dma: imx-sdma: move to generic device tree bindings

Update imx-sdma driver to adopt generic DMA device tree bindings.  It
calls of_dma_controller_register() with imx-sdma specific of_dma_xlate
to get the generic DMA device tree helper support.  The #dma-cells for
imx-sdma must be 3, which includes request ID, peripheral type and
priority.

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

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 96 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
index d1e3f443e205..68cee4f5539f 100644
--- a/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
+++ b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
@@ -4,14 +4,70 @@ Required properties:
 - compatible : Should be "fsl,<chip>-sdma"
 - reg : Should contain SDMA registers location and length
 - interrupts : Should contain SDMA interrupt
+- #dma-cells : Must be <3>.
+  The first cell specifies the DMA request/event ID.  See details below
+  about the second and third cell.
 - fsl,sdma-ram-script-name : Should contain the full path of SDMA RAM
   scripts firmware
 
+The second cell of dma phandle specifies the peripheral type of DMA transfer.
+The full ID of peripheral types can be found below.
+
+        ID      transfer type
+        ---------------------
+        0       MCU domain SSI
+        1       Shared SSI
+        2       MMC
+        3       SDHC
+        4       MCU domain UART
+        5       Shared UART
+        6       FIRI
+        7       MCU domain CSPI
+        8       Shared CSPI
+        9       SIM
+        10      ATA
+        11      CCM
+        12      External peripheral
+        13      Memory Stick Host Controller
+        14      Shared Memory Stick Host Controller
+        15      DSP
+        16      Memory
+        17      FIFO type Memory
+        18      SPDIF
+        19      IPU Memory
+        20      ASRC
+        21      ESAI
+
+The third cell specifies the transfer priority as below.
+
+        ID      transfer priority
+        -------------------------
+        0       High
+        1       Medium
+        2       Low
+
 Examples:
 
 sdma@83fb0000 {
         compatible = "fsl,imx51-sdma", "fsl,imx35-sdma";
         reg = <0x83fb0000 0x4000>;
         interrupts = <6>;
+        #dma-cells = <3>;
         fsl,sdma-ram-script-name = "sdma-imx51.bin";
 };
+
+DMA clients connected to the i.MX SDMA controller must use the format
+described in the dma.txt file.
+
+Examples:
+
+ssi2: ssi@70014000 {
+        compatible = "fsl,imx51-ssi", "fsl,imx21-ssi";
+        reg = <0x70014000 0x4000>;
+        interrupts = <30>;
+        clocks = <&clks 49>;
+        dmas = <&sdma 24 1 0>,
+               <&sdma 25 1 0>;
+        dma-names = "rx", "tx";
+        fsl,fifo-depth = <15>;
+};
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 092867bf795c..1e44b8cf95da 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -36,6 +36,7 @@
 #include <linux/dmaengine.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 
 #include <asm/irq.h>
 #include <linux/platform_data/dma-imx-sdma.h>
@@ -1296,6 +1297,35 @@ err_dma_alloc:
         return ret;
 }
 
+static bool sdma_filter_fn(struct dma_chan *chan, void *fn_param)
+{
+        struct imx_dma_data *data = fn_param;
+
+        if (!imx_dma_is_general_purpose(chan))
+                return false;
+
+        chan->private = data;
+
+        return true;
+}
+
+static struct dma_chan *sdma_xlate(struct of_phandle_args *dma_spec,
+                                   struct of_dma *ofdma)
+{
+        struct sdma_engine *sdma = ofdma->of_dma_data;
+        dma_cap_mask_t mask = sdma->dma_device.cap_mask;
+        struct imx_dma_data data;
+
+        if (dma_spec->args_count != 3)
+                return NULL;
+
+        data.dma_request = dma_spec->args[0];
+        data.peripheral_type = dma_spec->args[1];
+        data.priority = dma_spec->args[2];
+
+        return dma_request_channel(mask, sdma_filter_fn, &data);
+}
+
 static int __init sdma_probe(struct platform_device *pdev)
 {
         const struct of_device_id *of_id =
@@ -1443,10 +1473,20 @@ static int __init sdma_probe(struct platform_device *pdev)
                 goto err_init;
         }
 
+        if (np) {
+                ret = of_dma_controller_register(np, sdma_xlate, sdma);
+                if (ret) {
+                        dev_err(&pdev->dev, "failed to register controller\n");
+                        goto err_register;
+                }
+        }
+
         dev_info(sdma->dev, "initialized\n");
 
         return 0;
 
+err_register:
+        dma_async_device_unregister(&sdma->dma_device);
 err_init:
         kfree(sdma->script_addrs);
 err_alloc: