From 0db2c5fa4f09bc4b212e953448035483344cc4c2 Mon Sep 17 00:00:00 2001 From: Shivaraj Shetty Date: Sat, 18 Apr 2015 00:11:22 +0530 Subject: [PATCH] msm: mdss: protect iommu refcount with mutex for mdp3 On mdp3 targets iommu refcount is not properly protected by mutex lock. This is causing iommu to be detached while hardware is fetching the data from the iommu mapped address leading to SNOC errors. Add mutex lock while using the iommu refcounts to fix the issue. Change-Id: Ife59791b08b123f6b60d3ffa6d8061839244934c Signed-off-by: Shivaraj Shetty --- drivers/video/fbdev/msm/mdp3.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/video/fbdev/msm/mdp3.c b/drivers/video/fbdev/msm/mdp3.c index 1e3ab52a849b..8bd80cd3d14d 100644 --- a/drivers/video/fbdev/msm/mdp3.c +++ b/drivers/video/fbdev/msm/mdp3.c @@ -726,11 +726,9 @@ int mdp3_iommu_attach(int context) if (context >= MDP3_IOMMU_CTX_MAX) return -EINVAL; - mutex_lock(&mdp3_res->iommu_lock); context_map = mdp3_res->iommu_contexts + context; if (context_map->attached) { pr_warn("mdp iommu already attached\n"); - mutex_unlock(&mdp3_res->iommu_lock); return 0; } @@ -743,7 +741,6 @@ int mdp3_iommu_attach(int context) } context_map->attached = true; - mutex_unlock(&mdp3_res->iommu_lock); return 0; } @@ -756,11 +753,9 @@ int mdp3_iommu_dettach(int context) context >= MDP3_IOMMU_CTX_MAX) return -EINVAL; - mutex_lock(&mdp3_res->iommu_lock); context_map = mdp3_res->iommu_contexts + context; if (!context_map->attached) { pr_warn("mdp iommu not attached\n"); - mutex_unlock(&mdp3_res->iommu_lock); return 0; } @@ -768,7 +763,6 @@ int mdp3_iommu_dettach(int context) iommu_detach_device(domain_map->domain, context_map->ctx); context_map->attached = false; - mutex_unlock(&mdp3_res->iommu_lock); return 0; } @@ -966,7 +960,11 @@ static void mdp3_res_deinit(void) mdp3_hw = &mdp3_res->mdp3_hw; mdp3_bus_scale_unregister(); + + mutex_lock(&mdp3_res->iommu_lock); mdp3_iommu_dettach(MDP3_IOMMU_CTX_MDP_0); + mutex_unlock(&mdp3_res->iommu_lock); + mdp3_iommu_deinit(); if (!IS_ERR_OR_NULL(mdp3_res->ion_client)) @@ -1366,6 +1364,7 @@ int mdp3_iommu_enable() { int i, rc = 0; + mutex_lock(&mdp3_res->iommu_lock); if (mdp3_res->iommu_ref_cnt == 0) { for (i = 0; i < MDP3_IOMMU_CTX_MAX; i++) { rc = mdp3_iommu_attach(i); @@ -1379,6 +1378,7 @@ int mdp3_iommu_enable() if (!rc) mdp3_res->iommu_ref_cnt++; + mutex_unlock(&mdp3_res->iommu_lock); return rc; } @@ -1387,6 +1387,7 @@ int mdp3_iommu_disable() { int i, rc = 0; + mutex_lock(&mdp3_res->iommu_lock); if (mdp3_res->iommu_ref_cnt) { mdp3_res->iommu_ref_cnt--; if (mdp3_res->iommu_ref_cnt == 0) { @@ -1396,6 +1397,7 @@ int mdp3_iommu_disable() } else { pr_err("iommu ref count unbalanced\n"); } + mutex_unlock(&mdp3_res->iommu_lock); return rc; }