Currently, Panfrost only supports MMU configuration in "LEGACY" (as
Bifrost calls it) mode, a (modified) version of LPAE "Large Physical
Address Extension", which in Linux we've called "mali_lpae".

This commit adds support for conditionally enabling AARCH64_4K page
table format. To achieve that, a "GPU optional quirks" field was added
to `struct panfrost_features` with the related flag.

Note that, in order to enable AARCH64_4K mode, the GPU variant must have
the HW_FEATURE_AARCH64_MMU feature flag present.

Signed-off-by: Ariel D'Alessandro <ariel.dalessan...@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_device.h |  16 +++
 drivers/gpu/drm/panfrost/panfrost_mmu.c    | 136 +++++++++++++++++++--
 drivers/gpu/drm/panfrost/panfrost_regs.h   |  34 ++++++
 3 files changed, 177 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h 
b/drivers/gpu/drm/panfrost/panfrost_device.h
index cffcb0ac7c111..ad95f2ed31d9a 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -42,6 +42,14 @@ enum panfrost_gpu_pm {
        GPU_PM_VREG_OFF,
 };
 
+/**
+ * enum panfrost_gpu_quirks - GPU optional quirks
+ * @GPU_QUIRK_FORCE_AARCH64_PGTABLE: Use AARCH64_4K page table format
+ */
+enum panfrost_gpu_quirks {
+       GPU_QUIRK_FORCE_AARCH64_PGTABLE,
+};
+
 struct panfrost_features {
        u16 id;
        u16 revision;
@@ -95,6 +103,9 @@ struct panfrost_compatible {
 
        /* Allowed PM features */
        u8 pm_features;
+
+       /* GPU configuration quirks */
+       u8 gpu_quirks;
 };
 
 struct panfrost_device {
@@ -162,6 +173,11 @@ struct panfrost_mmu {
        int as;
        atomic_t as_count;
        struct list_head list;
+       struct {
+               u64 transtab;
+               u64 memattr;
+               u64 transcfg;
+       } cfg;
 };
 
 struct panfrost_engine_usage {
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 294f86b3c25e7..f24c23e1f67b8 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -26,6 +26,48 @@
 #define mmu_write(dev, reg, data) writel(data, dev->iomem + reg)
 #define mmu_read(dev, reg) readl(dev->iomem + reg)
 
+static u64 mair_to_memattr(u64 mair, bool coherent)
+{
+       u64 memattr = 0;
+       u32 i;
+
+       for (i = 0; i < 8; i++) {
+               u8 in_attr = mair >> (8 * i), out_attr;
+               u8 outer = in_attr >> 4, inner = in_attr & 0xf;
+
+               /* For caching to be enabled, inner and outer caching policy
+                * have to be both write-back, if one of them is write-through
+                * or non-cacheable, we just choose non-cacheable. Device
+                * memory is also translated to non-cacheable.
+                */
+               if (!(outer & 3) || !(outer & 4) || !(inner & 4)) {
+                       out_attr = AS_MEMATTR_AARCH64_INNER_OUTER_NC |
+                                  AS_MEMATTR_AARCH64_SH_MIDGARD_INNER |
+                                  AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(false, 
false);
+               } else {
+                       out_attr = AS_MEMATTR_AARCH64_INNER_OUTER_WB |
+                                  AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(inner & 
1, inner & 2);
+                       /* Use SH_MIDGARD_INNER mode when device isn't coherent,
+                        * so SH_IS, which is used when IOMMU_CACHE is set, maps
+                        * to Mali's internal-shareable mode. As per the Mali
+                        * Spec, inner and outer-shareable modes aren't allowed
+                        * for WB memory when coherency is disabled.
+                        * Use SH_CPU_INNER mode when coherency is enabled, so
+                        * that SH_IS actually maps to the standard definition 
of
+                        * inner-shareable.
+                        */
+                       if (!coherent)
+                               out_attr |= AS_MEMATTR_AARCH64_SH_MIDGARD_INNER;
+                       else
+                               out_attr |= AS_MEMATTR_AARCH64_SH_CPU_INNER;
+               }
+
+               memattr |= (u64)out_attr << (8 * i);
+       }
+
+       return memattr;
+}
+
 static int wait_ready(struct panfrost_device *pfdev, u32 as_nr)
 {
        int ret;
@@ -124,9 +166,9 @@ static int mmu_hw_do_operation(struct panfrost_device 
*pfdev,
 static void panfrost_mmu_enable(struct panfrost_device *pfdev, struct 
panfrost_mmu *mmu)
 {
        int as_nr = mmu->as;
-       struct io_pgtable_cfg *cfg = &mmu->pgtbl_cfg;
-       u64 transtab = cfg->arm_mali_lpae_cfg.transtab;
-       u64 memattr = cfg->arm_mali_lpae_cfg.memattr;
+       u64 transtab = mmu->cfg.transtab;
+       u64 memattr = mmu->cfg.memattr;
+       u64 transcfg = mmu->cfg.transcfg;
 
        mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0ULL, 
AS_COMMAND_FLUSH_MEM);
 
@@ -139,6 +181,9 @@ static void panfrost_mmu_enable(struct panfrost_device 
*pfdev, struct panfrost_m
        mmu_write(pfdev, AS_MEMATTR_LO(as_nr), lower_32_bits(memattr));
        mmu_write(pfdev, AS_MEMATTR_HI(as_nr), upper_32_bits(memattr));
 
+       mmu_write(pfdev, AS_TRANSCFG_LO(as_nr), lower_32_bits(transcfg));
+       mmu_write(pfdev, AS_TRANSCFG_HI(as_nr), upper_32_bits(transcfg));
+
        write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
 }
 
@@ -152,9 +197,66 @@ static void panfrost_mmu_disable(struct panfrost_device 
*pfdev, u32 as_nr)
        mmu_write(pfdev, AS_MEMATTR_LO(as_nr), 0);
        mmu_write(pfdev, AS_MEMATTR_HI(as_nr), 0);
 
+       mmu_write(pfdev, AS_TRANSCFG_LO(as_nr), AS_TRANSCFG_ADRMODE_UNMAPPED);
+       mmu_write(pfdev, AS_TRANSCFG_HI(as_nr), 0);
+
        write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
 }
 
+static int mmu_cfg_init_mali_lpae(struct panfrost_mmu *mmu)
+{
+       struct io_pgtable_cfg *pgtbl_cfg = &mmu->pgtbl_cfg;
+
+       /* TODO: The following fields are duplicated between the MMU and Page
+        * Table config structs. Ideally, should be kept in one place.
+        */
+       mmu->cfg.transtab = pgtbl_cfg->arm_mali_lpae_cfg.transtab;
+       mmu->cfg.memattr = pgtbl_cfg->arm_mali_lpae_cfg.memattr;
+       mmu->cfg.transcfg = AS_TRANSCFG_ADRMODE_LEGACY;
+
+       return 0;
+}
+
+static int mmu_cfg_init_aarch64_4k(struct panfrost_mmu *mmu)
+{
+       struct io_pgtable_cfg *pgtbl_cfg = &mmu->pgtbl_cfg;
+       struct panfrost_device *pfdev = mmu->pfdev;
+
+       if (drm_WARN_ON(pfdev->ddev, pgtbl_cfg->arm_lpae_s1_cfg.ttbr &
+                                    ~AS_TRANSTAB_AARCH64_4K_ADDR_MASK))
+               return -EINVAL;
+
+       mmu->cfg.transtab = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
+
+       mmu->cfg.memattr = mair_to_memattr(pgtbl_cfg->arm_lpae_s1_cfg.mair,
+                                          pgtbl_cfg->coherent_walk);
+
+       mmu->cfg.transcfg = AS_TRANSCFG_PTW_MEMATTR_WB |
+                           AS_TRANSCFG_PTW_RA |
+                           AS_TRANSCFG_ADRMODE_AARCH64_4K |
+                           AS_TRANSCFG_INA_BITS(55 - pgtbl_cfg->ias);
+       if (pgtbl_cfg->coherent_walk)
+               mmu->cfg.transcfg |= AS_TRANSCFG_PTW_SH_OS;
+
+       return 0;
+}
+
+static int panfrost_mmu_cfg_init(struct panfrost_mmu *mmu,
+                                 enum io_pgtable_fmt fmt)
+{
+       struct panfrost_device *pfdev = mmu->pfdev;
+
+       switch (fmt) {
+       case ARM_64_LPAE_S1:
+               return mmu_cfg_init_aarch64_4k(mmu);
+       case ARM_MALI_LPAE:
+               return mmu_cfg_init_mali_lpae(mmu);
+       default:
+               /* This should never happen */
+               return drm_WARN_ON(pfdev->ddev, -EINVAL);
+       }
+}
+
 u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu 
*mmu)
 {
        int as;
@@ -618,6 +720,18 @@ struct panfrost_mmu *panfrost_mmu_ctx_create(struct 
panfrost_device *pfdev)
        u32 va_bits = GPU_MMU_FEATURES_VA_BITS(pfdev->features.mmu_features);
        u32 pa_bits = GPU_MMU_FEATURES_PA_BITS(pfdev->features.mmu_features);
        struct panfrost_mmu *mmu;
+       enum io_pgtable_fmt fmt;
+
+       if (pfdev->comp->gpu_quirks & BIT(GPU_QUIRK_FORCE_AARCH64_PGTABLE)) {
+               if (!panfrost_has_hw_feature(pfdev, HW_FEATURE_AARCH64_MMU)) {
+                       dev_err_once(pfdev->dev,
+                                    "AARCH64_4K page table not supported\n");
+                       return ERR_PTR(-EINVAL);
+               }
+               fmt = ARM_64_LPAE_S1;
+       } else {
+               fmt = ARM_MALI_LPAE;
+       }
 
