[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 7 Jul 2009 21:43:37 +0800
From: Ming Lei <tom.leiming@...il.com>
To: Russell King - ARM Linux <linux@....linux.org.uk>
Cc: Arnd Bergmann <arnd@...db.de>, Alan Cox <alan@...rguk.ukuu.org.uk>,
Joerg Roedel <joerg.roedel@....com>,
fujita.tomonori@....ntt.co.jp, linux-kernel@...r.kernel.org,
akpm@...ux-foundation.org,
linux-arm-kernel <linux-arm-kernel@...ts.arm.linux.org.uk>
Subject: Re: [PATCH][RFC] asm-generic:remove calling flush_write_buffers() in
dma_sync_*_for_cpu
2009/7/7 Russell King - ARM Linux <linux@....linux.org.uk>:
> On Tue, Jul 07, 2009 at 09:54:20AM +0800, Ming Lei wrote:
>> 2009/6/30 Arnd Bergmann <arnd@...db.de>:
>> > On Tuesday 30 June 2009, Alan Cox wrote:
>> > Well, not even that. dma-mapping-common.h only makes sense on architectures
>> > that have multiple dma-mapping implementations (parisc, mips, arm, powerpc,
>>
>> It seems that there is only one dma-mmaping implementation on ARM, doesn't it?
>> Is it necessary that using dma-mapping-common.h on ARM?
>
> ARM has two (normal, and dma bounce), and in the long run we need to do
OK, Can we use dma-mapping-common.h on ARM?
> cache handling on unmap as well as map due to CPU speculative fetches.
IMHO, it seems we can fix this problem now.
For DMA_TO_DEVICE transfer, clean cache in dma map, but does nothing in
dma unmap;
For DMA_FROM_DEVICE, we may do nothing in dma map, but invaliate cache
in dma unmap.
Is it doable?
Thanks.
--
Lei Ming
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists