dmaengine: provide a common function for completing a dma descriptor
Provide a common function to do the cookie mechanics for completing
a DMA descriptor.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
index 7692c86..47e0997 100644
--- a/drivers/dma/dmaengine.h
+++ b/drivers/dma/dmaengine.h
@@ -5,6 +5,7 @@
#ifndef DMAENGINE_H
#define DMAENGINE_H
+#include <linux/bug.h>
#include <linux/dmaengine.h>
/**
@@ -27,4 +28,21 @@
return cookie;
}
+/**
+ * dma_cookie_complete - complete a descriptor
+ * @tx: descriptor to complete
+ *
+ * Mark this descriptor complete by updating the channels completed
+ * cookie marker. Zero the descriptors cookie to prevent accidental
+ * repeated completions.
+ *
+ * Note: caller is expected to hold a lock to prevent concurrency.
+ */
+static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
+{
+ BUG_ON(tx->cookie < DMA_MIN_COOKIE);
+ tx->chan->completed_cookie = tx->cookie;
+ tx->cookie = 0;
+}
+
#endif