1 /*
2  *  linux/drivers/video/fbcmap.c -- Colormap handling for frame buffer devices
3  *
4  *	Created 15 Jun 1997 by Geert Uytterhoeven
5  *
6  *	2001 - Documented with DocBook
7  *	- Brad Douglas <brad@neruo.com>
8  *
9  *  This file is subject to the terms and conditions of the GNU General Public
10  *  License.  See the file COPYING in the main directory of this archive for
11  *  more details.
12  */
13 
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/fb.h>
17 #include <linux/slab.h>
18 #include <linux/uaccess.h>
19 
20 static u16 red2[] __read_mostly = {
21     0x0000, 0xaaaa
22 };
23 static u16 green2[] __read_mostly = {
24     0x0000, 0xaaaa
25 };
26 static u16 blue2[] __read_mostly = {
27     0x0000, 0xaaaa
28 };
29 
30 static u16 red4[] __read_mostly = {
31     0x0000, 0xaaaa, 0x5555, 0xffff
32 };
33 static u16 green4[] __read_mostly = {
34     0x0000, 0xaaaa, 0x5555, 0xffff
35 };
36 static u16 blue4[] __read_mostly = {
37     0x0000, 0xaaaa, 0x5555, 0xffff
38 };
39 
40 static u16 red8[] __read_mostly = {
41     0x0000, 0x0000, 0x0000, 0x0000, 0xaaaa, 0xaaaa, 0xaaaa, 0xaaaa
42 };
43 static u16 green8[] __read_mostly = {
44     0x0000, 0x0000, 0xaaaa, 0xaaaa, 0x0000, 0x0000, 0x5555, 0xaaaa
45 };
46 static u16 blue8[] __read_mostly = {
47     0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa
48 };
49 
50 static u16 red16[] __read_mostly = {
51     0x0000, 0x0000, 0x0000, 0x0000, 0xaaaa, 0xaaaa, 0xaaaa, 0xaaaa,
52     0x5555, 0x5555, 0x5555, 0x5555, 0xffff, 0xffff, 0xffff, 0xffff
53 };
54 static u16 green16[] __read_mostly = {
55     0x0000, 0x0000, 0xaaaa, 0xaaaa, 0x0000, 0x0000, 0x5555, 0xaaaa,
56     0x5555, 0x5555, 0xffff, 0xffff, 0x5555, 0x5555, 0xffff, 0xffff
57 };
58 static u16 blue16[] __read_mostly = {
59     0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa, 0x0000, 0xaaaa,
60     0x5555, 0xffff, 0x5555, 0xffff, 0x5555, 0xffff, 0x5555, 0xffff
61 };
62 
63 static const struct fb_cmap default_2_colors = {
64     .len=2, .red=red2, .green=green2, .blue=blue2
65 };
66 static const struct fb_cmap default_8_colors = {
67     .len=8, .red=red8, .green=green8, .blue=blue8
68 };
69 static const struct fb_cmap default_4_colors = {
70     .len=4, .red=red4, .green=green4, .blue=blue4
71 };
72 static const struct fb_cmap default_16_colors = {
73     .len=16, .red=red16, .green=green16, .blue=blue16
74 };
75 
76 
77 
78 /**
79  *	fb_alloc_cmap_gfp - allocate a colormap
80  *	@cmap: frame buffer colormap structure
81  *	@len: length of @cmap
82  *	@transp: boolean, 1 if there is transparency, 0 otherwise
83  *	@flags: flags for kmalloc memory allocation
84  *
85  *	Allocates memory for a colormap @cmap.  @len is the
86  *	number of entries in the palette.
87  *
88  *	Returns negative errno on error, or zero on success.
