drm/msm: register a fault handler for display mmu faults

In preparation to register a iommu fault handler for display
related modules, register a fault handler for the backing
mmu object of msm_kms.

Currently, the fault handler only captures the display snapshot
but we can expand this later if more information needs to be
added to debug display mmu faults.

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/638359/
Link: https://lore.kernel.org/r/20250219-abhinavk-smmu-fault-handler-v3-1-aa3f0bf4434a@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

diff --git a/drivers/gpu/drm/msm/msm_kms.c b/drivers/gpu/drm/msm/msm_kms.c
index 38965e12a6bfc9fafd534e9920c549ba094c3506..738aaf4dac32bdb6dff5648e49740606787b0c29 100644 (file)
--- a/drivers/gpu/drm/msm/msm_kms.c
+++ b/drivers/gpu/drm/msm/msm_kms.c
@@ -164,12 +164,23 @@ void msm_crtc_disable_vblank(struct drm_crtc *crtc)
        vblank_ctrl_queue_work(priv, crtc, false);
 }
 
+static int msm_kms_fault_handler(void *arg, unsigned long iova, int flags, void *data)
+{
+       struct msm_kms *kms = arg;
+
+       msm_disp_snapshot_state(kms->dev);
+
+       return -ENOSYS;
+}
+
 struct msm_gem_address_space *msm_kms_init_aspace(struct drm_device *dev)
 {
        struct msm_gem_address_space *aspace;
        struct msm_mmu *mmu;
        struct device *mdp_dev = dev->dev;
        struct device *mdss_dev = mdp_dev->parent;
+       struct msm_drm_private *priv = dev->dev_private;
+       struct msm_kms *kms = priv->kms;
        struct device *iommu_dev;
 
        /*
@@ -197,6 +208,8 @@ struct msm_gem_address_space *msm_kms_init_aspace(struct drm_device *dev)
                mmu->funcs->destroy(mmu);
        }
 
+       msm_mmu_set_fault_handler(aspace->mmu, kms, msm_kms_fault_handler);
+
        return aspace;
 }