Re: [PATCH] drm/i915/cnl: Fix SSEU Device Status.

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Sep 22, 2017 at 06:32:04PM +0000, Rodrigo Vivi wrote:
> On Fri, Sep 22, 2017 at 04:44:38PM +0000, Oscar Mateo wrote:
> > 
> > 
> > On 09/22/2017 06:15 AM, Rodrigo Vivi wrote:
> > > CNL adds an extra register for slice/subslice information.
> > > Although no SKU is planed with an extra slice let's already
> > > handle this extra piece of information so we don't have the
> > > risk in future of getting a part that might have chosen this
> > > part of the die instead of other slices or anything like that.
> > > 
> > > Also if subslice is disabled the information of eu ack for that
> > > is garbage, so let's skip checks for eu if subslice is disabled
> > > as we skip the subslice if slice is disabled.
> > > 
> > > The rest is pretty much like gen9.
> > > 
> > > v2: Remove IS_CANNONLAKE from gen9 status function.
> > > 
> > > v3: Consider s_max = 6 and ss_max=4 to run over all possible
> > >      slices and subslices possible by spec. Although no real
> > >      hardware will have that many slices/subslices.
> > >      To match with sseu info init.
> > > v4: Fix offset calculation for slices 4 and 5.
> > >      Removed Oscar's rv-b since this change also needs review.
> > > 
> > > Cc: Oscar Mateo <oscar.mateo@intel.com>
> > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > ---
> > >   drivers/gpu/drm/i915/i915_debugfs.c | 54 +++++++++++++++++++++++++++++++++++--
> > >   drivers/gpu/drm/i915/i915_reg.h     |  6 +++++
> > >   2 files changed, 58 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > > index ca6fa6d122c6..e197e5d99277 100644
> > > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > > @@ -4575,6 +4575,54 @@ static void cherryview_sseu_device_status(struct drm_i915_private *dev_priv,
> > >   	}
> > >   }
> > > +static void gen10_sseu_device_status(struct drm_i915_private *dev_priv,
> > > +				     struct sseu_dev_info *sseu)
> > > +{
> > > +	const struct intel_device_info *info = INTEL_INFO(dev_priv);
> > > +	int s_max = 6, ss_max = 4;
> > > +	int s, ss;
> > > +	u32 s_reg[s_max], eu_reg[2 * s_max], eu_mask[2];
> > > +
> > > +	for (s = 0; s < s_max; s++) {
> > > +		s_reg[s] = I915_READ(GEN10_SLICE_PGCTL_ACK(s));
> > > +		eu_reg[2 * s] = I915_READ(GEN10_SS01_EU_PGCTL_ACK(s));
> > > +		eu_reg[2 * s + 1] = I915_READ(GEN10_SS23_EU_PGCTL_ACK(s));
> > > +	}
> > > +
> > > +	eu_mask[0] = GEN9_PGCTL_SSA_EU08_ACK |
> > > +		     GEN9_PGCTL_SSA_EU19_ACK |
> > > +		     GEN9_PGCTL_SSA_EU210_ACK |
> > > +		     GEN9_PGCTL_SSA_EU311_ACK;
> > > +	eu_mask[1] = GEN9_PGCTL_SSB_EU08_ACK |
> > > +		     GEN9_PGCTL_SSB_EU19_ACK |
> > > +		     GEN9_PGCTL_SSB_EU210_ACK |
> > > +		     GEN9_PGCTL_SSB_EU311_ACK;
> > > +
> > > +	for (s = 0; s < s_max; s++) {
> > > +		if ((s_reg[s] & GEN9_PGCTL_SLICE_ACK) == 0)
> > > +			/* skip disabled slice */
> > > +			continue;
> > > +
> > > +		sseu->slice_mask |= BIT(s);
> > > +		sseu->subslice_mask = info->sseu.subslice_mask;
> > > +
> > > +		for (ss = 0; ss < ss_max; ss++) {
> > > +			unsigned int eu_cnt;
> > > +
> > > +			if (!(s_reg[s] & (GEN9_PGCTL_SS_ACK(ss))))
> > > +				/* skip disabled subslice */
> > > +				continue;
> > 
> > You are going to hate me, but I found something else:
> 
> Should I hate you for being a good reviewer? ;)
> You should hate me for not noticing that before...
> Thanks a lot for the patience
> 
> > 
> > SLICE0_PGCTL_ACK has powergate acknowledge bits for subslices 0, 1 & 2, but
> > not for subslice 3
> > SLICEn_PGCTL_ACK (where n = 1-5) has powergate acknowledge bits for
> > subslices 0 & 1, but not for subslices 2 & 3
> 
> hmmm... :(
> I will check...
> 
> > 
> > I have no idea where the missing bits went (maybe the BSpec is wrong?).
> 
> Do you know anyone at your end that could help us to clarify that?

