[Intel-gfx] [v4 2/4] drm/i915/icl: Add icl pipe degamma and gamma support

[Matt Roper]

On Fri, Dec 21, 2018 at 01:29:39AM +0530, Uma Shankar wrote:
> Add support for icl pipe degamma and gamma.
> 
> v2: Removed a POSTING_READ and corrected the Bit
> Definition as per Maarten's comments.
> 
> v3: Addressed Matt's review comments. Removed rmw patterns
> as suggested by Matt.
> 
> v4: Fixed Matt's review comments.
> 
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h    |  3 ++
>  drivers/gpu/drm/i915/intel_color.c | 67 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 70 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 02af9b5..1852c33 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7092,6 +7092,9 @@ enum {
>  #define GAMMA_MODE_MODE_12BIT	(2 << 0)
>  #define GAMMA_MODE_MODE_SPLIT	(3 << 0)
>  
> +#define	PRE_CSC_GAMMA_ENABLE	(1 << 31)
> +#define	POST_CSC_GAMMA_ENABLE	(1 << 30)
> +
>  /* DMC/CSR */
>  #define CSR_PROGRAM(i)		_MMIO(0x80000 + (i) * 4)
>  #define CSR_SSP_BASE_ADDR_GEN9	0x00002FC0
> diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
> index f32e4a7..e72d8d6 100644
> --- a/drivers/gpu/drm/i915/intel_color.c
> +++ b/drivers/gpu/drm/i915/intel_color.c
> @@ -534,6 +534,71 @@ static void glk_load_luts(struct intel_crtc_state *crtc_state)
>  	POSTING_READ(GAMMA_MODE(pipe));
>  }
>  
> +static void icl_load_degamma_lut(struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_device *dev = crtc_state->base.crtc->dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
> +	const uint32_t lut_size = INTEL_INFO(dev_priv)->color.degamma_lut_size;
> +	uint32_t i;
> +
> +	/*
> +	 * When setting the auto-increment bit, the hardware seems to
> +	 * ignore the index bits, so we need to reset it to index 0
> +	 * separately.
> +	 */
> +	I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), 0);
> +	I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), PRE_CSC_GAMC_AUTO_INCREMENT);
> +
> +	if (crtc_state->base.degamma_lut) {
> +		struct drm_color_lut *lut = crtc_state->base.degamma_lut->data;
> +
> +		for (i = 0; i < lut_size; i++) {
> +			/*
> +			 * First 33 entries represent range from 0 to 1.0
> +			 * 34th and 35th entry will represent extended range
> +			 * inputs 3.0 and 7.0 respectively, currently clamped
> +			 * at 1.0. Since the precision is 16bit, the user value
> +			 * can be directly filled to register.
> +			 * ToDo: Extend to max 7.0.
> +			 */
> +			I915_WRITE(PRE_CSC_GAMC_DATA(pipe), lut[i].red);

Since 1.0 = 0x100, should we scale this by (0x100 / 0xFF) until we have
the newer segmented gamma ABI you're working on?

> +		}
> +	} else {
> +		/* load a linear table. */
> +		for (i = 0; i < lut_size; i++) {
> +			uint32_t v = (i * (1 << 16)) / (lut_size - 1);
> +
> +			I915_WRITE(PRE_CSC_GAMC_DATA(pipe), v);
> +		}
> +	}
> +
> +	/* Clamp values > 1.0. */
> +	while (i++ < 35)
> +		I915_WRITE(PRE_CSC_GAMC_DATA(pipe), (1 << 16));
> +}
> +
> +static void icl_load_luts(struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_crtc *crtc = crtc_state->base.crtc;
> +	struct drm_device *dev = crtc_state->base.crtc->dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	enum pipe pipe = to_intel_crtc(crtc)->pipe;
> +	u32 gamma_mode = 0;
> +
> +	if (crtc_state_is_legacy_gamma(crtc_state)) {
> +		haswell_load_luts(crtc_state);
> +		return;
> +	}
> +
> +	icl_load_degamma_lut(crtc_state);
> +	bdw_load_gamma_lut(crtc_state, 0);
> +
> +	gamma_mode = GAMMA_MODE_MODE_10BIT | PRE_CSC_GAMMA_ENABLE
> +			| POST_CSC_GAMMA_ENABLE;
> +	I915_WRITE(GAMMA_MODE(pipe), gamma_mode);

We might as well just stick these constants right in the I915_WRITE
call; no need to create a separate local variable to hold them.


Matt

> +}
> +
>  /* Loads the palette/gamma unit for the CRTC on CherryView. */
>  static void cherryview_load_luts(struct intel_crtc_state *crtc_state)
>  {
> @@ -649,6 +714,8 @@ void intel_color_init(struct intel_crtc *crtc)
>  	} else if (IS_GEMINILAKE(dev_priv) || IS_CANNONLAKE(dev_priv)) {
>  		dev_priv->display.load_csc_matrix = ilk_load_csc_matrix;
>  		dev_priv->display.load_luts = glk_load_luts;
> +	} else if (IS_ICELAKE(dev_priv)) {
> +		dev_priv->display.load_luts = icl_load_luts;
>  	} else {
>  		dev_priv->display.load_luts = i9xx_load_luts;
>  	}
> -- 
> 1.9.1
> 

-- 
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795