9 messages, 6 authors, 2009-07-08 · open the first message on its own page
From: Kári Davíðsson <hidden>
Date: 2009-07-06 17:51:06
I am doing a driver that uses dma_map_single(). After changing to to linux 2.6.29.3 I am getting segfaults in dma_map_single() because dma_ops->map_page is NULL. Actually dma_ops looks funky too. The driver is an of_platform_driver which is declared as an child of the lbp (fsl,lpb) node of the device tree. This is on powerpc 5200b platform. rg kd
From: Mark Nelson <hidden>
Date: 2009-07-07 00:13:23
On Tuesday 07 July 2009 03:51:00 K=E1ri Dav=ED=F0sson wrote:
I am doing a driver that uses dma_map_single(). =20 After changing to to linux 2.6.29.3 I am getting segfaults in dma_map_single() because dma_ops->map_page is NULL. Actually dma_ops looks funky too.
When the 32 and 64bit DMA code was merged in .28 , map_/unmap_page() was added in favour of map_/unmap_single() (which was later removed in .29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address. Hope that helps! Mark.
=20 The driver is an of_platform_driver which is declared as an child of the lbp (fsl,lpb) node of the device tree. =20 This is on powerpc 5200b platform. =20 rg kd
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2009-07-07 11:08:44
On Tue, 2009-07-07 at 10:15 +1000, Mark Nelson wrote:
When the 32 and 64bit DMA code was merged in .28 , map_/unmap_page() was added in favour of map_/unmap_single() (which was later removed in .29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address.
Wait a minute ... dma_map_single() should still work, it will just call dma_map_page() underneath. All dma_ops should have a ->map page callback. Do you have any dma_ops set for your device at all ? I wonder how we set the dma_ops for platform devices nowadays ... We use to have this fallback to direct ops when the dma_ops are NULL but that is gone and I see no suitable replacement to set them on platform devices for embedded archs ... oops... Kumar, Becky, what's the situation there ? Cheers, Ben.
From: Jon Smirl <hidden>
Date: 2009-07-07 12:56:36
On Mon, Jul 6, 2009 at 1:51 PM, K=E1ri Dav=ED=F0sson<kari.davidsson@marel.c= om> wrote:
I am doing a driver that uses dma_map_single(). After changing to to linux 2.6.29.3 I am getting segfaults in dma_map_single() because dma_ops->map_page is NULL. Actually dma_ops looks funky too. The driver is an of_platform_driver which is declared as an child of the lbp (fsl,lpb) node of the device tree. This is on powerpc 5200b platform.
I have hit this before, in my case the driver pointer was null. It faulted on dma_ops->map_page which had nothing to do with the real problem which was the null driver pointer. I spent a long time looking at this until I figured out that the reported error was bogus compared to the actual problem.
rg kd _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
--=20 Jon Smirl jonsmirl@gmail.com
From: Kumar Gala <hidden>
Date: 2009-07-07 14:37:59
On Jul 7, 2009, at 6:08 AM, Benjamin Herrenschmidt wrote:
On Tue, 2009-07-07 at 10:15 +1000, Mark Nelson wrote:quoted
When the 32 and 64bit DMA code was merged in .28 , map_/ unmap_page() was added in favour of map_/unmap_single() (which was later removed in . 29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address.Wait a minute ... dma_map_single() should still work, it will just call dma_map_page() underneath. All dma_ops should have a ->map page callback. Do you have any dma_ops set for your device at all ? I wonder how we set the dma_ops for platform devices nowadays ... We use to have this fallback to direct ops when the dma_ops are NULL but that is gone and I see no suitable replacement to set them on platform devices for embedded archs ... oops... Kumar, Becky, what's the situation there ? Cheers, Ben.
