[PATCH V11 33/47] drm: Add Enhanced LUT precision structure

[Alex Hung]

From: Uma Shankar <uma.shankar at intel.com>

Existing LUT precision structure drm_color_lut has only 16 bit
precision. This is not enough for upcoming enhanced hardwares
and advance usecases like HDR processing. Hence added a new
structure with 32 bit precision values.

Signed-off-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
---
v11:
 - Update names from *_lut_32_* to *_lut32_* (Simon Ser)

v10:
 - Include drm_color_lut_32 from Intel to support 32BIT RGB in 1D & 3D
   LUTs (Uma Shankar)

 drivers/gpu/drm/drm_color_mgmt.c | 43 ++++++++++++++++++++++++++++++++
 include/drm/drm_color_mgmt.h     | 13 ++++++++++
 include/uapi/drm/drm_mode.h      | 12 +++++++++
 3 files changed, 68 insertions(+)

diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 37a3270bc3c2..9c469f7fe0df 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -840,3 +840,46 @@ void drm_crtc_fill_palette_8(struct drm_crtc *crtc, drm_crtc_set_lut_func set_pa
 		fill_palette_8(crtc, i, set_palette);
 }
 EXPORT_SYMBOL(drm_crtc_fill_palette_8);
+
+/**
+ * drm_color_lut32_check - check validity of extended lookup table
+ * @lut: property blob containing extended LUT to check
+ * @tests: bitmask of tests to run
+ *
+ * Helper to check whether a userspace-provided extended lookup table is valid and
+ * satisfies hardware requirements.  Drivers pass a bitmask indicating which of
+ * the tests in &drm_color_lut_tests should be performed.
+ *
+ * Returns 0 on success, -EINVAL on failure.
+ */
+int drm_color_lut32_check(const struct drm_property_blob *lut, u32 tests)
+{
+	const struct drm_color_lut32 *entry;
+	int i;
+
+	if (!lut || !tests)
+		return 0;
+
+	entry = lut->data;
+	for (i = 0; i < drm_color_lut32_size(lut); i++) {
+		if (tests & DRM_COLOR_LUT_EQUAL_CHANNELS) {
+			if (entry[i].red != entry[i].blue ||
+			    entry[i].red != entry[i].green) {
+				DRM_DEBUG_KMS("All LUT entries must have equal r/g/b\n");
+				return -EINVAL;
+			}
+		}
+
+		if (i > 0 && tests & DRM_COLOR_LUT_NON_DECREASING) {
+			if (entry[i].red < entry[i - 1].red ||
+			    entry[i].green < entry[i - 1].green ||
+			    entry[i].blue < entry[i - 1].blue) {
+				DRM_DEBUG_KMS("LUT entries must never decrease.\n");
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_color_lut32_check);
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index 6cb577f6dba6..c422f352a150 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -72,6 +72,18 @@ static inline int drm_color_lut_size(const struct drm_property_blob *blob)
 	return blob->length / sizeof(struct drm_color_lut);
 }
 
+/**
+ * drm_color_lut32_size - calculate the number of entries in the extended LUT
+ * @blob: blob containing the LUT
+ *
+ * Returns:
+ * The number of entries in the color LUT stored in @blob.
+ */
+static inline int drm_color_lut32_size(const struct drm_property_blob *blob)
+{
+	return blob->length / sizeof(struct drm_color_lut32);
+}
+
 enum drm_color_encoding {
 	DRM_COLOR_YCBCR_BT601,
 	DRM_COLOR_YCBCR_BT709,
@@ -145,4 +157,5 @@ void drm_crtc_load_palette_8(struct drm_crtc *crtc, const struct drm_color_lut *
 
 void drm_crtc_fill_palette_8(struct drm_crtc *crtc, drm_crtc_set_lut_func set_palette);
 
+int drm_color_lut32_check(const struct drm_property_blob *lut, u32 tests);
 #endif
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index f309d2863180..bcc4e9845881 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -872,6 +872,18 @@ struct drm_color_lut {
 	__u16 reserved;
 };
 
+/*
+ * struct drm_color_lut32
+ *
+ * 32-bit per channel color LUT entry, similar to drm_color_lut.
+ */
+struct drm_color_lut32 {
+	__u32 red;
+	__u32 green;
+	__u32 blue;
+	__u32 reserved;
+};
+
 /**
  * enum drm_colorop_type - Type of color operation
  *
-- 
2.43.0