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/tty.h>
19 #include <linux/slab.h>
20 #include <linux/vmalloc.h>
21 #include <linux/delay.h>
22 #include <linux/interrupt.h>
23 #include <linux/platform_device.h>
25 #include <asm/uaccess.h>
27 #include <linux/init.h>
30 * RAM we reserve for the frame buffer. This defines the maximum screen
33 * The default can be overridden if the driver is compiled as a module
36 #define VIDEOMEMSIZE (1*1024*1024) /* 1 MB */
38 static void *videomemory
;
39 static u_long videomemorysize
= VIDEOMEMSIZE
;
40 module_param(videomemorysize
, ulong
, 0);
42 static struct fb_var_screeninfo vfb_default __initdata
= {
51 .activate
= FB_ACTIVATE_TEST
,
61 .vmode
= FB_VMODE_NONINTERLACED
,
64 static struct fb_fix_screeninfo vfb_fix __initdata
= {
66 .type
= FB_TYPE_PACKED_PIXELS
,
67 .visual
= FB_VISUAL_PSEUDOCOLOR
,
71 .accel
= FB_ACCEL_NONE
,
74 static int vfb_enable __initdata
= 0; /* disabled by default */
75 module_param(vfb_enable
, bool, 0);
77 static int vfb_check_var(struct fb_var_screeninfo
*var
,
78 struct fb_info
*info
);
79 static int vfb_set_par(struct fb_info
*info
);
80 static int vfb_setcolreg(u_int regno
, u_int red
, u_int green
, u_int blue
,
81 u_int transp
, struct fb_info
*info
);
82 static int vfb_pan_display(struct fb_var_screeninfo
*var
,
83 struct fb_info
*info
);
84 static int vfb_mmap(struct fb_info
*info
, struct file
*file
,
85 struct vm_area_struct
*vma
);
87 static struct fb_ops vfb_ops
= {
88 .fb_check_var
= vfb_check_var
,
89 .fb_set_par
= vfb_set_par
,
90 .fb_setcolreg
= vfb_setcolreg
,
91 .fb_pan_display
= vfb_pan_display
,
92 .fb_fillrect
= cfb_fillrect
,
93 .fb_copyarea
= cfb_copyarea
,
94 .fb_imageblit
= cfb_imageblit
,
102 static u_long
get_line_length(int xres_virtual
, int bpp
)
106 length
= xres_virtual
* bpp
;
107 length
= (length
+ 31) & ~31;
113 * Setting the video mode has been split into two parts.
114 * First part, xxxfb_check_var, must not write anything
115 * to hardware, it should only verify and adjust var.
116 * This means it doesn't alter par but it does use hardware
117 * data from it to check this var.
120 static int vfb_check_var(struct fb_var_screeninfo
*var
,
121 struct fb_info
*info
)
126 * FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
127 * as FB_VMODE_SMOOTH_XPAN is only used internally
130 if (var
->vmode
& FB_VMODE_CONUPDATE
) {
131 var
->vmode
|= FB_VMODE_YWRAP
;
132 var
->xoffset
= info
->var
.xoffset
;
133 var
->yoffset
= info
->var
.yoffset
;
137 * Some very basic checks
143 if (var
->xres
> var
->xres_virtual
)
144 var
->xres_virtual
= var
->xres
;
145 if (var
->yres
> var
->yres_virtual
)
146 var
->yres_virtual
= var
->yres
;
147 if (var
->bits_per_pixel
<= 1)
148 var
->bits_per_pixel
= 1;
149 else if (var
->bits_per_pixel
<= 8)
150 var
->bits_per_pixel
= 8;
151 else if (var
->bits_per_pixel
<= 16)
152 var
->bits_per_pixel
= 16;
153 else if (var
->bits_per_pixel
<= 24)
154 var
->bits_per_pixel
= 24;
155 else if (var
->bits_per_pixel
<= 32)
156 var
->bits_per_pixel
= 32;
160 if (var
->xres_virtual
< var
->xoffset
+ var
->xres
)
161 var
->xres_virtual
= var
->xoffset
+ var
->xres
;
162 if (var
->yres_virtual
< var
->yoffset
+ var
->yres
)
163 var
->yres_virtual
= var
->yoffset
+ var
->yres
;
169 get_line_length(var
->xres_virtual
, var
->bits_per_pixel
);
170 if (line_length
* var
->yres_virtual
> videomemorysize
)
174 * Now that we checked it we alter var. The reason being is that the video
175 * mode passed in might not work but slight changes to it might make it
176 * work. This way we let the user know what is acceptable.
