LXR linux/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
  31static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
  32
  33static 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                    fb->reserved_mask_pos  == formats[i].transp.offset &&
  56                    fb->reserved_mask_size == formats[i].transp.length)
  57                        pdata.format = formats[i].name;
  58        }
  59        if (!pdata.format)
  60                return -ENODEV;
  61
  62        memset(&res, 0, sizeof(res));
  63        res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  64        res.name = "Coreboot Framebuffer";
  65        res.start = fb->physical_address;
  66        length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
  67        res.end = res.start + length - 1;
  68        if (res.end <= res.start)
  69                return -EINVAL;
  70
  71        pdev = platform_device_register_resndata(&dev->dev,
  72                                                 "simple-framebuffer", 0,
  73                                                 &res, 1, &pdata,
  74                                                 sizeof(pdata));
  75        if (IS_ERR(pdev))
  76                pr_warn("coreboot: could not register framebuffer\n");
  77        else
  78                dev_set_drvdata(&dev->dev, pdev);
  79
  80        return PTR_ERR_OR_ZERO(pdev);
  81}
  82
  83static int framebuffer_remove(struct coreboot_device *dev)
  84{
  85        struct platform_device *pdev = dev_get_drvdata(&dev->dev);
  86
  87        platform_device_unregister(pdev);
  88
  89        return 0;
  90}
  91
  92static struct coreboot_driver framebuffer_driver = {
  93        .probe = framebuffer_probe,
  94        .remove = framebuffer_remove,
  95        .drv = {
  96                .name = "framebuffer",
  97        },
  98        .tag = CB_TAG_FRAMEBUFFER,
  99};
 100
 101static int __init coreboot_framebuffer_init(void)
 102{
 103        return coreboot_driver_register(&framebuffer_driver);
 104}
 105
 106static void coreboot_framebuffer_exit(void)
 107{
 108        coreboot_driver_unregister(&framebuffer_driver);
 109}
 110
 111module_init(coreboot_framebuffer_init);
 112module_exit(coreboot_framebuffer_exit);
 113
 114MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
 115MODULE_LICENSE("GPL");
 116