tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SIRF hardware spinlock driver
4 *
5 * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/device.h>
11#include <linux/io.h>
12#include <linux/pm_runtime.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/hwspinlock.h>
16#include <linux/platform_device.h>
17#include <linux/of.h>
18#include <linux/of_address.h>
19
20#include "hwspinlock_internal.h"
21
22struct sirf_hwspinlock {
23 void __iomem *io_base;
24 struct hwspinlock_device bank;
25};
26
27/* Number of Hardware Spinlocks*/
28#define HW_SPINLOCK_NUMBER 30
29
30/* Hardware spinlock register offsets */
31#define HW_SPINLOCK_BASE 0x404
32#define HW_SPINLOCK_OFFSET(x) (HW_SPINLOCK_BASE + 0x4 * (x))
33
34static int sirf_hwspinlock_trylock(struct hwspinlock *lock)
35{
36 void __iomem *lock_addr = lock->priv;
37
38 /* attempt to acquire the lock by reading value == 1 from it */
39 return !!readl(lock_addr);
40}
41
42static void sirf_hwspinlock_unlock(struct hwspinlock *lock)
43{
44 void __iomem *lock_addr = lock->priv;
45
46 /* release the lock by writing 0 to it */
47 writel(0, lock_addr);
48}
49
50static const struct hwspinlock_ops sirf_hwspinlock_ops = {
51 .trylock = sirf_hwspinlock_trylock,
52 .unlock = sirf_hwspinlock_unlock,
53};
54
55static int sirf_hwspinlock_probe(struct platform_device *pdev)
56{
57 struct sirf_hwspinlock *hwspin;
58 struct hwspinlock *hwlock;
59 int idx, ret;
60
61 if (!pdev->dev.of_node)
62 return -ENODEV;
63
64 hwspin = devm_kzalloc(&pdev->dev,
65 struct_size(hwspin, bank.lock,
66 HW_SPINLOCK_NUMBER),
67 GFP_KERNEL);
68 if (!hwspin)
69 return -ENOMEM;
70
71 /* retrieve io base */
72 hwspin->io_base = of_iomap(pdev->dev.of_node, 0);
73 if (!hwspin->io_base)
74 return -ENOMEM;
75
76 for (idx = 0; idx < HW_SPINLOCK_NUMBER; idx++) {
77 hwlock = &hwspin->bank.lock[idx];
78 hwlock->priv = hwspin->io_base + HW_SPINLOCK_OFFSET(idx);
79 }
80
81 platform_set_drvdata(pdev, hwspin);
82
83 pm_runtime_enable(&pdev->dev);
84
85 ret = hwspin_lock_register(&hwspin->bank, &pdev->dev,
86 &sirf_hwspinlock_ops, 0,
87 HW_SPINLOCK_NUMBER);
88 if (ret)
89 goto reg_failed;
90
91 return 0;
92
93reg_failed:
94 pm_runtime_disable(&pdev->dev);
95 iounmap(hwspin->io_base);
96
97 return ret;
98}
99
100static int sirf_hwspinlock_remove(struct platform_device *pdev)
101{
102 struct sirf_hwspinlock *hwspin = platform_get_drvdata(pdev);
103 int ret;
104
105 ret = hwspin_lock_unregister(&hwspin->bank);
106 if (ret) {
107 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
108 return ret;
109 }
110
111 pm_runtime_disable(&pdev->dev);
112
113 iounmap(hwspin->io_base);
114
115 return 0;
116}
117
118static const struct of_device_id sirf_hwpinlock_ids[] = {
119 { .compatible = "sirf,hwspinlock", },
120 {},
121};
122MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids);
123
124static struct platform_driver sirf_hwspinlock_driver = {
125 .probe = sirf_hwspinlock_probe,
126 .remove = sirf_hwspinlock_remove,
127 .driver = {
128 .name = "atlas7_hwspinlock",
129 .of_match_table = of_match_ptr(sirf_hwpinlock_ids),
130 },
131};
132
133module_platform_driver(sirf_hwspinlock_driver);
134
135MODULE_LICENSE("GPL v2");
136MODULE_DESCRIPTION("SIRF Hardware spinlock driver");
137MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");