178 switch (var
->bits_per_pixel
) {
183 var
->green
.offset
= 0;
184 var
->green
.length
= 8;
185 var
->blue
.offset
= 0;
186 var
->blue
.length
= 8;
187 var
->transp
.offset
= 0;
188 var
->transp
.length
= 0;
190 case 16: /* RGBA 5551 */
191 if (var
->transp
.length
) {
194 var
->green
.offset
= 5;
195 var
->green
.length
= 5;
196 var
->blue
.offset
= 10;
197 var
->blue
.length
= 5;
198 var
->transp
.offset
= 15;
199 var
->transp
.length
= 1;
200 } else { /* RGB 565 */
203 var
->green
.offset
= 5;
204 var
->green
.length
= 6;
205 var
->blue
.offset
= 11;
206 var
->blue
.length
= 5;
207 var
->transp
.offset
= 0;
208 var
->transp
.length
= 0;
211 case 24: /* RGB 888 */
214 var
->green
.offset
= 8;
215 var
->green
.length
= 8;
216 var
->blue
.offset
= 16;
217 var
->blue
.length
= 8;
218 var
->transp
.offset
= 0;
219 var
->transp
.length
= 0;
221 case 32: /* RGBA 8888 */
224 var
->green
.offset
= 8;
225 var
->green
.length
= 8;
226 var
->blue
.offset
= 16;
227 var
->blue
.length
= 8;
228 var
->transp
.offset
= 24;
229 var
->transp
.length
= 8;
232 var
->red
.msb_right
= 0;
233 var
->green
.msb_right
= 0;
234 var
->blue
.msb_right
= 0;
235 var
->transp
.msb_right
= 0;
240 /* This routine actually sets the video mode. It's in here where we
241 * the hardware state info->par and fix which can be affected by the
242 * change in par. For this driver it doesn't do much.
244 static int vfb_set_par(struct fb_info
*info
)
246 info
->fix
.line_length
= get_line_length(info
->var
.xres_virtual
,
247 info
->var
.bits_per_pixel
);
252 * Set a single color register. The values supplied are already
253 * rounded down to the hardware's capabilities (according to the
254 * entries in the var structure). Return != 0 for invalid regno.
257 static int vfb_setcolreg(u_int regno
, u_int red
, u_int green
, u_int blue
,
258 u_int transp
, struct fb_info
*info
)
260 if (regno
>= 256) /* no. of hw registers */
263 * Program hardware... do anything you want with transp
266 /* grayscale works only partially under directcolor */
267 if (info
->var
.grayscale
) {
268 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
270 (red
* 77 + green
* 151 + blue
* 28) >> 8;
274 * var->{color}.offset contains start of bitfield
275 * var->{color}.length contains length of bitfield
276 * {hardwarespecific} contains width of RAMDAC
277 * cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
278 * RAMDAC[X] is programmed to (red, green, blue)
281 * uses offset = 0 && length = RAMDAC register width.
282 * var->{color}.offset is 0
283 * var->{color}.length contains widht of DAC
285 * RAMDAC[X] is programmed to (red, green, blue)
287 * does not use DAC. Usually 3 are present.
