tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 struct resource *res;
62 size_t array_size;
63 int i, ret;
64
65 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
66 io_base = devm_ioremap_resource(&pdev->dev, res);
67 if (IS_ERR(io_base))
68 return PTR_ERR(io_base);
69
70 array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
71 hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
72 if (!hw)
73 return -ENOMEM;
74
75 hw->clk = devm_clk_get(&pdev->dev, "hsem");
76 if (IS_ERR(hw->clk))
77 return PTR_ERR(hw->clk);
78
79 for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
80 hw->bank.lock[i].priv = io_base + i * sizeof(u32);
81
82 platform_set_drvdata(pdev, hw);
83 pm_runtime_enable(&pdev->dev);
84
85 ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
86 0, STM32_MUTEX_NUM_LOCKS);
87
88 if (ret)
89 pm_runtime_disable(&pdev->dev);
90
91 return ret;
92}
93
94static int stm32_hwspinlock_remove(struct platform_device *pdev)
95{
96 struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
97 int ret;
98
99 ret = hwspin_lock_unregister(&hw->bank);
100 if (ret)
101 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
102
103 pm_runtime_disable(&pdev->dev);
104
105 return 0;
106}
107
108static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
109{
110 struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
111
112 clk_disable_unprepare(hw->clk);
113
114 return 0;
115}
116
117static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
118{
119 struct stm32_hwspinlock *hw = dev_get_drvdata(dev);
120
121 clk_prepare_enable(hw->clk);
122
123 return 0;
124}
125
126static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
127 SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
128 stm32_hwspinlock_runtime_resume,
129 NULL)
130};
131
132static const struct of_device_id stm32_hwpinlock_ids[] = {
133 { .compatible = "st,stm32-hwspinlock", },
134 {},
135};
136MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
137
138static struct platform_driver stm32_hwspinlock_driver = {
139 .probe = stm32_hwspinlock_probe,
140 .remove = stm32_hwspinlock_remove,
141 .driver = {
142 .name = "stm32_hwspinlock",
143 .of_match_table = stm32_hwpinlock_ids,
144 .pm = &stm32_hwspinlock_pm_ops,
145 },
146};
147
148static int __init stm32_hwspinlock_init(void)
149{
150 return platform_driver_register(&stm32_hwspinlock_driver);
151}
152/* board init code might need to reserve hwspinlocks for predefined purposes */
153postcore_initcall(stm32_hwspinlock_init);
154
155static void __exit stm32_hwspinlock_exit(void)
156{
157 platform_driver_unregister(&stm32_hwspinlock_driver);
158}
159module_exit(stm32_hwspinlock_exit);
160
161MODULE_LICENSE("GPL v2");
162MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
163MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");