[PATCH 15/22] drm/i915: CHV: Pipe level CSC correction

[Emil Velikov]

On 9 October 2015 at 20:29, Shashank Sharma <shashank.sharma at intel.com> wrote:
> CHV/BSW supports Color Space Conversion (CSC) using a 3x3 matrix
> that needs to be programmed into CGM (Color Gamut Mapping) registers.
>
> This patch does the following:
> 1. Attaches CSC property to CRTC
> 2. Adds the core function to program CSC correction values
> 3. Adds CSC correction macros
>
> 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            |  8 +++
>  drivers/gpu/drm/i915/intel_color_manager.c | 94 ++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_color_manager.h | 19 ++++++
>  3 files changed, 121 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c32e35d..5825ab2 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -8056,4 +8056,12 @@ enum skl_disp_power_wells {
>  #define _PIPE_DEGAMMA_BASE(pipe) \
>         (_PIPE3(pipe, PIPEA_CGM_DEGAMMA, PIPEB_CGM_DEGAMMA, PIPEC_CGM_DEGAMMA))
>
> +#define PIPEA_CGM_CSC                          (VLV_DISPLAY_BASE + 0x67900)
> +#define PIPEB_CGM_CSC                          (VLV_DISPLAY_BASE + 0x69900)
> +#define PIPEC_CGM_CSC                          (VLV_DISPLAY_BASE + 0x6B900)
> +#define _PIPE_CSC_BASE(pipe) \
> +       (_PIPE3(pipe, PIPEA_CGM_CSC, PIPEB_CGM_CSC, PIPEC_CGM_CSC))
> +
> +
> +
>  #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 bbfe185..433e50a 100644
> --- a/drivers/gpu/drm/i915/intel_color_manager.c
> +++ b/drivers/gpu/drm/i915/intel_color_manager.c
> @@ -27,6 +27,93 @@
>
>  #include "intel_color_manager.h"
>
> +static s16 chv_prepare_csc_coeff(s64 csc_value)
> +{
> +       s32 csc_int_value;
> +       u32 csc_fract_value;
> +       s16 csc_s3_12_format;
The type of csc_s3_12_format and chv_prepare_csc_coeff() does not see
correct. Seem like the fix got merged into another patch :\

[snip]
> +static int chv_set_csc(struct drm_device *dev, struct drm_property_blob *blob,
> +               struct drm_crtc *crtc)
> +{
> +       struct drm_ctm *csc_data;
> +       struct drm_i915_private *dev_priv = dev->dev_private;
> +       u32 reg;
> +       enum pipe pipe;
> +       s32 word = 0, temp;
> +       int count = 0;
> +
> +       if (WARN_ON(!blob))
> +               return -EINVAL;
> +
> +       if (blob->length != sizeof(struct drm_ctm)) {
> +               DRM_ERROR("Invalid length of data received\n");
> +               return -EINVAL;
> +       }
> +
> +       csc_data = (struct drm_ctm *)blob->data;
> +       pipe = to_intel_crtc(crtc)->pipe;
> +
> +       /* Disable CSC functionality */
> +       reg = _PIPE_CGM_CONTROL(pipe);
> +       I915_WRITE(reg, I915_READ(reg) & (~CGM_CSC_EN));
> +
> +       DRM_DEBUG_DRIVER("Disabled CSC Functionality on Pipe %c\n",
> +                       pipe_name(pipe));
> +
> +       reg = _PIPE_CSC_BASE(pipe);
> +       while (count < CSC_MAX_VALS) {
> +               temp = chv_prepare_csc_coeff(
> +                                       csc_data->ctm_coeff[count]);
> +               SET_BITS(word, GET_BITS(temp, 16, 16), 0, 16);
> +
> +               /*
> +                * Last value to be written in 1 register.
> +                * Otherwise, each pair of CSC values go
> +                * into 1 register
> +                */
> +               if (count != (CSC_MAX_VALS - 1)) {
> +                       count++;
> +                       temp = chv_prepare_csc_coeff(
> +                                       csc_data->ctm_coeff[count]);
> +                       SET_BITS(word, GET_BITS(temp, 16, 16), 16, 16);
> +               }
This looks a bit odd. Use the same approach as in
bdw_write_12bit_gamma_precision() ?

Regards,
Emil