288 * var->{color}.offset contains start of bitfield
289 * var->{color}.length contains length of bitfield
290 * cmap is programmed to (red << red.offset) | (green << green.offset) |
291 * (blue << blue.offset) | (transp << transp.offset)
292 * RAMDAC does not exist
294 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
295 switch (info
->fix
.visual
) {
296 case FB_VISUAL_TRUECOLOR
:
297 case FB_VISUAL_PSEUDOCOLOR
:
298 red
= CNVT_TOHW(red
, info
->var
.red
.length
);
299 green
= CNVT_TOHW(green
, info
->var
.green
.length
);
300 blue
= CNVT_TOHW(blue
, info
->var
.blue
.length
);
301 transp
= CNVT_TOHW(transp
, info
->var
.transp
.length
);
303 case FB_VISUAL_DIRECTCOLOR
:
304 red
= CNVT_TOHW(red
, 8); /* expect 8 bit DAC */
305 green
= CNVT_TOHW(green
, 8);
306 blue
= CNVT_TOHW(blue
, 8);
307 /* hey, there is bug in transp handling... */
308 transp
= CNVT_TOHW(transp
, 8);
312 /* Truecolor has hardware independent palette */
313 if (info
->fix
.visual
== FB_VISUAL_TRUECOLOR
) {
319 v
= (red
<< info
->var
.red
.offset
) |
320 (green
<< info
->var
.green
.offset
) |
321 (blue
<< info
->var
.blue
.offset
) |
322 (transp
<< info
->var
.transp
.offset
);
323 switch (info
->var
.bits_per_pixel
) {
327 ((u32
*) (info
->pseudo_palette
))[regno
] = v
;
331 ((u32
*) (info
->pseudo_palette
))[regno
] = v
;
340 * Pan or Wrap the Display
342 * This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
345 static int vfb_pan_display(struct fb_var_screeninfo
*var
,
346 struct fb_info
*info
)
348 if (var
->vmode
& FB_VMODE_YWRAP
) {
350 || var
->yoffset
>= info
->var
.yres_virtual
354 if (var
->xoffset
+ var
->xres
> info
->var
.xres_virtual
||
355 var
->yoffset
+ var
->yres
> info
->var
.yres_virtual
)
358 info
->var
.xoffset
= var
->xoffset
;
359 info
->var
.yoffset
= var
->yoffset
;
360 if (var
->vmode
& FB_VMODE_YWRAP
)
361 info
->var
.vmode
|= FB_VMODE_YWRAP
;
363 info
->var
.vmode
&= ~FB_VMODE_YWRAP
;
368 * Most drivers don't need their own mmap function
371 static int vfb_mmap(struct fb_info
*info
, struct file
*file
,
372 struct vm_area_struct
*vma
)
378 static int __init
vfb_setup(char *options
)
384 if (!options
|| !*options
)
387 while ((this_opt
= strsep(&options
, ",")) != NULL
) {
390 if (!strncmp(this_opt
, "disable", 7))
401 static void vfb_platform_release(struct device
*device
)
403 // This is called when the reference count goes to zero.
406 static int __init
vfb_probe(struct platform_device
*dev
)
408 struct fb_info
*info
;
409 int retval
= -ENOMEM
;
412 * For real video cards we use ioremap.
414 if (!(videomemory
= vmalloc(videomemorysize
)))
418 * VFB must clear memory to prevent kernel info
419 * leakage into userspace
420 * VGA-based drivers MUST NOT clear memory if
421 * they want to be able to take over vgacon
423 memset(videomemory
, 0, videomemorysize
);
425 info
= framebuffer_alloc(sizeof(u32
) * 256, &dev
->dev
);
429 info
->screen_base
= (char __iomem
*)videomemory
;
430 info
->fbops
= &vfb_ops
;
432 retval
= fb_find_mode(&info
->var
, info
, NULL
,
435 if (!retval
|| (retval
== 4))
436 info
->var
= vfb_default
;
438 info
->pseudo_palette
= info
->par
;
440 info
->flags
= FBINFO_FLAG_DEFAULT
;
442 retval
= fb_alloc_cmap(&info
->cmap
, 256, 0);
446 retval
= register_framebuffer(info
);
449 platform_set_drvdata(dev
, info
);
452 "fb%d: Virtual frame buffer device, using %ldK of video memory\n",
453 info
->node
, videomemorysize
>> 10);
456 fb_dealloc_cmap(&info
->cmap
);
458 framebuffer_release(info
);
464 static int vfb_remove(struct platform_device
*dev
)
466 struct fb_info
*info
= platform_get_drvdata(dev
);
469 unregister_framebuffer(info
);
471 framebuffer_release(info
);
476 static struct platform_driver vfb_driver
= {
478 .remove
= vfb_remove
,
484 static struct platform_device vfb_device
= {
488 .release
= vfb_platform_release
,
492 static int __init
vfb_init(void)
499 if (fb_get_options("vfb", &option
))
507 ret
= platform_driver_register(&vfb_driver
);
510 ret
= platform_device_register(&vfb_device
);
512 platform_driver_unregister(&vfb_driver
);
517 module_init(vfb_init
);
520 static void __exit
vfb_exit(void)
522 platform_device_unregister(&vfb_device
);
523 platform_driver_unregister(&vfb_driver
);
526 module_exit(vfb_exit
);
528 MODULE_LICENSE("GPL");