tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
firmware: sysfb: Add sysfb_disable() helper function
This can be used by subsystems to unregister a platform device registered
by sysfb and also to disable future platform device registration in sysfb.
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220607182338.344270-3-javierm@redhat.com
+66
-6
+6
Documentation/driver-api/firmware/other_interfaces.rst
+6
Documentation/driver-api/firmware/other_interfaces.rst
···
13
13
.. kernel-doc:: drivers/firmware/edd.c
14
14
:internal:
15
15
16
+
Generic System Framebuffers Interface
17
+
-------------------------------------
18
+
19
+
.. kernel-doc:: drivers/firmware/sysfb.c
20
+
:export:
21
+
16
22
Intel Stratix10 SoC Service Layer
17
23
---------------------------------
18
24
Some features of the Intel Stratix10 SoC require a level of privilege
+48
-6
drivers/firmware/sysfb.c
+48
-6
drivers/firmware/sysfb.c
···
34
34
#include <linux/screen_info.h>
35
35
#include <linux/sysfb.h>
36
36
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
+
37
72
static __init int sysfb_init(void)
38
73
{
39
74
struct screen_info *si = &screen_info;
40
75
struct simplefb_platform_data mode;
41
-
struct platform_device *pd;
42
76
const char *name;
43
77
bool compatible;
44
-
int ret;
78
+
int ret = 0;
79
+
80
+
mutex_lock(&disable_lock);
81
+
if (disabled)
82
+
goto unlock_mutex;
45
83
46
84
/* try to create a simple-framebuffer device */
47
85
compatible = sysfb_parse_mode(si, &mode);
48
86
if (compatible) {
49
87
pd = sysfb_create_simplefb(si, &mode);
50
88
if (!IS_ERR(pd))
51
-
return 0;
89
+
goto unlock_mutex;
52
90
}
53
91
54
92
/* if the FB is incompatible, create a legacy framebuffer device */
···
98
60
name = "platform-framebuffer";
99
61
100
62
pd = platform_device_alloc(name, 0);
101
-
if (!pd)
102
-
return -ENOMEM;
63
+
if (!pd) {
64
+
ret = -ENOMEM;
65
+
goto unlock_mutex;
66
+
}
103
67
104
68
sysfb_apply_efi_quirks(pd);
105
69
···
113
73
if (ret)
114
74
goto err;
115
75
116
-
return 0;
76
+
goto unlock_mutex;
117
77
err:
118
78
platform_device_put(pd);
79
+
unlock_mutex:
80
+
mutex_unlock(&disable_lock);
119
81
return ret;
120
82
}
121
83
+12
include/linux/sysfb.h
+12
include/linux/sysfb.h
···
55
55
int flags;
56
56
};
57
57
58
+
#ifdef CONFIG_SYSFB
59
+
60
+
void sysfb_disable(void);
61
+
62
+
#else /* CONFIG_SYSFB */
63
+
64
+
static inline void sysfb_disable(void)
65
+
{
66
+
}
67
+
68
+
#endif /* CONFIG_SYSFB */
69
+
58
70
#ifdef CONFIG_EFI
59
71
60
72
extern struct efifb_dmi_info efifb_dmi_list[];