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1 | /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */ |
2 | /* | |
3 | * Copyright (C) 2018, STMicroelectronics - All Rights Reserved | |
4 | */ | |
5 | ||
6 | #ifndef _HWSPINLOCK_H_ | |
7 | #define _HWSPINLOCK_H_ | |
8 | ||
e2e69291 MK |
9 | #include <linux/errno.h> |
10 | ||
7f84fc67 BG |
11 | /** |
12 | * Implement a hwspinlock uclass. | |
13 | * Hardware spinlocks are used to perform hardware protection of | |
14 | * critical sections and synchronisation between multiprocessors. | |
15 | */ | |
16 | ||
17 | struct udevice; | |
18 | ||
19 | /** | |
20 | * struct hwspinlock - A handle to (allowing control of) a single hardware | |
21 | * spinlock. | |
22 | * | |
23 | * @dev: The device which implements the hardware spinlock. | |
24 | * @id: The hardware spinlock ID within the provider. | |
25 | */ | |
26 | struct hwspinlock { | |
27 | struct udevice *dev; | |
28 | unsigned long id; | |
29 | }; | |
30 | ||
31 | #if CONFIG_IS_ENABLED(DM_HWSPINLOCK) | |
32 | ||
33 | /** | |
34 | * hwspinlock_get_by_index - Get a hardware spinlock by integer index | |
35 | * | |
36 | * This looks up and request a hardware spinlock. The index is relative to the | |
37 | * client device; each device is assumed to have n hardware spinlock associated | |
38 | * with it somehow, and this function finds and requests one of them. | |
39 | * | |
40 | * @dev: The client device. | |
41 | * @index: The index of the hardware spinlock to request, within the | |
42 | * client's list of hardware spinlock. | |
43 | * @hws: A pointer to a hardware spinlock struct to initialize. | |
185f812c | 44 | * Return: 0 if OK, or a negative error code. |
7f84fc67 BG |
45 | */ |
46 | int hwspinlock_get_by_index(struct udevice *dev, | |
47 | int index, struct hwspinlock *hws); | |
48 | ||
49 | /** | |
50 | * Lock the hardware spinlock | |
51 | * | |
52 | * @hws: A hardware spinlock struct that previously requested by | |
53 | * hwspinlock_get_by_index | |
54 | * @timeout: Timeout value in msecs | |
55 | * @return: 0 if OK, -ETIMEDOUT if timeout, -ve on other errors | |
56 | */ | |
57 | int hwspinlock_lock_timeout(struct hwspinlock *hws, unsigned int timeout); | |
58 | ||
59 | /** | |
60 | * Unlock the hardware spinlock | |
61 | * | |
62 | * @hws: A hardware spinlock struct that previously requested by | |
63 | * hwspinlock_get_by_index | |
64 | * @return: 0 if OK, -ve on error | |
65 | */ | |
66 | int hwspinlock_unlock(struct hwspinlock *hws); | |
67 | ||
68 | #else | |
69 | ||
70 | static inline int hwspinlock_get_by_index(struct udevice *dev, | |
71 | int index, | |
72 | struct hwspinlock *hws) | |
73 | { | |
74 | return -ENOSYS; | |
75 | } | |
76 | ||
77 | static inline int hwspinlock_lock_timeout(struct hwspinlock *hws, | |
78 | int timeout) | |
79 | { | |
80 | return -ENOSYS; | |
81 | } | |
82 | ||
83 | static inline int hwspinlock_unlock(struct hwspinlock *hws) | |
84 | { | |
85 | return -ENOSYS; | |
86 | } | |
87 | ||
88 | #endif /* CONFIG_DM_HWSPINLOCK */ | |
89 | ||
90 | struct ofnode_phandle_args; | |
91 | ||
92 | /** | |
93 | * struct hwspinlock_ops - Driver model hwspinlock operations | |
94 | * | |
95 | * The uclass interface is implemented by all hwspinlock devices which use | |
96 | * driver model. | |
97 | */ | |
98 | struct hwspinlock_ops { | |
99 | /** | |
100 | * of_xlate - Translate a client's device-tree (OF) hardware specifier. | |
101 | * | |
102 | * The hardware core calls this function as the first step in | |
103 | * implementing a client's hwspinlock_get_by_*() call. | |
104 | * | |
105 | * @hws: The hardware spinlock struct to hold the translation | |
106 | * result. | |
107 | * @args: The hardware spinlock specifier values from device tree. | |
108 | * @return 0 if OK, or a negative error code. | |
109 | */ | |
110 | int (*of_xlate)(struct hwspinlock *hws, | |
111 | struct ofnode_phandle_args *args); | |
112 | ||
113 | /** | |
114 | * Lock the hardware spinlock | |
115 | * | |
116 | * @dev: hwspinlock Device | |
117 | * @index: index of the lock to be used | |
118 | * @return 0 if OK, -ve on error | |
119 | */ | |
120 | int (*lock)(struct udevice *dev, int index); | |
121 | ||
122 | /** | |
123 | * Unlock the hardware spinlock | |
124 | * | |
125 | * @dev: hwspinlock Device | |
126 | * @index: index of the lock to be unlocked | |
127 | * @return 0 if OK, -ve on error | |
128 | */ | |
129 | int (*unlock)(struct udevice *dev, int index); | |
130 | ||
131 | /** | |
132 | * Relax - optional | |
133 | * Platform-specific relax method, called by hwspinlock core | |
134 | * while spinning on a lock, between two successive call to | |
135 | * lock | |
136 | * | |
137 | * @dev: hwspinlock Device | |
138 | */ | |
139 | void (*relax)(struct udevice *dev); | |
140 | }; | |
141 | ||
142 | #endif /* _HWSPINLOCK_H_ */ |