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1/*
2 * OMAP hardware spinlock driver
3 *
4 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
5 *
6 * Contact: Simon Que <sque@ti.com>
7 * Hari Kanigeri <h-kanigeri2@ti.com>
8 * Ohad Ben-Cohen <ohad@wizery.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/device.h>
23#include <linux/delay.h>
24#include <linux/io.h>
25#include <linux/bitops.h>
26#include <linux/pm_runtime.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/hwspinlock.h>
30#include <linux/platform_device.h>
31
32#include "hwspinlock_internal.h"
33
34/* Spinlock register offsets */
35#define SYSSTATUS_OFFSET 0x0014
36#define LOCK_BASE_OFFSET 0x0800
37
38#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24)
39
40/* Possible values of SPINLOCK_LOCK_REG */
41#define SPINLOCK_NOTTAKEN (0) /* free */
42#define SPINLOCK_TAKEN (1) /* locked */
43
44#define to_omap_hwspinlock(lock) \
45 container_of(lock, struct omap_hwspinlock, lock)
46
47struct omap_hwspinlock {
48 struct hwspinlock lock;
49 void __iomem *addr;
50};
51
52struct omap_hwspinlock_state {
53 int num_locks; /* Total number of locks in system */
54 void __iomem *io_base; /* Mapped base address */
55};
56
57static int omap_hwspinlock_trylock(struct hwspinlock *lock)
58{
59 struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
60
61 /* attempt to acquire the lock by reading its value */
62 return (SPINLOCK_NOTTAKEN == readl(omap_lock->addr));
63}
64
65static void omap_hwspinlock_unlock(struct hwspinlock *lock)
66{
67 struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
68
69 /* release the lock by writing 0 to it */
70 writel(SPINLOCK_NOTTAKEN, omap_lock->addr);
71}
72
73/*
74 * relax the OMAP interconnect while spinning on it.
75 *
76 * The specs recommended that the retry delay time will be
77 * just over half of the time that a requester would be
78 * expected to hold the lock.
79 *
80 * The number below is taken from an hardware specs example,
81 * obviously it is somewhat arbitrary.
82 */
83static void omap_hwspinlock_relax(struct hwspinlock *lock)
84{
85 ndelay(50);
86}
87
88static const struct hwspinlock_ops omap_hwspinlock_ops = {
89 .trylock = omap_hwspinlock_trylock,
90 .unlock = omap_hwspinlock_unlock,
91 .relax = omap_hwspinlock_relax,
92};
93
94static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
95{
96 struct omap_hwspinlock *omap_lock;
97 struct omap_hwspinlock_state *state;
98 struct hwspinlock *lock;
99 struct resource *res;
100 void __iomem *io_base;
101 int i, ret;
102
103 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
104 if (!res)
105 return -ENODEV;
106
107 state = kzalloc(sizeof(*state), GFP_KERNEL);
108 if (!state)
109 return -ENOMEM;
110
111 io_base = ioremap(res->start, resource_size(res));
112 if (!io_base) {
113 ret = -ENOMEM;
114 goto free_state;
115 }
116
117 /* Determine number of locks */
118 i = readl(io_base + SYSSTATUS_OFFSET);
119 i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
120
121 /* one of the four lsb's must be set, and nothing else */
122 if (hweight_long(i & 0xf) != 1 || i > 8) {
123 ret = -EINVAL;
124 goto iounmap_base;
125 }
126
127 state->num_locks = i * 32;
128 state->io_base = io_base;
129
130 platform_set_drvdata(pdev, state);
131
132 /*
133 * runtime PM will make sure the clock of this module is
134 * enabled iff at least one lock is requested
135 */
136 pm_runtime_enable(&pdev->dev);
137
138 for (i = 0; i < state->num_locks; i++) {
139 omap_lock = kzalloc(sizeof(*omap_lock), GFP_KERNEL);
140 if (!omap_lock) {
141 ret = -ENOMEM;
142 goto free_locks;
143 }
144
145 omap_lock->lock.dev = &pdev->dev;
