* [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-17 3:42 ` Samuel Holland
0 siblings, 0 replies; 10+ messages in thread
From: Samuel Holland @ 2022-06-17 3:42 UTC (permalink / raw)
To: Chen-Yu Tsai, Jernej Skrabec, Vinod Koul
Cc: Samuel Holland, dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
explicitly stated in newer SoC documentation (H6, D1), and it is implied
in older documentation by the 25-bit width of the "bytes left in the
current segment" register field.
Exposing the real segment size limit (instead of the 64k default)
reduces the number of SG list segments needed for a transaction.
Signed-off-by: Samuel Holland <samuel@sholland.org>
---
Tested on A64, verified that the maximum ALSA PCM period increased, and
that audio playback still worked.
drivers/dma/sun6i-dma.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index b7557f437936..1425f87d97b7 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -9,6 +9,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
@@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&sdc->pending);
spin_lock_init(&sdc->lock);
+ dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
+
dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
--
2.35.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-17 3:42 ` Samuel Holland
0 siblings, 0 replies; 10+ messages in thread
From: Samuel Holland @ 2022-06-17 3:42 UTC (permalink / raw)
To: Chen-Yu Tsai, Jernej Skrabec, Vinod Koul
Cc: Samuel Holland, dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
explicitly stated in newer SoC documentation (H6, D1), and it is implied
in older documentation by the 25-bit width of the "bytes left in the
current segment" register field.
Exposing the real segment size limit (instead of the 64k default)
reduces the number of SG list segments needed for a transaction.
Signed-off-by: Samuel Holland <samuel@sholland.org>
---
Tested on A64, verified that the maximum ALSA PCM period increased, and
that audio playback still worked.
drivers/dma/sun6i-dma.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index b7557f437936..1425f87d97b7 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -9,6 +9,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
@@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&sdc->pending);
spin_lock_init(&sdc->lock);
+ dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
+
dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
2022-06-17 3:42 ` Samuel Holland
@ 2022-06-20 18:28 ` Jernej Škrabec
-1 siblings, 0 replies; 10+ messages in thread
From: Jernej Škrabec @ 2022-06-20 18:28 UTC (permalink / raw)
To: Chen-Yu Tsai, Vinod Koul, Samuel Holland
Cc: Samuel Holland, dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> in older documentation by the 25-bit width of the "bytes left in the
> current segment" register field.
At least A10 user manual says 128k max in description for Byte Counter
register (0x100+N*0x20+0xC), although field size is defined as 23:0, but that's
still less than 2^25-1. A20 supports only 128k too according to manual. New
quirk should be introduced for this.
Best regards,
Jernej
>
> Exposing the real segment size limit (instead of the 64k default)
> reduces the number of SG list segments needed for a transaction.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> Tested on A64, verified that the maximum ALSA PCM period increased, and
> that audio playback still worked.
>
> drivers/dma/sun6i-dma.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index b7557f437936..1425f87d97b7 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -9,6 +9,7 @@
>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> #include <linux/dmaengine.h>
> #include <linux/dmapool.h>
> #include <linux/interrupt.h>
> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
*pdev)
> INIT_LIST_HEAD(&sdc->pending);
> spin_lock_init(&sdc->lock);
>
> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
> +
> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
> --
> 2.35.1
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-20 18:28 ` Jernej Škrabec
0 siblings, 0 replies; 10+ messages in thread
From: Jernej Škrabec @ 2022-06-20 18:28 UTC (permalink / raw)
To: Chen-Yu Tsai, Vinod Koul, Samuel Holland
Cc: Samuel Holland, dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> in older documentation by the 25-bit width of the "bytes left in the
> current segment" register field.
At least A10 user manual says 128k max in description for Byte Counter
register (0x100+N*0x20+0xC), although field size is defined as 23:0, but that's
still less than 2^25-1. A20 supports only 128k too according to manual. New
quirk should be introduced for this.
Best regards,
Jernej
>
> Exposing the real segment size limit (instead of the 64k default)
> reduces the number of SG list segments needed for a transaction.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> Tested on A64, verified that the maximum ALSA PCM period increased, and
> that audio playback still worked.
