diff mbox series

[v10,5/9] dmaengine: dw: dmamux: Introduce RZN1 DMA router support

Message ID 20220412193936.63355-6-miquel.raynal@bootlin.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show
Series RZN1 DMA support | expand

Commit Message

Miquel Raynal April 12, 2022, 7:39 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>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/dma/dw/Kconfig       |   9 ++
 drivers/dma/dw/Makefile      |   2 +
 drivers/dma/dw/rzn1-dmamux.c | 160 +++++++++++++++++++++++++++++++++++
 3 files changed, 171 insertions(+)
 create mode 100644 drivers/dma/dw/rzn1-dmamux.c

Comments

Geert Uytterhoeven April 13, 2022, 7:53 a.m. UTC | #1 
Hi Miquel,

On Tue, Apr 12, 2022 at 9:39 PM Miquel Raynal <miquel.raynal@bootlin.com> 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>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/dma/dw/rzn1-dmamux.c
> @@ -0,0 +1,160 @@
> +// 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/bitops.h>
> +#include <linux/of_device.h>
> +#include <linux/of_dma.h>
> +#include <linux/slab.h>
> +#include <linux/soc/renesas/r9a06g032-sysctrl.h>
> +#include <linux/types.h>
> +
> +#define RNZ1_DMAMUX_NCELLS 6
> +#define RZN1_DMAMUX_LINES 64
> +#define RZN1_DMAMUX_MAX_LINES 16
> +
> +struct rzn1_dmamux_data {
> +       struct dma_router dmarouter;
> +       unsigned long *used_chans;

Why a pointer?

> +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;
> +
> +       dmamux->used_chans = devm_bitmap_zalloc(&pdev->dev, 2 * RZN1_DMAMUX_MAX_LINES,
> +                                               GFP_KERNEL);

... Oh, you want to allocate the bitmap separately, although you
know it's just a single long.

You might as well declare it in rzn1_dmamux_data as:

    unsigned long used_chans[BITS_TO_LONGS(2 * RZN1_DMAMUX_MAX_LINES)];

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Miquel Raynal April 13, 2022, 8 a.m. UTC | #2 
Hi Geert,

geert@linux-m68k.org wrote on Wed, 13 Apr 2022 09:53:09 +0200:

> Hi Miquel,
> 
> On Tue, Apr 12, 2022 at 9:39 PM Miquel Raynal <miquel.raynal@bootlin.com> 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>  
> 
> Thanks for your patch!
> 
> > --- /dev/null
> > +++ b/drivers/dma/dw/rzn1-dmamux.c
> > @@ -0,0 +1,160 @@
> > +// 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/bitops.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_dma.h>
> > +#include <linux/slab.h>
> > +#include <linux/soc/renesas/r9a06g032-sysctrl.h>
> > +#include <linux/types.h>
> > +
> > +#define RNZ1_DMAMUX_NCELLS 6
> > +#define RZN1_DMAMUX_LINES 64
> > +#define RZN1_DMAMUX_MAX_LINES 16
> > +
> > +struct rzn1_dmamux_data {
> > +       struct dma_router dmarouter;
> > +       unsigned long *used_chans;  
> 
> Why a pointer?
> 
> > +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;
> > +
> > +       dmamux->used_chans = devm_bitmap_zalloc(&pdev->dev, 2 * RZN1_DMAMUX_MAX_LINES,
> > +                                               GFP_KERNEL);  
> 
> ... Oh, you want to allocate the bitmap separately, although you
> know it's just a single long.
> 
> You might as well declare it in rzn1_dmamux_data as:
> 
>     unsigned long used_chans[BITS_TO_LONGS(2 * RZN1_DMAMUX_MAX_LINES)];

I've done that in versions v1..v8 and it was explicitly requested by
Ilpo that I used something more specific like a bitmap (or an idr, but
I don't think it fits well here). So now I'm using a bitmap...

Thanks,
Miquèl
Geert Uytterhoeven April 13, 2022, 8:05 a.m. UTC | #3 
Hi Miquel,

On Wed, Apr 13, 2022 at 10:00 AM Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
> geert@linux-m68k.org wrote on Wed, 13 Apr 2022 09:53:09 +0200:
> > On Tue, Apr 12, 2022 at 9:39 PM Miquel Raynal <miquel.raynal@bootlin.com> 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>
> >
> > Thanks for your patch!
> >
> > > --- /dev/null
> > > +++ b/drivers/dma/dw/rzn1-dmamux.c
> > > @@ -0,0 +1,160 @@
> > > +// 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/bitops.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_dma.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/soc/renesas/r9a06g032-sysctrl.h>
> > > +#include <linux/types.h>
> > > +
> > > +#define RNZ1_DMAMUX_NCELLS 6
> > > +#define RZN1_DMAMUX_LINES 64
> > > +#define RZN1_DMAMUX_MAX_LINES 16
> > > +
> > > +struct rzn1_dmamux_data {
> > > +       struct dma_router dmarouter;
> > > +       unsigned long *used_chans;
> >
> > Why a pointer?
> >
> > > +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;
> > > +
> > > +       dmamux->used_chans = devm_bitmap_zalloc(&pdev->dev, 2 * RZN1_DMAMUX_MAX_LINES,
> > > +                                               GFP_KERNEL);
> >
> > ... Oh, you want to allocate the bitmap separately, although you
> > know it's just a single long.
> >
> > You might as well declare it in rzn1_dmamux_data as:
> >
> >     unsigned long used_chans[BITS_TO_LONGS(2 * RZN1_DMAMUX_MAX_LINES)];
>
> I've done that in versions v1..v8 and it was explicitly requested by
> Ilpo that I used something more specific like a bitmap (or an idr, but
> I don't think it fits well here). So now I'm using a bitmap...

