[PATCH] drm/msm/dpu: Fix mmu init/destroy functions

[PATCH] drm/msm/dpu: Fix mmu init/destroy functions

[Sean Paul]

From: Sean Paul <seanpaul@chromium.org>

There's a comment in _dpu_kms_hw_destroy() that reads "safe to call
these more than once during shutdown", referring to
_dpu_kms_mmu_destroy(). Unfortunately that's not the case, mmu_destroy
will fail hard if it's called twice. So fix that function to ensure it
can be called multiple times without burning.

While I'm at it, fix the error paths in _dpu_kms_mmu_init() to properly
clean up the iommu domain and not call _dpu_kms_mmu_destroy() when
things are only partially setup.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index 885bf88afa3e..d50afbb37a0a 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -729,12 +729,16 @@ static int _dpu_kms_mmu_destroy(struct dpu_kms *dpu_kms)
 {
 	struct msm_mmu *mmu;
 
+	if (!dpu_kms->base.aspace)
+		return 0;
+
 	mmu = dpu_kms->base.aspace->mmu;
 
 	mmu->funcs->detach(mmu, (const char **)iommu_ports,
 			ARRAY_SIZE(iommu_ports));
 	msm_gem_address_space_put(dpu_kms->base.aspace);
 
+	dpu_kms->base.aspace = NULL;
 	return 0;
 }
 
@@ -754,25 +758,20 @@ static int _dpu_kms_mmu_init(struct dpu_kms *dpu_kms)
 	aspace = msm_gem_address_space_create(dpu_kms->dev->dev,
 			domain, "dpu1");
 	if (IS_ERR(aspace)) {
-		ret = PTR_ERR(aspace);
-		goto fail;
+		iommu_domain_free(domain);
+		return PTR_ERR(aspace);
 	}
 
-	dpu_kms->base.aspace = aspace;
-
 	ret = aspace->mmu->funcs->attach(aspace->mmu, iommu_ports,
 			ARRAY_SIZE(iommu_ports));
 	if (ret) {
 		DPU_ERROR("failed to attach iommu %d\n", ret);
 		msm_gem_address_space_put(aspace);
-		goto fail;
+		return ret;
 	}
 
+	dpu_kms->base.aspace = aspace;
 	return 0;
-fail:
-	_dpu_kms_mmu_destroy(dpu_kms);
-
-	return ret;
 }
 
 static struct dss_clk *_dpu_kms_get_clk(struct dpu_kms *dpu_kms,
-- 
Sean Paul, Software Engineer, Google / Chromium OS