>
> drivers/dma/sun6i-dma.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index b7557f437936..1425f87d97b7 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -9,6 +9,7 @@
>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> #include <linux/dmaengine.h>
> #include <linux/dmapool.h>
> #include <linux/interrupt.h>
> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
*pdev)
> INIT_LIST_HEAD(&sdc->pending);
> spin_lock_init(&sdc->lock);
>
> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
> +
> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
> --
> 2.35.1
>
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
2022-06-20 18:28 ` Jernej Škrabec
@ 2022-06-21 0:20 ` Samuel Holland
-1 siblings, 0 replies; 10+ messages in thread
From: Samuel Holland @ 2022-06-21 0:20 UTC (permalink / raw)
To: Jernej Škrabec, Chen-Yu Tsai, Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Hi Jernej,
On 6/20/22 1:28 PM, Jernej Škrabec wrote:
> Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
>> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
>> explicitly stated in newer SoC documentation (H6, D1), and it is implied
>> in older documentation by the 25-bit width of the "bytes left in the
>> current segment" register field.
>
> At least A10 user manual says 128k max in description for Byte Counter
> register (0x100+N*0x20+0xC), although field size is defined as 23:0, but that's
> still less than 2^25-1. A20 supports only 128k too according to manual. New
> quirk should be introduced for this.
Thanks for checking this. A10 and A20 use a separate driver (sun4i-dma). That
driver will also benefit from setting the max segment size, so I will send a
patch for it.
I think all of the variants supported by sun6i-dma have the same segment size
capability, so no quirk is needed here.
Regards,
Samuel
>>
>> Exposing the real segment size limit (instead of the 64k default)
>> reduces the number of SG list segments needed for a transaction.
>>
>> Signed-off-by: Samuel Holland <samuel@sholland.org>
>> ---
>> Tested on A64, verified that the maximum ALSA PCM period increased, and
>> that audio playback still worked.
>>
>> drivers/dma/sun6i-dma.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
>> index b7557f437936..1425f87d97b7 100644
>> --- a/drivers/dma/sun6i-dma.c
>> +++ b/drivers/dma/sun6i-dma.c
>> @@ -9,6 +9,7 @@
>>
>> #include <linux/clk.h>
>> #include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> #include <linux/dmaengine.h>
>> #include <linux/dmapool.h>
>> #include <linux/interrupt.h>
>> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
> *pdev)
>> INIT_LIST_HEAD(&sdc->pending);
>> spin_lock_init(&sdc->lock);
>>
>> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
>> +
>> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
>> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
>> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
>> --
>> 2.35.1
>>
>>
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-21 0:20 ` Samuel Holland
0 siblings, 0 replies; 10+ messages in thread
From: Samuel Holland @ 2022-06-21 0:20 UTC (permalink / raw)
To: Jernej Škrabec, Chen-Yu Tsai, Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Hi Jernej,
On 6/20/22 1:28 PM, Jernej Škrabec wrote:
> Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
>> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
>> explicitly stated in newer SoC documentation (H6, D1), and it is implied
>> in older documentation by the 25-bit width of the "bytes left in the
>> current segment" register field.
>
> At least A10 user manual says 128k max in description for Byte Counter
> register (0x100+N*0x20+0xC), although field size is defined as 23:0, but that's
> still less than 2^25-1. A20 supports only 128k too according to manual. New
> quirk should be introduced for this.
Thanks for checking this. A10 and A20 use a separate driver (sun4i-dma). That
driver will also benefit from setting the max segment size, so I will send a
patch for it.
I think all of the variants supported by sun6i-dma have the same segment size
capability, so no quirk is needed here.
Regards,
Samuel
>>
>> Exposing the real segment size limit (instead of the 64k default)
>> reduces the number of SG list segments needed for a transaction.
>>
>> Signed-off-by: Samuel Holland <samuel@sholland.org>
>> ---
>> Tested on A64, verified that the maximum ALSA PCM period increased, and
>> that audio playback still worked.
