drm/amdgpu: add a generic fb accessing helper function(v3)

add a generic helper function for accessing framebuffer via MMIO

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Tianci.Yin <tianci.yin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index b29bdf22c8bf..46218b36dc9e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -153,6 +153,36 @@ bool amdgpu_device_is_px(struct drm_device *dev)
 	return false;
 }
 
+/**
+ * VRAM access helper functions.
+ *
+ * amdgpu_device_vram_access - read/write a buffer in vram
+ *
+ * @adev: amdgpu_device pointer
+ * @pos: offset of the buffer in vram
+ * @buf: virtual address of the buffer in system memory
+ * @size: read/write size, sizeof(@buf) must > @size
+ * @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)
+{
+	uint64_t last;
+	unsigned long flags;
+
+	last = size - 4;
+	for (last += pos; pos <= last; pos += 4) {
+		spin_lock_irqsave(&adev->mmio_idx_lock, flags);
+		WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)pos) | 0x80000000);
+		WREG32_NO_KIQ(mmMM_INDEX_HI, pos >> 31);
+		if (write)
+			WREG32_NO_KIQ(mmMM_DATA, *buf++);
+		else
+			*buf++ = RREG32_NO_KIQ(mmMM_DATA);
+		spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
+	}
+}
+
 /*
  * MMIO register access helper functions.
  */