[RFC,2/5] dmaengine: Add function to request slave channel from a dma_device

From: Vinod Koul <vkoul@kernel.org>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: dan.j.williams@intel.com, dmaengine@vger.kernel.org,
	grygorii.strashko@ti.com
Subject: [RFC,2/5] dmaengine: Add function to request slave channel from a dma_device
Date: Tue, 9 Oct 2018 16:19:34 +0530	[thread overview]
Message-ID: <20181009104934.GL2372@vkoul-mobl> (raw)

On 24-09-18, 16:00, Peter Ujfalusi wrote:
> dma_get_any_slave_channel() would skip using the filter function, which
> in some cases needed to be executed before the alloc_chan_resources
> callback to make sure that all parameters are provided for the slave
> channel.

Another request API, i though you had solved that last time around :(

> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  drivers/dma/dmaengine.c   | 20 ++++++++++++++++++++
>  include/linux/dmaengine.h |  2 ++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 27b6d7c2d8a0..b80f1bdd8813 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -634,6 +634,26 @@ struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
>  }
>  EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
>  
> +struct dma_chan *dmadev_get_slave_channel(struct dma_device *device,
> +					  dma_filter_fn fn, void *fn_param)
> +{
> +	dma_cap_mask_t mask;
> +	struct dma_chan *chan;
> +
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_SLAVE, mask);
> +
> +	/* lock against __dma_request_channel */
> +	mutex_lock(&dma_list_mutex);
> +
> +	chan = find_candidate(device, &mask, fn, fn_param);
> +
> +	mutex_unlock(&dma_list_mutex);
> +
> +	return IS_ERR(chan) ? NULL : chan;
> +}
> +EXPORT_SYMBOL_GPL(dmadev_get_slave_channel);
> +
>  /**
>   * __dma_request_channel - try to allocate an exclusive channel
>   * @mask: capabilities that the channel must satisfy
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 16c9d021988a..32010c6ae13a 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -1542,6 +1542,8 @@ 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);
>  struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
> +struct dma_chan *dmadev_get_slave_channel(struct dma_device *device,
> +					  dma_filter_fn fn, void *fn_param);
>  #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
>  #define dma_request_slave_channel_compat(mask, x, y, dev, name) \
>  	__dma_request_slave_channel_compat(&(mask), x, y, dev, name)
> -- 
> Peter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
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