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1/*
2 * OMAP hardware spinlock driver
3 *
4 * Copyright (C) 2010-2015 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/of.h>
31#include <linux/platform_device.h>
32
33#include "hwspinlock_internal.h"
34
35/* Spinlock register offsets */
36#define SYSSTATUS_OFFSET 0x0014
37#define LOCK_BASE_OFFSET 0x0800
38
39#define SPINLOCK_NUMLOCKS_BIT_OFFSET (24)
40
41/* Possible values of SPINLOCK_LOCK_REG */
42#define SPINLOCK_NOTTAKEN (0) /* free */
43#define SPINLOCK_TAKEN (1) /* locked */
44
45static int omap_hwspinlock_trylock(struct hwspinlock *lock)
46{
47 void __iomem *lock_addr = lock->priv;
48
49 /* attempt to acquire the lock by reading its value */
50 return (SPINLOCK_NOTTAKEN == readl(lock_addr));
51}
52
53static void omap_hwspinlock_unlock(struct hwspinlock *lock)
54{
55 void __iomem *lock_addr = lock->priv;
56
57 /* release the lock by writing 0 to it */
58 writel(SPINLOCK_NOTTAKEN, lock_addr);
59}
60
61/*
62 * relax the OMAP interconnect while spinning on it.
63 *
64 * The specs recommended that the retry delay time will be
65 * just over half of the time that a requester would be
66 * expected to hold the lock.
67 *
68 * The number below is taken from an hardware specs example,
69 * obviously it is somewhat arbitrary.
70 */
71static void omap_hwspinlock_relax(struct hwspinlock *lock)
72{
73 ndelay(50);
74}
75
76static const struct hwspinlock_ops omap_hwspinlock_ops = {
77 .trylock = omap_hwspinlock_trylock,
78 .unlock = omap_hwspinlock_unlock,
79 .relax = omap_hwspinlock_relax,
80};
81
82static int omap_hwspinlock_probe(struct platform_device *pdev)
83{
84 struct device_node *node = pdev->dev.of_node;
85 struct hwspinlock_device *bank;
86 struct hwspinlock *hwlock;
87 struct resource *res;
88 void __iomem *io_base;
89 int num_locks, i, ret;
90 /* Only a single hwspinlock block device is supported */
91 int base_id = 0;
92
93 if (!node)
94 return -ENODEV;
95
96 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
97 if (!res)
98 return -ENODEV;
99
100 io_base = ioremap(res->start, resource_size(res));
101 if (!io_base)
102 return -ENOMEM;
103
104 /*
105 * make sure the module is enabled and clocked before reading
106 * the module SYSSTATUS register
107 */
108 pm_runtime_enable(&pdev->dev);
109 ret = pm_runtime_get_sync(&pdev->dev);
110 if (ret < 0) {
111 pm_runtime_put_noidle(&pdev->dev);
112 goto iounmap_base;
113 }
114
115 /* Determine number of locks */
116 i = readl(io_base + SYSSTATUS_OFFSET);
117 i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
118
119 /*
120 * runtime PM will make sure the clock of this module is
121 * enabled again iff at least one lock is requested
122 */
123 ret = pm_runtime_put(&pdev->dev);
124 if (ret < 0)
125 goto iounmap_base;
126
127 /* one of the four lsb's must be set, and nothing else */
128 if (hweight_long(i & 0xf) != 1 || i > 8) {
129 ret = -EINVAL;
130 goto iounmap_base;
131 }
132
133 num_locks = i * 32; /* actual number of locks in this device */
134
135 bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
136 if (!bank) {
137 ret = -ENOMEM;
138 goto iounmap_base;
139 }
140
141 platform_set_drvdata(pdev, bank);
142
143 for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
144 hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
145
146 ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops,
147 base_id, num_locks);
148 if (ret)
149 goto reg_fail;
150
151 return 0;
152
153reg_fail:
154 kfree(bank);
155iounmap_base:
156 pm_runtime_disable(&pdev->dev);
157 iounmap(io_base);
158 return ret;
159}
160
161static int omap_hwspinlock_remove(struct platform_device *pdev)
162{
163 struct hwspinlock_device *bank = platform_get_drvdata(pdev);
164 void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET;
165 int ret;
166
167 ret = hwspin_lock_unregister(bank);
168 if (ret) {
169 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
170 return ret;
171 }
172
173 pm_runtime_disable(&pdev->dev);
174 iounmap(io_base);
175 kfree(bank);
176
177 return 0;
178}
179
180static const struct of_device_id omap_hwspinlock_of_match[] = {
181 { .compatible = "ti,omap4-hwspinlock", },
182 { /* end */ },
183};
184MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match);
185
186static struct platform_driver omap_hwspinlock_driver = {
187 .probe = omap_hwspinlock_probe,
188 .remove = omap_hwspinlock_remove,
189 .driver = {
190 .name = "omap_hwspinlock",
191 .of_match_table = of_match_ptr(omap_hwspinlock_of_match),
192 },
193};
194
195static int __init omap_hwspinlock_init(void)
196{
197 return platform_driver_register(&omap_hwspinlock_driver);
198}
199/* board init code might need to reserve hwspinlocks for predefined purposes */
200postcore_initcall(omap_hwspinlock_init);
201
202static void __exit omap_hwspinlock_exit(void)
203{
204 platform_driver_unregister(&omap_hwspinlock_driver);
205}
206module_exit(omap_hwspinlock_exit);
207
208MODULE_LICENSE("GPL v2");
209MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
210MODULE_AUTHOR("Simon Que <sque@ti.com>");
211MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
212MODULE_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 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 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 = 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>");