[PATCH v2 1/3] iommu: io-pgtable: add DART pagetable format

[Sven Peter via iommu]

Apple's DART iommu uses a pagetable format that shares some
similarities with the ones already implemented by io-pgtable.c.
Add a new format variant to support the required differences
so that we don't have to duplicate the pagetable handling code.

Signed-off-by: Sven Peter <s...@svenpeter.dev>
---
 drivers/iommu/io-pgtable-arm.c | 59 ++++++++++++++++++++++++++++++++++
 drivers/iommu/io-pgtable.c     |  1 +
 include/linux/io-pgtable.h     |  6 ++++
 3 files changed, 66 insertions(+)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 87def58e79b5..2f63443fd115 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -127,6 +127,9 @@
 #define ARM_MALI_LPAE_MEMATTR_IMP_DEF  0x88ULL
 #define ARM_MALI_LPAE_MEMATTR_WRITE_ALLOC 0x8DULL
 
+#define APPLE_DART_PTE_PROT_NO_WRITE (1<<7)
+#define APPLE_DART_PTE_PROT_NO_READ (1<<8)
+
 /* IOPTE accessors */
 #define iopte_deref(pte,d) __va(iopte_to_paddr(pte, d))
 
@@ -381,6 +384,15 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct 
arm_lpae_io_pgtable *data,
 {
        arm_lpae_iopte pte;
 
+       if (data->iop.fmt == ARM_APPLE_DART) {
+               pte = 0;
+               if (!(prot & IOMMU_WRITE))
+                       pte |= APPLE_DART_PTE_PROT_NO_WRITE;
+               if (!(prot & IOMMU_READ))
+                       pte |= APPLE_DART_PTE_PROT_NO_READ;
+               return pte;
+       }
+
        if (data->iop.fmt == ARM_64_LPAE_S1 ||
            data->iop.fmt == ARM_32_LPAE_S1) {
                pte = ARM_LPAE_PTE_nG;
@@ -1043,6 +1055,48 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, 
void *cookie)
        return NULL;
 }
 
+static struct io_pgtable *
+apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
+{
+       struct arm_lpae_io_pgtable *data;
+
+       if (cfg->ias > 36)
+               return NULL;
+       if (cfg->oas > 36)
+               return NULL;
+
+       if (!cfg->coherent_walk)
+               return NULL;
+
+       cfg->pgsize_bitmap &= SZ_16K;
+       if (!cfg->pgsize_bitmap)
+               return NULL;
+
+       if (cfg->quirks)
+               return NULL;
+
+       data = arm_lpae_alloc_pgtable(cfg);
+       if (!data)
+               return NULL;
+
+       data->start_level = 2;
+       data->pgd_bits = 11;
+       data->bits_per_level = 11;
+
+       data->pgd = __arm_lpae_alloc_pages(ARM_LPAE_PGD_SIZE(data), GFP_KERNEL,
+                                          cfg);
+       if (!data->pgd)
+               goto out_free_data;
+
+       cfg->apple_dart_cfg.ttbr = virt_to_phys(data->pgd);
+
+       return &data->iop;
+
+out_free_data:
+       kfree(data);
+       return NULL;
+}
+
 struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = {
        .alloc  = arm_64_lpae_alloc_pgtable_s1,
        .free   = arm_lpae_free_pgtable,
@@ -1068,6 +1122,11 @@ struct io_pgtable_init_fns 
io_pgtable_arm_mali_lpae_init_fns = {
        .free   = arm_lpae_free_pgtable,
 };
 
+struct io_pgtable_init_fns io_pgtable_apple_dart_init_fns = {
+       .alloc  = apple_dart_alloc_pgtable,
+       .free   = arm_lpae_free_pgtable,
+};
+
 #ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST
 
 static struct io_pgtable_cfg *cfg_cookie __initdata;
diff --git a/drivers/iommu/io-pgtable.c b/drivers/iommu/io-pgtable.c
index 6e9917ce980f..6ec75f3e9c3b 100644
--- a/drivers/iommu/io-pgtable.c
+++ b/drivers/iommu/io-pgtable.c
@@ -27,6 +27,7 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
 #ifdef CONFIG_AMD_IOMMU
        [AMD_IOMMU_V1] = &io_pgtable_amd_iommu_v1_init_fns,
 #endif
+       [ARM_APPLE_DART] = &io_pgtable_apple_dart_init_fns,
 };
 
 struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index a4c9ca2c31f1..b06925eb20d3 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -16,6 +16,7 @@ enum io_pgtable_fmt {
        ARM_V7S,
        ARM_MALI_LPAE,
        AMD_IOMMU_V1,
+       ARM_APPLE_DART,
        IO_PGTABLE_NUM_FMTS,
 };
 
@@ -136,6 +137,10 @@ struct io_pgtable_cfg {
                        u64     transtab;
                        u64     memattr;
                } arm_mali_lpae_cfg;
+
+               struct {
+                       u64 ttbr;
+               } apple_dart_cfg;
        };
 };
 
@@ -250,5 +255,6 @@ extern struct io_pgtable_init_fns 
io_pgtable_arm_64_lpae_s2_init_fns;
 extern struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns;
 extern struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns;
 extern struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_apple_dart_init_fns;
 
 #endif /* __IO_PGTABLE_H */
-- 
2.25.1

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