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

[Emil Velikov]

On 10 October 2015 at 06:34, Sharma, Shashank <shashank.sharma at intel.com> wrote:
> On 10/10/2015 5:24 AM, Emil Velikov wrote:
>>
>> 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.
>>
> Agree. Looks like diff is messing up a bit. Will take care of this.
>
>>> +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 ?
>>
> Thats for GAMMA_MAX, not for CSC_MAX. Or you mean the whole (1 <<
> CSC_MAX_VALS -1) to be replaced with GET/SET bits ?
What I mean is - the above looks exactly like the GET_BIT_MASK (which
you introduced). Perhaps you can use it ?

Regards,
Emil