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551 lines
13 KiB
551 lines
13 KiB
/* |
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* linux/drivers/video/vfb.c -- Virtual frame buffer device |
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* |
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* Copyright (C) 2002 James Simmons |
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* |
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* Copyright (C) 1997 Geert Uytterhoeven |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file COPYING in the main directory of this archive for |
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* more details. |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/string.h> |
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#include <linux/mm.h> |
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#include <linux/vmalloc.h> |
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#include <linux/delay.h> |
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#include <linux/interrupt.h> |
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#include <linux/platform_device.h> |
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|
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#include <linux/fb.h> |
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#include <linux/init.h> |
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|
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/* |
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* RAM we reserve for the frame buffer. This defines the maximum screen |
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* size |
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* |
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* The default can be overridden if the driver is compiled as a module |
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*/ |
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#define VIDEOMEMSIZE (1*1024*1024) /* 1 MB */ |
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static void *videomemory; |
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static u_long videomemorysize = VIDEOMEMSIZE; |
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module_param(videomemorysize, ulong, 0); |
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MODULE_PARM_DESC(videomemorysize, "RAM available to frame buffer (in bytes)"); |
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static char *mode_option = NULL; |
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module_param(mode_option, charp, 0); |
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MODULE_PARM_DESC(mode_option, "Preferred video mode (e.g. 640x480-8@60)"); |
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static const struct fb_videomode vfb_default = { |
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.xres = 640, |
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.yres = 480, |
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.pixclock = 20000, |
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.left_margin = 64, |
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.right_margin = 64, |
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.upper_margin = 32, |
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.lower_margin = 32, |
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.hsync_len = 64, |
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.vsync_len = 2, |
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.vmode = FB_VMODE_NONINTERLACED, |
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}; |
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static struct fb_fix_screeninfo vfb_fix = { |
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.id = "Virtual FB", |
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.type = FB_TYPE_PACKED_PIXELS, |
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.visual = FB_VISUAL_PSEUDOCOLOR, |
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.xpanstep = 1, |
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.ypanstep = 1, |
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.ywrapstep = 1, |
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.accel = FB_ACCEL_NONE, |
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}; |
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static bool vfb_enable __initdata = 0; /* disabled by default */ |
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module_param(vfb_enable, bool, 0); |
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MODULE_PARM_DESC(vfb_enable, "Enable Virtual FB driver"); |
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static int vfb_check_var(struct fb_var_screeninfo *var, |
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struct fb_info *info); |
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static int vfb_set_par(struct fb_info *info); |
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static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue, |
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u_int transp, struct fb_info *info); |
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static int vfb_pan_display(struct fb_var_screeninfo *var, |
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struct fb_info *info); |
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static int vfb_mmap(struct fb_info *info, |
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struct vm_area_struct *vma); |
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static const struct fb_ops vfb_ops = { |
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.fb_read = fb_sys_read, |
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.fb_write = fb_sys_write, |
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.fb_check_var = vfb_check_var, |
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.fb_set_par = vfb_set_par, |
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.fb_setcolreg = vfb_setcolreg, |
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.fb_pan_display = vfb_pan_display, |
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.fb_fillrect = sys_fillrect, |
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.fb_copyarea = sys_copyarea, |
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.fb_imageblit = sys_imageblit, |
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.fb_mmap = vfb_mmap, |
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}; |
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/* |
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* Internal routines |
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*/ |
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static u_long get_line_length(int xres_virtual, int bpp) |
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{ |
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u_long length; |
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length = xres_virtual * bpp; |
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length = (length + 31) & ~31; |
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length >>= 3; |
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return (length); |
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} |
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/* |
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* Setting the video mode has been split into two parts. |
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* First part, xxxfb_check_var, must not write anything |
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* to hardware, it should only verify and adjust var. |
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* This means it doesn't alter par but it does use hardware |
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* data from it to check this var. |
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*/ |
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static int vfb_check_var(struct fb_var_screeninfo *var, |
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struct fb_info *info) |
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{ |
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u_long line_length; |
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/* |
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* FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal! |
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* as FB_VMODE_SMOOTH_XPAN is only used internally |
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*/ |
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if (var->vmode & FB_VMODE_CONUPDATE) { |
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var->vmode |= FB_VMODE_YWRAP; |
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var->xoffset = info->var.xoffset; |
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var->yoffset = info->var.yoffset; |
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} |
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/* |
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* Some very basic checks |
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*/ |
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if (!var->xres) |
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var->xres = 1; |
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if (!var->yres) |
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var->yres = 1; |
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if (var->xres > var->xres_virtual) |
