summaryrefslogtreecommitdiffstats
path: root/drivers/video/fbdev/vfb.c
blob: 54127905bfe7473d6e034be066291d7fc71f29fe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
/*
 *  linux/drivers/video/vfb.c -- Virtual frame buffer device
 *
 *      Copyright (C) 2002 James Simmons
 *
 *	Copyright (C) 1997 Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>

#include <linux/fb.h>
#include <linux/init.h>

    /*
     *  RAM we reserve for the frame buffer. This defines the maximum screen
     *  size
     *
     *  The default can be overridden if the driver is compiled as a module
     */

#define VIDEOMEMSIZE	(1*1024*1024)	/* 1 MB */

static void *videomemory;
static u_long videomemorysize = VIDEOMEMSIZE;
module_param(videomemorysize, ulong, 0);
MODULE_PARM_DESC(videomemorysize, "RAM available to frame buffer (in bytes)");

static char *mode_option = NULL;
module_param(mode_option, charp, 0);
MODULE_PARM_DESC(mode_option, "Preferred video mode (e.g. 640x480-8@60)");

static const struct fb_videomode vfb_default = {
	.xres =		640,
	.yres =		480,
	.pixclock =	20000,
	.left_margin =	64,
	.right_margin =	64,
	.upper_margin =	32,
	.lower_margin =	32,
	.hsync_len =	64,
	.vsync_len =	2,
	.vmode =	FB_VMODE_NONINTERLACED,
};

static struct fb_fix_screeninfo vfb_fix = {
	.id =		"Virtual FB",
	.type =		FB_TYPE_PACKED_PIXELS,
	.visual =	FB_VISUAL_PSEUDOCOLOR,
	.xpanstep =	1,
	.ypanstep =	1,
	.ywrapstep =	1,
	.accel =	FB_ACCEL_NONE,
};

static bool vfb_enable __initdata = 0;	/* disabled by default */
module_param(vfb_enable, bool, 0);
MODULE_PARM_DESC(vfb_enable, "Enable Virtual FB driver");

static int vfb_check_var(struct fb_var_screeninfo *var,
			 struct fb_info *info);
static int vfb_set_par(struct fb_info *info);
static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			 u_int transp, struct fb_info *info);
static int vfb_pan_display(struct fb_var_screeninfo *var,
			   struct fb_info *info);
static int vfb_mmap(struct fb_info *info,
		    struct vm_area_struct *vma);

static struct fb_ops vfb_ops = {
	.fb_read        = fb_sys_read,
	.fb_write       = fb_sys_write,
	.fb_check_var	= vfb_check_var,
	.fb_set_par	= vfb_set_par,
	.fb_setcolreg	= vfb_setcolreg,
	.fb_pan_display	= vfb_pan_display,
	.fb_fillrect	= sys_fillrect,
	.fb_copyarea	= sys_copyarea,
	.fb_imageblit	= sys_imageblit,
	.fb_mmap	= vfb_mmap,
};

    /*
     *  Internal routines
     */

static u_long get_line_length(int xres_virtual, int bpp)
{
	u_long length;

	length = xres_virtual * bpp;
	length = (length + 31) & ~31;
	length >>= 3;
	return (length);
}

    /*
     *  Setting the video mode has been split into two parts.
     *  First part, xxxfb_check_var, must not write anything
     *  to hardware, it should only verify and adjust var.
     *  This means it doesn't alter par but it does use hardware
     *  data from it to check this var. 
     */

static int vfb_check_var(struct fb_var_screeninfo *var,
			 struct fb_info *info)
{
	u_long line_length;

	/*
	 *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
	 *  as FB_VMODE_SMOOTH_XPAN is only used internally
	 */

	if (var->vmode & FB_VMODE_CONUPDATE) {
		var->vmode |= FB_VMODE_YWRAP;
		var->xoffset = info->var.xoffset;
		var->yoffset = info->var.yoffset;
	}

	/*
	 *  Some very basic checks
	 */
	if (!var->xres)
		var->xres = 1;
	if (!var->yres)
		var->yres = 1;
	if (var->xres > var->xres_virtual)
		var->xres_virtual = var->xres;
	if (var->yres > var->yres_virtual)
		var->yres_virtual = var->yres;
	if (var->bits_per_pixel <= 1)
		var->bits_per_pixel = 1;
	else if (var->bits_per_pixel <= 8)
		var->bits_per_pixel = 8;
	else if (var->bits_per_pixel <= 16)
		var->bits_per_pixel = 16;
	else if (var->bits_per_pixel <= 24)
		var->bits_per_pixel = 24;
	else if (var->bits_per_pixel <= 32)
		var->bits_per_pixel = 32;
	else
		return -EINVAL;

	if (var->xres_virtual < var->xoffset + var->xres)
		var->xres_virtual = var->xoffset + var->xres;
	if (var->yres_virtual < var->yoffset + var->yres)
		var->yres_virtual = var->yoffset + var->yres;

