[PATCH] drm/amdgpu: add non-aligned address supported in amdgpu_device_vram_access()

Kevin Wang kevin1.wang at amd.com
Fri Jun 25 03:24:09 UTC 2021


1. add non-aligned address support in amdgpu_device_vram_access()
2. reduce duplicate code in amdgpu_ttm_access_memory()

because the MM_INDEX{HI}/DATA are protected register, it is not working
in sriov environment when mmio protect feature is enabled (in some asics),
and the old function amdgpu_ttm_access_memory() will force using MM_INDEX/DATA
to handle non-aligned address by default, it will cause the register(MM_DATA)
is always return 0.

with the patch, the memory will be accessed in the aper way first.
(in visible memory or enable pcie large-bar feature), then using
MM_INDEX{HI}/MM_DATA to access rest vram memroy.

Signed-off-by: Kevin Wang <kevin1.wang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 69 ++++++++++++++++------
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 42 ++-----------
 3 files changed, 58 insertions(+), 55 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index d14b4968a026..8095d9a9c857 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1103,7 +1103,7 @@ void amdgpu_device_fini(struct amdgpu_device *adev);
 int amdgpu_gpu_wait_for_idle(struct amdgpu_device *adev);
 
 void amdgpu_device_vram_access(struct amdgpu_device *adev, loff_t pos,
-			       uint32_t *buf, size_t size, bool write);
+			       void *buf, size_t size, bool write);
 uint32_t amdgpu_device_rreg(struct amdgpu_device *adev,
 			    uint32_t reg, uint32_t acc_flags);
 void amdgpu_device_wreg(struct amdgpu_device *adev,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index e6702d136a6d..2047e3c2b365 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -280,6 +280,54 @@ bool amdgpu_device_supports_smart_shift(struct drm_device *dev)
 		amdgpu_acpi_is_power_shift_control_supported());
 }
 
+static inline void amdgpu_device_vram_mmio_align_access_locked(struct amdgpu_device *adev, loff_t pos,
+							       uint32_t *value, bool write)
+{
+	BUG_ON(!IS_ALIGNED(pos, 4));
+
+	WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)pos) | 0x80000000);
+	WREG32_NO_KIQ(mmMM_INDEX_HI, pos >> 31);
+	if (write)
+		WREG32_NO_KIQ(mmMM_DATA, *value);
+	else
+		*value = RREG32_NO_KIQ(mmMM_DATA);
+}
+
+static void amdgpu_device_vram_mmio_access_locked(struct amdgpu_device *adev, loff_t pos,
+						  void *buf, size_t size, bool write)
+{
+	while (size) {
+		uint64_t aligned_pos = ALIGN_DOWN(pos, 4);
+		uint64_t bytes = 4 - (pos & 0x3);
+		uint32_t shift = (pos & 0x3) * 8;
+		uint32_t mask = 0xffffffff << shift;
+		uint32_t value = 0;
+
+		if (size < bytes) {
+			mask &= 0xffffffff >> (bytes - size) * 8;
+			bytes = size;
+		}
+
+		if (mask != 0xffffffff) {
+			amdgpu_device_vram_mmio_align_access_locked(adev, aligned_pos, &value, false);
+			if (write) {
+				value &= ~mask;
+				value |= (*(uint32_t *)buf << shift) & mask;
+				amdgpu_device_vram_mmio_align_access_locked(adev, aligned_pos, &value, true);
+			} else {
+				value = (value & mask) >> shift;
+				memcpy(buf, &value, bytes);
+			}
+		} else {
+			amdgpu_device_vram_mmio_align_access_locked(adev, aligned_pos, buf, write);
+		}
+
+		pos += bytes;
+		buf += bytes;
+		size -= bytes;
+	}
+}
+
 /*
  * VRAM access helper functions
  */
@@ -294,13 +342,11 @@ bool amdgpu_device_supports_smart_shift(struct drm_device *dev)
  * @write: true - write to vram, otherwise - read from vram
  */
 void amdgpu_device_vram_access(struct amdgpu_device *adev, loff_t pos,
-			       uint32_t *buf, size_t size, bool write)
+			       void *buf, size_t size, bool write)
 {
 	unsigned long flags;
-	uint32_t hi = ~0;
 	uint64_t last;
 
