diff options
Diffstat (limited to 'drivers/hwspinlock/stm32_hwspinlock.c')
| -rw-r--r-- | drivers/hwspinlock/stm32_hwspinlock.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c new file mode 100644 index 000000000000..441839288893 --- /dev/null +++ b/drivers/hwspinlock/stm32_hwspinlock.c @@ -0,0 +1,156 @@ +// 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/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 const struct hwspinlock_ops stm32_hwspinlock_ops = { + .trylock = stm32_hwspinlock_trylock, + .unlock = stm32_hwspinlock_unlock, +}; + +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>"); |