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Commit aa9145c4 authored by Animesh Manna's avatar Animesh Manna Committed by Daniel Vetter
Browse files

drm/i915/skl: Documentation for CSR firmware 



Added docbook info regarding context save and restore (CSR)
firmware support added from gen9 onwards to drive newly added
DMC (Display microcontroller) in display engine.

v1: Initial version as RFC.

v2: Used "DOC:" tag for csr description based on review comment from Daniel.

Signed-off-by: default avatarAnimesh Manna <animesh.manna@intel.com>
Signed-off-by: default avatarA.Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 5c1a8875

Documentation/DocBook/drm.tmpl

+6 −1
Original line number Diff line number Diff line
@@ -4153,6 +4153,12 @@ int num_ioctls;</synopsis> 
	  </tgroup>

	</table>

      </sect2>



      <sect2>

       <title>CSR firmware support for DMC</title>

!Pdrivers/gpu/drm/i915/intel_csr.c csr support for dmc

!Idrivers/gpu/drm/i915/intel_csr.c

      </sect2>

    </sect1>



    <sect1>
@@ -4204,7 +4210,6 @@ int num_ioctls;</synopsis> 
!Idrivers/gpu/drm/i915/i915_gem_shrinker.c

      </sect2>

    </sect1>



    <sect1>

      <title> Tracing </title>

      <para>

drivers/gpu/drm/i915/intel_csr.c

+53 −0
Original line number Diff line number Diff line
@@ -25,6 +25,22 @@ 
#include "i915_drv.h"

#include "i915_reg.h"



/**

 * DOC: csr support for dmc

 *

 * Display Context Save and Restore (CSR) firmware support added from gen9

 * onwards to drive newly added DMC (Display microcontroller) in display

 * engine to save and restore the state of display engine when it enter into

 * low-power state and comes back to normal.

 *

 * Firmware loading status will be one of the below states: FW_UNINITIALIZED,

 * FW_LOADED, FW_FAILED.

 *

 * Once the firmware is written into the registers status will be moved from

 * FW_UNINITIALIZED to FW_LOADED and for any erroneous condition status will

 * be moved to FW_FAILED.

 */



#define I915_CSR_SKL "i915/skl_dmc_ver4.bin"



MODULE_FIRMWARE(I915_CSR_SKL);
@@ -183,6 +199,14 @@ static char intel_get_substepping(struct drm_device *dev) 
		return -ENODATA;

}



/**

 * intel_csr_load_status_get() - to get firmware loading status.

 * @dev_priv: i915 device.

 *

 * This function helps to get the firmware loading status.

 *

 * Return: Firmware loading status.

 */

enum csr_state intel_csr_load_status_get(struct drm_i915_private *dev_priv)

{

	enum csr_state state;
@@ -194,6 +218,13 @@ enum csr_state intel_csr_load_status_get(struct drm_i915_private *dev_priv) 
	return state;

}



/**

 * intel_csr_load_status_set() - help to set firmware loading status.

 * @dev_priv: i915 device.

 * @state: enumeration of firmware loading status.

 *

 * Set the firmware loading status.

 */

void intel_csr_load_status_set(struct drm_i915_private *dev_priv,

			enum csr_state state)

{
@@ -202,6 +233,14 @@ void intel_csr_load_status_set(struct drm_i915_private *dev_priv, 
	mutex_unlock(&dev_priv->csr_lock);

}



/**

 * intel_csr_load_program() - write the firmware from memory to register.

 * @dev: drm device.

 *

 * CSR firmware is read from a .bin file and kept in internal memory one time.

 * Everytime display comes back from low power state this function is called to

 * copy the firmware from internal memory to registers.

 */

void intel_csr_load_program(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -359,6 +398,13 @@ static void finish_csr_load(const struct firmware *fw, void *context) 
	release_firmware(fw);

}



/**

 * intel_csr_ucode_init() - initialize the firmware loading.

 * @dev: drm device.

 *

 * This function is called at the time of loading the display driver to read

 * firmware from a .bin file and copied into a internal memory.

 */

void intel_csr_ucode_init(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -393,6 +439,13 @@ void intel_csr_ucode_init(struct drm_device *dev) 
	}

}



/**

 * intel_csr_ucode_fini() - unload the CSR firmware.

 * @dev: drm device.

 *

 * Firmmware unloading includes freeing the internal momory and reset the

 * firmware loading status.

 */

void intel_csr_ucode_fini(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;