GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / hwspinlock / qcom_hwspinlock.c
1 /*
2  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
3  * Copyright (c) 2015, Sony Mobile Communications AB
4  *
5  * This software is licensed under the terms of the GNU General Public
6  * License version 2, as published by the Free Software Foundation, and
7  * may be copied, distributed, and modified under those terms.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  */
14
15 #include <linux/hwspinlock.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/syscon.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/of_device.h>
22 #include <linux/platform_device.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/regmap.h>
25
26 #include "hwspinlock_internal.h"
27
28 #define QCOM_MUTEX_APPS_PROC_ID 1
29 #define QCOM_MUTEX_NUM_LOCKS    32
30
31 static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
32 {
33         struct regmap_field *field = lock->priv;
34         u32 lock_owner;
35         int ret;
36
37         ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
38         if (ret)
39                 return ret;
40
41         ret = regmap_field_read(field, &lock_owner);
42         if (ret)
43                 return ret;
44
45         return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
46 }
47
48 static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
49 {
50         struct regmap_field *field = lock->priv;
51         u32 lock_owner;
52         int ret;
53
54         ret = regmap_field_read(field, &lock_owner);
55         if (ret) {
56                 pr_err("%s: unable to query spinlock owner\n", __func__);
57                 return;
58         }
59
60         if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
61                 pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
62                                 __func__, lock_owner);
63         }
64
65         ret = regmap_field_write(field, 0);
66         if (ret)
67                 pr_err("%s: failed to unlock spinlock\n", __func__);
68 }
69
70 static const struct hwspinlock_ops qcom_hwspinlock_ops = {
71         .trylock        = qcom_hwspinlock_trylock,
72         .unlock         = qcom_hwspinlock_unlock,
73 };
74
75 static const struct of_device_id qcom_hwspinlock_of_match[] = {
76         { .compatible = "qcom,sfpb-mutex" },
77         { .compatible = "qcom,tcsr-mutex" },
78         { }
79 };
80 MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
81
82 static int qcom_hwspinlock_probe(struct platform_device *pdev)
83 {
84         struct hwspinlock_device *bank;
85         struct device_node *syscon;
86         struct reg_field field;
87         struct regmap *regmap;
88         size_t array_size;
89         u32 stride;
90         u32 base;
91         int ret;
92         int i;
93
94         syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
95         if (!syscon) {
96                 dev_err(&pdev->dev, "no syscon property\n");
97                 return -ENODEV;
98         }
99
100         regmap = syscon_node_to_regmap(syscon);
101         if (IS_ERR(regmap))
102                 return PTR_ERR(regmap);
103
104         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, &base);
105         if (ret < 0) {
106                 dev_err(&pdev->dev, "no offset in syscon\n");
107                 return -EINVAL;
108         }
109
110         ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, &stride);
111         if (ret < 0) {
112                 dev_err(&pdev->dev, "no stride syscon\n");
113                 return -EINVAL;
114         }
115
116         array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
117         bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
118         if (!bank)
119                 return -ENOMEM;
120
121         platform_set_drvdata(pdev, bank);
122
123         for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
124                 field.reg = base + i * stride;
125                 field.lsb = 0;
126                 field.msb = 31;
127
128                 bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
129                                                              regmap, field);
130         }
131
132         pm_runtime_enable(&pdev->dev);
133
134         ret = hwspin_lock_register(bank, &pdev->dev, &qcom_hwspinlock_ops,
135                                    0, QCOM_MUTEX_NUM_LOCKS);
136         if (ret)
137                 pm_runtime_disable(&pdev->dev);
138
139         return ret;
140 }
141
142 static int qcom_hwspinlock_remove(struct platform_device *pdev)
143 {
144         struct hwspinlock_device *bank = platform_get_drvdata(pdev);
145         int ret;
146
147         ret = hwspin_lock_unregister(bank);
148         if (ret) {
149                 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
150                 return ret;
151         }
152
153         pm_runtime_disable(&pdev->dev);
154
155         return 0;
156 }
157
158 static struct platform_driver qcom_hwspinlock_driver = {
159         .probe          = qcom_hwspinlock_probe,
160         .remove         = qcom_hwspinlock_remove,
161         .driver         = {
162                 .name   = "qcom_hwspinlock",
163                 .of_match_table = qcom_hwspinlock_of_match,
164         },
165 };
166
167 static int __init qcom_hwspinlock_init(void)
168 {
169         return platform_driver_register(&qcom_hwspinlock_driver);
170 }
171 /* board init code might need to reserve hwspinlocks for predefined purposes */
172 postcore_initcall(qcom_hwspinlock_init);
173
174 static void __exit qcom_hwspinlock_exit(void)
175 {
176         platform_driver_unregister(&qcom_hwspinlock_driver);
177 }
178 module_exit(qcom_hwspinlock_exit);
179
180 MODULE_LICENSE("GPL v2");
181 MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");