arch/x86/kernel/sysfb_simplefb.c

   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
  27 static const char simplefb_resname[] = "BOOTFB";
  28 static 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         if (IS_ERR(pd))
  92                 return PTR_ERR(pd);
  93
  94         return 0;
  95 }