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 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 46 static void stm32_hwspinlock_relax(struct hwspinlock *lock) 47 { 48 ndelay(50); 49 } 50 51 static const struct hwspinlock_ops stm32_hwspinlock_ops = { 52 .trylock = stm32_hwspinlock_trylock, 53 .unlock = stm32_hwspinlock_unlock, 54 .relax = stm32_hwspinlock_relax, 55 }; 56 57 static 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 71 static 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 } 120 121 static 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 } 129 130 static 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 } 138 139 static 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 }; 144 145 static const struct of_device_id stm32_hwpinlock_ids[] = { 146 { .compatible = "st,stm32-hwspinlock", }, 147 {}, 148 }; 149 MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids); 150 151 static 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 }; 159 160 static 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 */ 165 postcore_initcall(stm32_hwspinlock_init); 166 167 static void __exit stm32_hwspinlock_exit(void) 168 { 169 platform_driver_unregister(&stm32_hwspinlock_driver); 170 } 171 module_exit(stm32_hwspinlock_exit); 172 173 MODULE_LICENSE("GPL v2"); 174 MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs"); 175 MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>"); 176