drivers/firmware/google/framebuffer-coreboot.c

   1 /*
   2  * framebuffer-coreboot.c
   3  *
   4  * Memory based framebuffer accessed through coreboot table.
   5  *
   6  * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
   7  * Copyright 2017 Google Inc.
   8  * Copyright 2017 Samuel Holland <samuel@sholland.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License v2.0 as published by
  12  * the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/kernel.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/platform_data/simplefb.h>
  25 #include <linux/platform_device.h>
  26
  27 #include "coreboot_table.h"
  28
  29 #define CB_TAG_FRAMEBUFFER 0x12
  30
  31 static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
  32
  33 static int framebuffer_probe(struct coreboot_device *dev)
  34 {
  35         int i;
  36         u32 length;
  37         struct lb_framebuffer *fb = &dev->framebuffer;
  38         struct platform_device *pdev;
  39         struct resource res;
  40         struct simplefb_platform_data pdata = {
  41                 .width = fb->x_resolution,
  42                 .height = fb->y_resolution,
  43                 .stride = fb->bytes_per_line,
  44                 .format = NULL,
  45         };
  46
  47         for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  48                 if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&
  49                     fb->red_mask_pos       == formats[i].red.offset &&
  50                     fb->red_mask_size      == formats[i].red.length &&
  51                     fb->green_mask_pos     == formats[i].green.offset &&
  52                     fb->green_mask_size    == formats[i].green.length &&
  53                     fb->blue_mask_pos      == formats[i].blue.offset &&
  54                     fb->blue_mask_size     == formats[i].blue.length)
  55                         pdata.format = formats[i].name;
  56         }
  57         if (!pdata.format)
  58                 return -ENODEV;
  59
  60         memset(&res, 0, sizeof(res));
  61         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  62         res.name = "Coreboot Framebuffer";
  63         res.start = fb->physical_address;
  64         length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
  65         res.end = res.start + length - 1;
  66         if (res.end <= res.start)
  67                 return -EINVAL;
  68
  69         pdev = platform_device_register_resndata(&dev->dev,
  70                                                  "simple-framebuffer", 0,
  71                                                  &res, 1, &pdata,
  72                                                  sizeof(pdata));
  73         if (IS_ERR(pdev))
  74                 pr_warn("coreboot: could not register framebuffer\n");
  75         else
  76                 dev_set_drvdata(&dev->dev, pdev);
  77
  78         return PTR_ERR_OR_ZERO(pdev);
  79 }
  80
  81 static int framebuffer_remove(struct coreboot_device *dev)
  82 {
  83         struct platform_device *pdev = dev_get_drvdata(&dev->dev);
  84
  85         platform_device_unregister(pdev);
  86
  87         return 0;
  88 }
  89
  90 static struct coreboot_driver framebuffer_driver = {
  91         .probe = framebuffer_probe,
  92         .remove = framebuffer_remove,
  93         .drv = {
  94                 .name = "framebuffer",
  95         },
  96         .tag = CB_TAG_FRAMEBUFFER,
  97 };
  98
  99 static int __init coreboot_framebuffer_init(void)
 100 {
 101         return coreboot_driver_register(&framebuffer_driver);
 102 }
 103
 104 static void coreboot_framebuffer_exit(void)
 105 {
 106         coreboot_driver_unregister(&framebuffer_driver);
 107 }
 108
 109 module_init(coreboot_framebuffer_init);
 110 module_exit(coreboot_framebuffer_exit);
 111
 112 MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
 113 MODULE_LICENSE("GPL");