2 * linux/drivers/video/vfb.c -- Virtual frame buffer device
4 * Copyright (C) 2002 James Simmons
6 * Copyright (C) 1997 Geert Uytterhoeven
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file COPYING in the main directory of this archive for
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/string.h>
18 #include <linux/vmalloc.h>
19 #include <linux/delay.h>
20 #include <linux/interrupt.h>
21 #include <linux/platform_device.h>
24 #include <linux/init.h>
27 * RAM we reserve for the frame buffer. This defines the maximum screen
30 * The default can be overridden if the driver is compiled as a module
33 #define VIDEOMEMSIZE (1*1024*1024) /* 1 MB */
35 static void *videomemory;
36 static u_long videomemorysize = VIDEOMEMSIZE;
37 module_param(videomemorysize, ulong, 0);
39 /**********************************************************************
43 **********************************************************************/
44 static void *rvmalloc(unsigned long size)
49 size = PAGE_ALIGN(size);
50 mem = vmalloc_32(size);
55 * VFB must clear memory to prevent kernel info
56 * leakage into userspace
57 * VGA-based drivers MUST NOT clear memory if
58 * they want to be able to take over vgacon
62 adr = (unsigned long) mem;
64 SetPageReserved(vmalloc_to_page((void *)adr));
72 static void rvfree(void *mem, unsigned long size)
79 adr = (unsigned long) mem;
80 while ((long) size > 0) {
81 ClearPageReserved(vmalloc_to_page((void *)adr));
88 static struct fb_var_screeninfo vfb_default = {
97 .activate = FB_ACTIVATE_TEST,
107 .vmode = FB_VMODE_NONINTERLACED,
110 static struct fb_fix_screeninfo vfb_fix = {
112 .type = FB_TYPE_PACKED_PIXELS,
113 .visual = FB_VISUAL_PSEUDOCOLOR,
117 .accel = FB_ACCEL_NONE,
120 static bool vfb_enable __initdata = 0; /* disabled by default */
121 module_param(vfb_enable, bool, 0);
123 static int vfb_check_var(struct fb_var_screeninfo *var,
124 struct fb_info *info);
125 static int vfb_set_par(struct fb_info *info);
126 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
127 u_int transp, struct fb_info *info);
128 static int vfb_pan_display(struct fb_var_screeninfo *var,
129 struct fb_info *info);
130 static int vfb_mmap(struct fb_info *info,
131 struct vm_area_struct *vma);
133 static struct fb_ops vfb_ops = {
134 .fb_read = fb_sys_read,
135 .fb_write = fb_sys_write,
136 .fb_check_var = vfb_check_var,
137 .fb_set_par = vfb_set_par,
138 .fb_setcolreg = vfb_setcolreg,
139 .fb_pan_display = vfb_pan_display,
140 .fb_fillrect = sys_fillrect,
141 .fb_copyarea = sys_copyarea,
142 .fb_imageblit = sys_imageblit,
150 static u_long get_line_length(int xres_virtual, int bpp)
154 length = xres_virtual * bpp;
155 length = (length + 31) & ~31;
161 * Setting the video mode has been split into two parts.
162 * First part, xxxfb_check_var, must not write anything
163 * to hardware, it should only verify and adjust var.
164 * This means it doesn't alter par but it does use hardware
165 * data from it to check this var.
168 static int vfb_check_var(struct fb_var_screeninfo *var,
169 struct fb_info *info)
174 * FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
175 * as FB_VMODE_SMOOTH_XPAN is only used internally
178 if (var->vmode & FB_VMODE_CONUPDATE) {
179 var->vmode |= FB_VMODE_YWRAP;
180 var->xoffset = info->var.xoffset;
181 var->yoffset = info->var.yoffset;
185 * Some very basic checks
191 if (var->xres > var->xres_virtual)
192 var->xres_virtual = var->xres;
193 if (var->yres > var->yres_virtual)
194 var->yres_virtual = var->yres;
195 if (var->bits_per_pixel <= 1)
196 var->bits_per_pixel = 1;
197 else if (var->bits_per_pixel <= 8)
198 var->bits_per_pixel = 8;
199 else if (var->bits_per_pixel <= 16)
200 var->bits_per_pixel = 16;
201 else if (var->bits_per_pixel <= 24)
202 var->bits_per_pixel = 24;
203 else if (var->bits_per_pixel <= 32)
204 var->bits_per_pixel = 32;
208 if (var->xres_virtual < var->xoffset + var->xres)
209 var->xres_virtual = var->xoffset + var->xres;
210 if (var->yres_virtual < var->yoffset + var->yres)
211 var->yres_virtual = var->yoffset + var->yres;
217 get_line_length(var->xres_virtual, var->bits_per_pixel);
218 if (line_length * var->yres_virtual > videomemorysize)
222 * Now that we checked it we alter var. The reason being is that the video
223 * mode passed in might not work but slight changes to it might make it
224 * work. This way we let the user know what is acceptable.
