drm/amdgpu: add debugfs interface for reading MQDs

Provide a debugfs interface to access the MQD.  Useful for
debugging issues with the CP and MES hardware scheduler.

v2: fix missing unreserve/unmap when pos >= size (Alex)

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index eaf0f82..1e9ae3b 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -509,6 +509,59 @@ static const struct file_operations amdgpu_debugfs_ring_fops = {
        .llseek = default_llseek
 };
 
+static ssize_t amdgpu_debugfs_mqd_read(struct file *f, char __user *buf,
+                                      size_t size, loff_t *pos)
+{
+       struct amdgpu_ring *ring = file_inode(f)->i_private;
+       volatile u32 *mqd;
+       int r;
+       uint32_t value, result;
+
+       if (*pos & 3 || size & 3)
+               return -EINVAL;
+
+       result = 0;
+
+       r = amdgpu_bo_reserve(ring->mqd_obj, false);
+       if (unlikely(r != 0))
+               return r;
+
+       r = amdgpu_bo_kmap(ring->mqd_obj, (void **)&mqd);
+       if (r) {
+               amdgpu_bo_unreserve(ring->mqd_obj);
+               return r;
+       }
+
+       while (size) {
+               if (*pos >= ring->mqd_size)
+                       goto done;
+
+               value = mqd[*pos/4];
+               r = put_user(value, (uint32_t *)buf);
+               if (r)
+                       goto done;
+               buf += 4;
+               result += 4;
+               size -= 4;
+               *pos += 4;
+       }
+
+done:
+       amdgpu_bo_kunmap(ring->mqd_obj);
+       mqd = NULL;
+       amdgpu_bo_unreserve(ring->mqd_obj);
+       if (r)
+               return r;
+
+       return result;
+}
+
+static const struct file_operations amdgpu_debugfs_mqd_fops = {
+       .owner = THIS_MODULE,
+       .read = amdgpu_debugfs_mqd_read,
+       .llseek = default_llseek
+};
+
 #endif
 
 void amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
@@ -524,6 +577,12 @@ void amdgpu_debugfs_ring_init(struct amdgpu_device *adev,
                                 &amdgpu_debugfs_ring_fops,
                                 ring->ring_size + 12);
 
+       if (ring->mqd_obj) {
+               sprintf(name, "amdgpu_mqd_%s", ring->name);
+               debugfs_create_file_size(name, S_IFREG | S_IRUGO, root, ring,
+                                        &amdgpu_debugfs_mqd_fops,
+                                        ring->mqd_size);
+       }
 #endif
 }