drm/msm: fix IOMMU cleanup for -EPROBE_DEFER

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>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c

@@ -20,6 +20,10 @@
 #include "msm_mmu.h"
 #include "mdp5_kms.h"
 
+static const char *iommu_ports[] = {
+		"mdp_0",
+};
+
 static struct mdp5_platform_config *mdp5_get_config(struct platform_device *dev);
 
 static int mdp5_hw_init(struct msm_kms *kms)
@@ -104,6 +108,12 @@ static void mdp5_preclose(struct msm_kms *kms, struct drm_file *file)
 static void mdp5_destroy(struct msm_kms *kms)
 {
 	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(kms));
+	struct msm_mmu *mmu = mdp5_kms->mmu;
+
+	if (mmu) {
+		mmu->funcs->detach(mmu, iommu_ports, ARRAY_SIZE(iommu_ports));
+		mmu->funcs->destroy(mmu);
+	}
 	kfree(mdp5_kms);
 }
 
@@ -216,10 +226,6 @@ fail:
 	return ret;
 }
 
-static const char *iommu_ports[] = {
-		"mdp_0",
-};
-
 static int get_clk(struct platform_device *pdev, struct clk **clkp,
 		const char *name)
 {
@@ -317,17 +323,23 @@ struct msm_kms *mdp5_kms_init(struct drm_device *dev)
 		mmu = msm_iommu_new(dev, config->iommu);
 		if (IS_ERR(mmu)) {
 			ret = PTR_ERR(mmu);
+			dev_err(dev->dev, "failed to init iommu: %d\n", ret);
 			goto fail;
 		}
+
 		ret = mmu->funcs->attach(mmu, iommu_ports,
 				ARRAY_SIZE(iommu_ports));
-		if (ret)
+		if (ret) {
+			dev_err(dev->dev, "failed to attach iommu: %d\n", ret);
+			mmu->funcs->destroy(mmu);
 			goto fail;
+		}
 	} else {
 		dev_info(dev->dev, "no iommu, fallback to phys "
 				"contig buffers for scanout\n");
 		mmu = NULL;
 	}
+	mdp5_kms->mmu = mmu;
 
 	mdp5_kms->id = msm_register_mmu(dev, mmu);
 	if (mdp5_kms->id < 0) {

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.h

@@ -33,6 +33,7 @@ struct mdp5_kms {
 
 	/* mapper-id used to request GEM buffer mapped for scanout: */
 	int id;
+	struct msm_mmu *mmu;
 
 	/* for tracking smp allocation amongst pipes: */
 	mdp5_smp_state_t smp_state;