1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STMicroelectronics SA 2018
4 * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
5 */
6
7#include <linux/clk.h>
8#include <linux/delay.h>
9#include <linux/hwspinlock.h>
10#include <linux/io.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/pm_runtime.h>
16
17#include "hwspinlock_internal.h"
18
19#define STM32_MUTEX_COREID	BIT(8)
20#define STM32_MUTEX_LOCK_BIT	BIT(31)
21#define STM32_MUTEX_NUM_LOCKS	32
22
23struct stm32_hwspinlock {
24	struct clk *clk;
25	struct hwspinlock_device bank;
26};
27
28static int stm32_hwspinlock_trylock(struct hwspinlock *lock)
29{
30	void __iomem *lock_addr = lock->priv;
31	u32 status;
32
33	writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr);
34	status = readl(lock_addr);
35
36	return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID);
37}
38
39static void stm32_hwspinlock_unlock(struct hwspinlock *lock)
40{
41	void __iomem *lock_addr = lock->priv;
42
43	writel(STM32_MUTEX_COREID, lock_addr);
44}
45
46static void stm32_hwspinlock_relax(struct hwspinlock *lock)
47{
48	ndelay(50);
49}
50
51static const struct hwspinlock_ops stm32_hwspinlock_ops = {
52	.trylock	= stm32_hwspinlock_trylock,
53	.unlock		= stm32_hwspinlock_unlock,
54	.relax		= stm32_hwspinlock_relax,
55};
56
57static int stm32_hwspinlock_probe(struct platform_device *pdev)
58{
59	struct stm32_hwspinlock *hw;
60	void __iomem *io_base;
61	size_t array_size;
62	int i, ret;
63
64	io_base = devm_platform_ioremap_resource(pdev, 0);
65	if (IS_ERR(io_base))
66		return PTR_ERR(io_base);
67
68	array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
69	hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
70	if (!hw)
71		return -ENOMEM;
72
73	hw->clk = devm_clk_get(&pdev->dev, "hsem");
74	if (IS_ERR(hw->clk))
75		return PTR_ERR(hw->clk);
76
77	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
78		hw->bank.lock[i].priv = io_base + i * sizeof(u32);
79
80	platform_set_drvdata(pdev, hw);
81	pm_runtime_enable(&pdev->dev);
82
83	ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
84				   0, STM32_MUTEX_NUM_LOCKS);
85
86	if (ret)
87		pm_runtime_disable(&pdev->dev);
88
89	return ret;
90}
91
92static int stm32_hwspinlock_remove(struct platform_device *pdev)
93{
94	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
95	int ret;
96
97	ret = hwspin_lock_unregister(&hw->bank);
98	if (ret)
99		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
100
101	pm_runtime_disable(&pdev->dev);
102
103	return 0;
104}
105
106static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
107{
108	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
109
110	clk_disable_unprepare(hw->clk);
111
112	return 0;
113}
114
115static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
116{
117	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
118
119	clk_prepare_enable(hw->clk);
120
121	return 0;
122}
123
124static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
125	SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
126			   stm32_hwspinlock_runtime_resume,
127			   NULL)
128};
129
130static const struct of_device_id stm32_hwpinlock_ids[] = {
131	{ .compatible = "st,stm32-hwspinlock", },
132	{},
133};
134MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
135
136static struct platform_driver stm32_hwspinlock_driver = {
137	.probe		= stm32_hwspinlock_probe,
138	.remove		= stm32_hwspinlock_remove,
139	.driver		= {
140		.name	= "stm32_hwspinlock",
141		.of_match_table = stm32_hwpinlock_ids,
142		.pm	= &stm32_hwspinlock_pm_ops,
143	},
144};
145
146static int __init stm32_hwspinlock_init(void)
147{
148	return platform_driver_register(&stm32_hwspinlock_driver);
149}
150/* board init code might need to reserve hwspinlocks for predefined purposes */
151postcore_initcall(stm32_hwspinlock_init);
152
153static void __exit stm32_hwspinlock_exit(void)
154{
155	platform_driver_unregister(&stm32_hwspinlock_driver);
156}
157module_exit(stm32_hwspinlock_exit);
158
159MODULE_LICENSE("GPL v2");
160MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
161MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
162