Right, my bad ;-)

    DECLARE_BITMAP(used_chans, 2 * RZN1_DMAMUX_MAX_LINES);

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Andy Shevchenko April 13, 2022, 10:40 a.m. UTC | #4 
On Wed, Apr 13, 2022 at 09:53:09AM +0200, Geert Uytterhoeven wrote:
> On Tue, Apr 12, 2022 at 9:39 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:

...

> You might as well declare it in rzn1_dmamux_data as:
> 
>     unsigned long used_chans[BITS_TO_LONGS(2 * RZN1_DMAMUX_MAX_LINES)];

But better to use proper macro instead of open coding this...
Andy Shevchenko April 13, 2022, 10:41 a.m. UTC | #5 
On Wed, Apr 13, 2022 at 10:05:43AM +0200, Geert Uytterhoeven wrote:
> On Wed, Apr 13, 2022 at 10:00 AM Miquel Raynal
> <miquel.raynal@bootlin.com> wrote:

...

>     DECLARE_BITMAP(used_chans, 2 * RZN1_DMAMUX_MAX_LINES);

Yep, this one.
Miquel Raynal April 13, 2022, 12:53 p.m. UTC | #6 
Hi Andy, Geert,

andriy.shevchenko@linux.intel.com wrote on Wed, 13 Apr 2022 13:41:23
+0300:

> On Wed, Apr 13, 2022 at 10:05:43AM +0200, Geert Uytterhoeven wrote:
> > On Wed, Apr 13, 2022 at 10:00 AM Miquel Raynal
> > <miquel.raynal@bootlin.com> wrote:  
> 
> ...
> 
> >     DECLARE_BITMAP(used_chans, 2 * RZN1_DMAMUX_MAX_LINES);  

I'll make the update. Do you mind if I send only this patch as a v11?
There is no change in any of the other patches anyway and I think I've
received all the acks required.

Thanks,
Miquèl
Miquel Raynal April 13, 2022, 1:10 p.m. UTC | #7 
Hi Andy,

andriy.shevchenko@linux.intel.com wrote on Wed, 13 Apr 2022 13:40:27
+0300:

> On Wed, Apr 13, 2022 at 09:53:09AM +0200, Geert Uytterhoeven wrote:
> > On Tue, Apr 12, 2022 at 9:39 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:  
> 
> ...
> 
> > You might as well declare it in rzn1_dmamux_data as:
> > 
> >     unsigned long used_chans[BITS_TO_LONGS(2 * RZN1_DMAMUX_MAX_LINES)];  

Now at the top of the driver I have

#define RZN1_DMAMUX_LINES 64
#define RZN1_DMAMUX_MAX_LINES 16

Which does not look right. So FYI I decided to change them to

#define RZN1_DMAMUX_MAX_LINES 64
#define RZN1_DMAMUX_LINES_PER_CTLR 16

which feels much more clear.

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..95db9b7cf88b
--- /dev/null
+++ b/drivers/dma/dw/rzn1-dmamux.c
@@ -0,0 +1,160 @@ 
+// 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/bitops.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/slab.h>
+#include <linux/soc/renesas/r9a06g032-sysctrl.h>
+#include <linux/types.h>
+
+#define RNZ1_DMAMUX_NCELLS 6
+#define RZN1_DMAMUX_LINES 64
+#define RZN1_DMAMUX_MAX_LINES 16
+
+struct rzn1_dmamux_data {
+	struct dma_router dmarouter;
+	unsigned long *used_chans;
+};
+
+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);
+
+	clear_bit(map->req_idx, dmamux->used_chans);
+
+	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 != RNZ1_DMAMUX_NCELLS)
+		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);
+
+	if (test_and_set_bit(map->req_idx, dmamux->used_chans)) {
+		ret = -EBUSY;
+		goto free_map;
+	}
+
+	mask = BIT(map->req_idx);
+	ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
+	if (ret)
+		goto clear_bitmap;
+
+	return map;
+
+clear_bitmap:
+	clear_bit(map->req_idx, dmamux->used_chans);
+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;
+
+	dmamux->used_chans = devm_bitmap_zalloc(&pdev->dev, 2 * RZN1_DMAMUX_MAX_LINES,
+						GFP_KERNEL);
+	if (!dmamux->used_chans)
+		return -ENOMEM;
+
+	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");