1 files changed, 41 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index ce384ed9b9ef..6ea96e1fb273 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1671,10 +1671,50 @@ static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
         return result;
 }
 
+static ssize_t amdgpu_ttm_vram_write(struct file *f, const char __user *buf,
+                                    size_t size, loff_t *pos)
+{
+        struct amdgpu_device *adev = file_inode(f)->i_private;
+        ssize_t result = 0;
+        int r;
+
+        if (size & 0x3 || *pos & 0x3)
+                return -EINVAL;
+
+        if (*pos >= adev->mc.mc_vram_size)
+                return -ENXIO;
+
+        while (size) {
+                unsigned long flags;
+                uint32_t value;
+
+                if (*pos >= adev->mc.mc_vram_size)
+                        return result;
+
+                r = get_user(value, (uint32_t *)buf);
+                if (r)
+                        return r;
+
+                spin_lock_irqsave(&adev->mmio_idx_lock, flags);
+                WREG32(mmMM_INDEX, ((uint32_t)*pos) | 0x80000000);
+                WREG32(mmMM_INDEX_HI, *pos >> 31);
+                WREG32(mmMM_DATA, value);
+                spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
+
+                result += 4;
+                buf += 4;
+                *pos += 4;
+                size -= 4;
+        }
+
+        return result;
+}
+
 static const struct file_operations amdgpu_ttm_vram_fops = {
         .owner = THIS_MODULE,
         .read = amdgpu_ttm_vram_read,
-        .llseek = default_llseek
+        .write = amdgpu_ttm_vram_write,
+        .llseek = default_llseek,
 };
 
 #ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS