[PATCH v2 9/9] drm/amdgpu: Add CSB documentation

[Rodrigo Siqueira]

Add a description for the get_csb_buffer callback and an entry for CSB
in the glossary.

Signed-off-by: Rodrigo Siqueira <siqueira at igalia.com>
---
 Documentation/gpu/amdgpu/amdgpu-glossary.rst |  3 +++
 drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h      | 14 ++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/Documentation/gpu/amdgpu/amdgpu-glossary.rst b/Documentation/gpu/amdgpu/amdgpu-glossary.rst
index 080c3f2250d1..8fb5f6de4df3 100644
--- a/Documentation/gpu/amdgpu/amdgpu-glossary.rst
+++ b/Documentation/gpu/amdgpu/amdgpu-glossary.rst
@@ -33,6 +33,9 @@ we have a dedicated glossary for Display Core at
     CS
       Command Submission
 
+    CSB
+      Clear State Indirect Buffer
+
     CU
       Compute Unit
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h
index fce22d3f816b..c210625be220 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_rlc.h
@@ -237,6 +237,20 @@ struct amdgpu_rlc_funcs {
 	void (*unset_safe_mode)(struct amdgpu_device *adev, int xcc_id);
 	int  (*init)(struct amdgpu_device *adev);
 	u32  (*get_csb_size)(struct amdgpu_device *adev);
+
+	/**
+	 * @get_csb_buffer: Get the clear state to be put into the hardware.
+	 *
+	 * The parameter adev is used to get the CS data and other gfx info,
+	 * and buffer is the RLC CS pointer
+	 *
+	 * Sometimes, the user space puts a request to clear the state in the
+	 * command buffer; this function provides the clear state that gets put
+	 * into the hardware. Note that the driver programs Clear State
+	 * Indirect Buffer (CSB) explicitly when it sets up the kernel rings,
+	 * and it also provides a pointer to it which is used by the firmware
+	 * to load the clear state in some cases.
+	 */
 	void (*get_csb_buffer)(struct amdgpu_device *adev, volatile u32 *buffer);
 	int  (*get_cp_table_num)(struct amdgpu_device *adev);
 	int  (*resume)(struct amdgpu_device *adev);
-- 
2.49.0