LXR linux/arch/x86/kernel/sysfb

   1/*
   2 * Generic System Framebuffers on x86
   3 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License as published by the Free
   7 * Software Foundation; either version 2 of the License, or (at your option)
   8 * any later version.
   9 */
  10
  11/*
  12 * simple-framebuffer probing
  13 * Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
  14 * If the mode is incompatible, we return "false" and let the caller create
  15 * legacy nodes instead.
  16 */
  17
  18#include <linux/err.h>
  19#include <linux/init.h>
  20#include <linux/kernel.h>
  21#include <linux/mm.h>
  22#include <linux/platform_data/simplefb.h>
  23#include <linux/platform_device.h>
  24#include <linux/screen_info.h>
  25#include <asm/sysfb.h>
  26
  27static const char simplefb_resname[] = "BOOTFB";
  28static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
  29
  30/* try parsing x86 screen_info into a simple-framebuffer mode struct */
  31__init bool parse_mode(const struct screen_info *si,
  32                       struct simplefb_platform_data *mode)
  33{
  34        const struct simplefb_format *f;
  35        __u8 type;
  36        unsigned int i;
  37
  38        type = si->orig_video_isVGA;
  39        if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
  40                return false;
  41
  42        for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  43                f = &formats[i];
  44                if (si->lfb_depth == f->bits_per_pixel &&
  45                    si->red_size == f->red.length &&
  46                    si->red_pos == f->red.offset &&
  47                    si->green_size == f->green.length &&
  48                    si->green_pos == f->green.offset &&
  49                    si->blue_size == f->blue.length &&
  50                    si->blue_pos == f->blue.offset &&
  51                    si->rsvd_size == f->transp.length &&
  52                    si->rsvd_pos == f->transp.offset) {
  53                        mode->format = f->name;
  54                        mode->width = si->lfb_width;
  55                        mode->height = si->lfb_height;
  56                        mode->stride = si->lfb_linelength;
  57                        return true;
  58                }
  59        }
  60
  61        return false;
  62}
  63
  64__init int create_simplefb(const struct screen_info *si,
  65                           const struct simplefb_platform_data *mode)
  66{
  67        struct platform_device *pd;
  68        struct resource res;
  69        unsigned long len;
  70
  71        /* don't use lfb_size as it may contain the whole VMEM instead of only
  72         * the part that is occupied by the framebuffer */
  73        len = mode->height * mode->stride;
  74        len = PAGE_ALIGN(len);
  75        if (len > (u64)si->lfb_size << 16) {
  76                printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
  77                return -EINVAL;
  78        }
  79
  80        /* setup IORESOURCE_MEM as framebuffer memory */
  81        memset(&res, 0, sizeof(res));
  82        res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  83        res.name = simplefb_resname;
  84        res.start = si->lfb_base;
  85        res.end = si->lfb_base + len - 1;
  86        if (res.end <= res.start)
  87                return -EINVAL;
  88
  89        pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0,
  90                                               &res, 1, mode, sizeof(*mode));
  91        return PTR_ERR_OR_ZERO(pd);
  92}
  93