146 omap_lock->lock.owner = THIS_MODULE;
147 omap_lock->lock.id = i;
148 omap_lock->lock.ops = &omap_hwspinlock_ops;
149 omap_lock->addr = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
150
151 ret = hwspin_lock_register(&omap_lock->lock);
152 if (ret) {
153 kfree(omap_lock);
154 goto free_locks;
155 }
156 }
157
158 return 0;
159
160free_locks:
161 while (--i >= 0) {
162 lock = hwspin_lock_unregister(i);
163 /* this should't happen, but let's give our best effort */
164 if (!lock) {
165 dev_err(&pdev->dev, "%s: cleanups failed\n", __func__);
166 continue;
167 }
168 omap_lock = to_omap_hwspinlock(lock);
169 kfree(omap_lock);
170 }
171 pm_runtime_disable(&pdev->dev);
172iounmap_base:
173 iounmap(io_base);
174free_state:
175 kfree(state);
176 return ret;
177}
178
179static int omap_hwspinlock_remove(struct platform_device *pdev)
180{
181 struct omap_hwspinlock_state *state = platform_get_drvdata(pdev);
182 struct hwspinlock *lock;
183 struct omap_hwspinlock *omap_lock;
184 int i;
185
186 for (i = 0; i < state->num_locks; i++) {
187 lock = hwspin_lock_unregister(i);
188 /* this shouldn't happen at this point. if it does, at least
189 * don't continue with the remove */
190 if (!lock) {
191 dev_err(&pdev->dev, "%s: failed on %d\n", __func__, i);
192 return -EBUSY;
193 }
194
195 omap_lock = to_omap_hwspinlock(lock);
196 kfree(omap_lock);
197 }
198
199 pm_runtime_disable(&pdev->dev);
200 iounmap(state->io_base);
201 kfree(state);
202
203 return 0;
204}
205
206static struct platform_driver omap_hwspinlock_driver = {
207 .probe = omap_hwspinlock_probe,
208 .remove = omap_hwspinlock_remove,
209 .driver = {
210 .name = "omap_hwspinlock",
211 },
212};
213
214static int __init omap_hwspinlock_init(void)
215{
216 return platform_driver_register(&omap_hwspinlock_driver);
217}
218/* board init code might need to reserve hwspinlocks for predefined purposes */
219postcore_initcall(omap_hwspinlock_init);
220
221static void __exit omap_hwspinlock_exit(void)
222{
223 platform_driver_unregister(&omap_hwspinlock_driver);
224}
225module_exit(omap_hwspinlock_exit);
226
227MODULE_LICENSE("GPL v2");
228MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
229MODULE_AUTHOR("Simon Que <sque@ti.com>");
230MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
231MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");
1/*
2 * OMAP hardware spinlock driver
3 *
4 * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
5 *
6 * Contact: Simon Que <sque@ti.com>
7 * Hari Kanigeri <h-kanigeri2@ti.com>
8 * Ohad Ben-Cohen <ohad@wizery.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/device.h>
23#include <linux/delay.h>
24#include <linux/io.h>
25#include <linux/bitops.h>
26#include <linux/pm_runtime.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/hwspinlock.h>
30#include <linux/platform_device.h>
31
32#include "hwspinlock_internal.h"
33
34/* Spinlock register offsets */
35#define SYSSTATUS_OFFSET 0x0014
36#define LOCK_BASE_OFFSET 0x0800
37
38#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24)
39
40/* Possible values of SPINLOCK_LOCK_REG */
41#define SPINLOCK_NOTTAKEN (0) /* free */
42#define SPINLOCK_TAKEN (1) /* locked */
43
44static int omap_hwspinlock_trylock(struct hwspinlock *lock)
45{
46 void __iomem *lock_addr = lock->priv;
47
48 /* attempt to acquire the lock by reading its value */
49 return (SPINLOCK_NOTTAKEN == readl(lock_addr));
50}
51
52static void omap_hwspinlock_unlock(struct hwspinlock *lock)
53{
54 void __iomem *lock_addr = lock->priv;
55
56 /* release the lock by writing 0 to it */
57 writel(SPINLOCK_NOTTAKEN, lock_addr);
58}
59
60/*
61 * relax the OMAP interconnect while spinning on it.
