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/slab.h>
13#include <linux/spinlock.h>
14#include <linux/hwspinlock.h>
15#include <linux/platform_device.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18
19#include "hwspinlock_internal.h"
20
21struct sirf_hwspinlock {
22	void __iomem *io_base;
23	struct hwspinlock_device bank;
24};
25
26/* Number of Hardware Spinlocks*/
27#define	HW_SPINLOCK_NUMBER	30
28
29/* Hardware spinlock register offsets */
30#define HW_SPINLOCK_BASE	0x404
31#define HW_SPINLOCK_OFFSET(x)	(HW_SPINLOCK_BASE + 0x4 * (x))
32
33static int sirf_hwspinlock_trylock(struct hwspinlock *lock)
34{
35	void __iomem *lock_addr = lock->priv;
36
37	/* attempt to acquire the lock by reading value == 1 from it */
38	return !!readl(lock_addr);
39}
40
41static void sirf_hwspinlock_unlock(struct hwspinlock *lock)
42{
43	void __iomem *lock_addr = lock->priv;
44
45	/* release the lock by writing 0 to it */
46	writel(0, lock_addr);
47}
48
49static const struct hwspinlock_ops sirf_hwspinlock_ops = {
50	.trylock = sirf_hwspinlock_trylock,
51	.unlock = sirf_hwspinlock_unlock,
52};
53
54static int sirf_hwspinlock_probe(struct platform_device *pdev)
55{
56	struct sirf_hwspinlock *hwspin;
57	struct hwspinlock *hwlock;
58	int idx;
59
60	if (!pdev->dev.of_node)
61		return -ENODEV;
62
63	hwspin = devm_kzalloc(&pdev->dev,
64			      struct_size(hwspin, bank.lock,
65					  HW_SPINLOCK_NUMBER),
66			      GFP_KERNEL);
67	if (!hwspin)
68		return -ENOMEM;
69
70	/* retrieve io base */
71	hwspin->io_base = devm_platform_ioremap_resource(pdev, 0);
72	if (IS_ERR(hwspin->io_base))
73		return PTR_ERR(hwspin->io_base);
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	return devm_hwspin_lock_register(&pdev->dev, &hwspin->bank,
83					 &sirf_hwspinlock_ops, 0,
84					 HW_SPINLOCK_NUMBER);
85}
86
87static const struct of_device_id sirf_hwpinlock_ids[] = {
88	{ .compatible = "sirf,hwspinlock", },
89	{},
90};
91MODULE_DEVICE_TABLE(of, sirf_hwpinlock_ids);
92
93static struct platform_driver sirf_hwspinlock_driver = {
94	.probe = sirf_hwspinlock_probe,
95	.driver = {
96		.name = "atlas7_hwspinlock",
97		.of_match_table = of_match_ptr(sirf_hwpinlock_ids),
98	},
99};
100
101module_platform_driver(sirf_hwspinlock_driver);
102
103MODULE_LICENSE("GPL v2");
104MODULE_DESCRIPTION("SIRF Hardware spinlock driver");
105MODULE_AUTHOR("Wei Chen <wei.chen@csr.com>");
106