Re: [PATCH 8/8] drm/i915/uc: Simplify firmware path handling

[Arkadiusz Hiler <arkadiusz.hiler@intel.com>]

On Wed, Feb 22, 2017 at 04:30:49PM +0100, Arkadiusz Hiler wrote:
> On Wed, Feb 22, 2017 at 12:53:47PM +0000, Chris Wilson wrote:
> > 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@intel.com>
> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> > > Cc: Michal Winiarski <michal.winiarski@intel.com>
> > > Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> > > Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@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?
> 
> Sorry, I do not quite understand the comment. Can you elaborate?

Nevermind, got it.

LGTM, but for it to fully work we need to make uc_fetch_fw (or however
it will end up being named) aware that -1 have special meaning.

Now the version cross-check looks like that:

if (uc_fw->major_ver_found != uc_fw->major_ver_wanted ||
    uc_fw->minor_ver_found < uc_fw->minor_ver_wanted) {


-- 
Cheers,
Arek
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