2 * Copyright (c) 2016 Intel Corporation
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5 * documentation for any purpose is hereby granted without fee, provided that
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24 #include <drm/drm_crtc.h>
25 #include <drm/drm_color_mgmt.h>
27 #include "drm_crtc_internal.h"
32 * Color management or color space adjustments is supported through a set of 5
33 * properties on the &drm_crtc object. They are set up by calling
34 * drm_crtc_enable_color_mgmt().
37 * Blob property to set the degamma lookup table (LUT) mapping pixel data
38 * from the framebuffer before it is given to the transformation matrix.
39 * The data is interpreted as an array of &struct drm_color_lut elements.
40 * Hardware might choose not to use the full precision of the LUT elements
41 * nor use all the elements of the LUT (for example the hardware might
42 * choose to interpolate between LUT[0] and LUT[4]).
44 * Setting this to NULL (blob property value set to 0) means a
45 * linear/pass-thru gamma table should be used. This is generally the
46 * driver boot-up state too. Drivers can access this blob through
47 * &drm_crtc_state.degamma_lut.
50 * Unsinged range property to give the size of the lookup table to be set
51 * on the DEGAMMA_LUT property (the size depends on the underlying
52 * hardware). If drivers support multiple LUT sizes then they should
53 * publish the largest size, and sub-sample smaller sized LUTs (e.g. for
54 * split-gamma modes) appropriately.
57 * Blob property to set the current transformation matrix (CTM) apply to
58 * pixel data after the lookup through the degamma LUT and before the
59 * lookup through the gamma LUT. The data is interpreted as a struct
62 * Setting this to NULL (blob property value set to 0) means a
63 * unit/pass-thru matrix should be used. This is generally the driver
64 * boot-up state too. Drivers can access the blob for the color conversion
65 * matrix through &drm_crtc_state.ctm.
68 * Blob property to set the gamma lookup table (LUT) mapping pixel data
69 * after the transformation matrix to data sent to the connector. The
70 * data is interpreted as an array of &struct drm_color_lut elements.
71 * Hardware might choose not to use the full precision of the LUT elements
72 * nor use all the elements of the LUT (for example the hardware might
73 * choose to interpolate between LUT[0] and LUT[4]).
75 * Setting this to NULL (blob property value set to 0) means a
76 * linear/pass-thru gamma table should be used. This is generally the
77 * driver boot-up state too. Drivers can access this blob through
78 * &drm_crtc_state.gamma_lut.
81 * Unsigned range property to give the size of the lookup table to be set
82 * on the GAMMA_LUT property (the size depends on the underlying hardware).
83 * If drivers support multiple LUT sizes then they should publish the
84 * largest size, and sub-sample smaller sized LUTs (e.g. for split-gamma
85 * modes) appropriately.
87 * There is also support for a legacy gamma table, which is set up by calling
88 * drm_mode_crtc_set_gamma_size(). Drivers which support both should use
89 * drm_atomic_helper_legacy_gamma_set() to alias the legacy gamma ramp with the
90 * "GAMMA_LUT" property above.
94 * drm_color_lut_extract - clamp and round LUT entries
95 * @user_input: input value
96 * @bit_precision: number of bits the hw LUT supports
98 * Extract a degamma/gamma LUT value provided by user (in the form of
99 * &drm_color_lut entries) and round it to the precision supported by the
102 uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision)
104 uint32_t val = user_input;
105 uint32_t max = 0xffff >> (16 - bit_precision);
107 /* Round only if we're not using full precision. */
108 if (bit_precision < 16) {
109 val += 1UL << (16 - bit_precision - 1);
110 val >>= 16 - bit_precision;
113 return clamp_val(val, 0, max);
115 EXPORT_SYMBOL(drm_color_lut_extract);
118 * drm_crtc_enable_color_mgmt - enable color management properties
120 * @degamma_lut_size: the size of the degamma lut (before CSC)
121 * @has_ctm: whether to attach ctm_property for CSC matrix
122 * @gamma_lut_size: the size of the gamma lut (after CSC)
124 * This function lets the driver enable the color correction
125 * properties on a CRTC. This includes 3 degamma, csc and gamma
126 * properties that userspace can set and 2 size properties to inform
127 * the userspace of the lut sizes. Each of the properties are
128 * optional. The gamma and degamma properties are only attached if
129 * their size is not 0 and ctm_property is only attached if has_ctm is
132 void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
133 uint degamma_lut_size,
137 struct drm_device *dev = crtc->dev;
138 struct drm_mode_config *config = &dev->mode_config;
140 if (degamma_lut_size) {
141 drm_object_attach_property(&crtc->base,
142 config->degamma_lut_property, 0);
143 drm_object_attach_property(&crtc->base,
144 config->degamma_lut_size_property,
149 drm_object_attach_property(&crtc->base,
150 config->ctm_property, 0);
152 if (gamma_lut_size) {
153 drm_object_attach_property(&crtc->base,
154 config->gamma_lut_property, 0);
155 drm_object_attach_property(&crtc->base,
156 config->gamma_lut_size_property,
160 EXPORT_SYMBOL(drm_crtc_enable_color_mgmt);
163 * drm_mode_crtc_set_gamma_size - set the gamma table size
164 * @crtc: CRTC to set the gamma table size for
165 * @gamma_size: size of the gamma table
167 * Drivers which support gamma tables should set this to the supported gamma
168 * table size when initializing the CRTC. Currently the drm core only supports a
169 * fixed gamma table size.
