[Intel-gfx] [PATCH 8/8] drm/i915/uc: Simplify firmware path handling

[Chris Wilson]

On Wed, Feb 22, 2017 at 01:41:25PM +0100, Arkadiusz Hiler wrote:
> Currently fw->path values can represent one of three possible states:
> 
>  1) NULL - device without the uC
>  2) '\0' - device with the uC but have no firmware
>  3) else - device with the uC and we have firmware
> 
> Second case is used only to WARN at a later stage.
> 
> We can WARN right away and merge cases 1 and 2.
> 
> Code can be even further simplified and common (HuC/GuC logic) happening
> right before the fetch can be offloaded to the common function.
> 
> v2: fewer temporary variables, more straightforward flow (M. Wajdeczko)
> v3: DRM_ERROR instead of WARN (M. Wajdeczko)
> 
> Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Michal Winiarski <michal.winiarski at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_guc_loader.c | 39 +++++++++++----------------------
>  drivers/gpu/drm/i915/intel_huc.c        | 20 +++++------------
>  drivers/gpu/drm/i915/intel_uc.c         |  5 +++--
>  3 files changed, 22 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index 549a254..336e97d 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -433,12 +433,8 @@ int intel_guc_init_hw(struct drm_i915_private *dev_priv)
>  		intel_uc_fw_status_repr(guc_fw->load_status));
>  
>  	if (fw_path == NULL) {
> -		/* Device is known to have no uCode (e.g. no GuC) */
> +		/* We do not have uCode for the device */
>  		return -ENXIO;
> -	} else if (*fw_path == '\0') {
> -		/* Device has a GuC but we don't know what f/w to load? */
> -		WARN(1, "No GuC firmware known for this platform!\n");
> -		return -ENODEV;
>  	}
>  
>  	/* Fetch failed, or already fetched but failed to load? */
> @@ -474,7 +470,6 @@ int intel_guc_init_hw(struct drm_i915_private *dev_priv)
>  	return 0;
>  }
>  
> -
>  /**
>   * intel_guc_fetch_fw() - determine and fetch firmware
>   * @guc:	intel_guc struct
> @@ -487,39 +482,31 @@ int intel_guc_init_hw(struct drm_i915_private *dev_priv)
>  void intel_guc_fetch_fw(struct intel_guc *guc)
>  {
>  	struct drm_i915_private *dev_priv = guc_to_i915(guc);
> -	const char *fw_path;
>  
> -	if (!HAS_GUC_UCODE(dev_priv)) {
> -		fw_path = NULL;
> -	} else if (IS_SKYLAKE(dev_priv)) {
> -		fw_path = I915_SKL_GUC_UCODE;
> +	guc->fw.path = NULL;
> +	guc->fw.fetch_status = INTEL_UC_FIRMWARE_NONE;
> +	guc->fw.load_status = INTEL_UC_FIRMWARE_NONE;
> +	guc->fw.fw = INTEL_UC_FW_TYPE_GUC;
> +
> +	if (IS_SKYLAKE(dev_priv)) {
> +		guc->fw.path = I915_SKL_GUC_UCODE;
>  		guc->fw.major_ver_wanted = SKL_FW_MAJOR;
>  		guc->fw.minor_ver_wanted = SKL_FW_MINOR;
>  	} else if (IS_BROXTON(dev_priv)) {
> -		fw_path = I915_BXT_GUC_UCODE;
> +		guc->fw.path = I915_BXT_GUC_UCODE;
>  		guc->fw.major_ver_wanted = BXT_FW_MAJOR;
>  		guc->fw.minor_ver_wanted = BXT_FW_MINOR;
>  	} else if (IS_KABYLAKE(dev_priv)) {
> -		fw_path = I915_KBL_GUC_UCODE;
> +		guc->fw.path = I915_KBL_GUC_UCODE;
>  		guc->fw.major_ver_wanted = KBL_FW_MAJOR;
>  		guc->fw.minor_ver_wanted = KBL_FW_MINOR;
>  	} else {
> -		fw_path = "";	/* unknown device */
> +		DRM_ERROR("No GuC firmware known for platform with GuC!\n");
> +		i915.enable_guc_loading = 0;
> +		return;

Now plan for having fw_path overriden by a i915_param.guc_firmware.

Perhaps something like
	if (i915_param.guc_firmware) {
		guc->fw.path = i915_param.guc_firmware; /* needs 0400! */
		guc->fw.major_ver_wanted = -1;
		guc->fw.minor_ver_wanted = -1;
	} else if (IS_SKYLAKE....
works?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre