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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) STMicroelectronics SA 20184 * 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 3222 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 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(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, 0);79 if (IS_ERR(io_base))80 return PTR_ERR(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, "hsem");87 if (IS_ERR(hw->clk))88 return PTR_ERR(hw->clk);89 90 ret = clk_prepare_enable(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, 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, &hw->bank, &stm32_hwspinlock_ops,113 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(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(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