1/*
  2 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
  3 * Copyright (c) 2015, Sony Mobile Communications AB
  4 *
  5 * This software is licensed under the terms of the GNU General Public
  6 * License version 2, as published by the Free Software Foundation, and
  7 * may be copied, distributed, and modified under those terms.
  8 *
  9 * This program is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 */
 14
 15#include <linux/hwspinlock.h>
 16#include <linux/io.h>
 17#include <linux/kernel.h>
 18#include <linux/mfd/syscon.h>
 19#include <linux/module.h>
 20#include <linux/of.h>
 21#include <linux/of_device.h>
 22#include <linux/platform_device.h>
 23#include <linux/pm_runtime.h>
 24#include <linux/regmap.h>
 25
 26#include "hwspinlock_internal.h"
 27
 28#define QCOM_MUTEX_APPS_PROC_ID	1
 29#define QCOM_MUTEX_NUM_LOCKS	32
 30
 31static int qcom_hwspinlock_trylock(struct hwspinlock *lock)
 32{
 33	struct regmap_field *field = lock->priv;
 34	u32 lock_owner;
 35	int ret;
 36
 37	ret = regmap_field_write(field, QCOM_MUTEX_APPS_PROC_ID);
 38	if (ret)
 39		return ret;
 40
 41	ret = regmap_field_read(field, &lock_owner);
 42	if (ret)
 43		return ret;
 44
 45	return lock_owner == QCOM_MUTEX_APPS_PROC_ID;
 46}
 47
 48static void qcom_hwspinlock_unlock(struct hwspinlock *lock)
 49{
 50	struct regmap_field *field = lock->priv;
 51	u32 lock_owner;
 52	int ret;
 53
 54	ret = regmap_field_read(field, &lock_owner);
 55	if (ret) {
 56		pr_err("%s: unable to query spinlock owner\n", __func__);
 57		return;
 58	}
 59
 60	if (lock_owner != QCOM_MUTEX_APPS_PROC_ID) {
 61		pr_err("%s: spinlock not owned by us (actual owner is %d)\n",
 62				__func__, lock_owner);
 63	}
 64
 65	ret = regmap_field_write(field, 0);
 66	if (ret)
 67		pr_err("%s: failed to unlock spinlock\n", __func__);
 68}
 69
 70static const struct hwspinlock_ops qcom_hwspinlock_ops = {
 71	.trylock	= qcom_hwspinlock_trylock,
 72	.unlock		= qcom_hwspinlock_unlock,
 73};
 74
 75static const struct of_device_id qcom_hwspinlock_of_match[] = {
 76	{ .compatible = "qcom,sfpb-mutex" },
 77	{ .compatible = "qcom,tcsr-mutex" },
 78	{ }
 79};
 80MODULE_DEVICE_TABLE(of, qcom_hwspinlock_of_match);
 81
 82static int qcom_hwspinlock_probe(struct platform_device *pdev)
 83{
 84	struct hwspinlock_device *bank;
 85	struct device_node *syscon;
 86	struct reg_field field;
 87	struct regmap *regmap;
 88	size_t array_size;
 89	u32 stride;
 90	u32 base;
 91	int ret;
 92	int i;
 93
 94	syscon = of_parse_phandle(pdev->dev.of_node, "syscon", 0);
 95	if (!syscon) {
 96		dev_err(&pdev->dev, "no syscon property\n");
 97		return -ENODEV;
 98	}
 99
100	regmap = syscon_node_to_regmap(syscon);
101	if (IS_ERR(regmap))
102		return PTR_ERR(regmap);
103
104	ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 1, &base);
105	if (ret < 0) {
106		dev_err(&pdev->dev, "no offset in syscon\n");
107		return -EINVAL;
108	}
109
110	ret = of_property_read_u32_index(pdev->dev.of_node, "syscon", 2, &stride);
111	if (ret < 0) {
112		dev_err(&pdev->dev, "no stride syscon\n");
113		return -EINVAL;
114	}
115
116	array_size = QCOM_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
117	bank = devm_kzalloc(&pdev->dev, sizeof(*bank) + array_size, GFP_KERNEL);
118	if (!bank)
119		return -ENOMEM;
120
121	platform_set_drvdata(pdev, bank);
122
123	for (i = 0; i < QCOM_MUTEX_NUM_LOCKS; i++) {
124		field.reg = base + i * stride;
125		field.lsb = 0;
126		field.msb = 31;
127
128		bank->lock[i].priv = devm_regmap_field_alloc(&pdev->dev,
129							     regmap, field);
130	}
131
132	pm_runtime_enable(&pdev->dev);
133
134	ret = hwspin_lock_register(bank, &pdev->dev, &qcom_hwspinlock_ops,
135				   0, QCOM_MUTEX_NUM_LOCKS);
136	if (ret)
137		pm_runtime_disable(&pdev->dev);
138
139	return ret;
140}
141
142static int qcom_hwspinlock_remove(struct platform_device *pdev)
143{
144	struct hwspinlock_device *bank = platform_get_drvdata(pdev);
145	int ret;
146
147	ret = hwspin_lock_unregister(bank);
148	if (ret) {
149		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
150		return ret;
151	}
152
153	pm_runtime_disable(&pdev->dev);
154
155	return 0;
156}
157
158static struct platform_driver qcom_hwspinlock_driver = {
159	.probe		= qcom_hwspinlock_probe,
160	.remove		= qcom_hwspinlock_remove,
161	.driver		= {
162		.name	= "qcom_hwspinlock",
163		.of_match_table = qcom_hwspinlock_of_match,
164	},
165};
166
167static int __init qcom_hwspinlock_init(void)
168{
169	return platform_driver_register(&qcom_hwspinlock_driver);
170}
171/* board init code might need to reserve hwspinlocks for predefined purposes */
172postcore_initcall(qcom_hwspinlock_init);
173
174static void __exit qcom_hwspinlock_exit(void)
175{
176	platform_driver_unregister(&qcom_hwspinlock_driver);
177}
178module_exit(qcom_hwspinlock_exit);
179
180MODULE_LICENSE("GPL v2");
181MODULE_DESCRIPTION("Hardware spinlock driver for Qualcomm SoCs");