diff mbox

[RFC,2/2] ARM: shmobile: lager: Increase the size of ARM corehent DMA pool

Message ID 1390935213-12896-3-git-send-email-valentine.barshak@cogentembedded.com (mailing list archive)
State RFC
Headers show

Commit Message

Valentine Barshak Jan. 28, 2014, 6:53 p.m. UTC
This increases the size of ARM coherent DMA pool to 4MB to
avoid issues with DMA bounce for PCI DMA transfers.

Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
---
 arch/arm/boot/dts/r8a7790-lager.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Ben Dooks Jan. 29, 2014, 9:07 a.m. UTC | #1
On 28/01/14 18:53, Valentine Barshak wrote:
> This increases the size of ARM coherent DMA pool to 4MB to
> avoid issues with DMA bounce for PCI DMA transfers.

Would it be easier to enable CMA support given that the DU
driver really needs it.
Valentine Barshak Jan. 29, 2014, 9:52 a.m. UTC | #2
On 01/29/2014 01:07 PM, Ben Dooks wrote:
> On 28/01/14 18:53, Valentine Barshak wrote:
>> This increases the size of ARM coherent DMA pool to 4MB to
>> avoid issues with DMA bounce for PCI DMA transfers.
>
> Would it be easier to enable CMA support given that the DU
> driver really needs it.
>

It doesn't help since dmabounce driver does not allocate bounce buffers from CMA.

Thanks,
Val.
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diff mbox

Patch

diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
index 1081c5e..b2cac57 100644
--- a/arch/arm/boot/dts/r8a7790-lager.dts
+++ b/arch/arm/boot/dts/r8a7790-lager.dts
@@ -17,7 +17,7 @@ 
 	compatible = "renesas,lager", "renesas,r8a7790";
 
 	chosen {
-		bootargs = "console=ttySC6,115200 ignore_loglevel rw root=/dev/nfs ip=dhcp";
+		bootargs = "console=ttySC6,115200 ignore_loglevel rw root=/dev/nfs ip=dhcp coherent_pool=4M";
 	};
 
 	memory@40000000 {