Re: [PATCH 09/12] drm/i915: Add pipe level Gamma correction for CHV/BSW

["Malladi, Kausal" <Kausal.Malladi@intel.com>]

On Wednesday 08 July 2015 04:53 AM, Matt Roper wrote:
> On Fri, Jul 03, 2015 at 09:01:44AM +0530, Kausal Malladi wrote:
>> CHV/BSW platform supports various Gamma correction modes, which are:
>> 1. Legacy 8-bit mode
>> 2. 10-bit CGM (Color Gamut Mapping) mode
>>
>> This patch does the following:
>> 1. Adds the core function to program Gamma correction values for CHV/BSW
>>     platform
>> 2. Adds Gamma correction macros/defines
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
>> Signed-off-by: Kausal Malladi <Kausal.Malladi@intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_reg.h            |  10 ++
>>   drivers/gpu/drm/i915/intel_atomic.c        |   6 ++
>>   drivers/gpu/drm/i915/intel_color_manager.c | 154 +++++++++++++++++++++++++++++
>>   drivers/gpu/drm/i915/intel_color_manager.h |  12 +++
>>   drivers/gpu/drm/i915/intel_drv.h           |   2 +
>>   5 files changed, 184 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 313b1f9..36672e7 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -7900,4 +7900,14 @@ enum skl_disp_power_wells {
>>   #define _PALETTE_A (dev_priv->info.display_mmio_offset + 0xa000)
>>   #define _PALETTE_B (dev_priv->info.display_mmio_offset + 0xa800)
>>   
>> +/* Color Management */
>> +#define PIPEA_CGM_CONTROL			(VLV_DISPLAY_BASE + 0x67A00)
>> +#define PIPEA_CGM_GAMMA_MIN			(VLV_DISPLAY_BASE + 0x67000)
>> +#define CGM_OFFSET				0x2000
>> +#define GAMMA_OFFSET				0x2000
>> +#define _PIPE_CGM_CONTROL(pipe) \
>> +	(PIPEA_CGM_CONTROL + (pipe * CGM_OFFSET))
>> +#define _PIPE_GAMMA_BASE(pipe) \
>> +	(PIPEA_CGM_GAMMA_MIN + (pipe * GAMMA_OFFSET))
>> +
>>   #endif /* _I915_REG_H_ */
>> diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
>> index d2674a6..21f0ac2 100644
>> --- a/drivers/gpu/drm/i915/intel_atomic.c
>> +++ b/drivers/gpu/drm/i915/intel_atomic.c
>> @@ -473,6 +473,12 @@ int intel_crtc_atomic_set_property(struct drm_crtc *crtc,
>>   				   struct drm_property *property,
>>   				   uint64_t val)
>>   {
>> +	struct drm_device *dev = crtc->dev;
>> +	struct drm_mode_config *config = &dev->mode_config;
>> +
>> +	if (property == config->prop_palette_after_ctm)
>> +		return intel_color_manager_set_gamma(dev, &crtc->base, val);
>> +
> I think we discussed this on a previous iteration of the patch series,
> but .atomic_set_property() isn't supposed to actually update the
> hardware at all itself (as you're doing here); it's only supposed to
> update the 'state' parameter that was passed here.  Further down the
> atomic pipeline the driver will decide whether it really wants to
> program any of the state or not and then the CRTC's atomic commit
> function should program the registers according to whatever value is set
> in the state object.
Thanks Matt for your suggestions offline. We will implement it this way 
in our next set of patches.
>
>>   	DRM_DEBUG_KMS("Unknown crtc property '%s'\n", property->name);
>>   	return -EINVAL;
>>   }
>> diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
>> index 71b4c05..84cc3e47 100644
>> --- a/drivers/gpu/drm/i915/intel_color_manager.c
>> +++ b/drivers/gpu/drm/i915/intel_color_manager.c
>> @@ -27,6 +27,160 @@
>>   
>>   #include "intel_color_manager.h"
>>   
>> +int chv_set_gamma(struct drm_device *dev, uint32_t blob_id,
>> +		  struct drm_crtc *crtc)
>> +{
>> +	struct drm_palette *gamma_data;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	struct drm_property_blob *blob;
>> +	struct drm_mode_config *config = &dev->mode_config;
>> +	u32 cgm_control_reg = 0;
>> +	u32 cgm_gamma_reg = 0;
>> +	u32 reg, val;
>> +	enum pipe pipe;
>> +	u16 red, green, blue;
>> +	u32 count = 0;
>> +	struct drm_r32g32b32 *correction_values = NULL;
>> +	u32 num_samples;
>> +	u32 word;
>> +	u32 palette;
>> +	int ret = 0, length;
>> +
>> +	blob = drm_property_lookup_blob(dev, blob_id);
>> +	if (!blob) {
>> +		DRM_ERROR("Invalid Blob ID\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	gamma_data = (struct drm_palette *)blob->data;
> Do we need to validate that the blob we receive is of the expected size
> or does something in the DRM core's blob handling take care of that for
> us?  We don't want userspace to be able to trigger a panic by passing a
> smaller than expected blob here.
