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>");