iommu/io-pgtable-dart: Add DART PTE support for t6000

The DARTs present in the M1 Pro/Max/Ultra SoC use a diffent PTE format.
They support a 42bit physical address space by shifting the paddr and
extending its mask inside the PTE.
They also come with mandatory sub-page protection now which we just
configure to always allow access to the entire page. This feature is
already present but optional on the previous DARTs which allows to
unconditionally configure it.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
Co-developed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20220916094152.87137-5-j@jannau.net
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/io-pgtable-dart.c

@@ -45,12 +45,19 @@
 #define APPLE_DART_PTE_SUBPAGE_END     GENMASK_ULL(51, 40)
 
 #define APPLE_DART1_PADDR_MASK	GENMASK_ULL(35, 12)
+#define APPLE_DART2_PADDR_MASK	GENMASK_ULL(37, 10)
+#define APPLE_DART2_PADDR_SHIFT	(4)
 
 /* Apple DART1 protection bits */
 #define APPLE_DART1_PTE_PROT_NO_READ	BIT(8)
 #define APPLE_DART1_PTE_PROT_NO_WRITE	BIT(7)
 #define APPLE_DART1_PTE_PROT_SP_DIS	BIT(1)
 
+/* Apple DART2 protection bits */
+#define APPLE_DART2_PTE_PROT_NO_READ	BIT(3)
+#define APPLE_DART2_PTE_PROT_NO_WRITE	BIT(2)
+#define APPLE_DART2_PTE_PROT_NO_CACHE	BIT(1)
+
 /* marks PTE as valid */
 #define APPLE_DART_PTE_VALID		BIT(0)
 
@@ -72,13 +79,31 @@ typedef u64 dart_iopte;
 static dart_iopte paddr_to_iopte(phys_addr_t paddr,
 				     struct dart_io_pgtable *data)
 {
-	return paddr & APPLE_DART1_PADDR_MASK;
+	dart_iopte pte;
+
+	if (data->iop.fmt == APPLE_DART)
+		return paddr & APPLE_DART1_PADDR_MASK;
+
+	/* format is APPLE_DART2 */
+	pte = paddr >> APPLE_DART2_PADDR_SHIFT;
+	pte &= APPLE_DART2_PADDR_MASK;
+
+	return pte;
 }
 
 static phys_addr_t iopte_to_paddr(dart_iopte pte,
 				  struct dart_io_pgtable *data)
 {
-	return pte & APPLE_DART1_PADDR_MASK;
+	u64 paddr;
+
+	if (data->iop.fmt == APPLE_DART)
+		return pte & APPLE_DART1_PADDR_MASK;
+
+	/* format is APPLE_DART2 */
+	paddr = pte & APPLE_DART2_PADDR_MASK;
+	paddr <<= APPLE_DART2_PADDR_SHIFT;
+
+	return paddr;
 }
 
 static void *__dart_alloc_pages(size_t size, gfp_t gfp,
@@ -190,10 +215,20 @@ static dart_iopte dart_prot_to_pte(struct dart_io_pgtable *data,
 {
 	dart_iopte pte = 0;
 
-	if (!(prot & IOMMU_WRITE))
-		pte |= APPLE_DART1_PTE_PROT_NO_WRITE;
-	if (!(prot & IOMMU_READ))
-		pte |= APPLE_DART1_PTE_PROT_NO_READ;
+	if (data->iop.fmt == APPLE_DART) {
+		if (!(prot & IOMMU_WRITE))
+			pte |= APPLE_DART1_PTE_PROT_NO_WRITE;
+		if (!(prot & IOMMU_READ))
+			pte |= APPLE_DART1_PTE_PROT_NO_READ;
+	}
+	if (data->iop.fmt == APPLE_DART2) {
+		if (!(prot & IOMMU_WRITE))
+			pte |= APPLE_DART2_PTE_PROT_NO_WRITE;
+		if (!(prot & IOMMU_READ))
+			pte |= APPLE_DART2_PTE_PROT_NO_READ;
+		if (!(prot & IOMMU_CACHE))
+			pte |= APPLE_DART2_PTE_PROT_NO_CACHE;
+	}
 
 	return pte;
 }
@@ -368,7 +403,7 @@ apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
 	if (!cfg->coherent_walk)
 		return NULL;
 
-	if (cfg->oas > DART1_MAX_ADDR_BITS)
+	if (cfg->oas != 36 && cfg->oas != 42)
 		return NULL;
 
 	if (cfg->ias > cfg->oas)

drivers/iommu/io-pgtable.c

@@ -23,6 +23,7 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
 #endif
 #ifdef CONFIG_IOMMU_IO_PGTABLE_DART
 	[APPLE_DART] = &io_pgtable_apple_dart_init_fns,
+	[APPLE_DART2] = &io_pgtable_apple_dart_init_fns,
 #endif
 #ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
 	[ARM_V7S] = &io_pgtable_arm_v7s_init_fns,

include/linux/io-pgtable.h

@@ -17,6 +17,7 @@ enum io_pgtable_fmt {
 	ARM_MALI_LPAE,
 	AMD_IOMMU_V1,
 	APPLE_DART,
+	APPLE_DART2,
 	IO_PGTABLE_NUM_FMTS,
 };