1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * framebuffer-coreboot.c
 4 *
 5 * Memory based framebuffer accessed through coreboot table.
 6 *
 7 * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
 8 * Copyright 2017 Google Inc.
 9 * Copyright 2017 Samuel Holland <samuel@sholland.org>
10 */
11
12#include <linux/device.h>
13#include <linux/kernel.h>
14#include <linux/mm.h>
15#include <linux/module.h>
16#include <linux/platform_data/simplefb.h>
17#include <linux/platform_device.h>
18
19#include "coreboot_table.h"
20
21#define CB_TAG_FRAMEBUFFER 0x12
22
23static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
24
25static int framebuffer_probe(struct coreboot_device *dev)
26{
27	int i;
28	u32 length;
29	struct lb_framebuffer *fb = &dev->framebuffer;
30	struct platform_device *pdev;
31	struct resource res;
32	struct simplefb_platform_data pdata = {
33		.width = fb->x_resolution,
34		.height = fb->y_resolution,
35		.stride = fb->bytes_per_line,
36		.format = NULL,
37	};
38
39	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
40		if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&
41		    fb->red_mask_pos       == formats[i].red.offset &&
42		    fb->red_mask_size      == formats[i].red.length &&
43		    fb->green_mask_pos     == formats[i].green.offset &&
44		    fb->green_mask_size    == formats[i].green.length &&
45		    fb->blue_mask_pos      == formats[i].blue.offset &&
46		    fb->blue_mask_size     == formats[i].blue.length &&
47		    fb->reserved_mask_pos  == formats[i].transp.offset &&
48		    fb->reserved_mask_size == formats[i].transp.length)
49			pdata.format = formats[i].name;
50	}
51	if (!pdata.format)
52		return -ENODEV;
53
54	memset(&res, 0, sizeof(res));
55	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
56	res.name = "Coreboot Framebuffer";
57	res.start = fb->physical_address;
58	length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
59	res.end = res.start + length - 1;
60	if (res.end <= res.start)
61		return -EINVAL;
62
63	pdev = platform_device_register_resndata(&dev->dev,
64						 "simple-framebuffer", 0,
65						 &res, 1, &pdata,
66						 sizeof(pdata));
67	if (IS_ERR(pdev))
68		pr_warn("coreboot: could not register framebuffer\n");
69	else
70		dev_set_drvdata(&dev->dev, pdev);
71
72	return PTR_ERR_OR_ZERO(pdev);
73}
74
75static int framebuffer_remove(struct coreboot_device *dev)
76{
77	struct platform_device *pdev = dev_get_drvdata(&dev->dev);
78
79	platform_device_unregister(pdev);
80
81	return 0;
82}
83
84static struct coreboot_driver framebuffer_driver = {
85	.probe = framebuffer_probe,
86	.remove = framebuffer_remove,
87	.drv = {
88		.name = "framebuffer",
89	},
90	.tag = CB_TAG_FRAMEBUFFER,
91};
92module_coreboot_driver(framebuffer_driver);
93
94MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
95MODULE_LICENSE("GPL");