226 switch (var->bits_per_pixel) {
231 var->green.offset = 0;
232 var->green.length = 8;
233 var->blue.offset = 0;
234 var->blue.length = 8;
235 var->transp.offset = 0;
236 var->transp.length = 0;
238 case 16: /* RGBA 5551 */
239 if (var->transp.length) {
242 var->green.offset = 5;
243 var->green.length = 5;
244 var->blue.offset = 10;
245 var->blue.length = 5;
246 var->transp.offset = 15;
247 var->transp.length = 1;
248 } else { /* RGB 565 */
251 var->green.offset = 5;
252 var->green.length = 6;
253 var->blue.offset = 11;
254 var->blue.length = 5;
255 var->transp.offset = 0;
256 var->transp.length = 0;
259 case 24: /* RGB 888 */
262 var->green.offset = 8;
263 var->green.length = 8;
264 var->blue.offset = 16;
265 var->blue.length = 8;
266 var->transp.offset = 0;
267 var->transp.length = 0;
269 case 32: /* RGBA 8888 */
272 var->green.offset = 8;
273 var->green.length = 8;
274 var->blue.offset = 16;
275 var->blue.length = 8;
276 var->transp.offset = 24;
277 var->transp.length = 8;
280 var->red.msb_right = 0;
281 var->green.msb_right = 0;
282 var->blue.msb_right = 0;
283 var->transp.msb_right = 0;
288 /* This routine actually sets the video mode. It's in here where we
289 * the hardware state info->par and fix which can be affected by the
290 * change in par. For this driver it doesn't do much.
292 static int vfb_set_par(struct fb_info *info)
294 info->fix.line_length = get_line_length(info->var.xres_virtual,
295 info->var.bits_per_pixel);
300 * Set a single color register. The values supplied are already
301 * rounded down to the hardware's capabilities (according to the
302 * entries in the var structure). Return != 0 for invalid regno.
305 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
306 u_int transp, struct fb_info *info)
308 if (regno >= 256) /* no. of hw registers */
311 * Program hardware... do anything you want with transp
314 /* grayscale works only partially under directcolor */
315 if (info->var.grayscale) {
316 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
318 (red * 77 + green * 151 + blue * 28) >> 8;
322 * var->{color}.offset contains start of bitfield
323 * var->{color}.length contains length of bitfield
324 * {hardwarespecific} contains width of RAMDAC
325 * cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
326 * RAMDAC[X] is programmed to (red, green, blue)
329 * var->{color}.offset is 0 unless the palette index takes less than
330 * bits_per_pixel bits and is stored in the upper
331 * bits of the pixel value
332 * var->{color}.length is set so that 1 << length is the number of available
335 * RAMDAC[X] is programmed to (red, green, blue)
338 * does not use DAC. Usually 3 are present.
