dmaengine i.MX SDMA: lock channel 0

channel0 of the sdma engine is the configuration channel. It
is a shared resource and thus must be protected by a mutex.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 7bd7e98548cd..f50c87c303dd 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -318,6 +318,7 @@ struct sdma_engine {
         dma_addr_t                      context_phys;
         struct dma_device               dma_device;
         struct clk                      *clk;
+        struct mutex                    channel_0_lock;
         struct sdma_script_start_addrs  *script_addrs;
 };
 
@@ -415,11 +416,15 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
         dma_addr_t buf_phys;
         int ret;
 
+        mutex_lock(&sdma->channel_0_lock);
+
         buf_virt = dma_alloc_coherent(NULL,
                         size,
                         &buf_phys, GFP_KERNEL);
-        if (!buf_virt)
-                return -ENOMEM;
+        if (!buf_virt) {
+                ret = -ENOMEM;
+                goto err_out;
+        }
 
         bd0->mode.command = C0_SETPM;
         bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
@@ -433,6 +438,9 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
 
         dma_free_coherent(NULL, size, buf_virt, buf_phys);
 
+err_out:
+        mutex_unlock(&sdma->channel_0_lock);
+
         return ret;
 }
 
@@ -656,6 +664,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)
         dev_dbg(sdma->dev, "event_mask0 = 0x%08x\n", sdmac->event_mask0);
         dev_dbg(sdma->dev, "event_mask1 = 0x%08x\n", sdmac->event_mask1);
 
+        mutex_lock(&sdma->channel_0_lock);
+
         memset(context, 0, sizeof(*context));
         context->channel_state.pc = load_address;
 
@@ -676,6 +686,8 @@ static int sdma_load_context(struct sdma_channel *sdmac)
 
         ret = sdma_run_channel(&sdma->channel[0]);
 
+        mutex_unlock(&sdma->channel_0_lock);
+
         return ret;
 }
 
@@ -1274,6 +1286,8 @@ static int __init sdma_probe(struct platform_device *pdev)
         if (!sdma)
                 return -ENOMEM;
 
+        mutex_init(&sdma->channel_0_lock);
+
         sdma->dev = &pdev->dev;
 
         iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);