From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Ding Tianhong <dingtianhong@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: For the problem when using swiotlb
Date: Thu, 20 Nov 2014 08:40 +0100 [thread overview]
Message-ID: <2522857.bNQToYpBNt@wuerfel> (raw)
In-Reply-To: <546D58B1.60108@huawei.com>
On Thursday 20 November 2014 10:57:53 Ding Tianhong wrote:
> On 2014/11/19 16:45, Arnd Bergmann wrote:
> > On Wednesday 19 November 2014 11:17:15 Ding Tianhong wrote:
> >> On 2014/11/18 2:09, Catalin Marinas wrote:
> >>> On Mon, Nov 17, 2014 at 12:18:42PM +0000, Arnd Bergmann wrote:
> >> Thanks everyone, I think I found the way to fix it, need to enable DMA_CMA, to reserve a big memory
> >> for CMA and set coherent mask for dev, then dma_alloc and dma_mapping will not use the swiotlb until
> >> the memory out of mask or swiotlb_force is enabled.
> >>
> >> If I still understand uncorrectly, please inform me.
> >>
> >
> > Please do not use CMA to work around the problem, but fix the underlying bug
> > instead.
> >
> > The driver should call 'dma_set_mask_and_coherent()' with the appropriate
> > dma mask, and check whether that succeeded. However, the code implementing
> > dma_set_mask_and_coherent on arm64 also needs to be changed to look up
> > the dma-ranges property (see of_dma_configure()), and check if the mask
> > is possible.
> >
> The dma_pfn_offset looks only support arm32, but my platform is aarch64 and I check the latest kernel version,
> I think the dma-rangs still could not work for aarch64, so maybe we should add dma_pfn_offset for aarch64 first.
>
I didn't mean the dma_pfn_offset. The problem is that the of_dma_configure
code currently doesn't look at the mask. As I explained in my reply to
Catalin, it should set the mask to the size of the dma-ranges if that is
32-bit or smaller, and dma_set_mask should look at the same dma-ranges
property to decide what to set the mask to when a driver asks for a
mask larger than 64-bit.
Arnd
next prev parent reply other threads:[~2014-11-20 7:40 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-17 11:56 For the problem when using swiotlb Ding Tianhong
2014-11-17 12:18 ` Arnd Bergmann
2014-11-17 18:09 ` Catalin Marinas
2014-11-19 3:17 ` Ding Tianhong
2014-11-19 8:45 ` Arnd Bergmann
2014-11-19 11:29 ` Catalin Marinas
2014-11-19 12:48 ` Arnd Bergmann
2014-11-19 15:46 ` Catalin Marinas
2014-11-19 15:56 ` Arnd Bergmann
2014-11-21 11:06 ` Catalin Marinas
2014-11-21 11:26 ` Arnd Bergmann
2014-11-21 11:36 ` Catalin Marinas
2014-11-21 12:27 ` Arnd Bergmann
2014-11-20 2:57 ` Ding Tianhong
2014-11-20 7:40 ` Arnd Bergmann [this message]
2014-11-20 8:34 ` Ding Tianhong
2014-11-20 9:02 ` Arnd Bergmann
2014-11-20 9:21 ` Ding Tianhong
2014-11-21 9:35 ` Catalin Marinas
2014-11-21 10:32 ` Catalin Marinas
2014-11-21 12:48 ` Arnd Bergmann
2014-11-21 16:57 ` Catalin Marinas
2014-11-21 17:04 ` Arnd Bergmann
2014-11-21 17:51 ` Catalin Marinas
2014-11-21 18:09 ` Catalin Marinas
2014-11-24 20:12 ` Arnd Bergmann
2014-11-25 10:58 ` Catalin Marinas
2014-11-25 11:29 ` Russell King - ARM Linux
2014-11-25 12:23 ` Catalin Marinas
2014-11-27 2:36 ` Ding Tianhong
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