	/*
	 *  Memory limit
	 */
	line_length =
	    get_line_length(var->xres_virtual, var->bits_per_pixel);
	if (line_length * var->yres_virtual > videomemorysize)
		return -ENOMEM;

	/*
	 * Now that we checked it we alter var. The reason being is that the video
	 * mode passed in might not work but slight changes to it might make it 
	 * work. This way we let the user know what is acceptable.
	 */
	switch (var->bits_per_pixel) {
	case 1:
	case 8:
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 0;
		var->green.length = 8;
		var->blue.offset = 0;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 16:		/* RGBA 5551 */
		if (var->transp.length) {
			var->red.offset = 0;
			var->red.length = 5;
			var->green.offset = 5;
			var->green.length = 5;
			var->blue.offset = 10;
			var->blue.length = 5;
			var->transp.offset = 15;
			var->transp.length = 1;
		} else {	/* RGB 565 */
			var->red.offset = 0;
			var->red.length = 5;
			var->green.offset = 5;
			var->green.length = 6;
			var->blue.offset = 11;
			var->blue.length = 5;
			var->transp.offset = 0;
			var->transp.length = 0;
		}
		break;
	case 24:		/* RGB 888 */
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 8;
		var->green.length = 8;
		var->blue.offset = 16;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 32:		/* RGBA 8888 */
		var->red.offset = 0;
		var->red.length = 8;
		var->green.offset = 8;
		var->green.length = 8;
		var->blue.offset = 16;
		var->blue.length = 8;
		var->transp.offset = 24;
		var->transp.length = 8;
		break;
	}
	var->red.msb_right = 0;
	var->green.msb_right = 0;
	var->blue.msb_right = 0;
	var->transp.msb_right = 0;

	return 0;
}

/* This routine actually sets the video mode. It's in here where we
 * the hardware state info->par and fix which can be affected by the 
 * change in par. For this driver it doesn't do much. 
 */
static int vfb_set_par(struct fb_info *info)
{
	switch (info->var.bits_per_pixel) {
	case 1:
		info->fix.visual = FB_VISUAL_MONO01;
		break;
	case 8:
		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
		break;
	case 16:
	case 24:
	case 32:
		info->fix.visual = FB_VISUAL_TRUECOLOR;
		break;
	}

	info->fix.line_length = get_line_length(info->var.xres_virtual,
						info->var.bits_per_pixel);

	return 0;
}

    /*
     *  Set a single color register. The values supplied are already
     *  rounded down to the hardware's capabilities (according to the
     *  entries in the var structure). Return != 0 for invalid regno.
     */

static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
			 u_int transp, struct fb_info *info)
{
	if (regno >= 256)	/* no. of hw registers */
		return 1;
	/*
	 * Program hardware... do anything you want with transp
	 */

	/* grayscale works only partially under directcolor */
	if (info->var.grayscale) {
		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
		red = green = blue =
		    (red * 77 + green * 151 + blue * 28) >> 8;
	}

	/* Directcolor:
	 *   var->{color}.offset contains start of bitfield
	 *   var->{color}.length contains length of bitfield
	 *   {hardwarespecific} contains width of RAMDAC
	 *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
	 *   RAMDAC[X] is programmed to (red, green, blue)
	 *
	 * Pseudocolor:
	 *    var->{color}.offset is 0 unless the palette index takes less than
	 *                        bits_per_pixel bits and is stored in the upper
	 *                        bits of the pixel value
	 *    var->{color}.length is set so that 1 << length is the number of available
	 *                        palette entries
	 *    cmap is not used
	 *    RAMDAC[X] is programmed to (red, green, blue)
	 *
	 * Truecolor:
	 *    does not use DAC. Usually 3 are present.
	 *    var->{color}.offset contains start of bitfield
	 *    var->{color}.length contains length of bitfield
	 *    cmap is programmed to (red << red.offset) | (green << green.offset) |
	 *                      (blue << blue.offset) | (transp << transp.offset)
	 *    RAMDAC does not exist
	 */
#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
	switch (info->fix.visual) {
	case FB_VISUAL_TRUECOLOR:
	case FB_VISUAL_PSEUDOCOLOR:
		red = CNVT_TOHW(red, info->var.red.length);
		green = CNVT_TOHW(green, info->var.green.length);
		blue = CNVT_TOHW(blue, info->var.blue.length);
		transp = CNVT_TOHW(transp, info->var.transp.length);
		break;
	case FB_VISUAL_DIRECTCOLOR:
		red = CNVT_TOHW(red, 8);	/* expect 8 bit DAC */
		green = CNVT_TOHW(green, 8);
		blue = CNVT_TOHW(blue, 8);
		/* hey, there is bug in transp handling... */
		transp = CNVT_TOHW(transp, 8);
		break;
	}
#undef CNVT_TOHW
	/* Truecolor has hardware independent palette */
	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
		u32 v;

		if (regno >= 16)
			return 1;

		v = (red << info->var.red.offset) |
		    (green << info->var.green.offset) |
		    (blue << info->var.blue.offset) |
		    (transp << info->var.transp.offset);
		switch (info->var.bits_per_pixel) {
		case 8:
			break;
		case 16:
			((u32 *) (info->pseudo_palette))[regno] = v;
			break;
		case 24:
		case 32:
			((u32 *) (info->pseudo_palette))[regno] = v;
			break;
		}
		return 0;
	}
	return 0;
}