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var->xres_virtual = var->xres; |
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if (var->yres > var->yres_virtual) |
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var->yres_virtual = var->yres; |
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if (var->bits_per_pixel <= 1) |
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var->bits_per_pixel = 1; |
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else if (var->bits_per_pixel <= 8) |
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var->bits_per_pixel = 8; |
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else if (var->bits_per_pixel <= 16) |
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var->bits_per_pixel = 16; |
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else if (var->bits_per_pixel <= 24) |
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var->bits_per_pixel = 24; |
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else if (var->bits_per_pixel <= 32) |
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var->bits_per_pixel = 32; |
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else |
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return -EINVAL; |
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if (var->xres_virtual < var->xoffset + var->xres) |
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var->xres_virtual = var->xoffset + var->xres; |
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if (var->yres_virtual < var->yoffset + var->yres) |
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var->yres_virtual = var->yoffset + var->yres; |
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/* |
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* Memory limit |
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*/ |
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line_length = |
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get_line_length(var->xres_virtual, var->bits_per_pixel); |
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if (line_length * var->yres_virtual > videomemorysize) |
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return -ENOMEM; |
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/* |
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* Now that we checked it we alter var. The reason being is that the video |
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* mode passed in might not work but slight changes to it might make it |
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* work. This way we let the user know what is acceptable. |
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*/ |
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switch (var->bits_per_pixel) { |
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case 1: |
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case 8: |
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var->red.offset = 0; |
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var->red.length = 8; |
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var->green.offset = 0; |
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var->green.length = 8; |
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var->blue.offset = 0; |
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var->blue.length = 8; |
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var->transp.offset = 0; |
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var->transp.length = 0; |
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break; |
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case 16: /* RGBA 5551 */ |
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if (var->transp.length) { |
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var->red.offset = 0; |
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var->red.length = 5; |
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var->green.offset = 5; |
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var->green.length = 5; |
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var->blue.offset = 10; |
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var->blue.length = 5; |
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var->transp.offset = 15; |
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var->transp.length = 1; |
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} else { /* RGB 565 */ |
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var->red.offset = 0; |
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var->red.length = 5; |
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var->green.offset = 5; |
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var->green.length = 6; |
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var->blue.offset = 11; |
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var->blue.length = 5; |
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var->transp.offset = 0; |
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var->transp.length = 0; |
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} |
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break; |
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case 24: /* RGB 888 */ |
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var->red.offset = 0; |
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var->red.length = 8; |
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var->green.offset = 8; |
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var->green.length = 8; |
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var->blue.offset = 16; |
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var->blue.length = 8; |
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var->transp.offset = 0; |
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var->transp.length = 0; |
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break; |
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case 32: /* RGBA 8888 */ |
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var->red.offset = 0; |
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var->red.length = 8; |
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var->green.offset = 8; |
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var->green.length = 8; |
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var->blue.offset = 16; |
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var->blue.length = 8; |
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var->transp.offset = 24; |
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var->transp.length = 8; |
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break; |
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} |
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var->red.msb_right = 0; |
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var->green.msb_right = 0; |
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var->blue.msb_right = 0; |
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var->transp.msb_right = 0; |
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return 0; |
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} |
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/* This routine actually sets the video mode. It's in here where we |
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* the hardware state info->par and fix which can be affected by the |
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* change in par. For this driver it doesn't do much. |
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*/ |
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static int vfb_set_par(struct fb_info *info) |
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{ |
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switch (info->var.bits_per_pixel) { |
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case 1: |
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info->fix.visual = FB_VISUAL_MONO01; |
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break; |
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case 8: |
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info->fix.visual = FB_VISUAL_PSEUDOCOLOR; |
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break; |
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case 16: |
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case 24: |
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case 32: |
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info->fix.visual = FB_VISUAL_TRUECOLOR; |
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break; |
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} |
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info->fix.line_length = get_line_length(info->var.xres_virtual, |
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info->var.bits_per_pixel); |
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return 0; |
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} |
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/* |
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* Set a single color register. The values supplied are already |
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* rounded down to the hardware's capabilities (according to the |
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* entries in the var structure). Return != 0 for invalid regno. |
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*/ |
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static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue, |