>>
>> drivers/dma/sun6i-dma.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
>> index b7557f437936..1425f87d97b7 100644
>> --- a/drivers/dma/sun6i-dma.c
>> +++ b/drivers/dma/sun6i-dma.c
>> @@ -9,6 +9,7 @@
>>
>> #include <linux/clk.h>
>> #include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> #include <linux/dmaengine.h>
>> #include <linux/dmapool.h>
>> #include <linux/interrupt.h>
>> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
> *pdev)
>> INIT_LIST_HEAD(&sdc->pending);
>> spin_lock_init(&sdc->lock);
>>
>> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
>> +
>> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
>> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
>> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
>> --
>> 2.35.1
>>
>>
>
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
2022-06-21 0:20 ` Samuel Holland
@ 2022-06-21 4:12 ` Jernej Škrabec
-1 siblings, 0 replies; 10+ messages in thread
From: Jernej Škrabec @ 2022-06-21 4:12 UTC (permalink / raw)
To: Chen-Yu Tsai, Vinod Koul, Samuel Holland
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Dne torek, 21. junij 2022 ob 02:20:11 CEST je Samuel Holland napisal(a):
> Hi Jernej,
>
> On 6/20/22 1:28 PM, Jernej Škrabec wrote:
> > Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
> >> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> >> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> >> in older documentation by the 25-bit width of the "bytes left in the
> >> current segment" register field.
> >
> > At least A10 user manual says 128k max in description for Byte Counter
> > register (0x100+N*0x20+0xC), although field size is defined as 23:0, but
that's
> > still less than 2^25-1. A20 supports only 128k too according to manual.
New
> > quirk should be introduced for this.
>
> Thanks for checking this. A10 and A20 use a separate driver (sun4i-dma).
That
> driver will also benefit from setting the max segment size, so I will send a
> patch for it.
>
> I think all of the variants supported by sun6i-dma have the same segment
size
> capability, so no quirk is needed here.
Ah, yes. Then this patch is:
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Best regards,
Jernej
>
> Regards,
> Samuel
>
> >>
> >> Exposing the real segment size limit (instead of the 64k default)
> >> reduces the number of SG list segments needed for a transaction.
> >>
> >> Signed-off-by: Samuel Holland <samuel@sholland.org>
> >> ---
> >> Tested on A64, verified that the maximum ALSA PCM period increased, and
> >> that audio playback still worked.
> >>
> >> drivers/dma/sun6i-dma.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> >> index b7557f437936..1425f87d97b7 100644
> >> --- a/drivers/dma/sun6i-dma.c
> >> +++ b/drivers/dma/sun6i-dma.c
> >> @@ -9,6 +9,7 @@
> >>
> >> #include <linux/clk.h>
> >> #include <linux/delay.h>
> >> +#include <linux/dma-mapping.h>
> >> #include <linux/dmaengine.h>
> >> #include <linux/dmapool.h>
> >> #include <linux/interrupt.h>
> >> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
> > *pdev)
> >> INIT_LIST_HEAD(&sdc->pending);
> >> spin_lock_init(&sdc->lock);
> >>
> >> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
> >> +
> >> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> >> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> >> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
> >> --
> >> 2.35.1
> >>
> >>
> >
> >
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-21 4:12 ` Jernej Škrabec
0 siblings, 0 replies; 10+ messages in thread
From: Jernej Škrabec @ 2022-06-21 4:12 UTC (permalink / raw)
To: Chen-Yu Tsai, Vinod Koul, Samuel Holland
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
Dne torek, 21. junij 2022 ob 02:20:11 CEST je Samuel Holland napisal(a):
> Hi Jernej,
>
> On 6/20/22 1:28 PM, Jernej Škrabec wrote:
> > Dne petek, 17. junij 2022 ob 05:42:09 CEST je Samuel Holland napisal(a):
> >> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> >> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> >> in older documentation by the 25-bit width of the "bytes left in the
> >> current segment" register field.
> >
> > At least A10 user manual says 128k max in description for Byte Counter
> > register (0x100+N*0x20+0xC), although field size is defined as 23:0, but
that's
> > still less than 2^25-1. A20 supports only 128k too according to manual.
New
> > quirk should be introduced for this.
>
> Thanks for checking this. A10 and A20 use a separate driver (sun4i-dma).
That
> driver will also benefit from setting the max segment size, so I will send a
> patch for it.
>
> I think all of the variants supported by sun6i-dma have the same segment
size
> capability, so no quirk is needed here.
Ah, yes. Then this patch is:
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Best regards,
Jernej
>
> Regards,
> Samuel
>
> >>
> >> Exposing the real segment size limit (instead of the 64k default)
> >> reduces the number of SG list segments needed for a transaction.
> >>
> >> Signed-off-by: Samuel Holland <samuel@sholland.org>
> >> ---
> >> Tested on A64, verified that the maximum ALSA PCM period increased, and
> >> that audio playback still worked.
