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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic System Framebuffers
4 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
5 */
6
7/*
8 * Simple-Framebuffer support
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 *
19 * If CONFIG_SYSFB_SIMPLEFB is not selected, never register "simple-framebuffer"
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
24 * other OF/DT parsers to create such devices, too. However, they must
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>
35#include <linux/sysfb.h>
36
37static struct platform_device *pd;
38static DEFINE_MUTEX(disable_lock);
39static bool disabled;
40
41static 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 */
63void sysfb_disable(void)
64{
65 mutex_lock(&disable_lock);
66 sysfb_unregister();
67 disabled = true;
68 mutex_unlock(&disable_lock);
69}
70EXPORT_SYMBOL_GPL(sysfb_disable);
71
72static __init int sysfb_init(void)
73{
74 struct screen_info *si = &screen_info;
75 struct simplefb_platform_data mode;
76 const char *name;
77 bool compatible;
78 int ret = 0;
79
80 mutex_lock(&disable_lock);
81 if (disabled)
82 goto unlock_mutex;
83
84 sysfb_apply_efi_quirks();
85
86 /* try to create a simple-framebuffer device */
87 compatible = sysfb_parse_mode(si, &mode);
88 if (compatible) {
89 pd = sysfb_create_simplefb(si, &mode);
90 if (!IS_ERR(pd))
91 goto unlock_mutex;
92 }
93
94 /* if the FB is incompatible, create a legacy framebuffer device */
95 if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
96 name = "efi-framebuffer";
97 else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
98 name = "vesa-framebuffer";
99 else if (si->orig_video_isVGA == VIDEO_TYPE_VGAC)
100 name = "vga-framebuffer";
101 else if (si->orig_video_isVGA == VIDEO_TYPE_EGAC)
102 name = "ega-framebuffer";
103 else
104 name = "platform-framebuffer";
105
106 pd = platform_device_alloc(name, 0);
107 if (!pd) {
108 ret = -ENOMEM;
109 goto unlock_mutex;
110 }
111
112 sysfb_set_efifb_fwnode(pd);
113
114 ret = platform_device_add_data(pd, si, sizeof(*si));
115 if (ret)
116 goto err;
117
118 ret = platform_device_add(pd);
119 if (ret)
120 goto err;
121
122 goto unlock_mutex;
123err:
124 platform_device_put(pd);
125unlock_mutex:
126 mutex_unlock(&disable_lock);
127 return ret;
128}
129
130/* must execute after PCI subsystem for EFI quirks */
131device_initcall(sysfb_init);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic System Framebuffers
4 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
5 */
6
7/*
8 * Simple-Framebuffer support
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 *
19 * If CONFIG_SYSFB_SIMPLEFB is not selected, never register "simple-framebuffer"
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
24 * other OF/DT parsers to create such devices, too. However, they must
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>
35#include <linux/sysfb.h>
36
37static struct platform_device *pd;
38static DEFINE_MUTEX(disable_lock);
39static bool disabled;
40
41static 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 */
63void sysfb_disable(void)
64{
65 mutex_lock(&disable_lock);
66 sysfb_unregister();
67 disabled = true;
68 mutex_unlock(&disable_lock);
69}
70EXPORT_SYMBOL_GPL(sysfb_disable);
71
72static __init int sysfb_init(void)
73{
74 struct screen_info *si = &screen_info;
75 struct simplefb_platform_data mode;
76 const char *name;
77 bool compatible;
78 int ret = 0;
79
80 mutex_lock(&disable_lock);
81 if (disabled)
82 goto unlock_mutex;
83
84 /* try to create a simple-framebuffer device */
85 compatible = sysfb_parse_mode(si, &mode);
86 if (compatible) {
87 pd = sysfb_create_simplefb(si, &mode);
88 if (!IS_ERR(pd))
89 goto unlock_mutex;
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 if (si->orig_video_isVGA == VIDEO_TYPE_VGAC)
98 name = "vga-framebuffer";
99 else if (si->orig_video_isVGA == VIDEO_TYPE_EGAC)
100 name = "ega-framebuffer";
101 else
102 name = "platform-framebuffer";
103
104 pd = platform_device_alloc(name, 0);
105 if (!pd) {
106 ret = -ENOMEM;
107 goto unlock_mutex;
108 }
109
110 sysfb_apply_efi_quirks(pd);
111
112 ret = platform_device_add_data(pd, si, sizeof(*si));
113 if (ret)
114 goto err;
115
116 ret = platform_device_add(pd);
117 if (ret)
118 goto err;
119
120 goto unlock_mutex;
121err:
122 platform_device_put(pd);
123unlock_mutex:
124 mutex_unlock(&disable_lock);
125 return ret;
126}
127
128/* must execute after PCI subsystem for EFI quirks */
129device_initcall(sysfb_init);