Re: [PATCH 04/43] drm/i915: Parametrize fence registers

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Sep 21, 2015 at 03:33:00PM +0300, Ville Syrjälä wrote:
> On Mon, Sep 21, 2015 at 10:45:46AM +0300, Jani Nikula wrote:
> > On Fri, 18 Sep 2015, ville.syrjala@linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > >
> > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/i915_gem_fence.c | 42 +++++++++++++++++------------------
> > >  drivers/gpu/drm/i915/i915_gpu_error.c | 21 ++++++++----------
> > >  drivers/gpu/drm/i915/i915_reg.h       | 12 +++++-----
> > >  3 files changed, 37 insertions(+), 38 deletions(-)
> > >
> <snip>
> > > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> > > index 3379f9c..e873eb4 100644
> > > --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> > > +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> > > @@ -787,19 +787,16 @@ static void i915_gem_record_fences(struct drm_device *dev,
> > >  
> > >  	if (IS_GEN3(dev) || IS_GEN2(dev)) {
> > >  		for (i = 0; i < 8; i++)
> > > -			error->fence[i] = I915_READ(FENCE_REG_830_0 + (i * 4));
> > > -		if (IS_I945G(dev) || IS_I945GM(dev) || IS_G33(dev))
> > > -			for (i = 0; i < 8; i++)
> > > -				error->fence[i+8] = I915_READ(FENCE_REG_945_8 +
> > > -							      (i * 4));
> > > -	} else if (IS_GEN5(dev) || IS_GEN4(dev))
> > > -		for (i = 0; i < 16; i++)
> > > -			error->fence[i] = I915_READ64(FENCE_REG_965_0 +
> > > -						      (i * 8));
> > > -	else if (INTEL_INFO(dev)->gen >= 6)
> > > +			error->fence[i] = I915_READ(FENCE_REG_830(i));
> > > +		for (i = 8; i < dev_priv->num_fence_regs; i++)
> > > +			error->fence[i] = I915_READ(FENCE_REG_945_8(i));
> > > +	} else if (IS_GEN5(dev) || IS_GEN4(dev)) {
> > >  		for (i = 0; i < dev_priv->num_fence_regs; i++)
> > > -			error->fence[i] = I915_READ64(FENCE_REG_SANDYBRIDGE_0 +
> > > -						      (i * 8));
> > > +			error->fence[i] = I915_READ64(FENCE_REG_965_LO(i));
> > > +	} else if (INTEL_INFO(dev)->gen >= 6) {
> > > +		for (i = 0; i < dev_priv->num_fence_regs; i++)
> > > +			error->fence[i] = I915_READ64(FENCE_REG_GEN6_LO(i));
> > > +	}
> > >  }
> > >  
> > >  
> > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > index 44cedbf..b1cf17a 100644
> > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > @@ -1437,8 +1437,8 @@ enum skl_disp_power_wells {
> > >  /*
> > >   * Fence registers
> > >   */
> > > -#define FENCE_REG_830_0			0x2000
> > > -#define FENCE_REG_945_8			0x3000
> > > +#define FENCE_REG_830(i)		(0x2000 + (i) * 4) /* 8 registers */
> > > +#define FENCE_REG_945_8(i)		(0x3000 + ((i) - 8) * 4) /* 8 registers */
> > 
> > How about defining that as
> > 
> > #define FENCE_REG_945(i) (i < 8 ? FENCE_REG_830(i) : (0x3000 + ((i) - 8) * 4))
> > 
> > and changing the code to look at platforms, not reg number?
> 
> Yeah, I guess we can hide the magic entirely. In fact we wouldn't even
> need any gen2 vs. gen3 platforms checks anymore with that macro.

Oh I think I already considered making this even more magic with
something like this:
(0x2000 + (((i) & 8) << 9) + ((i) & 7) * 4)
or
(0x2000 + (((i) >> 3) * 0x1000) + ((i) & 7) * 4)

Not sure if that's too obscure for people? I suppose I could toss in a
comment in there to explain it a bit.

> 
> > 
> > 
> > BR,
> > Jani.
> > 
> > 
> > >  #define   I830_FENCE_START_MASK		0x07f80000
> > >  #define   I830_FENCE_TILING_Y_SHIFT	12
> > >  #define   I830_FENCE_SIZE_BITS(size)	((ffs((size) >> 19) - 1) << 8)
> > > @@ -1451,14 +1451,16 @@ enum skl_disp_power_wells {
> > >  #define   I915_FENCE_START_MASK		0x0ff00000
> > >  #define   I915_FENCE_SIZE_BITS(size)	((ffs((size) >> 20) - 1) << 8)
> > >  
> > > -#define FENCE_REG_965_0			0x03000
> > > +#define FENCE_REG_965_LO(i)		(0x03000 + (i) * 8)
> > > +#define FENCE_REG_965_HI(i)		(0x03000 + (i) * 8 + 4)
> > >  #define   I965_FENCE_PITCH_SHIFT	2
> > >  #define   I965_FENCE_TILING_Y_SHIFT	1
> > >  #define   I965_FENCE_REG_VALID		(1<<0)
> > >  #define   I965_FENCE_MAX_PITCH_VAL	0x0400
> > >  
> > > -#define FENCE_REG_SANDYBRIDGE_0		0x100000
> > > -#define   SANDYBRIDGE_FENCE_PITCH_SHIFT	32
> > > +#define FENCE_REG_GEN6_LO(i)	(0x100000 + (i) * 8)
> > > +#define FENCE_REG_GEN6_HI(i)	(0x100000 + (i) * 8 + 4)
> > > +#define   GEN6_FENCE_PITCH_SHIFT	32
> > >  #define   GEN7_FENCE_MAX_PITCH_VAL	0x0800
> > >  
> > >  
> > > -- 
> > > 2.4.6
> > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > -- 
> > Jani Nikula, Intel Open Source Technology Center
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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