Yes, it was an oversight.
>
>
>> +
>> +	if (gamma_data->version != CHV_GAMMA_DATA_STRUCT_VERSION) {
>> +		DRM_ERROR("Invalid Gamma Data struct version\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	pipe = to_intel_crtc(crtc)->pipe;
>> +	num_samples = gamma_data->palette_num_samples;
>> +	length = num_samples * sizeof(struct drm_r32g32b32);
>> +
>> +	if (num_samples == 0) {
>> +
>> +		/* Disable Gamma functionality on Pipe - CGM Block */
>> +		cgm_control_reg = I915_READ(_PIPE_CGM_CONTROL(pipe));
>> +		cgm_control_reg &= ~CGM_GAMMA_EN;
>> +		I915_WRITE(_PIPE_CGM_CONTROL(pipe), cgm_control_reg);
>> +
>> +		DRM_DEBUG_DRIVER("Gamma disabled on Pipe %c\n",
>> +				pipe_name(pipe));
>> +		ret = 0;
>> +	} else if (num_samples == CHV_8BIT_GAMMA_MAX_VALS) {
>> +
>> +		/* Disable CGM Gamma, if already set */
>> +		cgm_control_reg = I915_READ(_PIPE_CGM_CONTROL(pipe));
>> +		cgm_control_reg &= ~CGM_GAMMA_EN;
>> +		I915_WRITE(_PIPE_CGM_CONTROL(pipe), cgm_control_reg);
>> +
>> +		/* Write LUT values to registers */
>> +		palette = _PIPE_GAMMA_BASE(pipe);
>> +		count = 0;
>> +		correction_values =
>> +			(struct drm_r32g32b32 *)&gamma_data->palette_lut;
>> +		while (count < num_samples) {
>> +			blue = correction_values[count].b32;
>> +			green = correction_values[count].g32;
>> +			red = correction_values[count].r32;
>> +
>> +			blue = blue >> CHV_8BIT_GAMMA_MSB_SHIFT;
>> +			green = green >> CHV_8BIT_GAMMA_MSB_SHIFT;
>> +			red = red >> CHV_8BIT_GAMMA_MSB_SHIFT;
>> +
>> +			/* Red (23:16), Green (15:8), Blue (7:0) */
>> +			word = (red << CHV_8BIT_GAMMA_SHIFT_RED_REG) |
>> +				(green <<
>> +				 CHV_8BIT_GAMMA_SHIFT_GREEN_REG) |
>> +				blue;
>> +			I915_WRITE(palette, word);
>> +
>> +			palette += 4;
>> +			count++;
>> +		}
>> +		DRM_DEBUG_DRIVER("Gamma LUT loaded successfully for Pipe %c\n",
>> +				pipe_name(pipe));
>> +
>> +		/* Enable Gamma on Pipe */
>> +		reg = PIPECONF(pipe);
>> +		val = I915_READ(reg) | PIPECONF_GAMMA;
>> +		I915_WRITE(reg, val);
>> +		DRM_DEBUG_DRIVER("Legacy Gamma enabled on Pipe %c\n",
>> +				pipe_name(pipe));
>> +
>> +		ret = 0;
>> +	} else if (num_samples == CHV_10BIT_GAMMA_MAX_VALS) {
>> +		cgm_gamma_reg = _PIPE_GAMMA_BASE(pipe);
>> +
>> +		count = 0;
>> +		correction_values =
>> +			(struct drm_r32g32b32 *)&gamma_data->palette_lut;
>> +		while (count < num_samples) {
>> +			blue = correction_values[count].b32;
>> +			green = correction_values[count].g32;
>> +			red = correction_values[count].r32;
>> +
>> +			blue = blue >> CHV_10BIT_GAMMA_MSB_SHIFT;
>> +			green = green >> CHV_10BIT_GAMMA_MSB_SHIFT;
>> +			red = red >> CHV_10BIT_GAMMA_MSB_SHIFT;
>> +
>> +			/* Green (25:16) and Blue (9:0) to be written */
>> +			word = (green << CHV_GAMMA_SHIFT_GREEN) | blue;
>> +			I915_WRITE(cgm_gamma_reg, word);
>> +			cgm_gamma_reg += 4;
>> +
>> +			/* Red (9:0) to be written */
>> +			word = red;
>> +			I915_WRITE(cgm_gamma_reg, word);
>> +
>> +			cgm_gamma_reg += 4;
>> +			count++;
>> +		}
>> +		DRM_DEBUG_DRIVER("Gamma LUT loaded successfully for Pipe %c\n",
>> +			pipe_name(pipe));
>> +
>> +		/* Enable (CGM) Gamma on Pipe */
>> +		I915_WRITE(_PIPE_CGM_CONTROL(pipe),
