[PATCH 1/2] iommu/io-pgtable-arm-v7s: Add a quirk to support TTBR up to 35bit for MediaTek

[yf.wang]

From: Yunfei Wang <yf.wang@xxxxxxxxxxxx>

The calling to kmem_cache_alloc for level 2 page table allocation may
run in atomic context, and it fails sometimes when DMA32 zone runs out
of memory.

Since Mediatek IOMMU hardware support at most 35bit PA in page table,
so add a quirk to allow the PA of level 2 pgtable support bit35.

Signed-off-by: Ning Li <ning.li@xxxxxxxxxxxx>
Signed-off-by: Yunfei Wang <yf.wang@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.*
---
 drivers/iommu/io-pgtable-arm-v7s.c | 38 +++++++++++++++++++++---------
 include/linux/io-pgtable.h         | 15 ++++++++----
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index be066c1503d3..785e10f88690 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -182,14 +182,9 @@ static bool arm_v7s_is_mtk_enabled(struct io_pgtable_cfg *cfg)
 		(cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_EXT);
 }
 
-static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl,
-				    struct io_pgtable_cfg *cfg)
+static arm_v7s_iopte to_iopte_mtk(phys_addr_t paddr, arm_v7s_iopte pte,
+				  struct io_pgtable_cfg *cfg)
 {
-	arm_v7s_iopte pte = paddr & ARM_V7S_LVL_MASK(lvl);
-
-	if (!arm_v7s_is_mtk_enabled(cfg))
-		return pte;
-
 	if (paddr & BIT_ULL(32))
 		pte |= ARM_V7S_ATTR_MTK_PA_BIT32;
 	if (paddr & BIT_ULL(33))
@@ -199,6 +194,17 @@ static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl,
 	return pte;
 }
 
+static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl,
+				    struct io_pgtable_cfg *cfg)
+{
+	arm_v7s_iopte pte = paddr & ARM_V7S_LVL_MASK(lvl);
+
+	if (!arm_v7s_is_mtk_enabled(cfg))
+		return pte;
+
+	return to_iopte_mtk(paddr, pte, cfg);
+}
+
 static phys_addr_t iopte_to_paddr(arm_v7s_iopte pte, int lvl,
 				  struct io_pgtable_cfg *cfg)
 {
@@ -251,7 +257,8 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp,
 		return NULL;
 
 	phys = virt_to_phys(table);
-	if (phys != (arm_v7s_iopte)phys) {
+	if (phys != (arm_v7s_iopte)phys &&
+	    !(cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT)) {
 		/* Doesn't fit in PTE */
 		dev_err(dev, "Page table does not fit in PTE: %pa", &phys);
 		goto out_free;
@@ -457,9 +464,14 @@ static arm_v7s_iopte arm_v7s_install_table(arm_v7s_iopte *table,
 					   arm_v7s_iopte curr,
 					   struct io_pgtable_cfg *cfg)
 {
+	phys_addr_t phys = virt_to_phys(table);
 	arm_v7s_iopte old, new;
 
-	new = virt_to_phys(table) | ARM_V7S_PTE_TYPE_TABLE;
+	new = phys | ARM_V7S_PTE_TYPE_TABLE;
+
+	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT)
+		new = to_iopte_mtk(phys, new, cfg);
+
 	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS)
 		new |= ARM_V7S_ATTR_NS_TABLE;
 
@@ -778,6 +790,7 @@ static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
 static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 						void *cookie)
 {
+	slab_flags_t slab_flag = ARM_V7S_TABLE_SLAB_FLAGS;
 	struct arm_v7s_io_pgtable *data;
 
 	if (cfg->ias > (arm_v7s_is_mtk_enabled(cfg) ? 34 : ARM_V7S_ADDR_BITS))
@@ -788,7 +801,8 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 
 	if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |
 			    IO_PGTABLE_QUIRK_NO_PERMS |
-			    IO_PGTABLE_QUIRK_ARM_MTK_EXT))
+			    IO_PGTABLE_QUIRK_ARM_MTK_EXT |
+			    IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT))
 		return NULL;
 
 	/* If ARM_MTK_4GB is enabled, the NO_PERMS is also expected. */
@@ -801,10 +815,12 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 		return NULL;
 
 	spin_lock_init(&data->split_lock);
+	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT)
+		slab_flag = 0;
 	data->l2_tables = kmem_cache_create("io-pgtable_armv7s_l2",
 					    ARM_V7S_TABLE_SIZE(2, cfg),
 					    ARM_V7S_TABLE_SIZE(2, cfg),
-					    ARM_V7S_TABLE_SLAB_FLAGS, NULL);
+					    slab_flag, NULL);
 	if (!data->l2_tables)
 		goto out_free_data;
 
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index 86af6f0a00a2..7ed15ad4710c 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -74,17 +74,22 @@ struct io_pgtable_cfg {
 	 *	to support up to 35 bits PA where the bit32, bit33 and bit34 are
 	 *	encoded in the bit9, bit4 and bit5 of the PTE respectively.
 	 *
+	 * IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT: (ARM v7s format) MediaTek IOMMUs
+	 *	extend the translation table support up to 35 bits PA, the
+	 *	encoding format is same with IO_PGTABLE_QUIRK_ARM_MTK_EXT.
+	 *
 	 * IO_PGTABLE_QUIRK_ARM_TTBR1: (ARM LPAE format) Configure the table
 	 *	for use in the upper half of a split address space.
 	 *
 	 * IO_PGTABLE_QUIRK_ARM_OUTER_WBWA: Override the outer-cacheability
 	 *	attributes set in the TCR for a non-coherent page-table walker.
 	 */
-	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)
-	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)
-	#define IO_PGTABLE_QUIRK_ARM_MTK_EXT	BIT(3)
-	#define IO_PGTABLE_QUIRK_ARM_TTBR1	BIT(5)
-	#define IO_PGTABLE_QUIRK_ARM_OUTER_WBWA	BIT(6)
+	#define IO_PGTABLE_QUIRK_ARM_NS			BIT(0)
+	#define IO_PGTABLE_QUIRK_NO_PERMS		BIT(1)
+	#define IO_PGTABLE_QUIRK_ARM_MTK_EXT		BIT(3)
+	#define IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT	BIT(4)
+	#define IO_PGTABLE_QUIRK_ARM_TTBR1		BIT(5)
+	#define IO_PGTABLE_QUIRK_ARM_OUTER_WBWA		BIT(6)
 	unsigned long			quirks;
 	unsigned long			pgsize_bitmap;
 	unsigned int			ias;
-- 
2.18.0