[PATCH v2 1/2] dmaengine: add a new helper dmaenginem_async_device_register

[PATCH v2 1/2] dmaengine: add a new helper dmaenginem_async_device_register

[Huang Shijie]

This patch adds the dmaenginem_async_device_register for DMA code.
Use the Devres to call the release for the DMA engine driver.

Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
---
v1 --> v2:
    change the name to dmaenginem_async_device_register().
---
 Documentation/driver-model/devres.txt |  1 +
 drivers/dma/dmaengine.c               | 35 +++++++++++++++++++++++++++
 include/linux/dmaengine.h             |  1 +
 3 files changed, 37 insertions(+)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index a3e8bceb5f19..15720cd17958 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -240,6 +240,7 @@ CLOCK
   devm_of_clk_add_hw_provider()
 
 DMA
+  dmaenginem_async_device_register()
   dmam_alloc_coherent()
   dmam_alloc_attrs()
   dmam_declare_coherent_memory()
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 84ac38dbdb65..fa6fdc5f2a04 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1135,6 +1135,41 @@ void dma_async_device_unregister(struct dma_device *device)
 }
 EXPORT_SYMBOL(dma_async_device_unregister);
 
+static void dmam_device_release(struct device *dev, void *res)
+{
+	struct dma_device *device;
+
+	device = *(struct dma_device **)res;
+	dma_async_device_unregister(device);
+}
+
+/**
+ * dmaenginem_async_device_register - registers DMA devices found
+ * @device: &dma_device
+ *
+ * The operation is managed and will be undone on driver detach.
+ */
+int dmaenginem_async_device_register(struct dma_device *device)
+{
+	void *p;
+	int ret;
+
+	p = devres_alloc(dmam_device_release, sizeof(void *), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	ret = dma_async_device_register(device);
+	if (!ret) {
+		*(struct dma_device **)p = device;
+		devres_add(device->dev, p);
+	} else {
+		devres_free(p);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(dmaenginem_async_device_register);
+
 struct dmaengine_unmap_pool {
 	struct kmem_cache *cache;
 	const char *name;
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index c8c3a7a93802..d49ec5c31944 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1406,6 +1406,7 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
 /* --- DMA device --- */
 
 int dma_async_device_register(struct dma_device *device);
+int dmaenginem_async_device_register(struct dma_device *device);
 void dma_async_device_unregister(struct dma_device *device);
 void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
 struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
-- 
2.17.1

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[PATCH v2 2/2] dmaengine: mic_x100_dma: use the new helper to simplify the code

[Huang Shijie]

Use dmaenginem_async_device_register() to simplify the code:
    remove the mic_dma_unregister_dma_device()

Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
---
    Just add a user for the new helper.
---
 drivers/dma/mic_x100_dma.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
index 68dd79783b54..b76cb17d879c 100644
--- a/drivers/dma/mic_x100_dma.c
+++ b/drivers/dma/mic_x100_dma.c
@@ -470,11 +470,6 @@ static void mic_dma_chan_destroy(struct mic_dma_chan *ch)
 	mic_dma_chan_mask_intr(ch);
 }
 
-static void mic_dma_unregister_dma_device(struct mic_dma_device *mic_dma_dev)
-{
-	dma_async_device_unregister(&mic_dma_dev->dma_dev);
-}
-
 static int mic_dma_setup_irq(struct mic_dma_chan *ch)
 {
 	ch->cookie =
@@ -630,7 +625,7 @@ static int mic_dma_register_dma_device(struct mic_dma_device *mic_dma_dev,
 		list_add_tail(&mic_dma_dev->mic_ch[i].api_ch.device_node,
 			      &mic_dma_dev->dma_dev.channels);
 	}
-	return dma_async_device_register(&mic_dma_dev->dma_dev);
+	return dmaenginem_async_device_register(&mic_dma_dev->dma_dev);
 }
 
 /*
@@ -678,7 +673,6 @@ static struct mic_dma_device *mic_dma_dev_reg(struct mbus_device *mbdev,
 
 static void mic_dma_dev_unreg(struct mic_dma_device *mic_dma_dev)
 {
-	mic_dma_unregister_dma_device(mic_dma_dev);
 	mic_dma_uninit(mic_dma_dev);
 	kfree(mic_dma_dev);
 }
-- 
2.17.1

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Re: [PATCH v2 1/2] dmaengine: add a new helper dmaenginem_async_device_register

[Vinod]

On 26-07-18, 14:45, Huang Shijie wrote:
> This patch adds the dmaenginem_async_device_register for DMA code.
> Use the Devres to call the release for the DMA engine driver.

Applied both, thanks

-- 
~Vinod
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