[PATCH v1 1/3] dmaengine: sf-pdma: Support of_dma_controller_register()

shravan chippa
2023-09-22T09:50:28Z

From: Shravan Chippa <shravan.chippa@microchip.com>

Update sf-pdma driver to adopt generic DMA device tree bindings.
It calls of_dma_controller_register() with sf-pdma specific
of_dma_xlate to get the generic DMA device tree helper support
and the DMA clients can look up the sf-pdma controller using
standard APIs.

Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com>
---
drivers/dma/sf-pdma/sf-pdma.c | 41 +++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c
index d1c6956af452..c7558c9f9ac3 100644
--- a/drivers/dma/sf-pdma/sf-pdma.c
+++ b/drivers/dma/sf-pdma/sf-pdma.c
@@ -20,6 +20,7 @@
#include <linux/mod_devicetable.h>
#include <linux/dma-mapping.h>
#include <linux/of.h>
+#include <linux/of_dma.h>
#include <linux/slab.h>

#include "sf-pdma.h"
@@ -490,6 +491,33 @@ static void sf_pdma_setup_chans(struct sf_pdma *pdma)
}
}

+static struct dma_chan *sf_pdma_of_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct sf_pdma *pdma = ofdma->of_dma_data;
+ struct device *dev = pdma->dma_dev.dev;
+ struct sf_pdma_chan *chan;
+ struct dma_chan *c;
+ u32 channel_id;
+
+ if (dma_spec->args_count != 1) {
+ dev_err(dev, "Bad number of cells\n");
+ return NULL;
+ }
+
+ channel_id = dma_spec->args[0];
+
+ chan = &pdma->chans[channel_id];
+
+ c = dma_get_slave_channel(&chan->vchan.chan);
+ if (!c) {
+ dev_err(dev, "No more channels available\n");
+ return NULL;
+ }
+
+ return c;
+}
+
static int sf_pdma_probe(struct platform_device *pdev)
{
struct sf_pdma *pdma;
@@ -563,7 +591,20 @@ static int sf_pdma_probe(struct platform_device *pdev)
return ret;
}

+ ret = of_dma_controller_register(pdev->dev.of_node,
+ sf_pdma_of_xlate, pdma);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Can't register SiFive Platform OF_DMA. (%d)\n", ret);
+ goto err_unregister;
+ }
+
return 0;
+
+err_unregister:
+ dma_async_device_unregister(&pdma->dma_dev);
+
+ return ret;
}

static int sf_pdma_remove(struct platform_device *pdev)
--
2.34.1