    /*
     *  Pan or Wrap the Display
     *
     *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
     */

static int vfb_pan_display(struct fb_var_screeninfo *var,
			   struct fb_info *info)
{
	if (var->vmode & FB_VMODE_YWRAP) {
		if (var->yoffset >= info->var.yres_virtual ||
		    var->xoffset)
			return -EINVAL;
	} else {
		if (var->xoffset + info->var.xres > info->var.xres_virtual ||
		    var->yoffset + info->var.yres > info->var.yres_virtual)
			return -EINVAL;
	}
	info->var.xoffset = var->xoffset;
	info->var.yoffset = var->yoffset;
	if (var->vmode & FB_VMODE_YWRAP)
		info->var.vmode |= FB_VMODE_YWRAP;
	else
		info->var.vmode &= ~FB_VMODE_YWRAP;
	return 0;
}

    /*
     *  Most drivers don't need their own mmap function 
     */

static int vfb_mmap(struct fb_info *info,
		    struct vm_area_struct *vma)
{
	return remap_vmalloc_range(vma, (void *)info->fix.smem_start, vma->vm_pgoff);
}

#ifndef MODULE
/*
 * The virtual framebuffer driver is only enabled if explicitly
 * requested by passing 'video=vfb:' (or any actual options).
 */
static int __init vfb_setup(char *options)
{
	char *this_opt;

	vfb_enable = 0;

	if (!options)
		return 1;

	vfb_enable = 1;

	if (!*options)
		return 1;

	while ((this_opt = strsep(&options, ",")) != NULL) {
		if (!*this_opt)
			continue;
		/* Test disable for backwards compatibility */
		if (!strcmp(this_opt, "disable"))
			vfb_enable = 0;
		else
			mode_option = this_opt;
	}
	return 1;
}
#endif  /*  MODULE  */

    /*
     *  Initialisation
     */

static int vfb_probe(struct platform_device *dev)
{
	struct fb_info *info;
	unsigned int size = PAGE_ALIGN(videomemorysize);
	int retval = -ENOMEM;

	/*
	 * For real video cards we use ioremap.
	 */
	if (!(videomemory = vmalloc_32_user(size)))
		return retval;

	info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
	if (!info)
		goto err;

	info->screen_base = (char __iomem *)videomemory;
	info->fbops = &vfb_ops;

	if (!fb_find_mode(&info->var, info, mode_option,
			  NULL, 0, &vfb_default, 8)){
		fb_err(info, "Unable to find usable video mode.\n");
		retval = -EINVAL;
		goto err1;
	}

	vfb_fix.smem_start = (unsigned long) videomemory;
	vfb_fix.smem_len = videomemorysize;
	info->fix = vfb_fix;
	info->pseudo_palette = info->par;
	info->par = NULL;
	info->flags = FBINFO_FLAG_DEFAULT;

	retval = fb_alloc_cmap(&info->cmap, 256, 0);
	if (retval < 0)
		goto err1;

	retval = register_framebuffer(info);
	if (retval < 0)
		goto err2;
	platform_set_drvdata(dev, info);

	vfb_set_par(info);

	fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
		videomemorysize >> 10);
	return 0;
err2:
	fb_dealloc_cmap(&info->cmap);
err1:
	framebuffer_release(info);
err:
	vfree(videomemory);
	return retval;
}

static int vfb_remove(struct platform_device *dev)
{
	struct fb_info *info = platform_get_drvdata(dev);

	if (info) {
		unregister_framebuffer(info);
		vfree(videomemory);
		fb_dealloc_cmap(&info->cmap);
		framebuffer_release(info);
	}
	return 0;
}

static struct platform_driver vfb_driver = {
	.probe	= vfb_probe,
	.remove = vfb_remove,
	.driver = {
		.name	= "vfb",
	},
};

static struct platform_device *vfb_device;

static int __init vfb_init(void)
{
	int ret = 0;

#ifndef MODULE
	char *option = NULL;

	if (fb_get_options("vfb", &option))
		return -ENODEV;
	vfb_setup(option);
#endif

	if (!vfb_enable)
		return -ENXIO;

	ret = platform_driver_register(&vfb_driver);

	if (!ret) {
		vfb_device = platform_device_alloc("vfb", 0);

		if (vfb_device)
			ret = platform_device_add(vfb_device);
		else
			ret = -ENOMEM;

		if (ret) {
			platform_device_put(vfb_device);
			platform_driver_unregister(&vfb_driver);
		}
	}

	return ret;
}

module_init(vfb_init);

#ifdef MODULE
static void __exit vfb_exit(void)
{
	platform_device_unregister(vfb_device);
	platform_driver_unregister(&vfb_driver);
}

module_exit(vfb_exit);

MODULE_LICENSE("GPL");
#endif				/* MODULE */