>> +			I915_READ(_PIPE_CGM_CONTROL(pipe))
>> +			| CGM_GAMMA_EN);
>> +		DRM_DEBUG_DRIVER("CGM Gamma enabled on Pipe %c\n",
>> +				pipe_name(pipe));
>> +
>> +		ret = 0;
>> +	} else {
>> +		DRM_ERROR("Invalid number of samples for Gamma LUT\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = drm_property_replace_global_blob(dev, &blob, length,
>> +			(void *) gamma_data, &crtc->base,
>> +			config->prop_palette_after_ctm);
>> +
>> +	if (ret) {
>> +		DRM_ERROR("Error updating Gamma blob\n");
>> +		return -EFAULT;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +int intel_color_manager_set_gamma(struct drm_device *dev,
>> +		struct drm_mode_object *obj, uint32_t blob_id)
>> +{
>> +	struct drm_crtc *crtc = obj_to_crtc(obj);
>> +
>> +	if (IS_CHERRYVIEW(dev))
>> +		return chv_set_gamma(dev, blob_id, crtc);
>> +
>> +	return -EINVAL;
> As noted earlier, it seems confusing to me to have userspace see a CRTC
> property for functionality that isn't supported at all on the platform,
> but if we're going to reject invalid platforms here, we should have at
> least a DRM_DEBUG message to give some clues as to why the -EINVAL was
> returned.
As suggested by you, if we put check while attaching, this is not 
required. So will have it there and remove here.
>
>
>> +}
>> +
>>   int get_chv_pipe_capabilities(struct drm_device *dev,
>>   		struct drm_color_caps *color_caps, struct drm_crtc *crtc)
>>   {
>> diff --git a/drivers/gpu/drm/i915/intel_color_manager.h b/drivers/gpu/drm/i915/intel_color_manager.h
>> index 32262ac..d83567a 100644
>> --- a/drivers/gpu/drm/i915/intel_color_manager.h
>> +++ b/drivers/gpu/drm/i915/intel_color_manager.h
>> @@ -31,6 +31,8 @@
>>   #define CHV_PALETTE_STRUCT_VERSION		1
>>   #define CHV_CTM_STRUCT_VERSION			1
>>   #define CHV_PLATFORM_STRUCT_VERSION		1
>> +#define CHV_GAMMA_DATA_STRUCT_VERSION		1
>> +
>>   #define CHV_MAX_PALETTE_CAPS_BEFORE_CTM		1
>>   #define CHV_MAX_PALETTE_CAPS_AFTER_CTM		2
>>   #define CHV_DEGAMMA_PRECISION			14
>> @@ -43,6 +45,16 @@
>>   #define CHV_10BIT_GAMMA_MAX_VALS		257
>>   #define CHV_8BIT_GAMMA_PRECISION		8
>>   #define CHV_8BIT_GAMMA_MAX_VALS			256
>> +#define CHV_8BIT_GAMMA_MSB_SHIFT		8
>> +#define CHV_8BIT_GAMMA_SHIFT_RED_REG		16
>> +#define CHV_8BIT_GAMMA_SHIFT_GREEN_REG		8
>> +#define CHV_10BIT_GAMMA_MSB_SHIFT		6
>> +#define CHV_GAMMA_SHIFT_GREEN			16
>> +
>>   #define CHV_CSC_COEFF_MAX_PRECISION		12
>>   #define CHV_CSC_COEFF_MAX_INT			7
>>   #define CHV_CSC_COEFF_MIN_INT			-7
>> +
>> +/* CHV CGM Block */
>> +/* Bit 2 to be enabled in CGM block for CHV */
>> +#define CGM_GAMMA_EN				4
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> index 053ceb0..a7aaadf 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -1453,5 +1453,7 @@ extern const struct drm_plane_helper_funcs intel_plane_helper_funcs;
>>   /* intel_color_manager.c */
>>   void intel_color_manager_attach(struct drm_device *dev,
>>   		struct drm_mode_object *mode_obj);
>> +int intel_color_manager_set_gamma(struct drm_device *dev,
>> +		struct drm_mode_object *obj, uint32_t blob_id);
>>   
>>   #endif /* __INTEL_DRV_H__ */
>> -- 
>> 2.4.5
>>

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