diff options
| -rw-r--r-- | drivers/iommu/tegra-smmu.c | 95 |
1 files changed, 84 insertions, 11 deletions
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c index 2574e716086b..046add7acb61 100644 --- a/drivers/iommu/tegra-smmu.c +++ b/drivers/iommu/tegra-smmu.c @@ -12,6 +12,7 @@ #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/slab.h> +#include <linux/spinlock.h> #include <linux/dma-mapping.h> #include <soc/tegra/ahb.h> @@ -50,6 +51,7 @@ struct tegra_smmu_as { struct iommu_domain domain; struct tegra_smmu *smmu; unsigned int use_count; + spinlock_t lock; u32 *count; struct page **pts; struct page *pd; @@ -309,6 +311,8 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type) return NULL; } + spin_lock_init(&as->lock); + /* setup aperture */ as->domain.geometry.aperture_start = 0; as->domain.geometry.aperture_end = 0xffffffff; @@ -570,19 +574,14 @@ static u32 *tegra_smmu_pte_lookup(struct tegra_smmu_as *as, unsigned long iova, } static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova, - dma_addr_t *dmap) + dma_addr_t *dmap, struct page *page) { unsigned int pde = iova_pd_index(iova); struct tegra_smmu *smmu = as->smmu; if (!as->pts[pde]) { - struct page *page; dma_addr_t dma; - page = alloc_page(GFP_KERNEL | __GFP_DMA | __GFP_ZERO); - if (!page) - return NULL; - dma = dma_map_page(smmu->dev, page, 0, SMMU_SIZE_PT, DMA_TO_DEVICE); if (dma_mapping_error(smmu->dev, dma)) { @@ -656,15 +655,61 @@ static void tegra_smmu_set_pte(struct tegra_smmu_as *as, unsigned long iova, smmu_flush(smmu); } -static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova, - phys_addr_t paddr, size_t size, int prot, gfp_t gfp) +static struct page *as_get_pde_page(struct tegra_smmu_as *as, + unsigned long iova, gfp_t gfp, + unsigned long *flags) +{ + unsigned int pde = iova_pd_index(iova); + struct page *page = as->pts[pde]; + + /* at first check whether allocation needs to be done at all */ + if (page) + return page; + + /* + * In order to prevent exhaustion of the atomic memory pool, we + * allocate page in a sleeping context if GFP flags permit. Hence + * spinlock needs to be unlocked and re-locked after allocation. + */ + if (!(gfp & __GFP_ATOMIC)) + spin_unlock_irqrestore(&as->lock, *flags); + + page = alloc_page(gfp | __GFP_DMA | __GFP_ZERO); + + if (!(gfp & __GFP_ATOMIC)) + spin_lock_irqsave(&as->lock, *flags); + + /* + * In a case of blocking allocation, a concurrent mapping may win + * the PDE allocation. In this case the allocated page isn't needed + * if allocation succeeded and the allocation failure isn't fatal. + */ + if (as->pts[pde]) { + if (page) + __free_page(page); + + page = as->pts[pde]; + } + + return page; +} + +static int +__tegra_smmu_map(struct iommu_domain *domain, unsigned long iova, + phys_addr_t paddr, size_t size, int prot, gfp_t gfp, + unsigned long *flags) { struct tegra_smmu_as *as = to_smmu_as(domain); dma_addr_t pte_dma; + struct page *page; u32 pte_attrs; u32 *pte; - pte = as_get_pte(as, iova, &pte_dma); + page = as_get_pde_page(as, iova, gfp, flags); + if (!page) + return -ENOMEM; + + pte = as_get_pte(as, iova, &pte_dma, page); if (!pte) return -ENOMEM; @@ -686,8 +731,9 @@ static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova, return 0; } -static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, - size_t size, struct iommu_iotlb_gather *gather) +static size_t +__tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, + size_t size, struct iommu_iotlb_gather *gather) { struct tegra_smmu_as *as = to_smmu_as(domain); dma_addr_t pte_dma; @@ -703,6 +749,33 @@ static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, return size; } +static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova, + phys_addr_t paddr, size_t size, int prot, gfp_t gfp) +{ + struct tegra_smmu_as *as = to_smmu_as(domain); + unsigned long flags; + int ret; + + spin_lock_irqsave(&as->lock, flags); + ret = __tegra_smmu_map(domain, iova, paddr, size, prot, gfp, &flags); + spin_unlock_irqrestore(&as->lock, flags); + + return ret; +} + +static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, + size_t size, struct iommu_iotlb_gather *gather) +{ + struct tegra_smmu_as *as = to_smmu_as(domain); + unsigned long flags; + + spin_lock_irqsave(&as->lock, flags); + size = __tegra_smmu_unmap(domain, iova, size, gather); + spin_unlock_irqrestore(&as->lock, flags); + + return size; +} + static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) { |