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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e3263ab3 | 2 | /* |
8633ef82 | 3 | * Generic System Framebuffers |
e3263ab3 | 4 | * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> |
e3263ab3 DH |
5 | */ |
6 | ||
7 | /* | |
8633ef82 | 8 | * Simple-Framebuffer support |
e3263ab3 DH |
9 | * Create a platform-device for any available boot framebuffer. The |
10 | * simple-framebuffer platform device is already available on DT systems, so | |
11 | * this module parses the global "screen_info" object and creates a suitable | |
12 | * platform device compatible with the "simple-framebuffer" DT object. If | |
13 | * the framebuffer is incompatible, we instead create a legacy | |
14 | * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and | |
15 | * pass the screen_info as platform_data. This allows legacy drivers | |
16 | * to pick these devices up without messing with simple-framebuffer drivers. | |
17 | * The global "screen_info" is still valid at all times. | |
18 | * | |
8633ef82 | 19 | * If CONFIG_SYSFB_SIMPLEFB is not selected, never register "simple-framebuffer" |
e3263ab3 DH |
20 | * platform devices, but only use legacy framebuffer devices for |
21 | * backwards compatibility. | |
22 | * | |
23 | * TODO: We set the dev_id field of all platform-devices to 0. This allows | |
8633ef82 | 24 | * other OF/DT parsers to create such devices, too. However, they must |
e3263ab3 DH |
25 | * start at offset 1 for this to work. |
26 | */ | |
27 | ||
28 | #include <linux/err.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/kernel.h> | |
31 | #include <linux/mm.h> | |
32 | #include <linux/platform_data/simplefb.h> | |
33 | #include <linux/platform_device.h> | |
34 | #include <linux/screen_info.h> | |
d391c582 | 35 | #include <linux/sysfb.h> |
e3263ab3 | 36 | |
bde376e9 JMC |
37 | static struct platform_device *pd; |
38 | static DEFINE_MUTEX(disable_lock); | |
39 | static bool disabled; | |
40 | ||
41 | static bool sysfb_unregister(void) | |
42 | { | |
43 | if (IS_ERR_OR_NULL(pd)) | |
44 | return false; | |
45 | ||
46 | platform_device_unregister(pd); | |
47 | pd = NULL; | |
48 | ||
49 | return true; | |
50 | } | |
51 | ||
52 | /** | |
53 | * sysfb_disable() - disable the Generic System Framebuffers support | |
54 | * | |
55 | * This disables the registration of system framebuffer devices that match the | |
56 | * generic drivers that make use of the system framebuffer set up by firmware. | |
57 | * | |
58 | * It also unregisters a device if this was already registered by sysfb_init(). | |
59 | * | |
60 | * Context: The function can sleep. A @disable_lock mutex is acquired to serialize | |
61 | * against sysfb_init(), that registers a system framebuffer device. | |
62 | */ | |
63 | void sysfb_disable(void) | |
64 | { | |
65 | mutex_lock(&disable_lock); | |
66 | sysfb_unregister(); | |
67 | disabled = true; | |
68 | mutex_unlock(&disable_lock); | |
69 | } | |
70 | EXPORT_SYMBOL_GPL(sysfb_disable); | |
71 | ||
e3263ab3 DH |
72 | static __init int sysfb_init(void) |
73 | { | |
74 | struct screen_info *si = &screen_info; | |
75 | struct simplefb_platform_data mode; | |
e3263ab3 DH |
76 | const char *name; |
77 | bool compatible; | |
bde376e9 JMC |
78 | int ret = 0; |
79 | ||
80 | mutex_lock(&disable_lock); | |
81 | if (disabled) | |
82 | goto unlock_mutex; | |
e3263ab3 DH |
83 | |
84 | /* try to create a simple-framebuffer device */ | |
8633ef82 | 85 | compatible = sysfb_parse_mode(si, &mode); |
e3263ab3 | 86 | if (compatible) { |
9e121040 JMC |
87 | pd = sysfb_create_simplefb(si, &mode); |
88 | if (!IS_ERR(pd)) | |
bde376e9 | 89 | goto unlock_mutex; |
e3263ab3 DH |
90 | } |
91 | ||
92 | /* if the FB is incompatible, create a legacy framebuffer device */ | |
93 | if (si->orig_video_isVGA == VIDEO_TYPE_EFI) | |
94 | name = "efi-framebuffer"; | |
95 | else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) | |
96 | name = "vesa-framebuffer"; | |
97 | else | |
98 | name = "platform-framebuffer"; | |
99 | ||
8633ef82 | 100 | pd = platform_device_alloc(name, 0); |
bde376e9 JMC |
101 | if (!pd) { |
102 | ret = -ENOMEM; | |
103 | goto unlock_mutex; | |
104 | } | |
8633ef82 JMC |
105 | |
106 | sysfb_apply_efi_quirks(pd); | |
107 | ||
108 | ret = platform_device_add_data(pd, si, sizeof(*si)); | |
109 | if (ret) | |
110 | goto err; | |
111 | ||
112 | ret = platform_device_add(pd); | |
113 | if (ret) | |
114 | goto err; | |
115 | ||
bde376e9 | 116 | goto unlock_mutex; |
8633ef82 JMC |
117 | err: |
118 | platform_device_put(pd); | |
bde376e9 JMC |
119 | unlock_mutex: |
120 | mutex_unlock(&disable_lock); | |
8633ef82 | 121 | return ret; |
e3263ab3 DH |
122 | } |
123 | ||
2995e506 | 124 | /* must execute after PCI subsystem for EFI quirks */ |
e3263ab3 | 125 | device_initcall(sysfb_init); |