diff options
Diffstat (limited to 'drivers/video/fbdev/vfb.c')
| -rw-r--r-- | drivers/video/fbdev/vfb.c | 551 |
1 files changed, 551 insertions, 0 deletions
diff --git a/drivers/video/fbdev/vfb.c b/drivers/video/fbdev/vfb.c new file mode 100644 index 000000000..95d3c5986 --- /dev/null +++ b/drivers/video/fbdev/vfb.c @@ -0,0 +1,551 @@ +/* + * 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 const 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 */ |