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[01/10] dmaengine: bcm2835: Allow reusable descriptors

Message ID 7b67f8d95154d25b3a360f580f1ca61f83f79a6f.1564825752.git.lukas@wunner.de (mailing list archive)
State Not Applicable
Headers show
Series Raspberry Pi SPI speedups | expand

Commit Message

Lukas Wunner Aug. 3, 2019, 10:10 a.m. UTC 
The DMA engine API requires DMA drivers to explicitly allow that
descriptors are prepared once and reused multiple times. Only a
single driver makes use of this functionality so far (pxa_dma.c,
to speed up pxa_camera.c).

We're about to add another use case for reusable descriptors in
the BCM2835 SPI driver, so allow that in the BCM2835 DMA driver.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Kauer <florian.kauer@koalo.de>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/dma/bcm2835-dma.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Vinod Koul Aug. 8, 2019, 12:30 p.m. UTC | #1 
On 03-08-19, 12:10, Lukas Wunner wrote:
> The DMA engine API requires DMA drivers to explicitly allow that
> descriptors are prepared once and reused multiple times. Only a
> single driver makes use of this functionality so far (pxa_dma.c,
> to speed up pxa_camera.c).
> 
> We're about to add another use case for reusable descriptors in
> the BCM2835 SPI driver, so allow that in the BCM2835 DMA driver.

Acked-by: Vinod Koul <vkoul@kernel.org>

> 
> Tested-by: Nuno Sá <nuno.sa@analog.com>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Cc: Martin Sperl <kernel@martin.sperl.org>
> Cc: Florian Kauer <florian.kauer@koalo.de>
> Cc: Robert Jarzmik <robert.jarzmik@free.fr>
> ---
>  drivers/dma/bcm2835-dma.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
> index 8101ff2f05c1..523c507ad69e 100644
> --- a/drivers/dma/bcm2835-dma.c
> +++ b/drivers/dma/bcm2835-dma.c
> @@ -907,6 +907,7 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
>  	od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
>  			      BIT(DMA_MEM_TO_MEM);
>  	od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
> +	od->ddev.descriptor_reuse = true;
>  	od->ddev.dev = &pdev->dev;
>  	INIT_LIST_HEAD(&od->ddev.channels);
>  
> -- 
> 2.20.1
diff mbox series

Patch

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 8101ff2f05c1..523c507ad69e 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -907,6 +907,7 @@  static int bcm2835_dma_probe(struct platform_device *pdev)
 	od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
 			      BIT(DMA_MEM_TO_MEM);
 	od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+	od->ddev.descriptor_reuse = true;
 	od->ddev.dev = &pdev->dev;
 	INIT_LIST_HEAD(&od->ddev.channels);