hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
[linux-2.6.git] / drivers / hwspinlock / omap_hwspinlock.c
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
47 struct omap_hwspinlock {
48         struct hwspinlock lock;
49         void __iomem *addr;
50 };
51
52 struct omap_hwspinlock_state {
53         int num_locks;                  /* Total number of locks in system */
54         void __iomem *io_base;          /* Mapped base address */
55         struct omap_hwspinlock lock[0]; /* Array of 'num_locks' locks */
56 };
57
58 static int omap_hwspinlock_trylock(struct hwspinlock *lock)
59 {
60         struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
61
62         /* attempt to acquire the lock by reading its value */
63         return (SPINLOCK_NOTTAKEN == readl(omap_lock->addr));
64 }
65
66 static void omap_hwspinlock_unlock(struct hwspinlock *lock)
67 {
68         struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
69
70         /* release the lock by writing 0 to it */
71         writel(SPINLOCK_NOTTAKEN, omap_lock->addr);
72 }
73
74 /*
75  * relax the OMAP interconnect while spinning on it.
76  *
77  * The specs recommended that the retry delay time will be
78  * just over half of the time that a requester would be
79  * expected to hold the lock.
80  *
81  * The number below is taken from an hardware specs example,
82  * obviously it is somewhat arbitrary.
83  */
84 static void omap_hwspinlock_relax(struct hwspinlock *lock)
85 {
86         ndelay(50);
87 }
88
89 static const struct hwspinlock_ops omap_hwspinlock_ops = {
90         .trylock = omap_hwspinlock_trylock,
91         .unlock = omap_hwspinlock_unlock,
92         .relax = omap_hwspinlock_relax,
93 };
94
95 static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
96 {
97         struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
98         struct omap_hwspinlock *omap_lock;
99         struct omap_hwspinlock_state *state;
100         struct resource *res;
101         void __iomem *io_base;
102         int i, ret;
103
104         if (!pdata)
105                 return -ENODEV;
106
107         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
108         if (!res)
109                 return -ENODEV;
110
111         io_base = ioremap(res->start, resource_size(res));
112         if (!io_base)
113                 return -ENOMEM;
114
115         /* Determine number of locks */
116         i = readl(io_base + SYSSTATUS_OFFSET);
117         i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
118
119         /* one of the four lsb's must be set, and nothing else */
120         if (hweight_long(i & 0xf) != 1 || i > 8) {
121                 ret = -EINVAL;
122                 goto iounmap_base;
123         }
124
125         i *= 32; /* actual number of locks in this device */
126
127         state = kzalloc(sizeof(*state) + i * sizeof(*omap_lock), GFP_KERNEL);
128         if (!state) {
129                 ret = -ENOMEM;
130                 goto iounmap_base;
131         }
132
133         state->num_locks = i;
134         state->io_base = io_base;
135
136         platform_set_drvdata(pdev, state);
137
138         /*
139          * runtime PM will make sure the clock of this module is
140          * enabled iff at least one lock is requested
141          */
142         pm_runtime_enable(&pdev->dev);
143
144         for (i = 0; i < state->num_locks; i++) {
145                 omap_lock = &state->lock[i];
146
147                 omap_lock->lock.dev = &pdev->dev;
148                 omap_lock->lock.id = pdata->base_id + i;
149                 omap_lock->lock.ops = &omap_hwspinlock_ops;
150                 omap_lock->addr = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
151
152                 ret = hwspin_lock_register(&omap_lock->lock);
153                 if (ret)
154                         goto free_locks;
155         }
156
157         return 0;
158
159 free_locks:
160         while (--i >= 0)
161                 hwspin_lock_unregister(i);
162         pm_runtime_disable(&pdev->dev);
163         kfree(state);
164 iounmap_base:
165         iounmap(io_base);
166         return ret;
167 }
168
169 static int omap_hwspinlock_remove(struct platform_device *pdev)
170 {
171         struct omap_hwspinlock_state *state = platform_get_drvdata(pdev);
172         struct hwspinlock *lock;
173         int i;
174
175         for (i = 0; i < state->num_locks; i++) {
176                 lock = hwspin_lock_unregister(i);
177                 /* this shouldn't happen at this point. if it does, at least
178                  * don't continue with the remove */
179                 if (!lock) {
180                         dev_err(&pdev->dev, "%s: failed on %d\n", __func__, i);
181                         return -EBUSY;
182                 }
183         }
184
185         pm_runtime_disable(&pdev->dev);
186         iounmap(state->io_base);
187         kfree(state);
188
189         return 0;
190 }
191
192 static struct platform_driver omap_hwspinlock_driver = {
193         .probe          = omap_hwspinlock_probe,
194         .remove         = omap_hwspinlock_remove,
195         .driver         = {
196                 .name   = "omap_hwspinlock",
197                 .owner  = THIS_MODULE,
198         },
199 };
200
201 static int __init omap_hwspinlock_init(void)
202 {
203         return platform_driver_register(&omap_hwspinlock_driver);
204 }
205 /* board init code might need to reserve hwspinlocks for predefined purposes */
206 postcore_initcall(omap_hwspinlock_init);
207
208 static void __exit omap_hwspinlock_exit(void)
209 {
210         platform_driver_unregister(&omap_hwspinlock_driver);
211 }
212 module_exit(omap_hwspinlock_exit);
213
214 MODULE_LICENSE("GPL v2");
215 MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
216 MODULE_AUTHOR("Simon Que <sque@ti.com>");
217 MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
218 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");