172 * Zero on success, negative errno on failure.
174 int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
177 uint16_t *r_base, *g_base, *b_base;
180 crtc->gamma_size = gamma_size;
182 crtc->gamma_store = kcalloc(gamma_size, sizeof(uint16_t) * 3,
184 if (!crtc->gamma_store) {
185 crtc->gamma_size = 0;
189 r_base = crtc->gamma_store;
190 g_base = r_base + gamma_size;
191 b_base = g_base + gamma_size;
192 for (i = 0; i < gamma_size; i++) {
201 EXPORT_SYMBOL(drm_mode_crtc_set_gamma_size);
204 * drm_mode_gamma_set_ioctl - set the gamma table
207 * @file_priv: DRM file info
209 * Set the gamma table of a CRTC to the one passed in by the user. Userspace can
210 * inquire the required gamma table size through drm_mode_gamma_get_ioctl.
212 * Called by the user via ioctl.
215 * Zero on success, negative errno on failure.
217 int drm_mode_gamma_set_ioctl(struct drm_device *dev,
218 void *data, struct drm_file *file_priv)
220 struct drm_mode_crtc_lut *crtc_lut = data;
221 struct drm_crtc *crtc;
222 void *r_base, *g_base, *b_base;
224 struct drm_modeset_acquire_ctx ctx;
227 if (!drm_core_check_feature(dev, DRIVER_MODESET))
230 crtc = drm_crtc_find(dev, crtc_lut->crtc_id);
234 if (crtc->funcs->gamma_set == NULL)
237 /* memcpy into gamma store */
238 if (crtc_lut->gamma_size != crtc->gamma_size)
241 drm_modeset_acquire_init(&ctx, 0);
243 ret = drm_modeset_lock_all_ctx(dev, &ctx);
247 size = crtc_lut->gamma_size * (sizeof(uint16_t));
248 r_base = crtc->gamma_store;
249 if (copy_from_user(r_base, (void __user *)(unsigned long)crtc_lut->red, size)) {
254 g_base = r_base + size;
255 if (copy_from_user(g_base, (void __user *)(unsigned long)crtc_lut->green, size)) {
260 b_base = g_base + size;
261 if (copy_from_user(b_base, (void __user *)(unsigned long)crtc_lut->blue, size)) {
266 ret = crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
267 crtc->gamma_size, &ctx);
270 if (ret == -EDEADLK) {
271 drm_modeset_backoff(&ctx);
274 drm_modeset_drop_locks(&ctx);
275 drm_modeset_acquire_fini(&ctx);
282 * drm_mode_gamma_get_ioctl - get the gamma table
285 * @file_priv: DRM file info
287 * Copy the current gamma table into the storage provided. This also provides
288 * the gamma table size the driver expects, which can be used to size the
291 * Called by the user via ioctl.
294 * Zero on success, negative errno on failure.
296 int drm_mode_gamma_get_ioctl(struct drm_device *dev,
297 void *data, struct drm_file *file_priv)
299 struct drm_mode_crtc_lut *crtc_lut = data;
300 struct drm_crtc *crtc;
301 void *r_base, *g_base, *b_base;
305 if (!drm_core_check_feature(dev, DRIVER_MODESET))
308 crtc = drm_crtc_find(dev, crtc_lut->crtc_id);
312 /* memcpy into gamma store */
313 if (crtc_lut->gamma_size != crtc->gamma_size)
316 drm_modeset_lock(&crtc->mutex, NULL);
317 size = crtc_lut->gamma_size * (sizeof(uint16_t));
318 r_base = crtc->gamma_store;
319 if (copy_to_user((void __user *)(unsigned long)crtc_lut->red, r_base, size)) {
324 g_base = r_base + size;
325 if (copy_to_user((void __user *)(unsigned long)crtc_lut->green, g_base, size)) {
330 b_base = g_base + size;
331 if (copy_to_user((void __user *)(unsigned long)crtc_lut->blue, b_base, size)) {
336 drm_modeset_unlock(&crtc->mutex);