[Intel-gfx] [PATCH v2 1/4] drm/i915/uc: Add ops to intel_uc

[Chris Wilson]

Quoting Michal Wajdeczko (2020-01-10 18:47:50)
> On Fri, 10 Jan 2020 17:57:22 +0100, Chris Wilson  
> <chris at chris-wilson.co.uk> wrote:
> 
> > Quoting Michal Wajdeczko (2020-01-10 16:29:27)
> >> Instead of spreading multiple conditionals across the uC code
> >> to find out current mode of uC operation, start using predefined
> >> set of function pointers that reflect that mode.
> >>
> >> Begin with pair of init_hw/fini_hw functions that are responsible
> >> for uC hardware initialization and cleanup.
> >>
> >> v2: drop ops_none, use macro to generate ops helpers
> >>
> >> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> >> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> >> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> >> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/gt/uc/intel_uc.c | 45 ++++++++++++++++++++++-----
> >>  drivers/gpu/drm/i915/gt/uc/intel_uc.h | 21 +++++++++++--
> >>  2 files changed, 57 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c  
> >> b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> >> index 3ffc6267f96e..da401e97bba3 100644
> >> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> >> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> >> @@ -12,6 +12,19 @@
> >>
> >>  #include "i915_drv.h"
> >>
> >> +static int __uc_check_hw(struct intel_uc *uc);
> >> +static int __uc_init_hw(struct intel_uc *uc);
> >> +static void __uc_fini_hw(struct intel_uc *uc);
> >> +
> >> +static const struct intel_uc_ops uc_ops_off = {
> >> +       .init_hw = __uc_check_hw,
> >> +};
> >> +
> >> +static const struct intel_uc_ops uc_ops_on = {
> >> +       .init_hw = __uc_init_hw,
> >> +       .fini_hw = __uc_fini_hw,
> >> +};
> >> +
> >>  /* Reset GuC providing us with fresh state for both GuC and HuC.
> >>   */
> >>  static int __intel_uc_reset_hw(struct intel_uc *uc)
> >> @@ -89,6 +102,11 @@ void intel_uc_init_early(struct intel_uc *uc)
> >>         intel_huc_init_early(&uc->huc);
> >>
> >>         __confirm_options(uc);
> >> +
> >> +       if (intel_uc_uses_guc(uc))
> >> +               uc->ops = &uc_ops_on;
> >> +       else
> >> +               uc->ops = &uc_ops_off;
> >>  }
> >>
> >>  void intel_uc_driver_late_release(struct intel_uc *uc)
> >> @@ -380,24 +398,37 @@ static bool uc_is_wopcm_locked(struct intel_uc  
> >> *uc)
> >>                (intel_uncore_read(uncore, DMA_GUC_WOPCM_OFFSET) &  
> >> GUC_WOPCM_OFFSET_VALID);
> >>  }
> >>
> >> -int intel_uc_init_hw(struct intel_uc *uc)
> >> +static int __uc_check_hw(struct intel_uc *uc)
> >> +{
> >> +       if (!intel_uc_supports_guc(uc))
> >> +               return 0;
> >> +
> >> +       /*
> >> +        * We can silently continue without GuC only if it was never  
> >> enabled
> >> +        * before on this system after reboot, otherwise we risk GPU  
> >> hangs.
> >> +        * To check if GuC was loaded before we look at WOPCM registers.
> >> +        */
> >> +       if (uc_is_wopcm_locked(uc))
> >> +               return -EIO;
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +static int __uc_init_hw(struct intel_uc *uc)
> >>  {
> >>         struct drm_i915_private *i915 = uc_to_gt(uc)->i915;
> >>         struct intel_guc *guc = &uc->guc;
> >>         struct intel_huc *huc = &uc->huc;
> >>         int ret, attempts;
> >>
> >> -       if (!intel_uc_supports_guc(uc))
> >> -               return 0;
> >> +       GEM_BUG_ON(!intel_uc_supports_guc(uc));
> >> +       GEM_BUG_ON(!intel_uc_uses_guc(uc));
> >>
> >>         /*
> >>          * We can silently continue without GuC only if it was never  
> >> enabled
> >>          * before on this system after reboot, otherwise we risk GPU  
> >> hangs.
> >>          * To check if GuC was loaded before we look at WOPCM registers.
> >>          */
> >
> > This comment still required?
> > Shouldn't there be a call here to __uc_check_hw() instead?
> 
> ok, will replace below call to uc_is_wopcm_locked() with __uc_check_hw()
> to avoid redundant (but otherwise still valid) comment
> 
> >
> >> -       if (!intel_uc_uses_guc(uc) && !uc_is_wopcm_locked(uc))
> >> -               return 0;
> >> -
> >>         if (!intel_uc_fw_is_available(&guc->fw)) {
> >>                 ret = uc_is_wopcm_locked(uc) ||
> 
>                           ^^^^^^^^^^^^^^^^^^

Ah, I see.

I think I still like the chaining up to __uc_check_hw() for the
continuity aspect, and only being scared once by the warning.
-Chris