iommu/io-pgtable: Add DART pagetable format

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.

Reviewed-by: Alexander Graf <graf@amazon.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Link: https://lore.kernel.org/r/20210803121651.61594-2-sven@svenpeter.dev
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 053df4048a2977099f22fb8a5dbfe557fc46fffb..0779eb96bd2938ce07b695209d65e2902d1080e8 100644 (file)
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -130,6 +130,9 @@
 #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))
 
@@ -402,6 +405,15 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 {
        arm_lpae_iopte pte;
 
+       if (data->iop.fmt == 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;
@@ -1102,6 +1114,52 @@ out_free_data:
        return NULL;
 }
 
+static struct io_pgtable *
+apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
+{
+       struct arm_lpae_io_pgtable *data;
+       int i;
+
+       if (cfg->oas > 36)
+               return NULL;
+
+       data = arm_lpae_alloc_pgtable(cfg);
+       if (!data)
+               return NULL;
+
+       /*
+        * The table format itself always uses two levels, but the total VA
+        * space is mapped by four separate tables, making the MMIO registers
+        * an effective "level 1". For simplicity, though, we treat this
+        * equivalently to LPAE stage 2 concatenation at level 2, with the
+        * additional TTBRs each just pointing at consecutive pages.
+        */
+       if (data->start_level < 1)
+               goto out_free_data;
+       if (data->start_level == 1 && data->pgd_bits > 2)
+               goto out_free_data;
+       if (data->start_level > 1)
+               data->pgd_bits = 0;
+       data->start_level = 2;
+       cfg->apple_dart_cfg.n_ttbrs = 1 << data->pgd_bits;
+       data->pgd_bits += data->bits_per_level;
+
+       data->pgd = __arm_lpae_alloc_pages(ARM_LPAE_PGD_SIZE(data), GFP_KERNEL,
+                                          cfg);
+       if (!data->pgd)
+               goto out_free_data;
+
+       for (i = 0; i < cfg->apple_dart_cfg.n_ttbrs; ++i)
+               cfg->apple_dart_cfg.ttbr[i] =
+                       virt_to_phys(data->pgd + i * ARM_LPAE_GRANULE(data));
+
+       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,
@@ -1127,6 +1185,11 @@ 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 6e9917ce980ffc7bb4465ed4bfac1d6d35d607a0..f4bfcef98297f4158f32ace205bbd50430d63421 100644 (file)
--- a/drivers/iommu/io-pgtable.c
+++ b/drivers/iommu/io-pgtable.c
@@ -20,6 +20,7 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
        [ARM_64_LPAE_S1] = &io_pgtable_arm_64_lpae_s1_init_fns,
        [ARM_64_LPAE_S2] = &io_pgtable_arm_64_lpae_s2_init_fns,
        [ARM_MALI_LPAE] = &io_pgtable_arm_mali_lpae_init_fns,
+       [APPLE_DART] = &io_pgtable_apple_dart_init_fns,
 #endif
 #ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
        [ARM_V7S] = &io_pgtable_arm_v7s_init_fns,

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index c43f3b899d2a49895c026cfbe42a6288aa2bb579..a738483fb4da3f3086aa5149aa1a00b7ce77b6ce 100644 (file)
--- 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,
+       APPLE_DART,
        IO_PGTABLE_NUM_FMTS,
 };
 
@@ -136,6 +137,11 @@ struct io_pgtable_cfg {
                        u64     transtab;
                        u64     memattr;
                } arm_mali_lpae_cfg;
+
+               struct {
+                       u64 ttbr[4];
+                       u32 n_ttbrs;
+               } apple_dart_cfg;
        };
 };
 
@@ -254,5 +260,6 @@ 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 */