Downstream kernel IOMMU had a non-standard way of dealing with multiple
devices and multiple ports/contexts. We don't need that on upstream
kernel, so rip out the crazy.
Note that we have to move the pinning of the ringbuffer to after the
IOMMU is attached. No idea how that managed to work properly on the
downstream kernel.
For now, I am leaving the IOMMU port name stuff in place, to simplify
things for folks trying to backport latest drm/msm to device kernels.
Once we no longer have to care about pre-DT kernels, we can drop this
and instead backport upstream IOMMU driver.
Signed-off-by: Rob Clark <robdclark@gmail.com>
If probe fails after IOMMU is attached, we need to detach in order to
clean up properly. Before this change, IOMMU faults would occur if the
probe failed (-EPROBE_DEFER).
Signed-off-by: Stephane Viau <sviau@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Add a VRAM carveout that is used for systems which do not have an IOMMU.
The VRAM carveout uses CMA. The arch code must setup a CMA pool for the
device (preferrably in highmem.. a 256m-512m VRAM pool in lowmem is not
cool). The user can configure the VRAM pool size using msm.vram module
param.
Technically, the abstraction of IOMMU behind msm_mmu is not strictly
needed, but it simplifies the GEM code a bit, and will be useful later
when I add support for a2xx devices with GPUMMU, so I decided to keep
this part.
It appears to be possible to configure the GPU to restrict access to
addresses within the VRAM pool, but this is not done yet. So for now
the GPU will refuse to load if there is no sort of mmu. Once address
based limits are supported and tested to confirm that we aren't giving
the GPU access to arbitrary memory, this restriction can be lifted
Signed-off-by: Rob Clark <robdclark@gmail.com>
