[PATCH] iommu/rockchip: Add missing set_platform_dma_ops callback

Steven Price steven.price at arm.com
Wed Mar 22 02:02:41 PDT 2023

On 21/03/2023 14:38, Jason Gunthorpe wrote:
> On Wed, Mar 15, 2023 at 04:41:52PM +0000, Steven Price wrote:
>> Similar to exynos, we need a set_platform_dma_ops() callback for proper
>> operation on ARM 32 bit after recent changes in the IOMMU framework
>> (detach ops removal).
>> Fixes: c1fe9119ee70 ("iommu: Add set_platform_dma_ops callbacks")
>> Signed-off-by: Steven Price <steven.price at arm.com>
>> ---
>> This fixes a splat I was seeing on a Firefly-RK3288, more details here:
>> https://lore.kernel.org/all/26a5d1b8-40b3-b1e4-bc85-740409c26838@arm.com/
> Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>

Thanks for the review.

> Do you know what state the iommu is left in after
> rk_iommu_detach_device()? Ie is it blocking DMA or doing identity or
> something else?

To be honest I really don't know for sure. But from my small
understanding of the code: rk_iommu_detach_device() ends up in
rk_iommu_disable_paging() which appears to switch to identity mode
("Disable memory translation").

But I don't actually have any familiarity with the hardware block, so I
might be missing something.


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