GNU Linux-libre 5.10.219-gnu1
[releases.git] / drivers / hwspinlock / omap_hwspinlock.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * OMAP hardware spinlock driver
4  *
5  * Copyright (C) 2010-2015 Texas Instruments Incorporated - http://www.ti.com
6  *
7  * Contact: Simon Que <sque@ti.com>
8  *          Hari Kanigeri <h-kanigeri2@ti.com>
9  *          Ohad Ben-Cohen <ohad@wizery.com>
10  */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/device.h>
15 #include <linux/delay.h>
16 #include <linux/io.h>
17 #include <linux/bitops.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21 #include <linux/hwspinlock.h>
22 #include <linux/of.h>
23 #include <linux/platform_device.h>
24
25 #include "hwspinlock_internal.h"
26
27 /* Spinlock register offsets */
28 #define SYSSTATUS_OFFSET                0x0014
29 #define LOCK_BASE_OFFSET                0x0800
30
31 #define SPINLOCK_NUMLOCKS_BIT_OFFSET    (24)
32
33 /* Possible values of SPINLOCK_LOCK_REG */
34 #define SPINLOCK_NOTTAKEN               (0)     /* free */
35 #define SPINLOCK_TAKEN                  (1)     /* locked */
36
37 static int omap_hwspinlock_trylock(struct hwspinlock *lock)
38 {
39         void __iomem *lock_addr = lock->priv;
40
41         /* attempt to acquire the lock by reading its value */
42         return (SPINLOCK_NOTTAKEN == readl(lock_addr));
43 }
44
45 static void omap_hwspinlock_unlock(struct hwspinlock *lock)
46 {
47         void __iomem *lock_addr = lock->priv;
48
49         /* release the lock by writing 0 to it */
50         writel(SPINLOCK_NOTTAKEN, lock_addr);
51 }
52
53 /*
54  * relax the OMAP interconnect while spinning on it.
55  *
56  * The specs recommended that the retry delay time will be
57  * just over half of the time that a requester would be
58  * expected to hold the lock.
59  *
60  * The number below is taken from an hardware specs example,
61  * obviously it is somewhat arbitrary.
62  */
63 static void omap_hwspinlock_relax(struct hwspinlock *lock)
64 {
65         ndelay(50);
66 }
67
68 static const struct hwspinlock_ops omap_hwspinlock_ops = {
69         .trylock = omap_hwspinlock_trylock,
70         .unlock = omap_hwspinlock_unlock,
71         .relax = omap_hwspinlock_relax,
72 };
73
74 static int omap_hwspinlock_probe(struct platform_device *pdev)
75 {
76         struct device_node *node = pdev->dev.of_node;
77         struct hwspinlock_device *bank;
78         struct hwspinlock *hwlock;
79         void __iomem *io_base;
80         int num_locks, i, ret;
81         /* Only a single hwspinlock block device is supported */
82         int base_id = 0;
83
84         if (!node)
85                 return -ENODEV;
86
87         io_base = devm_platform_ioremap_resource(pdev, 0);
88         if (IS_ERR(io_base))
89                 return PTR_ERR(io_base);
90
91         /*
92          * make sure the module is enabled and clocked before reading
93          * the module SYSSTATUS register
94          */
95         pm_runtime_enable(&pdev->dev);
96         ret = pm_runtime_get_sync(&pdev->dev);
97         if (ret < 0) {
98                 pm_runtime_put_noidle(&pdev->dev);
99                 goto runtime_err;
100         }
101
102         /* Determine number of locks */
103         i = readl(io_base + SYSSTATUS_OFFSET);
104         i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET;
105
106         /*
107          * runtime PM will make sure the clock of this module is
108          * enabled again iff at least one lock is requested
109          */
110         ret = pm_runtime_put(&pdev->dev);
111         if (ret < 0)
112                 goto runtime_err;
113
114         /* one of the four lsb's must be set, and nothing else */
115         if (hweight_long(i & 0xf) != 1 || i > 8) {
116                 ret = -EINVAL;
117                 goto runtime_err;
118         }
119
120         num_locks = i * 32; /* actual number of locks in this device */
121
122         bank = devm_kzalloc(&pdev->dev, struct_size(bank, lock, num_locks),
123                             GFP_KERNEL);
124         if (!bank) {
125                 ret = -ENOMEM;
126                 goto runtime_err;
127         }
128
129         platform_set_drvdata(pdev, bank);
130
131         for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
132                 hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
133
134         ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops,
135                                                 base_id, num_locks);
136         if (ret)
137                 goto runtime_err;
138
139         dev_dbg(&pdev->dev, "Registered %d locks with HwSpinlock core\n",
140                 num_locks);
141
142         return 0;
143
144 runtime_err:
145         pm_runtime_disable(&pdev->dev);
146         return ret;
147 }
148
149 static int omap_hwspinlock_remove(struct platform_device *pdev)
150 {
151         struct hwspinlock_device *bank = platform_get_drvdata(pdev);
152         int ret;
153
154         ret = hwspin_lock_unregister(bank);
155         if (ret) {
156                 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
157                 return ret;
158         }
159
160         pm_runtime_disable(&pdev->dev);
161
162         return 0;
163 }
164
165 static const struct of_device_id omap_hwspinlock_of_match[] = {
166         { .compatible = "ti,omap4-hwspinlock", },
167         { .compatible = "ti,am654-hwspinlock", },
168         { /* end */ },
169 };
170 MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match);
171
172 static struct platform_driver omap_hwspinlock_driver = {
173         .probe          = omap_hwspinlock_probe,
174         .remove         = omap_hwspinlock_remove,
175         .driver         = {
176                 .name   = "omap_hwspinlock",
177                 .of_match_table = of_match_ptr(omap_hwspinlock_of_match),
178         },
179 };
180
181 static int __init omap_hwspinlock_init(void)
182 {
183         return platform_driver_register(&omap_hwspinlock_driver);
184 }
185 /* board init code might need to reserve hwspinlocks for predefined purposes */
186 postcore_initcall(omap_hwspinlock_init);
187
188 static void __exit omap_hwspinlock_exit(void)
189 {
190         platform_driver_unregister(&omap_hwspinlock_driver);
191 }
192 module_exit(omap_hwspinlock_exit);
193
194 MODULE_LICENSE("GPL v2");
195 MODULE_DESCRIPTION("Hardware spinlock driver for OMAP");
196 MODULE_AUTHOR("Simon Que <sque@ti.com>");
197 MODULE_AUTHOR("Hari Kanigeri <h-kanigeri2@ti.com>");
198 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");