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gerrit-public.fairphone.software / kernel / msm-4.9 / 737f18992ee81cab897336e84c5c7f4e179dfd61 / . / drivers / hwspinlock / sirf_hwspinlock.c
blob: 16018544d4317a6aeb323640b09f431ec4b9f30d [file] [log] [blame]
Wei Chencc16d662015-05-26 08:28:29 +0000[diff] [blame]1/*
2 * SIRF hardware spinlock driver
3 *
4 * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
5 *
6 * Licensed under GPLv2.
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/device.h>
12#include <linux/io.h>
13#include <linux/pm_runtime.h>
14#include <linux/slab.h>
15#include <linux/spinlock.h>
16#include <linux/hwspinlock.h>
17#include <linux/platform_device.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20
21#include "hwspinlock_internal.h"
22
23struct sirf_hwspinlock {
24 void __iomem *io_base;
25 struct hwspinlock_device bank;
26};
27
28/* Number of Hardware Spinlocks*/
29#define HW_SPINLOCK_NUMBER 30
30
31/* Hardware spinlock register offsets */
32#define HW_SPINLOCK_BASE 0x404
33#define HW_SPINLOCK_OFFSET(x) (HW_SPINLOCK_BASE + 0x4 * (x))
34
35static int sirf_hwspinlock_trylock(struct hwspinlock *lock)
36{
37 void __iomem *lock_addr = lock->priv;
38
39 /* attempt to acquire the lock by reading value == 1 from it */
40 return !!readl(lock_addr);
41}
42
43static void sirf_hwspinlock_unlock(struct hwspinlock *lock)
44{
45 void __iomem *lock_addr = lock->priv;
46
47 /* release the lock by writing 0 to it */
48 writel(0, lock_addr);
49}
50
51static const struct hwspinlock_ops sirf_hwspinlock_ops = {
52 .trylock = sirf_hwspinlock_trylock,
53 .unlock = sirf_hwspinlock_unlock,
54};
55
56static int sirf_hwspinlock_probe(struct platform_device *pdev)
57{
58 struct sirf_hwspinlock *hwspin;
59 struct hwspinlock *hwlock;
60 int idx, ret;
61
62 if (!pdev->dev.of_node)
63 return -ENODEV;
64
65 hwspin = devm_kzalloc(&pdev->dev, sizeof(*hwspin) +
66 sizeof(*hwlock) * HW_SPINLOCK_NUMBER, GFP_KERNEL);
67 if (!hwspin)
68 return -ENOMEM;
69
70 /* retrieve io base */
71 hwspin->io_base = of_iomap(pdev->dev.of_node, 0);
72 if (!hwspin->io_base)
73 return -ENOMEM;
74
75 for (idx = 0; idx < HW_SPINLOCK_NUMBER; idx++) {
76 hwlock = &hwspin->bank.lock[idx];
77 hwlock->priv = hwspin->io_base + HW_SPINLOCK_OFFSET(idx);
78 }
79
80 platform_set_drvdata(pdev, hwspin);
81
82 pm_runtime_enable(&pdev->dev);
83
84 ret = hwspin_lock_register(&hwspin->bank, &pdev->dev,
85 &sirf_hwspinlock_ops, 0,
86 HW_SPINLOCK_NUMBER);
87 if (ret)
88 goto reg_failed;
89
90 return 0;
91
92reg_failed:
93 pm_runtime_disable(&pdev->dev);
94 iounmap(hwspin->io_base);
95
96 return ret;
97}
98
99static int sirf_hwspinlock_remove(struct platform_device *pdev)
100{
101 struct sirf_hwspinlock *hwspin = platform_get_drvdata(pdev);
102 int ret;
103
104 ret = hwspin_lock_unregister(&hwspin->bank);
105 if (ret) {
106 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
107 return ret;
108 }
109
110 pm_runtime_disable(&pdev->dev);
111
112 iounmap(hwspin->io_base);
113
114 return 0;
115}
116
117static const struct of_device_id sirf_hwpinlock_ids[] = {
118 { .compatible = "sirf,hwspinlock", },
119 {},
120};
121MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids);
122
123static struct platform_driver sirf_hwspinlock_driver = {
124 .probe = sirf_hwspinlock_probe,
125 .remove = sirf_hwspinlock_remove,
126 .driver = {
127 .name = "atlas7_hwspinlock",
128 .of_match_table = of_match_ptr(sirf_hwpinlock_ids),
129 },
130};
131
132module_platform_driver(sirf_hwspinlock_driver);
133
134MODULE_LICENSE("GPL v2");
135MODULE_DESCRIPTION("SIRF Hardware spinlock driver");
136MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");