Is it possible the dev pointer is not valid? I can't remember if that was a .29 or .30 change that requires us to start passing a valid dev pointer to get the proper dma_ops. - k
From: Kári Davíðsson <hidden>
Date: 2009-07-07 15:24:59
Yes the device pointer was invalid. I was passing the of_device pointer instead of the address of of_device->dev. But I am sure this was working (passing of_device pointer) with earlier kernels. Thanks for the help. rg kd Kumar Gala wrote:
On Jul 7, 2009, at 6:08 AM, Benjamin Herrenschmidt wrote:quoted
On Tue, 2009-07-07 at 10:15 +1000, Mark Nelson wrote:quoted
When the 32 and 64bit DMA code was merged in .28 , map_/ unmap_page() was added in favour of map_/unmap_single() (which was later removed in . 29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address.Wait a minute ... dma_map_single() should still work, it will just call dma_map_page() underneath. All dma_ops should have a ->map page callback. Do you have any dma_ops set for your device at all ? I wonder how we set the dma_ops for platform devices nowadays ... We use to have this fallback to direct ops when the dma_ops are NULL but that is gone and I see no suitable replacement to set them on platform devices for embedded archs ... oops... Kumar, Becky, what's the situation there ? Cheers, Ben.Is it possible the dev pointer is not valid? I can't remember if that was a .29 or .30 change that requires us to start passing a valid dev pointer to get the proper dma_ops. - k
From: Becky Bruce <hidden>
Date: 2009-07-07 15:49:30
On Jul 7, 2009, at 9:37 AM, Kumar Gala wrote:
On Jul 7, 2009, at 6:08 AM, Benjamin Herrenschmidt wrote:quoted
On Tue, 2009-07-07 at 10:15 +1000, Mark Nelson wrote:quoted
When the 32 and 64bit DMA code was merged in .28 , map_/ unmap_page() was added in favour of map_/unmap_single() (which was later removed in .29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address.Wait a minute ... dma_map_single() should still work, it will just call dma_map_page() underneath. All dma_ops should have a ->map page callback.
quoted
Do you have any dma_ops set for your device at all ? I wonder how we set the dma_ops for platform devices nowadays ... We use to have this fallback to direct ops when the dma_ops are NULL but that is gone and I see no suitable replacement to set them on platform devices for embedded archs ... oops...
There is a platform/of bus notifier that sets the dma_ops to a default value in arch/powerpc/kernel/setup-common.c.
quoted
Kumar, Becky, what's the situation there ? Cheers, Ben.Is it possible the dev pointer is not valid? I can't remember if that was a .29 or .30 change that requires us to start passing a valid dev pointer to get the proper dma_ops.
I'm pretty sure that went into .29. And invalid dev pointer is the most likely culprit. IIRC, the usual cause of this is that you're passing in the *wrong* dev pointer. There are often struct hierarchies with, confusingly, multiple struct device pointers. You need the one which has archdata dma_ops setup properly. For an of device, you want the dev pointer that is part of the of_device struct. If this isn't your problem, then please post some code so we can look at this further, and post a log of what's happening. Cheers, Becky
From: Kumar Gala <hidden>
Date: 2009-07-07 16:05:09
On Jul 7, 2009, at 10:24 AM, K=E1ri Dav=ED=F0sson wrote:
Yes the device pointer was invalid. I was passing the of_device pointer instead of the address of of_device->dev. But I am sure this was working (passing of_device pointer) with earlier kernels. Thanks for the help. rg kd
earlier kernels didn't care if the dev pointer was valid and thus let =20= it pass if you didn't give the proper thing. - k=
From: Mark Nelson <hidden>
Date: 2009-07-08 00:42:46
On Tuesday 07 July 2009 21:08:25 Benjamin Herrenschmidt wrote:
On Tue, 2009-07-07 at 10:15 +1000, Mark Nelson wrote:quoted
When the 32 and 64bit DMA code was merged in .28 , map_/unmap_page() was added in favour of map_/unmap_single() (which was later removed in .29) so you'll have to replace your calls to dma_map_single() with dma_map_page(). Just pass it the page and offset rather than the address.Wait a minute ... dma_map_single() should still work, it will just call dma_map_page() underneath. All dma_ops should have a ->map page callback.
Sorry my mistake - I was thinking of when we removed the map/unmap_single() from the dma_mapping_ops. Mark.