[Linaro-mm-sig] [PATCHv7 9/9] ARM: dma-mapping: add support for IOMMU mapper
subashrp at gmail.com
Fri Mar 30 07:14:47 UTC 2012
On 03/22/2012 07:29 PM, Subash Patel wrote:
> Hi KyongHo,
> On 03/21/2012 05:26 AM, KyongHo Cho wrote:
>> On Tue, Mar 20, 2012 at 10:50 PM, Subash Patel<subashrp at gmail.com> wrote:
>>> Sorry for digging this very late. But as part of integrating dma_map v7&
>>> sysmmu v12 on 3.3-rc5, I am facing below issue:
>>> a) By un-selecting IOMMU in menu config, I am able to allocate memory in
>>> b) When I enable SYSMMU support for the IP's, I am receiving below
>>> Unhandled fault: external abort on non-linefetch (0x818) at 0xb6f55000
>>> I think this has something to do with the access to the SYSMMU
>>> registers for
>>> writing the page table. Has anyone of you faced this issue while testing
>>> these(dma_map+iommu) patches on kernel mentioned above? This must be
>>> something related to recent changes, as I didn't have issues with these
>>> patches on 3.2 kernel.
>> 0xb6f55000 is not an address of SYSMMU register if your kernel starts
>> at 0xc0000000.
>> Can you tell me any detailed information or situation?
> I hate to say this, but I am not able to catch the fault location even
> with JTAG. Once the fault comes, the debugger looses all control over. I
> think now possible method is reproduction at your end :)
Thanks to you, Issue is now figured out. This was due to generic Power
Domain code added recently. SYSMMU registers were not getting enabled
due to this. I reverted the PD changes from the machine to architecture
specific, and voila, SYSMMU is back into action using the
dma-mapping-v7. I will have to see how the same would behave when the
complete PD changes comes to mainline from maintainers for-next in future.
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