89  *
90  */
91 
fb_alloc_cmap_gfp(struct fb_cmap * cmap,int len,int transp,gfp_t flags)92 int fb_alloc_cmap_gfp(struct fb_cmap *cmap, int len, int transp, gfp_t flags)
93 {
94 	int size = len * sizeof(u16);
95 	int ret = -ENOMEM;
96 
97 	flags |= __GFP_NOWARN;
98 
99 	if (cmap->len != len) {
100 		fb_dealloc_cmap(cmap);
101 		if (!len)
102 			return 0;
103 
104 		cmap->red = kzalloc(size, flags);
105 		if (!cmap->red)
106 			goto fail;
107 		cmap->green = kzalloc(size, flags);
108 		if (!cmap->green)
109 			goto fail;
110 		cmap->blue = kzalloc(size, flags);
111 		if (!cmap->blue)
112 			goto fail;
113 		if (transp) {
114 			cmap->transp = kzalloc(size, flags);
115 			if (!cmap->transp)
116 				goto fail;
117 		} else {
118 			cmap->transp = NULL;
119 		}
120 	}
121 	cmap->start = 0;
122 	cmap->len = len;
123 	ret = fb_copy_cmap(fb_default_cmap(len), cmap);
124 	if (ret)
125 		goto fail;
126 	return 0;
127 
128 fail:
129 	fb_dealloc_cmap(cmap);
130 	return ret;
131 }
132 
fb_alloc_cmap(struct fb_cmap * cmap,int len,int transp)133 int fb_alloc_cmap(struct fb_cmap *cmap, int len, int transp)
134 {
135 	return fb_alloc_cmap_gfp(cmap, len, transp, GFP_ATOMIC);
136 }
137 
138 /**
139  *      fb_dealloc_cmap - deallocate a colormap
140  *      @cmap: frame buffer colormap structure
141  *
142  *      Deallocates a colormap that was previously allocated with
143  *      fb_alloc_cmap().
144  *
145  */
146 
fb_dealloc_cmap(struct fb_cmap * cmap)147 void fb_dealloc_cmap(struct fb_cmap *cmap)
148 {
149 	kfree(cmap->red);
150 	kfree(cmap->green);
151 	kfree(cmap->blue);
152 	kfree(cmap->transp);
153 
154 	cmap->red = cmap->green = cmap->blue = cmap->transp = NULL;
155 	cmap->len = 0;
156 }
157 
158 /**
159  *	fb_copy_cmap - copy a colormap
160  *	@from: frame buffer colormap structure
161  *	@to: frame buffer colormap structure
162  *
163  *	Copy contents of colormap from @from to @to.
164  */
165 
fb_copy_cmap(const struct fb_cmap * from,struct fb_cmap * to)166 int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to)
167 {
168 	unsigned int tooff = 0, fromoff = 0;
169 	size_t size;
170 
171 	if (to->start > from->start)
172 		fromoff = to->start - from->start;
173 	else
174 		tooff = from->start - to->start;
175 	if (fromoff >= from->len || tooff >= to->len)
176 		return -EINVAL;
177 
178 	size = min_t(size_t, to->len - tooff, from->len - fromoff);
179 	if (size == 0)
180 		return -EINVAL;
181 	size *= sizeof(u16);
182 
183 	memcpy(to->red+tooff, from->red+fromoff, size);
184 	memcpy(to->green+tooff, from->green+fromoff, size);
185 	memcpy(to->blue+tooff, from->blue+fromoff, size);
186 	if (from->transp && to->transp)
187 		memcpy(to->transp+tooff, from->transp+fromoff, size);
188 	return 0;
189 }
190 
fb_cmap_to_user(const struct fb_cmap * from,struct fb_cmap_user * to)191 int fb_cmap_to_user(const struct fb_cmap *from, struct fb_cmap_user *to)
192 {
193 	unsigned int tooff = 0, fromoff = 0;
194 	size_t size;
195 
196 	if (to->start > from->start)
197 		fromoff = to->start - from->start;
198 	else
199 		tooff = from->start - to->start;
200 	if (fromoff >= from->len || tooff >= to->len)
201 		return -EINVAL;
202 
203 	size = min_t(size_t, to->len - tooff, from->len - fromoff);
204 	if (size == 0)
205 		return -EINVAL;
206 	size *= sizeof(u16);
207 
208 	if (copy_to_user(to->red+tooff, from->red+fromoff, size))
209 		return -EFAULT;
210 	if (copy_to_user(to->green+tooff, from->green+fromoff, size))
211 		return -EFAULT;
212 	if (copy_to_user(to->blue+tooff, from->blue+fromoff, size))
213 		return -EFAULT;
214 	if (from->transp && to->transp)
215 		if (copy_to_user(to->transp+tooff, from->transp+fromoff, size))
216 			return -EFAULT;
217 	return 0;
218 }
219 
220 /**
221  *	fb_set_cmap - set the colormap
222  *	@cmap: frame buffer colormap structure
223  *	@info: frame buffer info structure
224  *
225  *	Sets the colormap @cmap for a screen of device @info.
226  *
227  *	Returns negative errno on error, or zero on success.