62 *
63 * The specs recommended that the retry delay time will be
64 * just over half of the time that a requester would be
65 * expected to hold the lock.
66 *
67 * The number below is taken from an hardware specs example,
68 * obviously it is somewhat arbitrary.
69 */
70static void omap_hwspinlock_relax(struct hwspinlock *lock)
71{
72 ndelay(50);
73}
74
75static const struct hwspinlock_ops omap_hwspinlock_ops = {
76 .trylock = omap_hwspinlock_trylock,
77 .unlock = omap_hwspinlock_unlock,
78 .relax = omap_hwspinlock_relax,
79};
80
81static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
82{
83 struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
84 struct hwspinlock_device *bank;
85 struct hwspinlock *hwlock;
86 struct resource *res;
87 void __iomem *io_base;
88 int num_locks, i, ret;
89
90 if (!pdata)
91 return -ENODEV;
92
93 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
94 if (!res)
95 return -ENODEV;
96
97 io_base = ioremap(res->start, resource_size(res));
98 if (!io_base)
99 return -ENOMEM;
100
101 /* Determine number of locks */
102 i = readl(io_base + SYSSTATUS_OFFSET);
103 i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
104
105 /* one of the four lsb's must be set, and nothing else */
106 if (hweight_long(i & 0xf) != 1 || i > 8) {
107 ret = -EINVAL;
108 goto iounmap_base;
109 }
110
111 num_locks = i * 32; /* actual number of locks in this device */
112
113 bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
114 if (!bank) {
115 ret = -ENOMEM;
116 goto iounmap_base;
117 }
118
119 platform_set_drvdata(pdev, bank);
120
121 for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
122 hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
123
124 /*
125 * runtime PM will make sure the clock of this module is
126 * enabled iff at least one lock is requested
127 */
128 pm_runtime_enable(&pdev->dev);
129
130 ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops,
131 pdata->base_id, num_locks);
132 if (ret)
133 goto reg_fail;
134
135 return 0;
136
137reg_fail:
138 pm_runtime_disable(&pdev->dev);
139 kfree(bank);
140iounmap_base:
141 iounmap(io_base);
142 return ret;
143}
144
145static int __devexit omap_hwspinlock_remove(struct platform_device *pdev)
146{
147 struct hwspinlock_device *bank = platform_get_drvdata(pdev);
148 void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET;
149 int ret;
150
151 ret = hwspin_lock_unregister(bank);
152 if (ret) {
153 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
154 return ret;
155 }
156
157 pm_runtime_disable(&pdev->dev);
158 iounmap(io_base);
159 kfree(bank);
160
161 return 0;
162}
163
164static struct platform_driver omap_hwspinlock_driver = {
165 .probe = omap_hwspinlock_probe,
166 .remove = __devexit_p(omap_hwspinlock_remove),
167 .driver = {
168 .name = "omap_hwspinlock",
169 .owner = THIS_MODULE,
170 },
171};
172
173static int __init omap_hwspinlock_init(void)
174{
175 return platform_driver_register(&omap_hwspinlock_driver);
176}
177/* board init code might need to reserve hwspinlocks for predefined purposes */
178postcore_initcall(omap_hwspinlock_init);
179
180static void __exit omap_hwspinlock_exit(void)
181{
182 platform_driver_unregister(&omap_hwspinlock_driver);
183}
184module_exit(omap_hwspinlock_exit);
185
186MODULE_LICENSE("GPL v2");
187MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
188MODULE_AUTHOR("Simon Que <sque@ti.com>");
189MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
190MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");