drm: introduce pipe color correction properties

Patch based on a previous series by Shashank Sharma.

This introduces optional properties to enable color correction at the
pipe level. It relies on 3 transformations applied to every pixels
displayed. First a lookup into a degamma table, then a multiplication
of the rgb components by a 3x3 matrix and finally another lookup into
a gamma table.

The following properties can be added to a pipe :
  - DEGAMMA_LUT : blob containing degamma LUT
  - DEGAMMA_LUT_SIZE : number of elements in DEGAMMA_LUT
  - CTM : transformation matrix applied after the degamma LUT
  - GAMMA_LUT : blob containing gamma LUT
  - GAMMA_LUT_SIZE : number of elements in GAMMA_LUT

DEGAMMA_LUT_SIZE and GAMMA_LUT_SIZE are read only properties, set by
the driver to tell userspace applications what sizes should be the
lookup tables in DEGAMMA_LUT and GAMMA_LUT.

A helper is also provided so legacy gamma correction is redirected
through these new properties.

v2: Register LUT size properties as range

v3: Fix round in drm_color_lut_get_value() helper
    More docs on how degamma/gamma properties are used

v4: Update contributors

v5: Rename CTM_MATRIX property to CTM (Doh!)
    Add legacy gamma_set atomic helper
    Describe CTM/LUT acronyms in the kernel doc

v6: Fix missing blob unref in drm_atomic_helper_crtc_reset

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kumar, Kiran S <kiran.s.kumar@intel.com>
Signed-off-by: Kausal Malladi <kausalmalladi@gmail.com>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Rob Bradford <robert.bradford@intel.com>
[danvet: CrOS maintainers are also happy with the userspacde side:
https://codereview.chromium.org/1182063002/ ]
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1456506302-640-4-git-send-email-lionel.g.landwerlin@intel.com

1 files changed, 109 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 7a034b231792..3e49a0993191 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2495,8 +2495,12 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_dpms);
  */
 void drm_atomic_helper_crtc_reset(struct drm_crtc *crtc)
 {
-	if (crtc->state)
+	if (crtc->state) {
 		drm_property_unreference_blob(crtc->state->mode_blob);
+		drm_property_unreference_blob(crtc->state->degamma_lut);
+		drm_property_unreference_blob(crtc->state->ctm);
+		drm_property_unreference_blob(crtc->state->gamma_lut);
+	}
 	kfree(crtc->state);
 	crtc->state = kzalloc(sizeof(*crtc->state), GFP_KERNEL);
 
@@ -2520,10 +2524,17 @@ void __drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc,
 
 	if (state->mode_blob)
 		drm_property_reference_blob(state->mode_blob);
+	if (state->degamma_lut)
+		drm_property_reference_blob(state->degamma_lut);
+	if (state->ctm)
+		drm_property_reference_blob(state->ctm);
+	if (state->gamma_lut)
+		drm_property_reference_blob(state->gamma_lut);
 	state->mode_changed = false;
 	state->active_changed = false;
 	state->planes_changed = false;
 	state->connectors_changed = false;
+	state->color_mgmt_changed = false;
 	state->event = NULL;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_crtc_duplicate_state);
@@ -2564,6 +2575,9 @@ void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc *crtc,
 					    struct drm_crtc_state *state)
 {
 	drm_property_unreference_blob(state->mode_blob);
+	drm_property_unreference_blob(state->degamma_lut);
+	drm_property_unreference_blob(state->ctm);
+	drm_property_unreference_blob(state->gamma_lut);
 }
 EXPORT_SYMBOL(__drm_atomic_helper_crtc_destroy_state);
 
@@ -2877,3 +2891,97 @@ void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
 	kfree(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
+
+/**
+ * drm_atomic_helper_legacy_gamma_set - set the legacy gamma correction table
+ * @crtc: CRTC object
+ * @red: red correction table
+ * @green: green correction table
+ * @blue: green correction table
+ * @start:
+ * @size: size of the tables
+ *
+ * Implements support for legacy gamma correction table for drivers
+ * that support color management through the DEGAMMA_LUT/GAMMA_LUT
+ * properties.
+ */
+void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
+					u16 *red, u16 *green, u16 *blue,
+					uint32_t start, uint32_t size)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_atomic_state *state;
+	struct drm_crtc_state *crtc_state;
+	struct drm_property_blob *blob = NULL;
+	struct drm_color_lut *blob_data;
+	int i, ret = 0;
+
+	state = drm_atomic_state_alloc(crtc->dev);
+	if (!state)
+		return;
+
+	blob = drm_property_create_blob(dev,
+					sizeof(struct drm_color_lut) * size,
+					NULL);
+	if (!blob) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* Prepare GAMMA_LUT with the legacy values. */
+	blob_data = (struct drm_color_lut *) blob->data;
+	for (i = 0; i < size; i++) {
+		blob_data[i].red = red[i];
+		blob_data[i].green = green[i];
+		blob_data[i].blue = blue[i];
+	}
+
+	state->acquire_ctx = crtc->dev->mode_config.acquire_ctx;
+retry:
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto fail;
+	}
+
+	/* Reset DEGAMMA_LUT and CTM properties. */
+	ret = drm_atomic_crtc_set_property(crtc, crtc_state,
+			config->degamma_lut_property, 0);
+	if (ret)
+		goto fail;
+
+	ret = drm_atomic_crtc_set_property(crtc, crtc_state,
+			config->ctm_property, 0);
+	if (ret)
+		goto fail;
+
+	ret = drm_atomic_crtc_set_property(crtc, crtc_state,
+			config->gamma_lut_property, blob->base.id);
+	if (ret)
+		goto fail;
+
+	ret = drm_atomic_commit(state);
+	if (ret)
+		goto fail;
+
+	/* Driver takes ownership of state on successful commit. */
+
+	drm_property_unreference_blob(blob);
+
+	return;
+fail:
+	if (ret == -EDEADLK)
+		goto backoff;
+
+	drm_atomic_state_free(state);
+	drm_property_unreference_blob(blob);
+
+	return;
+backoff:
+	drm_atomic_state_clear(state);
+	drm_atomic_legacy_backoff(state);
+
+	goto retry;
+}
+EXPORT_SYMBOL(drm_atomic_helper_legacy_gamma_set);