Re: [RFC 3/3] dmaengine: Support for requesting channels preferring DMA domain controller

Peter Ujfalusi
2019-09-08T07:46:05Z

On 06/09/2019 17.18, Peter Ujfalusi wrote:
> In case the channel is not requested via the slave API, use the
> of_find_dma_domain() to see if a system default DMA controller is
> specified.
>
> Add new function which can be used by clients to request channels by mask
> from their DMA domain controller if specified.
>
> Client drivers can take advantage of the domain support by moving from
> dma_request_chan_by_mask() to dma_domain_request_chan_by_mask()
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
> drivers/dma/dmaengine.c | 17 ++++++++++++-----
> include/linux/dmaengine.h | 9 ++++++---
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 6baddf7dcbfd..087450eed68c 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -640,6 +640,10 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> struct dma_device *device, *_d;
> struct dma_chan *chan = NULL;
>
> + /* If np is not specified, get the default DMA domain controller */
> + if (!np)
> + np = of_find_dma_domain(NULL);
> +
> /* Find a channel */
> mutex_lock(&dma_list_mutex);
> list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
> @@ -751,19 +755,22 @@ struct dma_chan *dma_request_slave_channel(struct device *dev,
> EXPORT_SYMBOL_GPL(dma_request_slave_channel);
>
> /**
> - * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
> - * @mask: capabilities that the channel must satisfy
> + * dma_domain_request_chan_by_mask - allocate a channel by mask from DMA domain
> + * @dev: pointer to client device structure
> + * @mask: capabilities that the channel must satisfy
> *
> * Returns pointer to appropriate DMA channel on success or an error pointer.
> */
> -struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
> +struct dma_chan *dma_domain_request_chan_by_mask(struct device *dev,
> + const dma_cap_mask_t *mask)
> {
> struct dma_chan *chan;
>
> if (!mask)
> return ERR_PTR(-ENODEV);
>
> - chan = __dma_request_channel(mask, NULL, NULL, NULL);

if (dev)
> + chan = __dma_request_channel(mask, NULL, NULL,
> + of_find_dma_domain(dev->of_node));else
chan = __dma_request_channel(mask, NULL, NULL, NULL);

> if (!chan) {
> mutex_lock(&dma_list_mutex);
> if (list_empty(&dma_device_list))
> @@ -775,7 +782,7 @@ struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
>
> return chan;
> }
> -EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
> +EXPORT_SYMBOL_GPL(dma_domain_request_chan_by_mask);
>
> void dma_release_channel(struct dma_chan *chan)
> {
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 3b2e8e302f6c..9f94df81e83f 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -1438,7 +1438,8 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
> struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
>
> 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 *dma_domain_request_chan_by_mask(struct device *dev,
> + const dma_cap_mask_t *mask);
>
> void dma_release_channel(struct dma_chan *chan);
> int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
> @@ -1475,8 +1476,8 @@ static inline struct dma_chan *dma_request_chan(struct device *dev,
> {
> return ERR_PTR(-ENODEV);
> }
> -static inline struct dma_chan *dma_request_chan_by_mask(
> - const dma_cap_mask_t *mask)
> +static inline struct dma_chan *dma_domain_request_chan_by_mask(struct device *dev,
> + const dma_cap_mask_t *mask)
> {
> return ERR_PTR(-ENODEV);
> }
> @@ -1537,6 +1538,8 @@ struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
> __dma_request_channel(&(mask), x, y, NULL)
> #define dma_request_slave_channel_compat(mask, x, y, dev, name) \
> __dma_request_slave_channel_compat(&(mask), x, y, dev, name)
> +#define dma_request_chan_by_mask(mask) \
> + dma_domain_request_chan_by_mask(NULL, mask)
>
> static inline struct dma_chan
> *__dma_request_slave_channel_compat(const dma_cap_mask_t *mask,
>

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