ||
> +	    (map->req_idx % RZN1_DMAMUX_MAX_LINES) != chan) {
> +		dev_err(&pdev->dev, "Invalid MUX request line: %u\n", map->req_idx);
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	dmac_idx = map->req_idx >= RZN1_DMAMUX_MAX_LINES ? 1 : 0;
> +	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", dmac_idx);
> +	if (!dma_spec->np) {
> +		dev_err(&pdev->dev, "Can't get DMA master\n");
> +		ret = -EINVAL;
> +		goto free_map;
> +	}
> +
> +	dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
> +		map->req_idx, dmac_idx, chan);
> +
> +	mask = BIT(map->req_idx);
> +	mutex_lock(&dmamux->lock);
> +	dmamux->used_chans |= mask;
> +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);

I guess due to this it would be merged by whosoever merges this api.
Please mention this in cover letter and how you propose this should be
merged
Miquel Raynal April 12, 2022, 10:12 a.m. UTC | #5
Hi Vinod,


> > +static void rzn1_dmamux_free(struct device *dev, void *route_data)
> > +{
> > +	struct rzn1_dmamux_data *dmamux = dev_get_drvdata(dev);
> > +	struct rzn1_dmamux_map *map = route_data;
> > +
> > +	dev_dbg(dev, "Unmapping DMAMUX request %u\n", map->req_idx);
> > +
> > +	mutex_lock(&dmamux->lock);
> > +	dmamux->used_chans &= ~BIT(map->req_idx);
> > +	mutex_unlock(&dmamux->lock);  
> 
> Why not use idr or bitmap for this. Hint: former does locking as well

I've changed the code to use a proper bitmap.

> 
> > +
> > +	kfree(map);
> > +}
> > +
> > +static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
> > +					struct of_dma *ofdma)
> > +{
> > +	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
> > +	struct rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
> > +	struct rzn1_dmamux_map *map;
> > +	unsigned int dmac_idx, chan, val;
> > +	u32 mask;
> > +	int ret;
> > +
> > +	if (dma_spec->args_count != 6)  
> 
> magic

Defined.

> 
> > +		return ERR_PTR(-EINVAL);
> > +
> > +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> > +	if (!map)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	chan = dma_spec->args[0];
> > +	map->req_idx = dma_spec->args[4];
> > +	val = dma_spec->args[5];
> > +	dma_spec->args_count -= 2;
> > +

[...]

> > +	dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
> > +		map->req_idx, dmac_idx, chan);
> > +
> > +	mask = BIT(map->req_idx);
> > +	mutex_lock(&dmamux->lock);
> > +	dmamux->used_chans |= mask;
> > +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);  
> 
> I guess due to this it would be merged by whosoever merges this api.
> Please mention this in cover letter and how you propose this should be
> merged

Yes, the cover letter mentions this issue, but since then Geert
proposed to take everything through the renesas trees, which I agree
with. I will send a v9 and if you agree with it please provide your Ack
so that Geert can take it.

Thanks,
Miquèl
Miquel Raynal April 12, 2022, 10:12 a.m. UTC | #6
Hi Ilpo, Andy,

ilpo.jarvinen@linux.intel.com wrote on Fri, 8 Apr 2022 15:38:48 +0300
(EEST):

