[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAL_JsqLGhNOZxAhuQMUdgmMLRxLakBpacfTufSWKGEGFSTqd3A@mail.gmail.com>
Date: Thu, 3 Oct 2013 13:35:22 -0500
From: Rob Herring <robherring2@...il.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Stefano Stabellini <stefano.stabellini@...citrix.com>,
xen-devel@...ts.xensource.com,
Rob Herring <rob.herring@...xeda.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Ian Campbell <Ian.Campbell@...rix.com>,
Russell King - ARM Linux <linux@....linux.org.uk>
Subject: Re: [PATCH v6 15/19] swiotlb-xen: call dma_capable only if
dev->dma_mask is allocated
On Wed, Oct 2, 2013 at 12:22 PM, Konrad Rzeszutek Wilk
<konrad.wilk@...cle.com> wrote:
> On Wed, Oct 02, 2013 at 06:13:35PM +0100, Stefano Stabellini wrote:
>> The real issue is that some devices (xgmac, I am looking at you), don't
>> set the dma_mask, even though they are perfectly capable of doing dma.
>
> So this looks like a bug in the drivers. I thought I saw a huge patchset
> by the ARM maintainer that tries to fix the dma_mask and dma_mask_coherent
> bugs? And also fix the drivers to use the dma mask?
I think Russell only fixed incorrect handling of masks, not missing handling.
>>
>> Maybe I should modify the arm implementation of dma_capable (see
>> http://marc.info/?l=linux-kernel&m=138029832007821&w=2) to ignore the
>> dma_mask.
>
> Or fix the 'xgmac'?
There's really some core changes needed to fix this and I'd guess
there are lots of other cases of missing dma_mask. The problem is
platform devices don't create a mask to assign to dma_mask in the
first place. I think the right solution is assigning dma_mask to
&coherent_dma_mask by default as Russell did for AMBA devices. I don't
know if doing that would break anything or not.
Rob
>>
>> On Mon, 30 Sep 2013, Konrad Rzeszutek Wilk wrote:
>> > On Fri, Sep 27, 2013 at 05:10:03PM +0100, Stefano Stabellini wrote:
>> >
>> > Why? I am looking at X86 and IA64 and I see:
>> >
>> > 79 if (!dev->dma_mask)
>> > 80 return 0;
>> >
>> >
>> > Why not port dma_capable over to ARM?
>> >
>> > > Signed-off-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
>> > > ---
>> > > drivers/xen/swiotlb-xen.c | 6 +++---
>> > > 1 files changed, 3 insertions(+), 3 deletions(-)
>> > >
>> > > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
>> > > index 790c2eb..3011736 100644
>> > > --- a/drivers/xen/swiotlb-xen.c
>> > > +++ b/drivers/xen/swiotlb-xen.c
>> > > @@ -512,7 +512,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>> > > * buffering it.
>> > > */
>> > > if (!xen_feature(XENFEAT_auto_translated_physmap) &&
>> > > - dma_capable(dev, dev_addr, size) &&
>> > > + dev->dma_mask && dma_capable(dev, dev_addr, size) &&
>> > > !range_straddles_page_boundary(phys, size) && !swiotlb_force)
>> > > return dev_addr;
>> > >
>> > > @@ -532,7 +532,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>> > > /*
>> > > * Ensure that the address returned is DMA'ble
>> > > */
>> > > - if (!dma_capable(dev, dev_addr, size)) {
>> > > + if (dev->dma_mask && !dma_capable(dev, dev_addr, size)) {
>> > > swiotlb_tbl_unmap_single(dev, map, size, dir);
>> > > dev_addr = 0;
>> > > }
>> > > @@ -660,7 +660,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
>> > >
>> > > if (swiotlb_force ||
>> > > xen_feature(XENFEAT_auto_translated_physmap) ||
>> > > - !dma_capable(hwdev, dev_addr, sg->length) ||
>> > > + (hwdev->dma_mask && !dma_capable(hwdev, dev_addr, sg->length)) ||
>> > > range_straddles_page_boundary(paddr, sg->length)) {
>> > > /*
>> > > * Pass the dma_addr of the first slab in the iotlb buffer as
>> > > --
>> > > 1.7.2.5
>> > >
>> >
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
--
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