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 int stm32_hwspinlock_probe(struct platform_device *pdev) 58 { 59 struct stm32_hwspinlock *hw; 60 void __iomem *io_base; 61 size_t array_size; 62 int i, ret; 63 64 io_base = devm_platform_ioremap_resource(pdev, 0); 65 if (IS_ERR(io_base)) 66 return PTR_ERR(io_base); 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>"); 162