iommu/tegra: smmu: Fix race condition in writing PTC registers

[sojka/nv-tegra/linux-3.10.git] / drivers / iommu / tegra-smmu.c

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 93986d6eddb51329bf22e61b5b3c18560f98ca0d..0db793621eae09a72df75653f7ff1dedf09a5ce9 100644 (file)
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -297,6 +297,7 @@ struct smmu_device {
        unsigned long   iovmm_base;     /* remappable base address */
        unsigned long   page_count;     /* total remappable size */
        spinlock_t      lock;
+       spinlock_t      ptc_lock;
        char            *name;
        struct device   *dev;
        u64             swgids;         /* memory client ID bitmap */
@@ -548,12 +549,14 @@ static void __smmu_flush_ptc(struct smmu_device *smmu, u32 *pte,
                             struct page *page)
 {
        u32 val;
+       ulong flags;
 
        if (!pte) {
                smmu_write(smmu, SMMU_PTC_FLUSH_TYPE_ALL, SMMU_PTC_FLUSH);
                return;
        }
 
+       spin_lock_irqsave(&smmu->ptc_lock, flags);
        if ((IS_ENABLED(CONFIG_ARCH_TEGRA_12x_SOC) &&
                (tegra_get_chipid() == TEGRA_CHIPID_TEGRA12)) ||
                (IS_ENABLED(CONFIG_ARCH_TEGRA_13x_SOC) &&
@@ -566,6 +569,7 @@ static void __smmu_flush_ptc(struct smmu_device *smmu, u32 *pte,
                (VA_PAGE_TO_PA(pte, page) & SMMU_PTC_FLUSH_ADR_MASK);
 
        smmu_write(smmu, val, SMMU_PTC_FLUSH);
+       spin_unlock_irqrestore(&smmu->ptc_lock, flags);
 }
 
 static void smmu_flush_ptc(struct smmu_device *smmu, u32 *pte,
@@ -1955,6 +1959,7 @@ static int tegra_smmu_probe(struct platform_device *pdev)
                INIT_LIST_HEAD(&as->client);
        }
        spin_lock_init(&smmu->lock);
+       spin_lock_init(&smmu->ptc_lock);
        smmu_setup_regs(smmu);
        platform_set_drvdata(pdev, smmu);