DMA: shdma: add DT support

This patch adds Device Tree support to the shdma driver. No special DT
properties are used, only standard DMA DT bindings are implemented. Since
shdma controllers reside on SoCs, their configuration is SoC-specific and
shall be passed to the driver from the SoC platform data, using the
auxdata procedure.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 20 insertions, 6 deletions

diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
index 4acb85a10250..28ca36121631 100644
--- a/drivers/dma/sh/shdma-base.c
+++ b/drivers/dma/sh/shdma-base.c
@@ -175,7 +175,18 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
 {
         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
         const struct shdma_ops *ops = sdev->ops;
-        int ret;
+        int ret, match;
+
+        if (schan->dev->of_node) {
+                match = schan->hw_req;
+                ret = ops->set_slave(schan, match, true);
+                if (ret < 0)
+                        return ret;
+
+                slave_id = schan->slave_id;
+        } else {
+                match = slave_id;
+        }
 
         if (slave_id < 0 || slave_id >= slave_num)
                 return -EINVAL;
@@ -183,7 +194,7 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
         if (test_and_set_bit(slave_id, shdma_slave_used))
                 return -EBUSY;
 
-        ret = ops->set_slave(schan, slave_id, false);
+        ret = ops->set_slave(schan, match, false);
         if (ret < 0) {
                 clear_bit(slave_id, shdma_slave_used);
                 return ret;
@@ -206,23 +217,26 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
  * services would have to provide their own filters, which first would check
  * the device driver, similar to how other DMAC drivers, e.g., sa11x0-dma.c, do
  * this, and only then, in case of a match, call this common filter.
+ * NOTE 2: This filter function is also used in the DT case by shdma_of_xlate().
+ * In that case the MID-RID value is used for slave channel filtering and is
+ * passed to this function in the "arg" parameter.
  */
 bool shdma_chan_filter(struct dma_chan *chan, void *arg)
 {
         struct shdma_chan *schan = to_shdma_chan(chan);
         struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
         const struct shdma_ops *ops = sdev->ops;
-        int slave_id = (int)arg;
+        int match = (int)arg;
         int ret;
 
-        if (slave_id < 0)
+        if (match < 0)
                 /* No slave requested - arbitrary channel */
                 return true;
 
-        if (slave_id >= slave_num)
+        if (!schan->dev->of_node && match >= slave_num)
                 return false;
 
-        ret = ops->set_slave(schan, slave_id, true);
+        ret = ops->set_slave(schan, match, true);
         if (ret < 0)
                 return false;