-
 #ifdef CONFIG_64BIT
 	last = min(pos + size, adev->gmc.visible_vram_size);
 	if (last > pos) {
@@ -321,25 +367,12 @@ void amdgpu_device_vram_access(struct amdgpu_device *adev, loff_t pos,
 			return;
 
 		pos += count;
-		buf += count / 4;
+		buf += count;
 		size -= count;
 	}
 #endif
-
 	spin_lock_irqsave(&adev->mmio_idx_lock, flags);
-	for (last = pos + size; pos < last; pos += 4) {
-		uint32_t tmp = pos >> 31;
-
-		WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)pos) | 0x80000000);
-		if (tmp != hi) {
-			WREG32_NO_KIQ(mmMM_INDEX_HI, tmp);
-			hi = tmp;
-		}
-		if (write)
-			WREG32_NO_KIQ(mmMM_DATA, *buf++);
-		else
-			*buf++ = RREG32_NO_KIQ(mmMM_DATA);
-	}
+	amdgpu_device_vram_mmio_access_locked(adev, pos, buf, size, write);
 	spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
 }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 6297363ab740..cf5b8bdc2dd3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1430,8 +1430,6 @@ static int amdgpu_ttm_access_memory(struct ttm_buffer_object *bo,
 	struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
 	struct amdgpu_device *adev = amdgpu_ttm_adev(abo->tbo.bdev);
 	struct amdgpu_res_cursor cursor;
-	unsigned long flags;
-	uint32_t value = 0;
 	int ret = 0;
 
 	if (bo->mem.mem_type != TTM_PL_VRAM)
@@ -1439,41 +1437,13 @@ static int amdgpu_ttm_access_memory(struct ttm_buffer_object *bo,
 
 	amdgpu_res_first(&bo->mem, offset, len, &cursor);
 	while (cursor.remaining) {
-		uint64_t aligned_pos = cursor.start & ~(uint64_t)3;
-		uint64_t bytes = 4 - (cursor.start & 3);
-		uint32_t shift = (cursor.start & 3) * 8;
-		uint32_t mask = 0xffffffff << shift;
-
-		if (cursor.size < bytes) {
-			mask &= 0xffffffff >> (bytes - cursor.size) * 8;
-			bytes = cursor.size;
-		}
+		amdgpu_device_vram_access(adev, cursor.start,
+					  buf, cursor.size,
+					  write);
 
-		if (mask != 0xffffffff) {
-			spin_lock_irqsave(&adev->mmio_idx_lock, flags);
-			WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)aligned_pos) | 0x80000000);
-			WREG32_NO_KIQ(mmMM_INDEX_HI, aligned_pos >> 31);
-			value = RREG32_NO_KIQ(mmMM_DATA);
-			if (write) {
-				value &= ~mask;
-				value |= (*(uint32_t *)buf << shift) & mask;
-				WREG32_NO_KIQ(mmMM_DATA, value);
-			}
-			spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
-			if (!write) {
-				value = (value & mask) >> shift;
-				memcpy(buf, &value, bytes);
-			}
-		} else {
-			bytes = cursor.size & ~0x3ULL;
-			amdgpu_device_vram_access(adev, cursor.start,
-						  (uint32_t *)buf, bytes,
-						  write);
-		}
-
-		ret += bytes;
-		buf = (uint8_t *)buf + bytes;
-		amdgpu_res_next(&cursor, bytes);
+		ret += cursor.size;
+		buf += cursor.size;
+		amdgpu_res_next(&cursor, cursor.size);
 	}
 
 	return ret;
-- 
2.17.1



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