dmaengine: add a new helper dmam_async_device_register

[Vinod Koul <vkoul@kernel.org>]

On 25-07-18, 13:46, Huang Shijie wrote:
> This patch adds the dmam_async_device_register for DMA code.
> Use the Devres to call the release for the DMA engine driver.

no users?

> 
> Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
> ---
>  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..26c6de621446 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
> +  dmam_async_device_register()

can we name it dmaengine_async_device_register, not to confuse with dma APIs

>    dmam_alloc_coherent()
>    dmam_alloc_attrs()
>    dmam_declare_coherent_memory()
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 84ac38dbdb65..2477af0bdfc7 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);
> +}
> +
> +/**
> + * dmam_async_device_register - registers DMA devices found
> + * @device: &dma_device
> + *
> + * The operation is managed and will be undone on driver detach.
> + */
> +int dmam_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(dmam_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..b98bced0b98e 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 dmam_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