[PATCH 22/22] drm/i915: BDW: Pipe level CSC correction

[Emil Velikov]

Hi Shashank,

On 9 October 2015 at 20:29, Shashank Sharma <shashank.sharma at intel.com> wrote:
> BDW/SKL/BXT support Color Space Conversion (CSC) using a 3x3 matrix
> that needs to be programmed into respective CSC registers.
>
> This patch does the following:
> 1. Adds the core function to program CSC correction values for
>    BDW/SKL/BXT platform
> 2. Adds CSC correction macros/defines
>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> Signed-off-by: Kausal Malladi <kausalmalladi at gmail.com>
> Signed-off-by: Kumar, Kiran S <kiran.s.kumar at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h            |   7 ++
>  drivers/gpu/drm/i915/intel_color_manager.c | 114 ++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_color_manager.h |  12 ++-
>  3 files changed, 129 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index ed50f75..0e9d252 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -8085,4 +8085,11 @@ enum skl_disp_power_wells {
>         (_PIPE3(pipe, PAL_PREC_GCMAX_A, PAL_PREC_GCMAX_B, PAL_PREC_GCMAX_C))
>
>
> +/* BDW CSC correction */
> +#define CSC_COEFF_A                            0x49010
> +#define CSC_COEFF_B                            0x49110
> +#define CSC_COEFF_C                            0x49210
> +#define _PIPE_CSC_COEFF(pipe) \
> +       (_PIPE3(pipe, CSC_COEFF_A, CSC_COEFF_B, CSC_COEFF_C))
> +
>  #endif /* _I915_REG_H_ */
> diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
> index e659382..0a6c00c 100644
> --- a/drivers/gpu/drm/i915/intel_color_manager.c
> +++ b/drivers/gpu/drm/i915/intel_color_manager.c
> @@ -330,11 +330,119 @@ static int bdw_set_degamma(struct drm_device *dev,
>         return 0;
>  }
>
> -static s16 chv_prepare_csc_coeff(s64 csc_value)
As mentioned previously, this should be part of the respective patch.

> +static uint32_t bdw_prepare_csc_coeff(int64_t coeff)
> +{
> +       uint32_t reg_val, ls_bit_pos, exponent_bits, sign_bit = 0;
> +       int32_t mantissa;
> +       uint64_t abs_coeff;
> +
> +       coeff = min_t(int64_t, coeff, BDW_CSC_COEFF_MAX_VAL);
> +       coeff = max_t(int64_t, coeff, BDW_CSC_COEFF_MIN_VAL);
> +
> +       abs_coeff = abs(coeff);
> +       if (abs_coeff < (BDW_CSC_COEFF_UNITY_VAL >> 3)) {
> +               /* abs_coeff < 0.125 */
> +               exponent_bits = 3;
> +               ls_bit_pos = 19;
> +       } else if (abs_coeff >= (BDW_CSC_COEFF_UNITY_VAL >> 3) &&
> +               abs_coeff < (BDW_CSC_COEFF_UNITY_VAL >> 2)) {
> +               /* abs_coeff >= 0.125 && val < 0.25 */
> +               exponent_bits = 2;
> +               ls_bit_pos = 20;
> +       } else if (abs_coeff >= (BDW_CSC_COEFF_UNITY_VAL >> 2)
> +               && abs_coeff < (BDW_CSC_COEFF_UNITY_VAL >> 1)) {
> +               /* abs_coeff >= 0.25 && val < 0.5 */
> +               exponent_bits = 1;
> +               ls_bit_pos = 21;
> +       } else if (abs_coeff >= (BDW_CSC_COEFF_UNITY_VAL >> 1)
> +               && abs_coeff < BDW_CSC_COEFF_UNITY_VAL) {
> +               /* abs_coeff >= 0.5 && val < 1.0 */
> +               exponent_bits = 0;
> +               ls_bit_pos = 22;
> +       } else if (abs_coeff >= BDW_CSC_COEFF_UNITY_VAL &&
> +               abs_coeff < (BDW_CSC_COEFF_UNITY_VAL << 1)) {
> +               /* abs_coeff >= 1.0 && val < 2.0 */
> +               exponent_bits = 7;
> +               ls_bit_pos = 23;
> +       } else {
> +               /* abs_coeff >= 2.0 && val < 4.0 */
> +               exponent_bits = 6;
> +               ls_bit_pos = 24;
> +       }
> +
> +       mantissa = GET_BITS_ROUNDOFF(abs_coeff, ls_bit_pos, CSC_MAX_VALS);
> +       if (coeff < 0) {
> +               sign_bit = 1;
> +               mantissa = -mantissa;
> +               mantissa &= ((1 << CSC_MAX_VALS) - 1);
I think there is a macro for this already ?

> +       }
> +
> +       reg_val = 0;
> +       SET_BITS(reg_val, exponent_bits, 12, 3);
> +       SET_BITS(reg_val, mantissa, 3, 9);
> +       SET_BITS(reg_val, sign_bit, 15, 1);
> +       DRM_DEBUG_DRIVER("CSC: reg_val=0x%x\n", reg_val);
> +       return reg_val;
> +}
> +
> +int bdw_set_csc(struct drm_device *dev, struct drm_property_blob *blob,
> +               struct drm_crtc *crtc)
> +{
The function should be static ?

Regards,
Emil