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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e3263ab3 DH |
2 | /* |
3 | * Generic System Framebuffers on x86 | |
4 | * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> | |
e3263ab3 DH |
5 | */ |
6 | ||
7 | /* | |
8 | * simple-framebuffer probing | |
9 | * Try to convert "screen_info" into a "simple-framebuffer" compatible mode. | |
10 | * If the mode is incompatible, we return "false" and let the caller create | |
11 | * legacy nodes instead. | |
12 | */ | |
13 | ||
14 | #include <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/platform_data/simplefb.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/screen_info.h> | |
21 | #include <asm/sysfb.h> | |
22 | ||
23 | static const char simplefb_resname[] = "BOOTFB"; | |
24 | static const struct simplefb_format formats[] = SIMPLEFB_FORMATS; | |
25 | ||
26 | /* try parsing x86 screen_info into a simple-framebuffer mode struct */ | |
27 | __init bool parse_mode(const struct screen_info *si, | |
28 | struct simplefb_platform_data *mode) | |
29 | { | |
30 | const struct simplefb_format *f; | |
31 | __u8 type; | |
32 | unsigned int i; | |
33 | ||
34 | type = si->orig_video_isVGA; | |
35 | if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI) | |
36 | return false; | |
37 | ||
38 | for (i = 0; i < ARRAY_SIZE(formats); ++i) { | |
39 | f = &formats[i]; | |
40 | if (si->lfb_depth == f->bits_per_pixel && | |
41 | si->red_size == f->red.length && | |
42 | si->red_pos == f->red.offset && | |
43 | si->green_size == f->green.length && | |
44 | si->green_pos == f->green.offset && | |
45 | si->blue_size == f->blue.length && | |
46 | si->blue_pos == f->blue.offset && | |
47 | si->rsvd_size == f->transp.length && | |
48 | si->rsvd_pos == f->transp.offset) { | |
49 | mode->format = f->name; | |
50 | mode->width = si->lfb_width; | |
51 | mode->height = si->lfb_height; | |
52 | mode->stride = si->lfb_linelength; | |
53 | return true; | |
54 | } | |
55 | } | |
56 | ||
57 | return false; | |
58 | } | |
59 | ||
60 | __init int create_simplefb(const struct screen_info *si, | |
61 | const struct simplefb_platform_data *mode) | |
62 | { | |
63 | struct platform_device *pd; | |
64 | struct resource res; | |
f96acec8 DH |
65 | u64 base, size; |
66 | u32 length; | |
9164b4ce DH |
67 | |
68 | /* | |
69 | * If the 64BIT_BASE capability is set, ext_lfb_base will contain the | |
70 | * upper half of the base address. Assemble the address, then make sure | |
71 | * it is valid and we can actually access it. | |
72 | */ | |
73 | base = si->lfb_base; | |
74 | if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) | |
75 | base |= (u64)si->ext_lfb_base << 32; | |
76 | if (!base || (u64)(resource_size_t)base != base) { | |
77 | printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n"); | |
78 | return -EINVAL; | |
79 | } | |
e3263ab3 | 80 | |
f96acec8 DH |
81 | /* |
82 | * Don't use lfb_size as IORESOURCE size, since it may contain the | |
83 | * entire VMEM, and thus require huge mappings. Use just the part we | |
84 | * need, that is, the part where the framebuffer is located. But verify | |
85 | * that it does not exceed the advertised VMEM. | |
86 | * Note that in case of VBE, the lfb_size is shifted by 16 bits for | |
87 | * historical reasons. | |
88 | */ | |
89 | size = si->lfb_size; | |
90 | if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) | |
91 | size <<= 16; | |
92 | length = mode->height * mode->stride; | |
93 | length = PAGE_ALIGN(length); | |
94 | if (length > size) { | |
e3263ab3 DH |
95 | printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); |
96 | return -EINVAL; | |
97 | } | |
98 | ||
99 | /* setup IORESOURCE_MEM as framebuffer memory */ | |
100 | memset(&res, 0, sizeof(res)); | |
29d274b8 | 101 | res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; |
e3263ab3 | 102 | res.name = simplefb_resname; |
9164b4ce | 103 | res.start = base; |
f96acec8 | 104 | res.end = res.start + length - 1; |
e3263ab3 DH |
105 | if (res.end <= res.start) |
106 | return -EINVAL; | |
107 | ||
108 | pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0, | |
109 | &res, 1, mode, sizeof(*mode)); | |
76ef0db7 | 110 | return PTR_ERR_OR_ZERO(pd); |
e3263ab3 | 111 | } |