Re: [PATCH v2 1/2] drm/i915/skl: Documentation for CSR firmware

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, May 13, 2015 at 10:13:29PM +0530, Animesh Manna wrote:
> 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: Animesh Manna <animesh.manna@intel.com>
> Signed-off-by: A.Sunil Kamath <sunil.kamath@intel.com>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  Documentation/DocBook/drm.tmpl   |  7 +++++-
>  drivers/gpu/drm/i915/intel_csr.c | 53 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 59 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index 7c68ecc..b6fc354 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -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>
> diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
> index 9311cdd..5cb8cc1 100644
> --- a/drivers/gpu/drm/i915/intel_csr.c
> +++ b/drivers/gpu/drm/i915/intel_csr.c
> @@ -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 @@ out:
>  	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;
> -- 
> 2.0.2
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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