[linux-block.git] / drivers / hwspinlock / stm32_hwspinlock.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics SA 2018
 * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/hwspinlock.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#include "hwspinlock_internal.h"

#define STM32_MUTEX_COREID	BIT(8)
#define STM32_MUTEX_LOCK_BIT	BIT(31)
#define STM32_MUTEX_NUM_LOCKS	32

struct stm32_hwspinlock {
	struct clk *clk;
	struct hwspinlock_device bank;
};

static int stm32_hwspinlock_trylock(struct hwspinlock *lock)
{
	void __iomem *lock_addr = lock->priv;
	u32 status;

	writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr);
	status = readl(lock_addr);

	return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID);
}

static void stm32_hwspinlock_unlock(struct hwspinlock *lock)
{
	void __iomem *lock_addr = lock->priv;

	writel(STM32_MUTEX_COREID, lock_addr);
}

static void stm32_hwspinlock_relax(struct hwspinlock *lock)
{
	ndelay(50);
}

static const struct hwspinlock_ops stm32_hwspinlock_ops = {
	.trylock	= stm32_hwspinlock_trylock,
	.unlock		= stm32_hwspinlock_unlock,
	.relax		= stm32_hwspinlock_relax,
};

static int stm32_hwspinlock_probe(struct platform_device *pdev)
{
	struct stm32_hwspinlock *hw;
	void __iomem *io_base;
	size_t array_size;
	int i, ret;

	io_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(io_base))
		return PTR_ERR(io_base);

	array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
	hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
	if (!hw)
		return -ENOMEM;

	hw->clk = devm_clk_get(&pdev->dev, "hsem");
	if (IS_ERR(hw->clk))
		return PTR_ERR(hw->clk);

	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
		hw->bank.lock[i].priv = io_base + i * sizeof(u32);

	platform_set_drvdata(pdev, hw);
	pm_runtime_enable(&pdev->dev);

	ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
				   0, STM32_MUTEX_NUM_LOCKS);

	if (ret)
		pm_runtime_disable(&pdev->dev);

	return ret;
}

static int stm32_hwspinlock_remove(struct platform_device *pdev)
{
	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
	int ret;

	ret = hwspin_lock_unregister(&hw->bank);
	if (ret)
		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);

	pm_runtime_disable(&pdev->dev);

	return 0;
}

static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
{
	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);

	clk_disable_unprepare(hw->clk);

	return 0;
}

static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev)
{
	struct stm32_hwspinlock *hw = dev_get_drvdata(dev);

	clk_prepare_enable(hw->clk);

	return 0;
}

static const struct dev_pm_ops stm32_hwspinlock_pm_ops = {
	SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend,
			   stm32_hwspinlock_runtime_resume,
			   NULL)
};

static const struct of_device_id stm32_hwpinlock_ids[] = {
	{ .compatible = "st,stm32-hwspinlock", },
	{},
};
MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);

static struct platform_driver stm32_hwspinlock_driver = {
	.probe		= stm32_hwspinlock_probe,
	.remove		= stm32_hwspinlock_remove,
	.driver		= {
		.name	= "stm32_hwspinlock",
		.of_match_table = stm32_hwpinlock_ids,
		.pm	= &stm32_hwspinlock_pm_ops,
	},
};

static int __init stm32_hwspinlock_init(void)
{
	return platform_driver_register(&stm32_hwspinlock_driver);
}
/* board init code might need to reserve hwspinlocks for predefined purposes */
postcore_initcall(stm32_hwspinlock_init);

static void __exit stm32_hwspinlock_exit(void)
{
	platform_driver_unregister(&stm32_hwspinlock_driver);
}
module_exit(stm32_hwspinlock_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
Commit	Line	Data
f24fcff1 BG	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>
5cd69f13	8	#include <linux/delay.h>
f24fcff1 BG	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
	23	struct stm32_hwspinlock {
	24	struct clk *clk;
	25	struct hwspinlock_device bank;
	26	};
	27
	28	static 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
	39	static 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
5cd69f13 FD	46	static void stm32_hwspinlock_relax(struct hwspinlock *lock)
	47	{
	48	ndelay(50);
	49	}
	50
f24fcff1 BG	51	static const struct hwspinlock_ops stm32_hwspinlock_ops = {
	52	.trylock = stm32_hwspinlock_trylock,
	53	.unlock = stm32_hwspinlock_unlock,
5cd69f13	54	.relax = stm32_hwspinlock_relax,
f24fcff1 BG	55	};
	56
	57	static int stm32_hwspinlock_probe(struct platform_device *pdev)
	58	{
	59	struct stm32_hwspinlock *hw;
	60	void __iomem *io_base;
f24fcff1 BG	61	size_t array_size;
	62	int i, ret;
	63
d4824486	64	io_base = devm_platform_ioremap_resource(pdev, 0);
4d5a91fd WY	65	if (IS_ERR(io_base))
4d5a91fd WY	66	return PTR_ERR(io_base);
f24fcff1 BG	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
	92	static 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
	106	static 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
	115	static 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
	124	static 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
	130	static const struct of_device_id stm32_hwpinlock_ids[] = {
131	{ .compatible = "st,stm32-hwspinlock", },
132	{},
133	};
134	MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
135
136	static 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
146	static 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 */
151	postcore_initcall(stm32_hwspinlock_init);
152
153	static void __exit stm32_hwspinlock_exit(void)
154	{
155	platform_driver_unregister(&stm32_hwspinlock_driver);
156	}
157	module_exit(stm32_hwspinlock_exit);
158
159	MODULE_LICENSE("GPL v2");
160	MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs");
161	MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");