aboutsummaryrefslogtreecommitdiff
path: root/drivers/firmware/sysfb_simplefb.c
blob: ca907f7e76c6562ed5f747f2ea6dd51bb160778d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Generic System Framebuffers
 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
 */

/*
 * simple-framebuffer probing
 * Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
 * If the mode is incompatible, we return "false" and let the caller create
 * legacy nodes instead.
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
#include <linux/screen_info.h>
#include <linux/sysfb.h>

static const char simplefb_resname[] = "BOOTFB";
static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;

/* try parsing screen_info into a simple-framebuffer mode struct */
__init bool sysfb_parse_mode(const struct screen_info *si,
			     struct simplefb_platform_data *mode)
{
	const struct simplefb_format *f;
	__u8 type;
	unsigned int i;

	type = si->orig_video_isVGA;
	if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
		return false;

	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
		f = &formats[i];
		if (si->lfb_depth == f->bits_per_pixel &&
		    si->red_size == f->red.length &&
		    si->red_pos == f->red.offset &&
		    si->green_size == f->green.length &&
		    si->green_pos == f->green.offset &&
		    si->blue_size == f->blue.length &&
		    si->blue_pos == f->blue.offset &&
		    si->rsvd_size == f->transp.length &&
		    si->rsvd_pos == f->transp.offset) {
			mode->format = f->name;
			mode->width = si->lfb_width;
			mode->height = si->lfb_height;
			mode->stride = si->lfb_linelength;
			return true;
		}
	}

	return false;
}

__init struct platform_device *sysfb_create_simplefb(const struct screen_info *si,
						     const struct simplefb_platform_data *mode)
{
	struct platform_device *pd;
	struct resource res;
	u64 base, size;
	u32 length;
	int ret;

	/*
	 * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
	 * upper half of the base address. Assemble the address, then make sure
	 * it is valid and we can actually access it.
	 */
	base = si->lfb_base;
	if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
		base |= (u64)si->ext_lfb_base << 32;
	if (!base || (u64)(resource_size_t)base != base) {
		printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
		return ERR_PTR(-EINVAL);
	}

	/*
	 * Don't use lfb_size as IORESOURCE size, since it may contain the
	 * entire VMEM, and thus require huge mappings. Use just the part we
	 * need, that is, the part where the framebuffer is located. But verify
	 * that it does not exceed the advertised VMEM.
	 * Note that in case of VBE, the lfb_size is shifted by 16 bits for
	 * historical reasons.
	 */
	size = si->lfb_size;
	if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
		size <<= 16;
	length = mode->height * mode->stride;
	if (length > size) {
		printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
		return ERR_PTR(-EINVAL);
	}
	length = PAGE_ALIGN(length);

	/* setup IORESOURCE_MEM as framebuffer memory */
	memset(&res, 0, sizeof(res));
	res.flags = IORESOURCE_MEM;
	res.name = simplefb_resname;
	res.start = base;
	res.end = res.start + length - 1;
	if (res.end <= res.start)
		return ERR_PTR(-EINVAL);

	pd = platform_device_alloc("simple-framebuffer", 0);
	if (!pd)
		return ERR_PTR(-ENOMEM);

	sysfb_set_efifb_fwnode(pd);

	ret = platform_device_add_resources(pd, &res, 1);
	if (ret)
		goto err_put_device;

	ret = platform_device_add_data(pd, mode, sizeof(*mode));
	if (ret)
		goto err_put_device;

	ret = platform_device_add(pd);
	if (ret)
		goto err_put_device;

	return pd;

err_put_device:
	platform_device_put(pd);

	return ERR_PTR(ret);
}