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/hwspinlock.h> 9 #include <linux/io.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 #include <linux/pm_runtime.h> 15 16 #include "hwspinlock_internal.h" 17 18 #define STM32_MUTEX_COREID BIT(8) 19 #define STM32_MUTEX_LOCK_BIT BIT(31) 20 #define STM32_MUTEX_NUM_LOCKS 32 21 22 struct stm32_hwspinlock { 23 struct clk *clk; 24 struct hwspinlock_device bank; 25 }; 26 27 static int stm32_hwspinlock_trylock(struct hwspinlock *lock) 28 { 29 void __iomem *lock_addr = lock->priv; 30 u32 status; 31 32 writel(STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID, lock_addr); 33 status = readl(lock_addr); 34 35 return status == (STM32_MUTEX_LOCK_BIT | STM32_MUTEX_COREID); 36 } 37 38 static void stm32_hwspinlock_unlock(struct hwspinlock *lock) 39 { 40 void __iomem *lock_addr = lock->priv; 41 42 writel(STM32_MUTEX_COREID, lock_addr); 43 } 44 45 static const struct hwspinlock_ops stm32_hwspinlock_ops = { 46 .trylock = stm32_hwspinlock_trylock, 47 .unlock = stm32_hwspinlock_unlock, 48 }; 49 50 static int stm32_hwspinlock_probe(struct platform_device *pdev) 51 { 52 struct stm32_hwspinlock *hw; 53 void __iomem *io_base; 54 struct resource *res; 55 size_t array_size; 56 int i, ret; 57 58 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 59 io_base = devm_ioremap_resource(&pdev->dev, res); 60 if (IS_ERR(io_base)) 61 return PTR_ERR(io_base); 62 63 array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock); 64 hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL); 65 if (!hw) 66 return -ENOMEM; 67 68 hw->clk = devm_clk_get(&pdev->dev, "hsem"); 69 if (IS_ERR(hw->clk)) 70 return PTR_ERR(hw->clk); 71 72 for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++) 73 hw->bank.lock[i].priv = io_base + i * sizeof(u32); 74 75 platform_set_drvdata(pdev, hw); 76 pm_runtime_enable(&pdev->dev); 77 78 ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops, 79 0, STM32_MUTEX_NUM_LOCKS); 80 81 if (ret) 82 pm_runtime_disable(&pdev->dev); 83 84 return ret; 85 } 86 87 static int stm32_hwspinlock_remove(struct platform_device *pdev) 88 { 89 struct stm32_hwspinlock *hw = platform_get_drvdata(pdev); 90 int ret; 91 92 ret = hwspin_lock_unregister(&hw->bank); 93 if (ret) 94 dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret); 95 96 pm_runtime_disable(&pdev->dev); 97 98 return 0; 99 } 100 101 static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev) 102 { 103 struct stm32_hwspinlock *hw = dev_get_drvdata(dev); 104 105 clk_disable_unprepare(hw->clk); 106 107 return 0; 108 } 109 110 static int __maybe_unused stm32_hwspinlock_runtime_resume(struct device *dev) 111 { 112 struct stm32_hwspinlock *hw = dev_get_drvdata(dev); 113 114 clk_prepare_enable(hw->clk); 115 116 return 0; 117 } 118 119 static const struct dev_pm_ops stm32_hwspinlock_pm_ops = { 120 SET_RUNTIME_PM_OPS(stm32_hwspinlock_runtime_suspend, 121 stm32_hwspinlock_runtime_resume, 122 NULL) 123 }; 124 125 static const struct of_device_id stm32_hwpinlock_ids[] = { 126 { .compatible = "st,stm32-hwspinlock", }, 127 {}, 128 }; 129 MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids); 130 131 static struct platform_driver stm32_hwspinlock_driver = { 132 .probe = stm32_hwspinlock_probe, 133 .remove = stm32_hwspinlock_remove, 134 .driver = { 135 .name = "stm32_hwspinlock", 136 .of_match_table = stm32_hwpinlock_ids, 137 .pm = &stm32_hwspinlock_pm_ops, 138 }, 139 }; 140 141 static int __init stm32_hwspinlock_init(void) 142 { 143 return platform_driver_register(&stm32_hwspinlock_driver); 144 } 145 /* board init code might need to reserve hwspinlocks for predefined purposes */ 146 postcore_initcall(stm32_hwspinlock_init); 147 148 static void __exit stm32_hwspinlock_exit(void) 149 { 150 platform_driver_unregister(&stm32_hwspinlock_driver); 151 } 152 module_exit(stm32_hwspinlock_exit); 153 154 MODULE_LICENSE("GPL v2"); 155 MODULE_DESCRIPTION("Hardware spinlock driver for STM32 SoCs"); 156 MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>"); 157