1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/*
* OMAP hardware spinlock driver
*
* Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
*
* Contact: Simon Que <sque@ti.com>
* Hari Kanigeri <h-kanigeri2@ti.com>
* Ohad Ben-Cohen <ohad@wizery.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/hwspinlock.h>
#include <linux/platform_device.h>
#include "hwspinlock_internal.h"
/* Spinlock register offsets */
#define SYSSTATUS_OFFSET 0x0014
#define LOCK_BASE_OFFSET 0x0800
#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24)
/* Possible values of SPINLOCK_LOCK_REG */
#define SPINLOCK_NOTTAKEN (0) /* free */
#define SPINLOCK_TAKEN (1) /* locked */
#define to_omap_hwspinlock(lock) \
container_of(lock, struct omap_hwspinlock, lock)
struct omap_hwspinlock {
struct hwspinlock lock;
void __iomem *addr;
};
struct omap_hwspinlock_state {
int num_locks; /* Total number of locks in system */
void __iomem *io_base; /* Mapped base address */
struct omap_hwspinlock lock[0]; /* Array of 'num_locks' locks */
};
static int omap_hwspinlock_trylock(struct hwspinlock *lock)
{
struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
/* attempt to acquire the lock by reading its value */
return (SPINLOCK_NOTTAKEN == readl(omap_lock->addr));
}
static void omap_hwspinlock_unlock(struct hwspinlock *lock)
{
struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
/* release the lock by writing 0 to it */
writel(SPINLOCK_NOTTAKEN, omap_lock->addr);
}
/*
* relax the OMAP interconnect while spinning on it.
*
* The specs recommended that the retry delay time will be
* just over half of the time that a requester would be
* expected to hold the lock.
*
* The number below is taken from an hardware specs example,
* obviously it is somewhat arbitrary.
*/
static void omap_hwspinlock_relax(struct hwspinlock *lock)
{
ndelay(50);
}
static const struct hwspinlock_ops omap_hwspinlock_ops = {
.trylock = omap_hwspinlock_trylock,
.unlock = omap_hwspinlock_unlock,
.relax = omap_hwspinlock_relax,
};
static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
{
struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
struct omap_hwspinlock *omap_lock;
struct omap_hwspinlock_state *state;
struct resource *res;
void __iomem *io_base;
int i, ret;
if (!pdata)
return -ENODEV;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
io_base = ioremap(res->start, resource_size(res));
if (!io_base)
return -ENOMEM;
/* Determine number of locks */
i = readl(io_base + SYSSTATUS_OFFSET);
i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
/* one of the four lsb's must be set, and nothing else */
if (hweight_long(i & 0xf) != 1 || i > 8) {
ret = -EINVAL;
goto iounmap_base;
}
i *= 32; /* actual number of locks in this device */
state = kzalloc(sizeof(*state) + i * sizeof(*omap_lock), GFP_KERNEL);
if (!state) {
ret = -ENOMEM;
goto iounmap_base;
}
state->num_locks = i;
state->io_base = io_base;
platform_set_drvdata(pdev, state);
/*
* runtime PM will make sure the clock of this module is
* enabled iff at least one lock is requested
*/
pm_runtime_enable(&pdev->dev);
for (i = 0; i < state->num_locks; i++) {
omap_lock = &state->lock[i];
omap_lock->lock.dev = &pdev->dev;
omap_lock->lock.id = pdata->base_id + i;
omap_lock->lock.ops = &omap_hwspinlock_ops;
omap_lock->addr = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
ret = hwspin_lock_register(&omap_lock->lock);
if (ret)
goto free_locks;
}
return 0;
free_locks:
while (--i >= 0)
hwspin_lock_unregister(i);
pm_runtime_disable(&pdev->dev);
kfree(state);
iounmap_base:
iounmap(io_base);
return ret;
}
static int omap_hwspinlock_remove(struct platform_device *pdev)
{
struct omap_hwspinlock_state *state = platform_get_drvdata(pdev);
struct hwspinlock *lock;
int i;
for (i = 0; i < state->num_locks; i++) {
lock = hwspin_lock_unregister(i);
/* this shouldn't happen at this point. if it does, at least
* don't continue with the remove */
if (!lock) {
dev_err(&pdev->dev, "%s: failed on %d\n", __func__, i);
return -EBUSY;
}
}
pm_runtime_disable(&pdev->dev);
iounmap(state->io_base);
kfree(state);
return 0;
}
static struct platform_driver omap_hwspinlock_driver = {
.probe = omap_hwspinlock_probe,
.remove = omap_hwspinlock_remove,
.driver = {
.name = "omap_hwspinlock",
.owner = THIS_MODULE,
},
};
static int __init omap_hwspinlock_init(void)
{
return platform_driver_register(&omap_hwspinlock_driver);
}
/* board init code might need to reserve hwspinlocks for predefined purposes */
postcore_initcall(omap_hwspinlock_init);
static void __exit omap_hwspinlock_exit(void)
{
platform_driver_unregister(&omap_hwspinlock_driver);
}
module_exit(omap_hwspinlock_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
MODULE_AUTHOR("Simon Que <sque@ti.com>");
MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");
|
