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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/video/vfb.c

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13 KiB
C
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/*
* 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/tty.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <asm/uaccess.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);
static struct fb_var_screeninfo vfb_default __initdata = {
.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 __initdata = {
.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 file *file,
struct vm_area_struct *vma);
static struct fb_ops vfb_ops = {
.fb_check_var = vfb_check_var,
.fb_set_par = vfb_set_par,
.fb_setcolreg = vfb_setcolreg,
.fb_pan_display = vfb_pan_display,
.fb_fillrect = cfb_fillrect,
.fb_copyarea = cfb_copyarea,
.fb_imageblit = cfb_imageblit,
.fb_cursor = soft_cursor,
.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:
* uses offset = 0 && length = RAMDAC register width.
* var->{color}.offset is 0
* var->{color}.length contains widht of DAC
* 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 + var->xres > info->var.xres_virtual ||
var->yoffset + 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 file *file,
struct vm_area_struct *vma)
{
return -EINVAL;
}
#ifndef MODULE
static int __init vfb_setup(char *options)
{
char *this_opt;
vfb_enable = 1;
if (!options || !*options)
return 1;
while ((this_opt = strsep(&options, ",")) != NULL) {
if (!*this_opt)
continue;
if (!strncmp(this_opt, "disable", 7))
vfb_enable = 0;
}
return 1;
}
#endif /* MODULE */
/*
* Initialisation
*/
static void vfb_platform_release(struct device *device)
{
// This is called when the reference count goes to zero.
}
static int __init vfb_probe(struct device *device)
{
struct platform_device *dev = to_platform_device(device);
struct fb_info *info;
int retval = -ENOMEM;
/*
* For real video cards we use ioremap.
*/
if (!(videomemory = vmalloc(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;
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;
dev_set_drvdata(&dev->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:
vfree(videomemory);
return retval;
}
static int vfb_remove(struct device *device)
{
struct fb_info *info = dev_get_drvdata(device);
if (info) {
unregister_framebuffer(info);
vfree(videomemory);
framebuffer_release(info);
}
return 0;
}
static struct device_driver vfb_driver = {
.name = "vfb",
.bus = &platform_bus_type,
.probe = vfb_probe,
.remove = vfb_remove,
};
static struct platform_device vfb_device = {
.name = "vfb",
.id = 0,
.dev = {
.release = vfb_platform_release,
}
};
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 = driver_register(&vfb_driver);
if (!ret) {
ret = platform_device_register(&vfb_device);
if (ret)
driver_unregister(&vfb_driver);
}
return ret;
}
module_init(vfb_init);
#ifdef MODULE
static void __exit vfb_exit(void)
{
platform_device_unregister(&vfb_device);
driver_unregister(&vfb_driver);
}
module_exit(vfb_exit);
MODULE_LICENSE("GPL");
#endif /* MODULE */
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