linux/drivers/video/vfb.c
Laurent Pinchart 2883cebabb vfb: use display information in info not in var for panning
We must not use any information in the passed var besides xoffset,
yoffset and vmode as otherwise applications might abuse it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2011-08-19 10:35:27 +02:00

610 lines
14 KiB
C

/*
* 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);
/**********************************************************************
*
* Memory management
*
**********************************************************************/
static void *rvmalloc(unsigned long size)
{
void *mem;
unsigned long adr;
size = PAGE_ALIGN(size);
mem = vmalloc_32(size);
if (!mem)
return NULL;
memset(mem, 0, size); /* Clear the ram out, no junk to the user */
adr = (unsigned long) mem;
while (size > 0) {
SetPageReserved(vmalloc_to_page((void *)adr));
adr += PAGE_SIZE;
size -= PAGE_SIZE;
}
return mem;
}
static void rvfree(void *mem, unsigned long size)
{
unsigned long adr;
if (!mem)
return;
adr = (unsigned long) mem;
while ((long) size > 0) {
ClearPageReserved(vmalloc_to_page((void *)adr));
adr += PAGE_SIZE;
size -= PAGE_SIZE;
}
vfree(mem);
}
static struct fb_var_screeninfo vfb_default __devinitdata = {
.xres = 640,
.yres = 480,
.xres_virtual = 640,
.yres_virtual = 480,
.bits_per_pixel = 8,
.red = { 0, 8, 0 },
.green = { 0, 8, 0 },
.blue = { 0, 8, 0 },
.activate = FB_ACTIVATE_TEST,
.height = -1,
.width = -1,
.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 __devinitdata = {
.id = "Virtual FB",
.type = FB_TYPE_PACKED_PIXELS,
.visual = FB_VISUAL_PSEUDOCOLOR,
.xpanstep = 1,
.ypanstep = 1,
.ywrapstep = 1,
.accel = FB_ACCEL_NONE,
};
static int vfb_enable __initdata = 0; /* disabled by default */
module_param(vfb_enable, bool, 0);
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)
{
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 < 0
|| 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)
{
unsigned long start = vma->vm_start;
unsigned long size = vma->vm_end - vma->vm_start;
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long page, pos;
if (offset + size > info->fix.smem_len) {
return -EINVAL;
}
pos = (unsigned long)info->fix.smem_start + offset;
while (size > 0) {
page = vmalloc_to_pfn((void *)pos);
if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {
return -EAGAIN;
}
start += PAGE_SIZE;
pos += PAGE_SIZE;
if (size > PAGE_SIZE)
size -= PAGE_SIZE;
else
size = 0;
}
vma->vm_flags |= VM_RESERVED; /* avoid to swap out this VMA */
return 0;
}
#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;
}
return 1;
}
#endif /* MODULE */
/*
* Initialisation
*/
static int __devinit vfb_probe(struct platform_device *dev)
{
struct fb_info *info;
int retval = -ENOMEM;
/*
* For real video cards we use ioremap.
*/
if (!(videomemory = rvmalloc(videomemorysize)))
return retval;
/*
* VFB must clear memory to prevent kernel info
* leakage into userspace
* VGA-based drivers MUST NOT clear memory if
* they want to be able to take over vgacon
*/
memset(videomemory, 0, videomemorysize);
info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
if (!info)
goto err;
info->screen_base = (char __iomem *)videomemory;
info->fbops = &vfb_ops;
retval = fb_find_mode(&info->var, info, NULL,
NULL, 0, NULL, 8);
if (!retval || (retval == 4))
info->var = vfb_default;
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);
printk(KERN_INFO
"fb%d: Virtual frame buffer device, using %ldK of video memory\n",
info->node, videomemorysize >> 10);
return 0;
err2:
fb_dealloc_cmap(&info->cmap);
err1:
framebuffer_release(info);
err:
rvfree(videomemory, videomemorysize);
return retval;
}
static int vfb_remove(struct platform_device *dev)
{
struct fb_info *info = platform_get_drvdata(dev);
if (info) {
unregister_framebuffer(info);
rvfree(videomemory, videomemorysize);
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 */