        mmu = kzalloc(sizeof(*mmu), GFP_KERNEL);
        if (!mmu)
@@ -642,16 +756,20 @@ struct panfrost_mmu *panfrost_mmu_ctx_create(struct 
panfrost_device *pfdev)
                .iommu_dev      = pfdev->dev,
        };
 
-       mmu->pgtbl_ops = alloc_io_pgtable_ops(ARM_MALI_LPAE, &mmu->pgtbl_cfg,
-                                             mmu);
-       if (!mmu->pgtbl_ops) {
-               kfree(mmu);
-               return ERR_PTR(-EINVAL);
-       }
+       mmu->pgtbl_ops = alloc_io_pgtable_ops(fmt, &mmu->pgtbl_cfg, mmu);
+       if (!mmu->pgtbl_ops)
+               goto err_free_mmu;
+
+       if (panfrost_mmu_cfg_init(mmu, fmt))
+               goto err_free_mmu;
 
        kref_init(&mmu->refcount);
 
        return mmu;
+
+err_free_mmu:
+       kfree(mmu);
+       return ERR_PTR(-EINVAL);
 }
 
 static const char *access_type_name(struct panfrost_device *pfdev,
diff --git a/drivers/gpu/drm/panfrost/panfrost_regs.h 
b/drivers/gpu/drm/panfrost/panfrost_regs.h
index b5f279a19a084..2b8f1617b8369 100644
--- a/drivers/gpu/drm/panfrost/panfrost_regs.h
+++ b/drivers/gpu/drm/panfrost/panfrost_regs.h
@@ -301,6 +301,17 @@
 #define AS_TRANSTAB_HI(as)             (MMU_AS(as) + 0x04) /* (RW) Translation 
Table Base Address for address space n, high word */
 #define AS_MEMATTR_LO(as)              (MMU_AS(as) + 0x08) /* (RW) Memory 
attributes for address space n, low word. */
 #define AS_MEMATTR_HI(as)              (MMU_AS(as) + 0x0C) /* (RW) Memory 
attributes for address space n, high word. */
+#define   AS_MEMATTR_AARCH64_INNER_ALLOC_IMPL          (2 << 2)
+#define   AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(w, r)    ((3 << 2) | \
+                                                        ((w) ? BIT(0) : 0) | \
+                                                        ((r) ? BIT(1) : 0))
+#define   AS_MEMATTR_AARCH64_SH_MIDGARD_INNER          (0 << 4)
+#define   AS_MEMATTR_AARCH64_SH_CPU_INNER              (1 << 4)
+#define   AS_MEMATTR_AARCH64_SH_CPU_INNER_SHADER_COH   (2 << 4)
+#define   AS_MEMATTR_AARCH64_SHARED                    (0 << 6)
+#define   AS_MEMATTR_AARCH64_INNER_OUTER_NC            (1 << 6)
+#define   AS_MEMATTR_AARCH64_INNER_OUTER_WB            (2 << 6)
+#define   AS_MEMATTR_AARCH64_FAULT                     (3 << 6)
 #define AS_LOCKADDR_LO(as)             (MMU_AS(as) + 0x10) /* (RW) Lock region 
address for address space n, low word */
