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
|
// SPDX-License-Identifier: GPL-2.0
/*
* OMAP hardware spinlock driver
*
* Copyright (C) 2010-2015 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>
*/
#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/of.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 */
static int omap_hwspinlock_trylock(struct hwspinlock *lock)
{
void __iomem *lock_addr = lock->priv;
/* attempt to acquire the lock by reading its value */
return (SPINLOCK_NOTTAKEN == readl(lock_addr));
}
static void omap_hwspinlock_unlock(struct hwspinlock *lock)
{
void __iomem *lock_addr = lock->priv;
/* release the lock by writing 0 to it */
writel(SPINLOCK_NOTTAKEN, 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 omap_hwspinlock_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct hwspinlock_device *bank;
struct hwspinlock *hwlock;
struct resource *res;
void __iomem *io_base;
int num_locks, i, ret;
/* Only a single hwspinlock block device is supported */
int base_id = 0;
if (!node)
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;
/*
* make sure the module is enabled and clocked before reading
* the module SYSSTATUS register
*/
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_get_sync(&pdev->dev);
if (ret < 0) {
pm_runtime_put_noidle(&pdev->dev);
goto iounmap_base;
}
/* Determine number of locks */
i = readl(io_base + SYSSTATUS_OFFSET);
i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
/*
* runtime PM will make sure the clock of this module is
* enabled again iff at least one lock is requested
*/
ret = pm_runtime_put(&pdev->dev);
if (ret < 0)
goto iounmap_base;
/* 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;
}
num_locks = i * 32; /* actual number of locks in this device */
bank = kzalloc(struct_size(bank, lock, num_locks), GFP_KERNEL);
if (!bank) {
ret = -ENOMEM;
goto iounmap_base;
}
platform_set_drvdata(pdev, bank);
for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops,
base_id, num_locks);
if (ret)
goto reg_fail;
return 0;
reg_fail:
kfree(bank);
iounmap_base:
pm_runtime_disable(&pdev->dev);
iounmap(io_base);
return ret;
}
static int omap_hwspinlock_remove(struct platform_device *pdev)
{
struct hwspinlock_device *bank = platform_get_drvdata(pdev);
void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET;
int ret;
ret = hwspin_lock_unregister(bank);
if (ret) {
dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
return ret;
}
pm_runtime_disable(&pdev->dev);
iounmap(io_base);
kfree(bank);
return 0;
}
static const struct of_device_id omap_hwspinlock_of_match[] = {
{ .compatible = "ti,omap4-hwspinlock", },
{ /* end */ },
};
MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match);
static struct platform_driver omap_hwspinlock_driver = {
.probe = omap_hwspinlock_probe,
.remove = omap_hwspinlock_remove,
.driver = {
.name = "omap_hwspinlock",
.of_match_table = of_match_ptr(omap_hwspinlock_of_match),
},
};
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>");
|
