[PATCH v2 01/12] drm: Inline drm_color_lut_extract()

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

This thing can get called several thousand times per LUT
so seems like we want to inline it to:
- avoid the function call overhead
- allow constant folding

A quick synthetic test (w/o any hardware interaction) with
a ridiculously large LUT size shows about 50% reduction in
runtime on my HSW and BSW boxes. Slightly less with more
reasonable LUT size but still easily measurable in tens
of microseconds.

v2: Include drm_color_mgmt.h in the .rst (Daniel)

Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 Documentation/gpu/drm-kms.rst    |  3 +++
 drivers/gpu/drm/drm_color_mgmt.c | 24 ------------------------
 include/drm/drm_color_mgmt.h     | 23 ++++++++++++++++++++++-
 3 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index 23a3c986ef6d..c68588ce4090 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -479,6 +479,9 @@ Color Management Properties
 .. kernel-doc:: drivers/gpu/drm/drm_color_mgmt.c
    :export:
 
+.. kernel-doc:: include/drm/drm_color_mgmt.h
+   :internal:
+
 Tile Group Property
 -------------------
 
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 4ce5c6d8de99..19c5f635992a 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -108,30 +108,6 @@
  * 	standard enum values supported by the DRM plane.
  */
 
-/**
- * drm_color_lut_extract - clamp and round LUT entries
- * @user_input: input value
- * @bit_precision: number of bits the hw LUT supports
- *
- * Extract a degamma/gamma LUT value provided by user (in the form of
- * &drm_color_lut entries) and round it to the precision supported by the
- * hardware.
- */
-uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision)
-{
-	uint32_t val = user_input;
-	uint32_t max = 0xffff >> (16 - bit_precision);
-
-	/* Round only if we're not using full precision. */
-	if (bit_precision < 16) {
-		val += 1UL << (16 - bit_precision - 1);
-		val >>= 16 - bit_precision;
-	}
-
-	return clamp_val(val, 0, max);
-}
-EXPORT_SYMBOL(drm_color_lut_extract);
-
 /**
  * drm_crtc_enable_color_mgmt - enable color management properties
  * @crtc: DRM CRTC
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index d1c662d92ab7..069b21d61871 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -29,7 +29,28 @@
 struct drm_crtc;
 struct drm_plane;
 
-uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision);
+/**
+ * drm_color_lut_extract - clamp and round LUT entries
+ * @user_input: input value
+ * @bit_precision: number of bits the hw LUT supports
+ *
+ * Extract a degamma/gamma LUT value provided by user (in the form of
+ * &drm_color_lut entries) and round it to the precision supported by the
+ * hardware.
+ */
+static inline u32 drm_color_lut_extract(u32 user_input, int bit_precision)
+{
+	u32 val = user_input;
+	u32 max = 0xffff >> (16 - bit_precision);
+
+	/* Round only if we're not using full precision. */
+	if (bit_precision < 16) {
+		val += 1UL << (16 - bit_precision - 1);
+		val >>= 16 - bit_precision;
+	}
+
+	return clamp_val(val, 0, max);
+}
 
 void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
 				uint degamma_lut_size,
-- 
2.23.0