diff options
Diffstat (limited to 'drivers/iommu/exynos-iommu.c')
| -rw-r--r-- | drivers/iommu/exynos-iommu.c | 51 |
1 files changed, 26 insertions, 25 deletions
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c index d037e87a1fe5..74233186f6f7 100644 --- a/drivers/iommu/exynos-iommu.c +++ b/drivers/iommu/exynos-iommu.c @@ -32,7 +32,7 @@ typedef u32 sysmmu_iova_t; typedef u32 sysmmu_pte_t; -/* We does not consider super section mapping (16MB) */ +/* We do not consider super section mapping (16MB) */ #define SECT_ORDER 20 #define LPAGE_ORDER 16 #define SPAGE_ORDER 12 @@ -307,7 +307,7 @@ static void show_fault_information(const char *name, static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id) { - /* SYSMMU is in blocked when interrupt occurred. */ + /* SYSMMU is in blocked state when interrupt occurred. */ struct sysmmu_drvdata *data = dev_id; enum exynos_sysmmu_inttype itype; sysmmu_iova_t addr = -1; @@ -567,8 +567,8 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, sysmmu_iova_t iova, /* * L2TLB invalidation required * 4KB page: 1 invalidation - * 64KB page: 16 invalidation - * 1MB page: 64 invalidation + * 64KB page: 16 invalidations + * 1MB page: 64 invalidations * because it is set-associative TLB * with 8-way and 64 sets. * 1MB page can be cached in one of all sets. @@ -714,7 +714,7 @@ static int exynos_iommu_domain_init(struct iommu_domain *domain) if (!priv->lv2entcnt) goto err_counter; - /* w/a of System MMU v3.3 to prevent caching 1MiB mapping */ + /* Workaround for System MMU v3.3 to prevent caching 1MiB mapping */ for (i = 0; i < NUM_LV1ENTRIES; i += 8) { priv->pgtable[i + 0] = ZERO_LV2LINK; priv->pgtable[i + 1] = ZERO_LV2LINK; @@ -861,14 +861,14 @@ static sysmmu_pte_t *alloc_lv2entry(struct exynos_iommu_domain *priv, pgtable_flush(sent, sent + 1); /* - * If pretched SLPD is a fault SLPD in zero_l2_table, FLPD cache - * may caches the address of zero_l2_table. This function - * replaces the zero_l2_table with new L2 page table to write - * valid mappings. + * If pre-fetched SLPD is a faulty SLPD in zero_l2_table, + * FLPD cache may cache the address of zero_l2_table. This + * function replaces the zero_l2_table with new L2 page table + * to write valid mappings. * Accessing the valid area may cause page fault since FLPD - * cache may still caches zero_l2_table for the valid area - * instead of new L2 page table that have the mapping - * information of the valid area + * cache may still cache zero_l2_table for the valid area + * instead of new L2 page table that has the mapping + * information of the valid area. * Thus any replacement of zero_l2_table with other valid L2 * page table must involve FLPD cache invalidation for System * MMU v3.3. @@ -963,27 +963,27 @@ static int lv2set_page(sysmmu_pte_t *pent, phys_addr_t paddr, size_t size, /* * *CAUTION* to the I/O virtual memory managers that support exynos-iommu: * - * System MMU v3.x have an advanced logic to improve address translation + * System MMU v3.x has advanced logic to improve address translation * performance with caching more page table entries by a page table walk. - * However, the logic has a bug that caching fault page table entries and System - * MMU reports page fault if the cached fault entry is hit even though the fault - * entry is updated to a valid entry after the entry is cached. - * To prevent caching fault page table entries which may be updated to valid - * entries later, the virtual memory manager should care about the w/a about the - * problem. The followings describe w/a. + * However, the logic has a bug that while caching faulty page table entries, + * System MMU reports page fault if the cached fault entry is hit even though + * the fault entry is updated to a valid entry after the entry is cached. + * To prevent caching faulty page table entries which may be updated to valid + * entries later, the virtual memory manager should care about the workaround + * for the problem. The following describes the workaround. * * Any two consecutive I/O virtual address regions must have a hole of 128KiB - * in maximum to prevent misbehavior of System MMU 3.x. (w/a of h/w bug) + * at maximum to prevent misbehavior of System MMU 3.x (workaround for h/w bug). * - * Precisely, any start address of I/O virtual region must be aligned by + * Precisely, any start address of I/O virtual region must be aligned with * the following sizes for System MMU v3.1 and v3.2. * System MMU v3.1: 128KiB * System MMU v3.2: 256KiB * * Because System MMU v3.3 caches page table entries more aggressively, it needs - * more w/a. - * - Any two consecutive I/O virtual regions must be have a hole of larger size - * than or equal size to 128KiB. + * more workarounds. + * - Any two consecutive I/O virtual regions must have a hole of size larger + * than or equal to 128KiB. * - Start address of an I/O virtual region must be aligned by 128KiB. */ static int exynos_iommu_map(struct iommu_domain *domain, unsigned long l_iova, @@ -1061,7 +1061,8 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain, goto err; } - *ent = ZERO_LV2LINK; /* w/a for h/w bug in Sysmem MMU v3.3 */ + /* workaround for h/w bug in System MMU v3.3 */ + *ent = ZERO_LV2LINK; pgtable_flush(ent, ent + 1); size = SECT_SIZE; goto done; |