339 * var->{color}.offset contains start of bitfield
340 * var->{color}.length contains length of bitfield
341 * cmap is programmed to (red << red.offset) | (green << green.offset) |
342 * (blue << blue.offset) | (transp << transp.offset)
343 * RAMDAC does not exist
345 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
346 switch (info->fix.visual) {
347 case FB_VISUAL_TRUECOLOR:
348 case FB_VISUAL_PSEUDOCOLOR:
349 red = CNVT_TOHW(red, info->var.red.length);
350 green = CNVT_TOHW(green, info->var.green.length);
351 blue = CNVT_TOHW(blue, info->var.blue.length);
352 transp = CNVT_TOHW(transp, info->var.transp.length);
354 case FB_VISUAL_DIRECTCOLOR:
355 red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */
356 green = CNVT_TOHW(green, 8);
357 blue = CNVT_TOHW(blue, 8);
358 /* hey, there is bug in transp handling... */
359 transp = CNVT_TOHW(transp, 8);
363 /* Truecolor has hardware independent palette */
364 if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
370 v = (red << info->var.red.offset) |
371 (green << info->var.green.offset) |
372 (blue << info->var.blue.offset) |
373 (transp << info->var.transp.offset);
374 switch (info->var.bits_per_pixel) {
378 ((u32 *) (info->pseudo_palette))[regno] = v;
382 ((u32 *) (info->pseudo_palette))[regno] = v;
391 * Pan or Wrap the Display
393 * This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
396 static int vfb_pan_display(struct fb_var_screeninfo *var,
397 struct fb_info *info)
399 if (var->vmode & FB_VMODE_YWRAP) {
400 if (var->yoffset >= info->var.yres_virtual ||
404 if (var->xoffset + info->var.xres > info->var.xres_virtual ||
405 var->yoffset + info->var.yres > info->var.yres_virtual)
408 info->var.xoffset = var->xoffset;
409 info->var.yoffset = var->yoffset;
410 if (var->vmode & FB_VMODE_YWRAP)
411 info->var.vmode |= FB_VMODE_YWRAP;
413 info->var.vmode &= ~FB_VMODE_YWRAP;
418 * Most drivers don't need their own mmap function
421 static int vfb_mmap(struct fb_info *info,
422 struct vm_area_struct *vma)
424 unsigned long start = vma->vm_start;
425 unsigned long size = vma->vm_end - vma->vm_start;
426 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
427 unsigned long page, pos;
429 if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
431 if (size > info->fix.smem_len)
433 if (offset > info->fix.smem_len - size)
436 pos = (unsigned long)info->fix.smem_start + offset;
439 page = vmalloc_to_pfn((void *)pos);
440 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {
445 if (size > PAGE_SIZE)
457 * The virtual framebuffer driver is only enabled if explicitly
458 * requested by passing 'video=vfb:' (or any actual options).
460 static int __init vfb_setup(char *options)
474 while ((this_opt = strsep(&options, ",")) != NULL) {
477 /* Test disable for backwards compatibility */
478 if (!strcmp(this_opt, "disable"))
489 static int vfb_probe(struct platform_device *dev)
491 struct fb_info *info;
492 int retval = -ENOMEM;
495 * For real video cards we use ioremap.
497 if (!(videomemory = rvmalloc(videomemorysize)))
500 info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
504 info->screen_base = (char __iomem *)videomemory;
505 info->fbops = &vfb_ops;
507 retval = fb_find_mode(&info->var, info, NULL,
510 if (!retval || (retval == 4))
511 info->var = vfb_default;
512 vfb_fix.smem_start = (unsigned long) videomemory;
513 vfb_fix.smem_len = videomemorysize;
515 info->pseudo_palette = info->par;
517 info->flags = FBINFO_FLAG_DEFAULT;
519 retval = fb_alloc_cmap(&info->cmap, 256, 0);
523 retval = register_framebuffer(info);
526 platform_set_drvdata(dev, info);
528 fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n",
529 videomemorysize >> 10);
532 fb_dealloc_cmap(&info->cmap);
534 framebuffer_release(info);
536 rvfree(videomemory, videomemorysize);
540 static int vfb_remove(struct platform_device *dev)
542 struct fb_info *info = platform_get_drvdata(dev);
545 unregister_framebuffer(info);
546 rvfree(videomemory, videomemorysize);
547 fb_dealloc_cmap(&info->cmap);
548 framebuffer_release(info);
553 static struct platform_driver vfb_driver = {
555 .remove = vfb_remove,
561 static struct platform_device *vfb_device;
563 static int __init vfb_init(void)
570 if (fb_get_options("vfb", &option))
578 ret = platform_driver_register(&vfb_driver);
581 vfb_device = platform_device_alloc("vfb", 0);
584 ret = platform_device_add(vfb_device);
589 platform_device_put(vfb_device);
590 platform_driver_unregister(&vfb_driver);
597 module_init(vfb_init);
600 static void __exit vfb_exit(void)
602 platform_device_unregister(vfb_device);
603 platform_driver_unregister(&vfb_driver);
606 module_exit(vfb_exit);
608 MODULE_LICENSE("GPL");