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