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
23 struct 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
sirf_hwspinlock_trylock(struct hwspinlock * lock)35 static 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
sirf_hwspinlock_unlock(struct hwspinlock * lock)43 static 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
51 static const struct hwspinlock_ops sirf_hwspinlock_ops = {
52 .trylock = sirf_hwspinlock_trylock,
53 .unlock = sirf_hwspinlock_unlock,
54 };
55
sirf_hwspinlock_probe(struct platform_device * pdev)56 static 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
92 reg_failed:
93 pm_runtime_disable(&pdev->dev);
94 iounmap(hwspin->io_base);
95
96 return ret;
97 }
98
sirf_hwspinlock_remove(struct platform_device * pdev)99 static 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
117 static const struct of_device_id sirf_hwpinlock_ids[] = {
118 { .compatible = "sirf,hwspinlock", },
119 {},
120 };
121 MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids);
122
123 static 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
132 module_platform_driver(sirf_hwspinlock_driver);
133
134 MODULE_LICENSE("GPL v2");
135 MODULE_DESCRIPTION("SIRF Hardware spinlock driver");
136 MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");
137