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, addr: lock_addr);
34 status = readl(addr: 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, addr: 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 void stm32_hwspinlock_disable_clk(void *data)
58{
59 struct platform_device *pdev = data;
60 struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
61 struct device *dev = &pdev->dev;
62
63 pm_runtime_get_sync(dev);
64 pm_runtime_disable(dev);
65 pm_runtime_set_suspended(dev);
66 pm_runtime_put_noidle(dev);
67
68 clk_disable_unprepare(clk: hw->clk);
69}
70
71static int stm32_hwspinlock_probe(struct platform_device *pdev)
72{
73 struct device *dev = &pdev->dev;
74 struct stm32_hwspinlock *hw;
75 void __iomem *io_base;
76 int i, ret;
77
78 io_base = devm_platform_ioremap_resource(pdev, index: 0);
79 if (IS_ERR(ptr: io_base))
80 return PTR_ERR(ptr: io_base);
81
82 hw = devm_kzalloc(dev, struct_size(hw, bank.lock, STM32_MUTEX_NUM_LOCKS), GFP_KERNEL);
83 if (!hw)
84 return -ENOMEM;
85
86 hw->clk = devm_clk_get(dev, id: "hsem");
87 if (IS_ERR(ptr: hw->clk))
88 return PTR_ERR(ptr: hw->clk);
89
90 ret = clk_prepare_enable(clk: hw->clk);
91 if (ret) {
92 dev_err(dev, "Failed to prepare_enable clock\n");
93 return ret;
94 }
95
96 platform_set_drvdata(pdev, data: hw);
97
98 pm_runtime_get_noresume(dev);
99 pm_runtime_set_active(dev);
100 pm_runtime_enable(dev);
101 pm_runtime_put(dev);
102
103 ret = devm_add_action_or_reset(dev, stm32_hwspinlock_disable_clk, pdev);
104 if (ret) {
105 dev_err(dev, "Failed to register action\n");
106 return ret;
107 }
108
109 for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
110 hw->bank.lock[i].priv = io_base + i * sizeof(u32);
111
112 ret = devm_hwspin_lock_register(dev, bank: &hw->bank, ops: &stm32_hwspinlock_ops,
113 base_id: 0, STM32_MUTEX_NUM_LOCKS);
114
115 if (ret)
116 dev_err(dev, "Failed to register hwspinlock\n");
117
118 return ret;
119}
120
121static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
122{
123 struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
124
125 clk_disable_unprepare(clk: hw->clk);
126
127 return 0;
128}
129
130static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
131{
132 struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
133
134 clk_prepare_enable(clk: hw->clk);
135
136 return 0;
137}
138
139static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
140 SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
141 stm32_hwspinlock_runtime_resume,
142 NULL)
143};
144
145static const struct of_device_id stm32_hwpinlock_ids[] = {
146 { .compatible = "st,stm32-hwspinlock", },
147 {},
148};
149MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
150
151static struct platform_driver stm32_hwspinlock_driver = {
152 .probe = stm32_hwspinlock_probe,
153 .driver = {
154 .name = "stm32_hwspinlock",
155 .of_match_table = stm32_hwpinlock_ids,
156 .pm = &stm32_hwspinlock_pm_ops,
157 },
158};
159
160static int __init stm32_hwspinlock_init(void)
161{
162 return platform_driver_register(&stm32_hwspinlock_driver);
163}
164/* board init code might need to reserve hwspinlocks for predefined purposes */
165postcore_initcall(stm32_hwspinlock_init);
166
167static void __exit stm32_hwspinlock_exit(void)
168{
169 platform_driver_unregister(&stm32_hwspinlock_driver);
170}
171module_exit(stm32_hwspinlock_exit);
172
173MODULE_LICENSE("GPL v2");
174MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
175MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
176

source code of linux/drivers/hwspinlock/stm32_hwspinlock.c