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>");