dmaengine: Add devm_dma_request_chan()

Expand the arsenal of devm functions for DMA devices, this time for
requesting channels.

Signed-off-by: Bence Csókás <csokas.bence@prolan.hu>
Link: https://lore.kernel.org/r/20250610082256.400492-2-csokas.bence@prolan.hu
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 758fcd0546d8bde8e8dddc6039848feeb1e24475..ca13cd39330ba4d822baaab412356a166b656350 100644 (file)
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -926,6 +926,36 @@ void dma_release_channel(struct dma_chan *chan)
 }
 EXPORT_SYMBOL_GPL(dma_release_channel);
 
+static void dmaenginem_release_channel(void *chan)
+{
+       dma_release_channel(chan);
+}
+
+/**
+ * devm_dma_request_chan - try to allocate an exclusive slave channel
+ * @dev:       pointer to client device structure
+ * @name:      slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
+ *
+ * The operation is managed and will be undone on driver detach.
+ */
+
+struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name)
+{
+       struct dma_chan *chan = dma_request_chan(dev, name);
+       int ret = 0;
+
+       if (!IS_ERR(chan))
+               ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan);
+
+       if (ret)
+               return ERR_PTR(ret);
+
+       return chan;
+}
+EXPORT_SYMBOL_GPL(devm_dma_request_chan);
+
 /**
  * dmaengine_get - register interest in dma_channels
  */

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index bb146c5ac3e4ccd7bc0afbf3b28e5b3d659ad62f..6de7c05d6bd8c99e176fe2fde0a9c3b55d40b37c 100644 (file)
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1524,6 +1524,7 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 
 struct dma_chan *dma_request_chan(struct device *dev, const char *name);
 struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
+struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name);
 
 void dma_release_channel(struct dma_chan *chan);
 int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
@@ -1560,6 +1561,12 @@ static inline struct dma_chan *dma_request_chan_by_mask(
 {
        return ERR_PTR(-ENODEV);
 }
+
+static inline struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name)
+{
+       return ERR_PTR(-ENODEV);
+}
+
 static inline void dma_release_channel(struct dma_chan *chan)
 {
 }