 #define AS_LOCKADDR_HI(as)             (MMU_AS(as) + 0x14) /* (RW) Lock region 
address for address space n, high word */
 #define AS_COMMAND(as)                 (MMU_AS(as) + 0x18) /* (WO) MMU command 
register for address space n */
@@ -311,6 +322,24 @@
 /* Additional Bifrost AS registers */
 #define AS_TRANSCFG_LO(as)             (MMU_AS(as) + 0x30) /* (RW) Translation 
table configuration for address space n, low word */
 #define AS_TRANSCFG_HI(as)             (MMU_AS(as) + 0x34) /* (RW) Translation 
table configuration for address space n, high word */
+#define   AS_TRANSCFG_ADRMODE_LEGACY                   (0 << 0)
+#define   AS_TRANSCFG_ADRMODE_UNMAPPED                 (1 << 0)
+#define   AS_TRANSCFG_ADRMODE_IDENTITY                 (2 << 0)
+#define   AS_TRANSCFG_ADRMODE_AARCH64_4K               (6 << 0)
+#define   AS_TRANSCFG_ADRMODE_AARCH64_64K              (8 << 0)
+#define   AS_TRANSCFG_INA_BITS(x)                      ((x) << 6)
+#define   AS_TRANSCFG_OUTA_BITS(x)                     ((x) << 14)
+#define   AS_TRANSCFG_SL_CONCAT                                BIT(22)
+#define   AS_TRANSCFG_PTW_MEMATTR_NC                   (1 << 24)
+#define   AS_TRANSCFG_PTW_MEMATTR_WB                   (2 << 24)
+#define   AS_TRANSCFG_PTW_SH_NS                                (0 << 28)
+#define   AS_TRANSCFG_PTW_SH_OS                                (2 << 28)
+#define   AS_TRANSCFG_PTW_SH_IS                                (3 << 28)
+#define   AS_TRANSCFG_PTW_RA                           BIT(30)
+#define   AS_TRANSCFG_DISABLE_HIER_AP                  BIT(33)
+#define   AS_TRANSCFG_DISABLE_AF_FAULT                 BIT(34)
+#define   AS_TRANSCFG_WXN                              BIT(35)
+#define   AS_TRANSCFG_XREADABLE                                BIT(36)
 #define AS_FAULTEXTRA_LO(as)           (MMU_AS(as) + 0x38) /* (RO) Secondary 
fault address for address space n, low word */
 #define AS_FAULTEXTRA_HI(as)           (MMU_AS(as) + 0x3C) /* (RO) Secondary 
fault address for address space n, high word */
 
@@ -326,6 +355,11 @@
 #define AS_TRANSTAB_LPAE_READ_INNER            BIT(2)
 #define AS_TRANSTAB_LPAE_SHARE_OUTER           BIT(4)
 
+/*
+ * Begin AARCH64_4K MMU TRANSTAB register values
+ */
+#define AS_TRANSTAB_AARCH64_4K_ADDR_MASK       0xfffffffffffffff0
+
 #define AS_STATUS_AS_ACTIVE                    0x01
 
 #define AS_FAULTSTATUS_ACCESS_TYPE_MASK                (0x3 << 8)
-- 
2.47.2

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