drm/msm: switch msm_kms_init_aspace() to use device_iommu_mapped()

Change msm_kms_init_aspace() to use generic function
device_iommu_mapped() instead of the fwnode-specific interface
dev_iommu_fwspec_get(). While we are at it, stop referencing
platform_bus_type directly and use the bus of the IOMMU device.

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/489703/
Link: https://lore.kernel.org/r/20220616081106.350262-6-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 1182c9f..984b937 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -277,21 +277,21 @@ struct msm_gem_address_space *msm_kms_init_aspace(struct drm_device *dev)
        struct device *mdss_dev = mdp_dev->parent;
        struct device *iommu_dev;
 
-       domain = iommu_domain_alloc(&platform_bus_type);
-       if (!domain) {
-               drm_info(dev, "no IOMMU, fallback to phys contig buffers for scanout\n");
-               return NULL;
-       }
-
        /*
         * IOMMUs can be a part of MDSS device tree binding, or the
         * MDP/DPU device.
         */
-       if (dev_iommu_fwspec_get(mdp_dev))
+       if (device_iommu_mapped(mdp_dev))
                iommu_dev = mdp_dev;
        else
                iommu_dev = mdss_dev;
 
+       domain = iommu_domain_alloc(iommu_dev->bus);
+       if (!domain) {
+               drm_info(dev, "no IOMMU, fallback to phys contig buffers for scanout\n");
+               return NULL;
+       }
+
        mmu = msm_iommu_new(iommu_dev, domain);
        if (IS_ERR(mmu)) {
                iommu_domain_free(domain);