1/*
  2 * Spreadtrum hardware spinlock driver
  3 * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.com
  4 *
  5 * This program is free software; you can redistribute it and/or
  6 * modify it under the terms of the GNU General Public License
  7 * version 2 as published by the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it will be useful, but
 10 * WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 12 * General Public License for more details.
 13 */
 14
 15#include <linux/bitops.h>
 16#include <linux/clk.h>
 17#include <linux/delay.h>
 18#include <linux/device.h>
 19#include <linux/hwspinlock.h>
 20#include <linux/io.h>
 21#include <linux/kernel.h>
 22#include <linux/module.h>
 23#include <linux/of.h>
 24#include <linux/of_device.h>
 25#include <linux/platform_device.h>
 26#include <linux/pm_runtime.h>
 27#include <linux/slab.h>
 28
 29#include "hwspinlock_internal.h"
 30
 31/* hwspinlock registers definition */
 32#define HWSPINLOCK_RECCTRL		0x4
 33#define HWSPINLOCK_MASTERID(_X_)	(0x80 + 0x4 * (_X_))
 34#define HWSPINLOCK_TOKEN(_X_)		(0x800 + 0x4 * (_X_))
 35
 36/* unlocked value */
 37#define HWSPINLOCK_NOTTAKEN		0x55aa10c5
 38/* bits definition of RECCTRL reg */
 39#define HWSPINLOCK_USER_BITS		0x1
 40
 41/* hwspinlock number */
 42#define SPRD_HWLOCKS_NUM		32
 43
 44struct sprd_hwspinlock_dev {
 45	void __iomem *base;
 46	struct clk *clk;
 47	struct hwspinlock_device bank;
 48};
 49
 50/* try to lock the hardware spinlock */
 51static int sprd_hwspinlock_trylock(struct hwspinlock *lock)
 52{
 53	struct sprd_hwspinlock_dev *sprd_hwlock =
 54		dev_get_drvdata(lock->bank->dev);
 55	void __iomem *addr = lock->priv;
 56	int user_id, lock_id;
 57
 58	if (!readl(addr))
 59		return 1;
 60
 61	lock_id = hwlock_to_id(lock);
 62	/* get the hardware spinlock master/user id */
 63	user_id = readl(sprd_hwlock->base + HWSPINLOCK_MASTERID(lock_id));
 64	dev_warn(sprd_hwlock->bank.dev,
 65		 "hwspinlock [%d] lock failed and master/user id = %d!\n",
 66		 lock_id, user_id);
 67	return 0;
 68}
 69
 70/* unlock the hardware spinlock */
 71static void sprd_hwspinlock_unlock(struct hwspinlock *lock)
 72{
 73	void __iomem *lock_addr = lock->priv;
 74
 75	writel(HWSPINLOCK_NOTTAKEN, lock_addr);
 76}
 77
 78/* The specs recommended below number as the retry delay time */
 79static void sprd_hwspinlock_relax(struct hwspinlock *lock)
 80{
 81	ndelay(10);
 82}
 83
 84static const struct hwspinlock_ops sprd_hwspinlock_ops = {
 85	.trylock = sprd_hwspinlock_trylock,
 86	.unlock = sprd_hwspinlock_unlock,
 87	.relax = sprd_hwspinlock_relax,
 88};
 89
 90static int sprd_hwspinlock_probe(struct platform_device *pdev)
 91{
 92	struct sprd_hwspinlock_dev *sprd_hwlock;
 93	struct hwspinlock *lock;
 94	struct resource *res;
 95	int i, ret;
 96
 97	if (!pdev->dev.of_node)
 98		return -ENODEV;
 99
100	sprd_hwlock = devm_kzalloc(&pdev->dev,
101				   sizeof(struct sprd_hwspinlock_dev) +
102				   SPRD_HWLOCKS_NUM * sizeof(*lock),
103				   GFP_KERNEL);
104	if (!sprd_hwlock)
105		return -ENOMEM;
106
107	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
108	sprd_hwlock->base = devm_ioremap_resource(&pdev->dev, res);
109	if (IS_ERR(sprd_hwlock->base))
110		return PTR_ERR(sprd_hwlock->base);
111
112	sprd_hwlock->clk = devm_clk_get(&pdev->dev, "enable");
113	if (IS_ERR(sprd_hwlock->clk)) {
114		dev_err(&pdev->dev, "get hwspinlock clock failed!\n");
115		return PTR_ERR(sprd_hwlock->clk);
116	}
117
118	clk_prepare_enable(sprd_hwlock->clk);
119
120	/* set the hwspinlock to record user id to identify subsystems */
121	writel(HWSPINLOCK_USER_BITS, sprd_hwlock->base + HWSPINLOCK_RECCTRL);
122
123	for (i = 0; i < SPRD_HWLOCKS_NUM; i++) {
124		lock = &sprd_hwlock->bank.lock[i];
125		lock->priv = sprd_hwlock->base + HWSPINLOCK_TOKEN(i);
126	}
127
128	platform_set_drvdata(pdev, sprd_hwlock);
129	pm_runtime_enable(&pdev->dev);
130
131	ret = hwspin_lock_register(&sprd_hwlock->bank, &pdev->dev,
132				   &sprd_hwspinlock_ops, 0, SPRD_HWLOCKS_NUM);
133	if (ret) {
134		pm_runtime_disable(&pdev->dev);
135		clk_disable_unprepare(sprd_hwlock->clk);
136		return ret;
137	}
138
139	return 0;
140}
141
142static int sprd_hwspinlock_remove(struct platform_device *pdev)
143{
144	struct sprd_hwspinlock_dev *sprd_hwlock = platform_get_drvdata(pdev);
145
146	hwspin_lock_unregister(&sprd_hwlock->bank);
147	pm_runtime_disable(&pdev->dev);
148	clk_disable_unprepare(sprd_hwlock->clk);
149	return 0;
150}
151
152static const struct of_device_id sprd_hwspinlock_of_match[] = {
153	{ .compatible = "sprd,hwspinlock-r3p0", },
154	{ /* sentinel */ }
155};
156MODULE_DEVICE_TABLE(of, sprd_hwspinlock_of_match);
157
158static struct platform_driver sprd_hwspinlock_driver = {
159	.probe = sprd_hwspinlock_probe,
160	.remove = sprd_hwspinlock_remove,
161	.driver = {
162		.name = "sprd_hwspinlock",
163		.of_match_table = of_match_ptr(sprd_hwspinlock_of_match),
164	},
165};
166
167static int __init sprd_hwspinlock_init(void)
168{
169	return platform_driver_register(&sprd_hwspinlock_driver);
170}
171postcore_initcall(sprd_hwspinlock_init);
172
173static void __exit sprd_hwspinlock_exit(void)
174{
175	platform_driver_unregister(&sprd_hwspinlock_driver);
176}
177module_exit(sprd_hwspinlock_exit);
178
179MODULE_LICENSE("GPL v2");
180MODULE_DESCRIPTION("Hardware spinlock driver for Spreadtrum");
181MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");
182MODULE_AUTHOR("Lanqing Liu <lanqing.liu@spreadtrum.com>");
183MODULE_AUTHOR("Long Cheng <aiden.cheng@spreadtrum.com>");