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authorJordan Crouse <jcrouse@codeaurora.org>2017-05-17 17:45:29 +0300
committerRob Clark <robdclark@gmail.com>2017-06-16 18:15:31 +0300
commit7c65817e6d38fad8ed4ae8632b3615980a2197b4 (patch)
tree97f1c8a2326fba7614f3191a6fba6661f7933049 /drivers/gpu/drm/msm/Kconfig
parent925344ccc91d7a7fd84cab2dece1c34bbd86fd8c (diff)
downloadlinux-7c65817e6d38fad8ed4ae8632b3615980a2197b4.tar.xz
drm/msm: gpu: Enable zap shader for A5XX
The A5XX GPU powers on in "secure" mode. In secure mode the GPU can only render to buffers that are marked as secure and inaccessible to the kernel and user through a series of hardware protections. In practice secure mode is used to draw things like a UI on a secure video frame. In order to switch out of secure mode the GPU executes a special shader that clears out the GMEM and other sensitve registers and then writes a register. Because the kernel can't be trusted the shader binary is signed and verified and programmed by the secure world. To do this we need to read the MDT header and the segments from the firmware location and put them in memory and present them for approval. For targets without secure support there is an out: if the secure world doesn't support secure then there are no hardware protections and we can freely write the SECVID_TRUST register from the CPU. We don't have 100% confidence that we can query the secure capabilities at run time but we have enough calls that need to go right to give us some confidence that we're at least doing something useful. Of course if we guess wrong you trigger a permissions violation which usually ends up in a system crash but thats a problem that shows up immediately. [v2: use child device per Bjorn] [v3: use generic MDT loader per Bjorn] [v4: use managed dma functions and ifdefs for the MDT loader] [v5: Add depends for QCOM_MDT_LOADER] Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> [robclark: fix Kconfig to use select instead of depends + #if IS_ENABLED()] Signed-off-by: Rob Clark <robdclark@gmail.com>
Diffstat (limited to 'drivers/gpu/drm/msm/Kconfig')
-rw-r--r--drivers/gpu/drm/msm/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
index 0a31cd6d01ce..b638d192ce5e 100644
--- a/drivers/gpu/drm/msm/Kconfig
+++ b/drivers/gpu/drm/msm/Kconfig
@@ -5,6 +5,7 @@ config DRM_MSM
depends on ARCH_QCOM || (ARM && COMPILE_TEST)
depends on OF && COMMON_CLK
depends on MMU
+ select QCOM_MDT_LOADER
select REGULATOR
select DRM_KMS_HELPER
select DRM_PANEL