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u_int transp, struct fb_info *info) |
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{ |
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if (regno >= 256) /* no. of hw registers */ |
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return 1; |
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/* |
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* Program hardware... do anything you want with transp |
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*/ |
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/* grayscale works only partially under directcolor */ |
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if (info->var.grayscale) { |
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/* grayscale = 0.30*R + 0.59*G + 0.11*B */ |
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red = green = blue = |
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(red * 77 + green * 151 + blue * 28) >> 8; |
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} |
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/* Directcolor: |
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* var->{color}.offset contains start of bitfield |
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* var->{color}.length contains length of bitfield |
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* {hardwarespecific} contains width of RAMDAC |
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* cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset) |
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* RAMDAC[X] is programmed to (red, green, blue) |
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* |
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* Pseudocolor: |
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* var->{color}.offset is 0 unless the palette index takes less than |
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* bits_per_pixel bits and is stored in the upper |
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* bits of the pixel value |
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* var->{color}.length is set so that 1 << length is the number of available |
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* palette entries |
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* cmap is not used |
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* RAMDAC[X] is programmed to (red, green, blue) |
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* |
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* Truecolor: |
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* does not use DAC. Usually 3 are present. |
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* var->{color}.offset contains start of bitfield |
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* var->{color}.length contains length of bitfield |
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* cmap is programmed to (red << red.offset) | (green << green.offset) | |
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* (blue << blue.offset) | (transp << transp.offset) |
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* RAMDAC does not exist |
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*/ |
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#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16) |
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switch (info->fix.visual) { |
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case FB_VISUAL_TRUECOLOR: |
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case FB_VISUAL_PSEUDOCOLOR: |
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red = CNVT_TOHW(red, info->var.red.length); |
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green = CNVT_TOHW(green, info->var.green.length); |
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blue = CNVT_TOHW(blue, info->var.blue.length); |
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transp = CNVT_TOHW(transp, info->var.transp.length); |
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break; |
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case FB_VISUAL_DIRECTCOLOR: |
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red = CNVT_TOHW(red, 8); /* expect 8 bit DAC */ |
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green = CNVT_TOHW(green, 8); |
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blue = CNVT_TOHW(blue, 8); |
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/* hey, there is bug in transp handling... */ |
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transp = CNVT_TOHW(transp, 8); |
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break; |
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} |
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#undef CNVT_TOHW |
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/* Truecolor has hardware independent palette */ |
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if (info->fix.visual == FB_VISUAL_TRUECOLOR) { |
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u32 v; |
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if (regno >= 16) |
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return 1; |
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v = (red << info->var.red.offset) | |
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(green << info->var.green.offset) | |
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(blue << info->var.blue.offset) | |
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(transp << info->var.transp.offset); |
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switch (info->var.bits_per_pixel) { |
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case 8: |
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break; |
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case 16: |
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((u32 *) (info->pseudo_palette))[regno] = v; |
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break; |
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case 24: |
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case 32: |
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((u32 *) (info->pseudo_palette))[regno] = v; |
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break; |
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} |
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return 0; |
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} |
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return 0; |
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} |
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/* |
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* Pan or Wrap the Display |
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* |
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* This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag |
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*/ |
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static int vfb_pan_display(struct fb_var_screeninfo *var, |
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struct fb_info *info) |
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{ |
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if (var->vmode & FB_VMODE_YWRAP) { |
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if (var->yoffset >= info->var.yres_virtual || |
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var->xoffset) |
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return -EINVAL; |
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} else { |
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if (var->xoffset + info->var.xres > info->var.xres_virtual || |
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var->yoffset + info->var.yres > info->var.yres_virtual) |
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return -EINVAL; |
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} |
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info->var.xoffset = var->xoffset; |
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info->var.yoffset = var->yoffset; |
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if (var->vmode & FB_VMODE_YWRAP) |
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info->var.vmode |= FB_VMODE_YWRAP; |
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else |
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info->var.vmode &= ~FB_VMODE_YWRAP; |
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return 0; |
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} |
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/* |
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* Most drivers don't need their own mmap function |
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*/ |
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static int vfb_mmap(struct fb_info *info, |
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struct vm_area_struct *vma) |
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{ |
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return remap_vmalloc_range(vma, (void *)info->fix.smem_start, vma->vm_pgoff); |
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} |
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#ifndef MODULE |
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/* |
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* The virtual framebuffer driver is only enabled if explicitly |
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* requested by passing 'video=vfb:' (or any actual options). |