> >>
> >> drivers/dma/sun6i-dma.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> >> index b7557f437936..1425f87d97b7 100644
> >> --- a/drivers/dma/sun6i-dma.c
> >> +++ b/drivers/dma/sun6i-dma.c
> >> @@ -9,6 +9,7 @@
> >>
> >> #include <linux/clk.h>
> >> #include <linux/delay.h>
> >> +#include <linux/dma-mapping.h>
> >> #include <linux/dmaengine.h>
> >> #include <linux/dmapool.h>
> >> #include <linux/interrupt.h>
> >> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device
> > *pdev)
> >> INIT_LIST_HEAD(&sdc->pending);
> >> spin_lock_init(&sdc->lock);
> >>
> >> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
> >> +
> >> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> >> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> >> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
> >> --
> >> 2.35.1
> >>
> >>
> >
> >
>
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
2022-06-17 3:42 ` Samuel Holland
@ 2022-06-21 12:53 ` Robin Murphy
-1 siblings, 0 replies; 10+ messages in thread
From: Robin Murphy @ 2022-06-21 12:53 UTC (permalink / raw)
To: Samuel Holland, Chen-Yu Tsai, Jernej Skrabec, Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
On 2022-06-17 04:42, Samuel Holland wrote:
> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> in older documentation by the 25-bit width of the "bytes left in the
> current segment" register field.
>
> Exposing the real segment size limit (instead of the 64k default)
> reduces the number of SG list segments needed for a transaction.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> Tested on A64, verified that the maximum ALSA PCM period increased, and
> that audio playback still worked.
>
> drivers/dma/sun6i-dma.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index b7557f437936..1425f87d97b7 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -9,6 +9,7 @@
>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> #include <linux/dmaengine.h>
> #include <linux/dmapool.h>
> #include <linux/interrupt.h>
> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> INIT_LIST_HEAD(&sdc->pending);
> spin_lock_init(&sdc->lock);
>
> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
Similarly to my comment on the DRM patch, "SZ_32M - 1" might be clearer
here.
Thanks,
Robin.
> +
> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] dmaengine: sun6i: Set the maximum segment size
@ 2022-06-21 12:53 ` Robin Murphy
0 siblings, 0 replies; 10+ messages in thread
From: Robin Murphy @ 2022-06-21 12:53 UTC (permalink / raw)
To: Samuel Holland, Chen-Yu Tsai, Jernej Skrabec, Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-kernel, linux-sunxi
On 2022-06-17 04:42, Samuel Holland wrote:
> The sun6i DMA engine supports segment sizes up to 2^25-1 bytes. This is
> explicitly stated in newer SoC documentation (H6, D1), and it is implied
> in older documentation by the 25-bit width of the "bytes left in the
> current segment" register field.
>
> Exposing the real segment size limit (instead of the 64k default)
> reduces the number of SG list segments needed for a transaction.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> Tested on A64, verified that the maximum ALSA PCM period increased, and
> that audio playback still worked.
>
> drivers/dma/sun6i-dma.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index b7557f437936..1425f87d97b7 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -9,6 +9,7 @@
>
> #include <linux/clk.h>
> #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> #include <linux/dmaengine.h>
> #include <linux/dmapool.h>
> #include <linux/interrupt.h>
> @@ -1334,6 +1335,8 @@ static int sun6i_dma_probe(struct platform_device *pdev)
> INIT_LIST_HEAD(&sdc->pending);
> spin_lock_init(&sdc->lock);
>
> + dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(25));
Similarly to my comment on the DRM patch, "SZ_32M - 1" might be clearer
here.
Thanks,
Robin.
> +
> dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
> dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
> dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
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^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-06-21 12:54 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-17 3:42 [PATCH] dmaengine: sun6i: Set the maximum segment size Samuel Holland
2022-06-17 3:42 ` Samuel Holland
2022-06-20 18:28 ` Jernej Škrabec
2022-06-20 18:28 ` Jernej Škrabec
2022-06-21 0:20 ` Samuel Holland
2022-06-21 0:20 ` Samuel Holland
2022-06-21 4:12 ` Jernej Škrabec
2022-06-21 4:12 ` Jernej Škrabec
2022-06-21 12:53 ` Robin Murphy
2022-06-21 12:53 ` Robin Murphy
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