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// 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;
struct resource *res;
size_t array_size;
int i, ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
io_base = devm_ioremap_resource(&pdev->dev, res);
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>");
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