> On Fri, 8 Apr 2022, Andy Shevchenko wrote:
> 
> > On Fri, Apr 08, 2022 at 12:55:47PM +0300, Ilpo Järvinen wrote:  
> > > On Wed, 6 Apr 2022, Miquel Raynal wrote:
> > >   
> > > > The Renesas RZN1 DMA IP is based on a DW core, with eg. an additional
> > > > dmamux register located in the system control area which can take up to
> > > > 32 requests (16 per DMA controller). Each DMA channel can be wired to
> > > > two different peripherals.
> > > > 
> > > > We need two additional information from the 'dmas' property: the channel
> > > > (bit in the dmamux register) that must be accessed and the value of the
> > > > mux for this channel.  
> >   
> > > > +	mask = BIT(map->req_idx);
> > > > +	mutex_lock(&dmamux->lock);
> > > > +	dmamux->used_chans |= mask;
> > > > +	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> > > > +	if (ret)
> > > > +		goto release_chan_and_unlock;
> > > > +
> > > > +	mutex_unlock(&dmamux->lock);
> > > > +
> > > > +	return map;
> > > > +
> > > > +release_chan_and_unlock:
> > > > +	dmamux->used_chans &= ~mask;  
> > > 
> > > Now that I check this again, I'm not sure why dmamux->used_chans |= mask; 
> > > couldn't be done after r9a06g032_sysctrl_set_dmamux() call so this 
> > > rollback of it wouldn't be necessary.  
> > 
> > I would still need the mutex unlock which I believe is down path there under
> > some other label. Hence you are proposing something like
> > 
> > 	mask = BIT(map->req_idx);
> > 
> > 	mutex_lock(&dmamux->lock);
> > 	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
> > 	if (ret)
> > 		goto err_unlock; // or whatever label is
> > 
> > 	dmamux->used_chans |= mask;
> > 	mutex_unlock(&dmamux->lock);
> > 
> > 	return map;
> > 
> > Is that correct? If so, I don't see impediments either.  
> 
> Yes, and yes, the mutex still has to be unlocked on that error path.
> 
> > > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>  

I've done the modification, thanks for your feedback.

Thanks,
Miquèl
diff mbox series

Patch

diff --git a/drivers/dma/dw/Kconfig b/drivers/dma/dw/Kconfig
index db25f9b7778c..a9828ddd6d06 100644
--- a/drivers/dma/dw/Kconfig
+++ b/drivers/dma/dw/Kconfig
@@ -16,6 +16,15 @@  config DW_DMAC
 	  Support the Synopsys DesignWare AHB DMA controller. This
 	  can be integrated in chips such as the Intel Cherrytrail.
 
+config RZN1_DMAMUX
+	tristate "Renesas RZ/N1 DMAMUX driver"
+	depends on DW_DMAC
+	depends on ARCH_RZN1 || COMPILE_TEST
+	help
+	  Support the Renesas RZ/N1 DMAMUX which is located in front of
+	  the Synopsys DesignWare AHB DMA controller located on Renesas
+	  SoCs.
+
 config DW_DMAC_PCI
 	tristate "Synopsys DesignWare AHB DMA PCI driver"
 	depends on PCI
diff --git a/drivers/dma/dw/Makefile b/drivers/dma/dw/Makefile
index a6f358ad8591..e1796015f213 100644
--- a/drivers/dma/dw/Makefile
+++ b/drivers/dma/dw/Makefile
@@ -9,3 +9,5 @@  dw_dmac-$(CONFIG_OF)		+= of.o
 
