[RFC PATCH 27/40] drm/amd/display: add CRTC regamma TF support

[Melissa Wen]

From: Joshua Ashton <joshua at froggi.es>

Add predefined transfer function programming. There is no out gamma ROM,
but we can use AMD color modules to program LUT parameters from a
predefined TF and an empty regamma LUT (or power LUT parameters with
predefined TF setup).

Signed-off-by: Joshua Ashton <joshua at froggi.es>
---
 .../amd/display/amdgpu_dm/amdgpu_dm_color.c   | 60 ++++++++++++++-----
 1 file changed, 44 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
index ff29be3929af..55aa876a5008 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -268,16 +268,18 @@ static int __set_output_tf(struct dc_transfer_func *func,
 	struct calculate_buffer cal_buffer = {0};
 	bool res;
 
-	ASSERT(lut && lut_size == MAX_COLOR_LUT_ENTRIES);
-
 	cal_buffer.buffer_index = -1;
 
-	gamma = dc_create_gamma();
-	if (!gamma)
-		return -ENOMEM;
+	if (lut_size) {
+		ASSERT(lut && lut_size == MAX_COLOR_LUT_ENTRIES);
 
-	gamma->num_entries = lut_size;
-	__drm_lut_to_dc_gamma(lut, gamma, false);
+		gamma = dc_create_gamma();
+		if (!gamma)
+			return -ENOMEM;
+
+		gamma->num_entries = lut_size;
+		__drm_lut_to_dc_gamma(lut, gamma, false);
+	}
 
 	if (func->tf == TRANSFER_FUNCTION_LINEAR) {
 		/*
@@ -285,30 +287,34 @@ static int __set_output_tf(struct dc_transfer_func *func,
 		 * on top of a linear input. But degamma params can be used
 		 * instead to simulate this.
 		 */
-		gamma->type = GAMMA_CUSTOM;
+		if (gamma)
+			gamma->type = GAMMA_CUSTOM;
 		res = mod_color_calculate_degamma_params(NULL, func,
-							gamma, true);
+							 gamma, gamma != NULL);
 	} else {
 		/*
 		 * Assume sRGB. The actual mapping will depend on whether the
 		 * input was legacy or not.
 		 */
-		gamma->type = GAMMA_CS_TFM_1D;
-		res = mod_color_calculate_regamma_params(func, gamma, false,
+		if (gamma)
+			gamma->type = GAMMA_CS_TFM_1D;
+		res = mod_color_calculate_regamma_params(func, gamma, gamma != NULL,
 							 has_rom, NULL, &cal_buffer);
 	}
 
-	dc_gamma_release(&gamma);
+	if (gamma)
+		dc_gamma_release(&gamma);
 
 	return res ? 0 : -ENOMEM;
 }
 
 static int amdgpu_dm_set_atomic_regamma(struct dc_stream_state *stream,
 					const struct drm_color_lut *regamma_lut,
-					uint32_t regamma_size, bool has_rom)
+					uint32_t regamma_size, bool has_rom,
+					enum dc_transfer_func_predefined tf)
 {
 	int ret = 0;
-	if (regamma_size) {
+	if (regamma_size || tf != TRANSFER_FUNCTION_LINEAR) {
 		/* CRTC RGM goes into RGM LUT.
 		 *
 		 * Note: there is no implicit sRGB regamma here. We are using
@@ -316,7 +322,7 @@ static int amdgpu_dm_set_atomic_regamma(struct dc_stream_state *stream,
 		 * from a linear base.
 		 */
 		stream->out_transfer_func->type = TF_TYPE_DISTRIBUTED_POINTS;
-		stream->out_transfer_func->tf = TRANSFER_FUNCTION_LINEAR;
+		stream->out_transfer_func->tf = tf;
 
 		ret = __set_output_tf(stream->out_transfer_func,
 				      regamma_lut, regamma_size, has_rom);
@@ -364,6 +370,25 @@ static int __set_input_tf(struct dc_transfer_func *func,
 }
 
 #ifdef CONFIG_STEAM_DECK
+static enum dc_transfer_func_predefined drm_tf_to_dc_tf(enum drm_transfer_function drm_tf)
+{
+	switch (drm_tf)
+	{
+	default:
+	case DRM_TRANSFER_FUNCTION_DEFAULT:	return TRANSFER_FUNCTION_LINEAR;
+	case DRM_TRANSFER_FUNCTION_SRGB:	return TRANSFER_FUNCTION_SRGB;
+
+	case DRM_TRANSFER_FUNCTION_BT709:	return TRANSFER_FUNCTION_BT709;
+	case DRM_TRANSFER_FUNCTION_PQ:		return TRANSFER_FUNCTION_PQ;
+	case DRM_TRANSFER_FUNCTION_LINEAR:	return TRANSFER_FUNCTION_LINEAR;
+	case DRM_TRANSFER_FUNCTION_UNITY:	return TRANSFER_FUNCTION_UNITY;
+	case DRM_TRANSFER_FUNCTION_HLG:		return TRANSFER_FUNCTION_HLG;
+	case DRM_TRANSFER_FUNCTION_GAMMA22:	return TRANSFER_FUNCTION_GAMMA22;
+	case DRM_TRANSFER_FUNCTION_GAMMA24:	return TRANSFER_FUNCTION_GAMMA24;
+	case DRM_TRANSFER_FUNCTION_GAMMA26:	return TRANSFER_FUNCTION_GAMMA26;
+	}
+}
+
 static void __to_dc_lut3d_color(struct dc_rgb *rgb,
 				const struct drm_color_lut lut,
 				int bit_precision)
@@ -640,6 +665,7 @@ int amdgpu_dm_update_crtc_color_mgmt(struct dm_crtc_state *crtc,
 	const struct drm_color_lut *degamma_lut, *regamma_lut;
 	uint32_t degamma_size, regamma_size;
 	bool has_regamma, has_degamma;
+	enum dc_transfer_func_predefined tf = TRANSFER_FUNCTION_LINEAR;
 	bool is_legacy;
 	int r;
 #ifdef CONFIG_STEAM_DECK
@@ -652,6 +678,8 @@ int amdgpu_dm_update_crtc_color_mgmt(struct dm_crtc_state *crtc,
 
 	lut3d = __extract_blob_lut(crtc->lut3d, &lut3d_size);
 	shaper_lut = __extract_blob_lut(crtc->shaper_lut, &shaper_size);
+
+	tf = drm_tf_to_dc_tf(crtc->gamma_tf);
 #endif
 
 	r = amdgpu_dm_verify_lut_sizes(&crtc->base);
@@ -718,7 +746,7 @@ int amdgpu_dm_update_crtc_color_mgmt(struct dm_crtc_state *crtc,
 		 */
 		regamma_size = has_regamma ? regamma_size : 0;
 		r = amdgpu_dm_set_atomic_regamma(stream, regamma_lut,
-						 regamma_size, has_rom);
+						 regamma_size, has_rom, tf);
 		if (r)
 			return r;
 	}
-- 
2.39.2