Based on the emails it seems that it is a spec bug. But we are
not going to merge this patch 2/2 while we don't get the official confirmation.

Meanwhile we need the first patch for userspace, so
I merged the first patch on dinq while we solve this mistery.

Thanks for all the reviews.

> 
> Thanks,
> Rodrigo.
> 
> > 
> > > +
> > > +			eu_cnt = 2 * hweight32(eu_reg[2 * s + ss / 2] &
> > > +					       eu_mask[ss % 2]);
> > > +			sseu->eu_total += eu_cnt;
> > > +			sseu->eu_per_subslice = max_t(unsigned int,
> > > +						      sseu->eu_per_subslice,
> > > +						      eu_cnt);
> > > +		}
> > > +	}
> > > +}
> > > +
> > >   static void gen9_sseu_device_status(struct drm_i915_private *dev_priv,
> > >   				    struct sseu_dev_info *sseu)
> > >   {
> > > @@ -4610,7 +4658,7 @@ static void gen9_sseu_device_status(struct drm_i915_private *dev_priv,
> > >   		sseu->slice_mask |= BIT(s);
> > > -		if (IS_GEN9_BC(dev_priv) || IS_CANNONLAKE(dev_priv))
> > > +		if (IS_GEN9_BC(dev_priv))
> > >   			sseu->subslice_mask =
> > >   				INTEL_INFO(dev_priv)->sseu.subslice_mask;
> > > @@ -4716,8 +4764,10 @@ static int i915_sseu_status(struct seq_file *m, void *unused)
> > >   		cherryview_sseu_device_status(dev_priv, &sseu);
> > >   	} else if (IS_BROADWELL(dev_priv)) {
> > >   		broadwell_sseu_device_status(dev_priv, &sseu);
> > > -	} else if (INTEL_GEN(dev_priv) >= 9) {
> > > +	} else if (IS_GEN9(dev_priv)) {
> > >   		gen9_sseu_device_status(dev_priv, &sseu);
> > > +	} else if (INTEL_GEN(dev_priv) >= 10) {
> > > +		gen10_sseu_device_status(dev_priv, &sseu);
> > >   	}
> > >   	intel_runtime_pm_put(dev_priv);
> > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > index 1c257797c583..9729145e6c03 100644
> > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > @@ -8020,11 +8020,17 @@ enum {
> > >   #define   CHV_EU311_PG_ENABLE		(1<<1)
> > >   #define GEN9_SLICE_PGCTL_ACK(slice)	_MMIO(0x804c + (slice)*0x4)
> > > +#define GEN10_SLICE_PGCTL_ACK(slice)	_MMIO(0x804c + ((slice) / 3) * 0x34 + \
> > > +					      ((slice) % 3) * 0x4)
> > >   #define   GEN9_PGCTL_SLICE_ACK		(1 << 0)
> > >   #define   GEN9_PGCTL_SS_ACK(subslice)	(1 << (2 + (subslice)*2))
> > >   #define GEN9_SS01_EU_PGCTL_ACK(slice)	_MMIO(0x805c + (slice)*0x8)
> > > +#define GEN10_SS01_EU_PGCTL_ACK(slice)	_MMIO(0x805c + ((slice) / 3) * 0x30 + \
> > > +					      ((slice) % 3) * 0x8)
> > >   #define GEN9_SS23_EU_PGCTL_ACK(slice)	_MMIO(0x8060 + (slice)*0x8)
> > > +#define GEN10_SS23_EU_PGCTL_ACK(slice)	_MMIO(0x8060 + ((slice) / 3) * 0x30 + \
> > > +					      ((slice) % 3) * 0x8)
> > >   #define   GEN9_PGCTL_SSA_EU08_ACK	(1 << 0)
> > >   #define   GEN9_PGCTL_SSA_EU19_ACK	(1 << 2)
> > >   #define   GEN9_PGCTL_SSA_EU210_ACK	(1 << 4)
> > 
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