 obj-$(CONFIG_DW_DMAC_PCI)	+= dw_dmac_pci.o
 dw_dmac_pci-y			:= pci.o
+
+obj-$(CONFIG_RZN1_DMAMUX)	+= rzn1-dmamux.o
diff --git a/drivers/dma/dw/rzn1-dmamux.c b/drivers/dma/dw/rzn1-dmamux.c
new file mode 100644
index 000000000000..5f878a55158f
--- /dev/null
+++ b/drivers/dma/dw/rzn1-dmamux.c
@@ -0,0 +1,157 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Schneider-Electric
+ * Author: Miquel Raynal <miquel.raynal@bootlin.com
+ * Based on TI crossbar driver written by Peter Ujfalusi <peter.ujfalusi@ti.com>
+ */
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/slab.h>
+#include <linux/soc/renesas/r9a06g032-sysctrl.h>
+
+#define RZN1_DMAMUX_LINES 64
+#define RZN1_DMAMUX_MAX_LINES 16
+
+struct rzn1_dmamux_data {
+	struct dma_router dmarouter;
+	u32 used_chans;
+	struct mutex lock;
+};
+
+struct rzn1_dmamux_map {
+	unsigned int req_idx;
+};
+
+static void rzn1_dmamux_free(struct device *dev, void *route_data)
+{
+	struct rzn1_dmamux_data *dmamux = dev_get_drvdata(dev);
+	struct rzn1_dmamux_map *map = route_data;
+
+	dev_dbg(dev, "Unmapping DMAMUX request %u\n", map->req_idx);
+
+	mutex_lock(&dmamux->lock);
+	dmamux->used_chans &= ~BIT(map->req_idx);
+	mutex_unlock(&dmamux->lock);
+
+	kfree(map);
+}
+
+static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
+					struct of_dma *ofdma)
+{
+	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
+	struct rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
+	struct rzn1_dmamux_map *map;
+	unsigned int dmac_idx, chan, val;
+	u32 mask;
+	int ret;
+
+	if (dma_spec->args_count != 6)
+		return ERR_PTR(-EINVAL);
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+
+	chan = dma_spec->args[0];
+	map->req_idx = dma_spec->args[4];
+	val = dma_spec->args[5];
+	dma_spec->args_count -= 2;
+
+	if (chan >= RZN1_DMAMUX_MAX_LINES) {
+		dev_err(&pdev->dev, "Invalid DMA request line: %u\n", chan);
+		ret = -EINVAL;
+		goto free_map;
+	}
+
+	if (map->req_idx >= RZN1_DMAMUX_LINES ||
+	    (map->req_idx % RZN1_DMAMUX_MAX_LINES) != chan) {
+		dev_err(&pdev->dev, "Invalid MUX request line: %u\n", map->req_idx);
+		ret = -EINVAL;
+		goto free_map;
+	}
+
+	dmac_idx = map->req_idx >= RZN1_DMAMUX_MAX_LINES ? 1 : 0;
+	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", dmac_idx);
+	if (!dma_spec->np) {
+		dev_err(&pdev->dev, "Can't get DMA master\n");
+		ret = -EINVAL;
+		goto free_map;
+	}
+
+	dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
+		map->req_idx, dmac_idx, chan);
+
+	mask = BIT(map->req_idx);
+	mutex_lock(&dmamux->lock);
+	dmamux->used_chans |= mask;
+	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
+	if (ret)
+		goto release_chan_and_unlock;
+
+	mutex_unlock(&dmamux->lock);
+
+	return map;
+
+release_chan_and_unlock:
+	dmamux->used_chans &= ~mask;
+	mutex_unlock(&dmamux->lock);
+free_map:
+	kfree(map);
+
+	return ERR_PTR(ret);
+}
+
+static const struct of_device_id rzn1_dmac_match[] = {
+	{ .compatible = "renesas,rzn1-dma" },
+	{}
+};
+
+static int rzn1_dmamux_probe(struct platform_device *pdev)
+{
+	struct device_node *mux_node = pdev->dev.of_node;
+	const struct of_device_id *match;
+	struct device_node *dmac_node;
+	struct rzn1_dmamux_data *dmamux;
+
+	dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
+	if (!dmamux)
+		return -ENOMEM;
+
+	mutex_init(&dmamux->lock);
+
+	dmac_node = of_parse_phandle(mux_node, "dma-masters", 0);
+	if (!dmac_node)
+		return dev_err_probe(&pdev->dev, -ENODEV, "Can't get DMA master node\n");
+
+	match = of_match_node(rzn1_dmac_match, dmac_node);
+	of_node_put(dmac_node);
+	if (!match)
+		return dev_err_probe(&pdev->dev, -EINVAL, "DMA master is not supported\n");
+
+	dmamux->dmarouter.dev = &pdev->dev;
+	dmamux->dmarouter.route_free = rzn1_dmamux_free;
+
+	platform_set_drvdata(pdev, dmamux);
+
+	return of_dma_router_register(mux_node, rzn1_dmamux_route_allocate,
+				      &dmamux->dmarouter);
+}
+
+static const struct of_device_id rzn1_dmamux_match[] = {
+	{ .compatible = "renesas,rzn1-dmamux" },
+	{}
+};
+
+static struct platform_driver rzn1_dmamux_driver = {
+	.driver = {
+		.name = "renesas,rzn1-dmamux",
+		.of_match_table = rzn1_dmamux_match,
+	},
+	.probe	= rzn1_dmamux_probe,
+};
+module_platform_driver(rzn1_dmamux_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
+MODULE_DESCRIPTION("Renesas RZ/N1 DMAMUX driver");