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*/ |
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static int __init vfb_setup(char *options) |
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{ |
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char *this_opt; |
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vfb_enable = 0; |
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if (!options) |
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return 1; |
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vfb_enable = 1; |
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if (!*options) |
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return 1; |
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while ((this_opt = strsep(&options, ",")) != NULL) { |
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if (!*this_opt) |
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continue; |
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/* Test disable for backwards compatibility */ |
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if (!strcmp(this_opt, "disable")) |
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vfb_enable = 0; |
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else |
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mode_option = this_opt; |
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} |
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return 1; |
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} |
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#endif /* MODULE */ |
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/* |
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* Initialisation |
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*/ |
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static int vfb_probe(struct platform_device *dev) |
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{ |
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struct fb_info *info; |
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unsigned int size = PAGE_ALIGN(videomemorysize); |
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int retval = -ENOMEM; |
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/* |
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* For real video cards we use ioremap. |
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*/ |
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if (!(videomemory = vmalloc_32_user(size))) |
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return retval; |
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info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev); |
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if (!info) |
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goto err; |
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info->screen_base = (char __iomem *)videomemory; |
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info->fbops = &vfb_ops; |
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if (!fb_find_mode(&info->var, info, mode_option, |
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NULL, 0, &vfb_default, 8)){ |
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fb_err(info, "Unable to find usable video mode.\n"); |
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retval = -EINVAL; |
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goto err1; |
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} |
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vfb_fix.smem_start = (unsigned long) videomemory; |
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vfb_fix.smem_len = videomemorysize; |
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info->fix = vfb_fix; |
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info->pseudo_palette = info->par; |
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info->par = NULL; |
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info->flags = FBINFO_FLAG_DEFAULT; |
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retval = fb_alloc_cmap(&info->cmap, 256, 0); |
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if (retval < 0) |
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goto err1; |
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retval = register_framebuffer(info); |
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if (retval < 0) |
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goto err2; |
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platform_set_drvdata(dev, info); |
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vfb_set_par(info); |
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fb_info(info, "Virtual frame buffer device, using %ldK of video memory\n", |
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videomemorysize >> 10); |
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return 0; |
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err2: |
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fb_dealloc_cmap(&info->cmap); |
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err1: |
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framebuffer_release(info); |
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err: |
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vfree(videomemory); |
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return retval; |
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} |
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static int vfb_remove(struct platform_device *dev) |
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{ |
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struct fb_info *info = platform_get_drvdata(dev); |
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if (info) { |
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unregister_framebuffer(info); |
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vfree(videomemory); |
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fb_dealloc_cmap(&info->cmap); |
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framebuffer_release(info); |
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} |
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return 0; |
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} |
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static struct platform_driver vfb_driver = { |
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.probe = vfb_probe, |
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.remove = vfb_remove, |
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.driver = { |
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.name = "vfb", |
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}, |
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}; |
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static struct platform_device *vfb_device; |
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static int __init vfb_init(void) |
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{ |
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int ret = 0; |
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#ifndef MODULE |
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char *option = NULL; |
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if (fb_get_options("vfb", &option)) |
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return -ENODEV; |
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vfb_setup(option); |
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#endif |
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if (!vfb_enable) |
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return -ENXIO; |
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ret = platform_driver_register(&vfb_driver); |
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if (!ret) { |
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vfb_device = platform_device_alloc("vfb", 0); |
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if (vfb_device) |
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ret = platform_device_add(vfb_device); |
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else |
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ret = -ENOMEM; |
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if (ret) { |
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platform_device_put(vfb_device); |
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platform_driver_unregister(&vfb_driver); |
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} |
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} |
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return ret; |
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} |
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module_init(vfb_init); |
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#ifdef MODULE |
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static void __exit vfb_exit(void) |
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{ |
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platform_device_unregister(vfb_device); |
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platform_driver_unregister(&vfb_driver); |
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} |
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module_exit(vfb_exit); |
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MODULE_LICENSE("GPL"); |
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#endif /* MODULE */
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