228  *
229  */
230 
fb_set_cmap(struct fb_cmap * cmap,struct fb_info * info)231 int fb_set_cmap(struct fb_cmap *cmap, struct fb_info *info)
232 {
233 	int i, start, rc = 0;
234 	u16 *red, *green, *blue, *transp;
235 	u_int hred, hgreen, hblue, htransp = 0xffff;
236 
237 	red = cmap->red;
238 	green = cmap->green;
239 	blue = cmap->blue;
240 	transp = cmap->transp;
241 	start = cmap->start;
242 
243 	if (start < 0 || (!info->fbops->fb_setcolreg &&
244 			  !info->fbops->fb_setcmap))
245 		return -EINVAL;
246 	if (info->fbops->fb_setcmap) {
247 		rc = info->fbops->fb_setcmap(cmap, info);
248 	} else {
249 		for (i = 0; i < cmap->len; i++) {
250 			hred = *red++;
251 			hgreen = *green++;
252 			hblue = *blue++;
253 			if (transp)
254 				htransp = *transp++;
255 			if (info->fbops->fb_setcolreg(start++,
256 						      hred, hgreen, hblue,
257 						      htransp, info))
258 				break;
259 		}
260 	}
261 	if (rc == 0)
262 		fb_copy_cmap(cmap, &info->cmap);
263 
264 	return rc;
265 }
266 
fb_set_user_cmap(struct fb_cmap_user * cmap,struct fb_info * info)267 int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
268 {
269 	int rc, size = cmap->len * sizeof(u16);
270 	struct fb_cmap umap;
271 
272 	if (size < 0 || size < cmap->len)
273 		return -E2BIG;
274 
275 	memset(&umap, 0, sizeof(struct fb_cmap));
276 	rc = fb_alloc_cmap_gfp(&umap, cmap->len, cmap->transp != NULL,
277 				GFP_KERNEL);
278 	if (rc)
279 		return rc;
280 	if (copy_from_user(umap.red, cmap->red, size) ||
281 	    copy_from_user(umap.green, cmap->green, size) ||
282 	    copy_from_user(umap.blue, cmap->blue, size) ||
283 	    (cmap->transp && copy_from_user(umap.transp, cmap->transp, size))) {
284 		rc = -EFAULT;
285 		goto out;
286 	}
287 	umap.start = cmap->start;
288 	lock_fb_info(info);
289 	rc = fb_set_cmap(&umap, info);
290 	unlock_fb_info(info);
291 out:
292 	fb_dealloc_cmap(&umap);
293 	return rc;
294 }
295 
296 /**
297  *	fb_default_cmap - get default colormap
298  *	@len: size of palette for a depth
299  *
300  *	Gets the default colormap for a specific screen depth.  @len
301  *	is the size of the palette for a particular screen depth.
302  *
303  *	Returns pointer to a frame buffer colormap structure.
304  *
305  */
306 
fb_default_cmap(int len)307 const struct fb_cmap *fb_default_cmap(int len)
308 {
309     if (len <= 2)
310 	return &default_2_colors;
311     if (len <= 4)
312 	return &default_4_colors;
313     if (len <= 8)
314 	return &default_8_colors;
315     return &default_16_colors;
316 }
317 
318 
319 /**
320  *	fb_invert_cmaps - invert all defaults colormaps
321  *
322  *	Invert all default colormaps.
323  *
324  */
325 
fb_invert_cmaps(void)326 void fb_invert_cmaps(void)
327 {
328     u_int i;
329 
330     for (i = 0; i < ARRAY_SIZE(red2); i++) {
331 	red2[i] = ~red2[i];
332 	green2[i] = ~green2[i];
333 	blue2[i] = ~blue2[i];
334     }
335     for (i = 0; i < ARRAY_SIZE(red4); i++) {
336 	red4[i] = ~red4[i];
337 	green4[i] = ~green4[i];
338 	blue4[i] = ~blue4[i];
339     }
340     for (i = 0; i < ARRAY_SIZE(red8); i++) {
341 	red8[i] = ~red8[i];
342 	green8[i] = ~green8[i];
343 	blue8[i] = ~blue8[i];
344     }
345     for (i = 0; i < ARRAY_SIZE(red16); i++) {
346 	red16[i] = ~red16[i];
347 	green16[i] = ~green16[i];
348 	blue16[i] = ~blue16[i];
349     }
350 }
351 
352 
353     /*
354      *  Visible symbols for modules
355      */
356 
357 EXPORT_SYMBOL(fb_alloc_cmap);
358 EXPORT_SYMBOL(fb_dealloc_cmap);
359 EXPORT_SYMBOL(fb_copy_cmap);
360 EXPORT_SYMBOL(fb_set_cmap);
361 EXPORT_SYMBOL(fb_default_cmap);
362 EXPORT_SYMBOL(fb_invert_cmaps);
363