Re: [PATCH 1/1] drm/i915/tgl: Implement Wa_1604555607

[Ramalingam C <ramalingam.c@intel.com>]

On 2019-11-21 at 10:19:13 +0000, Chris Wilson wrote:
> Quoting Ramalingam C (2019-11-21 10:12:26)
> > From: Michel Thierry <michel.thierry@intel.com>
> > 
> > Implement Wa_1604555607 (set the DS pairing timer to 128 cycles).
> > FF_MODE2 is part of the register state context, that's why it is
> > implemented here.
> > 
> > At TGL A0 stepping, FF_MODE2 register read back is broken, hence
> > disabling the WA verification.
> > 
> > v2: Rebased on top of the WA refactoring (Oscar)
> > v3: Correctly add to ctx_workarounds_init (Michel)
> > v4:
> >   uncore read is used [Tvrtko]
> >   Macros as used for MASK definition [Chris]
> > v5:
> >   Skip the Wa_1604555607 verification [Ram]
> >   i915 ptr retrieved from engine. [Tvrtko]
> > 
> > BSpec: 19363
> > HSDES: 1604555607
> > Signed-off-by: Michel Thierry <michel.thierry@intel.com>
> > Signed-off-by: Ramalingam C <ramlingam.c@intel.com>
> > ---
> >  drivers/gpu/drm/i915/gt/intel_workarounds.c | 25 ++++++++++++++++++---
> >  drivers/gpu/drm/i915/i915_reg.h             |  4 ++++
> >  2 files changed, 26 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > index 399acae2f33f..7cfd2442b736 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > @@ -147,19 +147,26 @@ static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
> >  }
> >  
> >  static void
> > -wa_write_masked_or(struct i915_wa_list *wal, i915_reg_t reg, u32 mask,
> > -                  u32 val)
> > +__wa_write_masked_or(struct i915_wa_list *wal, i915_reg_t reg, u32 mask,
> > +                    u32 val, u32 read_mask)
> >  {
> >         struct i915_wa wa = {
> >                 .reg  = reg,
> >                 .mask = mask,
> >                 .val  = val,
> > -               .read = mask,
> > +               .read = read_mask,
> >         };
> >  
> >         _wa_add(wal, &wa);
> 
> You might as well call it wa_add() since it takes all the arguments to
> _wa_add() and wraps them up into struct that we then copy.
> 
Something like this?

static void wa_add(struct i915_wa_list *wal, i915_reg_t reg, u32 mask,
                   u32 val, u32 read_mask)
{
        struct i915_wa wa = {
                .reg  = reg,
                .mask = mask,
                .val  = val,
                .read = read_mask,
        };

        _wa_add(wal, &wa);
}

static void
__wa_write_masked_or(struct i915_wa_list *wal, i915_reg_t reg, u32 mask,
                     u32 val, u32 read_mask)
{
        wa_add(wal, reg, mask, val, read_mask);
}


-Ram
> >  }
> >  
> > +static void
> > +wa_write_masked_or(struct i915_wa_list *wal, i915_reg_t reg, u32 mask,
> > +                  u32 val)
> > +{
> > +       __wa_write_masked_or(wal, reg, mask, val, mask);
> > +}
> > +
> >  static void
> >  wa_masked_en(struct i915_wa_list *wal, i915_reg_t reg, u32 val)
> >  {
> > @@ -568,9 +575,21 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine,
> >  static void tgl_ctx_workarounds_init(struct intel_engine_cs *engine,
> >                                      struct i915_wa_list *wal)
> >  {
> > +       u32 val;
> > +
> >         /* Wa_1409142259:tgl */
> >         WA_SET_BIT_MASKED(GEN11_COMMON_SLICE_CHICKEN3,
> >                           GEN12_DISABLE_CPS_AWARE_COLOR_PIPE);
> > +
> > +       /* Wa_1604555607:tgl */
> > +       val = intel_uncore_read(engine->uncore, FF_MODE2);
> > +       val &= ~FF_MODE2_TDS_TIMER_MASK;
> > +       val |= FF_MODE2_TDS_TIMER_128;
> > +       if (IS_TGL_REVID(engine->i915, 0, TGL_REVID_A0))
> > +               __wa_write_masked_or(wal, FF_MODE2,
> > +                                    FF_MODE2_TDS_TIMER_MASK, val, 0);
> > +       else
> > +               wa_write_masked_or(wal, FF_MODE2, FF_MODE2_TDS_TIMER_MASK, val);
> 
> I still have this plan to do this as MI_MATH ops... But it's not a
> blocker.
> -Chris
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