Re: [Intel-gfx] [PATCH v2 01/18] drm/i915: Clean up legacy palette defines

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

On Fri, Nov 11, 2022 at 05:09:37PM +0200, Jani Nikula wrote:
> On Thu, 10 Nov 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Use consistent bit definitions for the legacy gamma LUT. We just
> > define these alongside the pre-ilk register definitions and point
> > to those from the ilk+ defines.
> >
> > Also use the these appropriately in the LUT entry pack/unpack
> > functions.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_color.c | 24 +++++++++++-----------
> >  drivers/gpu/drm/i915/i915_reg.h            | 11 +++++-----
> >  2 files changed, 17 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
> > index 93509cf7bbcc..ff4a5167df57 100644
> > --- a/drivers/gpu/drm/i915/display/intel_color.c
> > +++ b/drivers/gpu/drm/i915/display/intel_color.c
> > @@ -424,32 +424,32 @@ static u32 intel_color_lut_pack(u32 val, int bit_precision)
> >  
> >  static u32 i9xx_lut_8(const struct drm_color_lut *color)
> >  {
> > -	return drm_color_lut_extract(color->red, 8) << 16 |
> > -		drm_color_lut_extract(color->green, 8) << 8 |
> > -		drm_color_lut_extract(color->blue, 8);
> > +	return REG_FIELD_PREP(PALETTE_RED_MASK, drm_color_lut_extract(color->red, 8)) |
> > +		REG_FIELD_PREP(PALETTE_GREEN_MASK, drm_color_lut_extract(color->green, 8)) |
> > +		REG_FIELD_PREP(PALETTE_BLUE_MASK, drm_color_lut_extract(color->blue, 8));
> >  }
> >  
> >  static void i9xx_lut_8_pack(struct drm_color_lut *entry, u32 val)
> >  {
> > -	entry->red = intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_RED_MASK, val), 8);
> > -	entry->green = intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_GREEN_MASK, val), 8);
> > -	entry->blue = intel_color_lut_pack(REG_FIELD_GET(LGC_PALETTE_BLUE_MASK, val), 8);
> > +	entry->red = intel_color_lut_pack(REG_FIELD_GET(PALETTE_RED_MASK, val), 8);
> > +	entry->green = intel_color_lut_pack(REG_FIELD_GET(PALETTE_GREEN_MASK, val), 8);
> > +	entry->blue = intel_color_lut_pack(REG_FIELD_GET(PALETTE_BLUE_MASK, val), 8);
> >  }
> >  
> >  /* i965+ "10.6" bit interpolated format "even DW" (low 8 bits) */
> >  static u32 i965_lut_10p6_ldw(const struct drm_color_lut *color)
> >  {
> > -	return (color->red & 0xff) << 16 |
> > -		(color->green & 0xff) << 8 |
> > -		(color->blue & 0xff);
> > +	return REG_FIELD_PREP(PALETTE_RED_MASK, color->red & 0xff) |
> > +		REG_FIELD_PREP(PALETTE_GREEN_MASK, color->green & 0xff) |
> > +		REG_FIELD_PREP(PALETTE_BLUE_MASK, color->blue & 0xff);
> 
> The & 0xff masking is redundant with REG_FIELD_PREP(), but I understand
> if you want to leave them in for consistency with the next function.

It's redundant as long as REG_FIELD_PREP() only checks
constexpr values. I have occasionally pondered about making
it do runtime checks for non-constexpr values as well, at
least for CI runs. Just never managed to write the patch
for that...

> 
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Thanks.

> 
> >  }
> >  
> >  /* i965+ "10.6" interpolated format "odd DW" (high 8 bits) */
> >  static u32 i965_lut_10p6_udw(const struct drm_color_lut *color)
> >  {
> > -	return (color->red >> 8) << 16 |
> > -		(color->green >> 8) << 8 |
> > -		(color->blue >> 8);
> > +	return REG_FIELD_PREP(PALETTE_RED_MASK, color->red >> 8) |
> > +		REG_FIELD_PREP(PALETTE_GREEN_MASK, color->green >> 8) |
> > +		REG_FIELD_PREP(PALETTE_BLUE_MASK, color->blue >> 8);
> >  }
> >  
> >  static void i965_lut_10p6_pack(struct drm_color_lut *entry, u32 ldw, u32 udw)
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index a37ed0c61f20..91ee00c347e4 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -1782,9 +1782,10 @@
> >  #define _PALETTE_A		0xa000
> >  #define _PALETTE_B		0xa800
> >  #define _CHV_PALETTE_C		0xc000
> > -#define PALETTE_RED_MASK        REG_GENMASK(23, 16)
> > -#define PALETTE_GREEN_MASK      REG_GENMASK(15, 8)
> > -#define PALETTE_BLUE_MASK       REG_GENMASK(7, 0)
> > +/* 8bit mode / i965+ 10.6 interpolated mode ldw/udw */
> > +#define   PALETTE_RED_MASK		REG_GENMASK(23, 16)
> > +#define   PALETTE_GREEN_MASK		REG_GENMASK(15, 8)
> > +#define   PALETTE_BLUE_MASK		REG_GENMASK(7, 0)
> >  #define PALETTE(pipe, i)	_MMIO(DISPLAY_MMIO_BASE(dev_priv) + \
> >  				      _PICK((pipe), _PALETTE_A,		\
> >  					    _PALETTE_B, _CHV_PALETTE_C) + \
> > @@ -5380,9 +5381,7 @@
> >  /* legacy palette */
> >  #define _LGC_PALETTE_A           0x4a000
> >  #define _LGC_PALETTE_B           0x4a800
> > -#define LGC_PALETTE_RED_MASK     REG_GENMASK(23, 16)
> > -#define LGC_PALETTE_GREEN_MASK   REG_GENMASK(15, 8)
> > -#define LGC_PALETTE_BLUE_MASK    REG_GENMASK(7, 0)
> > +/* see PALETTE_* for the bits */
> >  #define LGC_PALETTE(pipe, i) _MMIO(_PIPE(pipe, _LGC_PALETTE_A, _LGC_PALETTE_B) + (i) * 4)
> >  
> >  /* ilk/snb precision palette */
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Ville Syrjälä
Intel