dma: mxs-dma: move to generic device tree binding

Update mxs-dma driver to adopt generic DMA device tree binding.  It
calls of_dma_controller_register() with mxs specific of_dma_xlate to
get the generic DMA device tree helper support.  Then DMA clients only
need to call dma_request_slave_channel() for requesting a DMA channel
from dmaengine.

The existing way of requesting channel, clients directly call
dma_request_channel(), still work there, and will be removed after
all mxs-dma clients get converted to generic DMA device tree helper.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 66 insertions, 4 deletions

diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index bb86f7ff55d9..b48a79c28845 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -27,6 +27,7 @@
 #include <linux/stmp_device.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 
 #include <asm/irq.h>
 
@@ -139,6 +140,8 @@ struct mxs_dma_engine {
         struct dma_device               dma_device;
         struct device_dma_parameters    dma_parms;
         struct mxs_dma_chan             mxs_chans[MXS_DMA_CHANNELS];
+        struct platform_device          *pdev;
+        unsigned int                    nr_channels;
 };
 
 struct mxs_dma_type {
@@ -350,10 +353,8 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
         int ret;
 
-        if (!data)
-                return -EINVAL;
-
-        mxs_chan->chan_irq = data->chan_irq;
+        if (data)
+                mxs_chan->chan_irq = data->chan_irq;
 
         mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev,
                                 CCW_BLOCK_SIZE, &mxs_chan->ccw_phys,
@@ -665,8 +666,55 @@ err_out:
         return ret;
 }
 
+struct mxs_dma_filter_param {
+        struct device_node *of_node;
+        unsigned int chan_id;
+};
+
+static bool mxs_dma_filter_fn(struct dma_chan *chan, void *fn_param)
+{
+        struct mxs_dma_filter_param *param = fn_param;
+        struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+        struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+        int chan_irq;
+
+        if (mxs_dma->dma_device.dev->of_node != param->of_node)
+                return false;
+
+        if (chan->chan_id != param->chan_id)
+                return false;
+
+        chan_irq = platform_get_irq(mxs_dma->pdev, param->chan_id);
+        if (chan_irq < 0)
+                return false;
+
+        mxs_chan->chan_irq = chan_irq;
+
+        return true;
+}
+
+struct dma_chan *mxs_dma_xlate(struct of_phandle_args *dma_spec,
+                               struct of_dma *ofdma)
+{
+        struct mxs_dma_engine *mxs_dma = ofdma->of_dma_data;
+        dma_cap_mask_t mask = mxs_dma->dma_device.cap_mask;
+        struct mxs_dma_filter_param param;
+
+        if (dma_spec->args_count != 1)
+                return NULL;
+
+        param.of_node = ofdma->of_node;
+        param.chan_id = dma_spec->args[0];
+
+        if (param.chan_id >= mxs_dma->nr_channels)
+                return NULL;
+
+        return dma_request_channel(mask, mxs_dma_filter_fn, &param);
+}
+
 static int __init mxs_dma_probe(struct platform_device *pdev)
 {
+        struct device_node *np = pdev->dev.of_node;
         const struct platform_device_id *id_entry;
         const struct of_device_id *of_id;
         const struct mxs_dma_type *dma_type;
@@ -678,6 +726,12 @@ static int __init mxs_dma_probe(struct platform_device *pdev)
         if (!mxs_dma)
                 return -ENOMEM;
 
+        ret = of_property_read_u32(np, "dma-channels", &mxs_dma->nr_channels);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to read dma-channels\n");
+                return ret;
+        }
+
         of_id = of_match_device(mxs_dma_dt_ids, &pdev->dev);
         if (of_id)
                 id_entry = of_id->data;
@@ -723,6 +777,7 @@ static int __init mxs_dma_probe(struct platform_device *pdev)
         if (ret)
                 return ret;
 
+        mxs_dma->pdev = pdev;
         mxs_dma->dma_device.dev = &pdev->dev;
 
         /* mxs_dma gets 65535 bytes maximum sg size */
@@ -743,6 +798,13 @@ static int __init mxs_dma_probe(struct platform_device *pdev)
                 return ret;
         }
 
+        ret = of_dma_controller_register(np, mxs_dma_xlate, mxs_dma);
+        if (ret) {
+                dev_err(mxs_dma->dma_device.dev,
+                        "failed to register controller\n");
+                dma_async_device_unregister(&mxs_dma->dma_device);
+        }
+
         dev_info(mxs_dma->dma_device.dev, "initialized\n");
 
         return 0;