1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) STMicroelectronics 2022 - All Rights Reserved 4 * Author: Gabriel Fernandez <gabriel.fernandez@foss.st.com> for STMicroelectronics. 5 */ 6 7 #include <linux/of.h> 8 #include <linux/platform_device.h> 9 #include <linux/regmap.h> 10 #include <linux/reset-controller.h> 11 #include <linux/slab.h> 12 #include <linux/spinlock.h> 13 14 #include "reset-stm32.h" 15 16 struct stm32_reset_data { 17 /* reset lock */ 18 spinlock_t lock; 19 struct reset_controller_dev rcdev; 20 void __iomem *membase; 21 u32 clear_offset; 22 }; 23 24 static inline struct stm32_reset_data * 25 to_stm32_reset_data(struct reset_controller_dev *rcdev) 26 { 27 return container_of(rcdev, struct stm32_reset_data, rcdev); 28 } 29 30 static int stm32_reset_update(struct reset_controller_dev *rcdev, 31 unsigned long id, bool assert) 32 { 33 struct stm32_reset_data *data = to_stm32_reset_data(rcdev); 34 int reg_width = sizeof(u32); 35 int bank = id / (reg_width * BITS_PER_BYTE); 36 int offset = id % (reg_width * BITS_PER_BYTE); 37 38 if (data->clear_offset) { 39 void __iomem *addr; 40 41 addr = data->membase + (bank * reg_width); 42 if (!assert) 43 addr += data->clear_offset; 44 45 writel(BIT(offset), addr); 46 47 } else { 48 unsigned long flags; 49 u32 reg; 50 51 spin_lock_irqsave(&data->lock, flags); 52 53 reg = readl(data->membase + (bank * reg_width)); 54 55 if (assert) 56 reg |= BIT(offset); 57 else 58 reg &= ~BIT(offset); 59 60 writel(reg, data->membase + (bank * reg_width)); 61 62 spin_unlock_irqrestore(&data->lock, flags); 63 } 64 65 return 0; 66 } 67 68 static int stm32_reset_assert(struct reset_controller_dev *rcdev, 69 unsigned long id) 70 { 71 return stm32_reset_update(rcdev, id, true); 72 } 73 74 static int stm32_reset_deassert(struct reset_controller_dev *rcdev, 75 unsigned long id) 76 { 77 return stm32_reset_update(rcdev, id, false); 78 } 79 80 static int stm32_reset_status(struct reset_controller_dev *rcdev, 81 unsigned long id) 82 { 83 struct stm32_reset_data *data = to_stm32_reset_data(rcdev); 84 int reg_width = sizeof(u32); 85 int bank = id / (reg_width * BITS_PER_BYTE); 86 int offset = id % (reg_width * BITS_PER_BYTE); 87 u32 reg; 88 89 reg = readl(data->membase + (bank * reg_width)); 90 91 return !!(reg & BIT(offset)); 92 } 93 94 static const struct reset_control_ops stm32_reset_ops = { 95 .assert = stm32_reset_assert, 96 .deassert = stm32_reset_deassert, 97 .status = stm32_reset_status, 98 }; 99 100 int stm32_rcc_reset_init(struct device *dev, struct clk_stm32_reset_data *data, 101 void __iomem *base) 102 { 103 struct stm32_reset_data *reset_data; 104 105 reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL); 106 if (!reset_data) 107 return -ENOMEM; 108 109 spin_lock_init(&reset_data->lock); 110 111 reset_data->membase = base; 112 reset_data->rcdev.owner = THIS_MODULE; 113 reset_data->rcdev.ops = &stm32_reset_ops; 114 reset_data->rcdev.of_node = dev_of_node(dev); 115 reset_data->rcdev.nr_resets = data->nr_lines; 116 reset_data->clear_offset = data->clear_offset; 117 118 return reset_controller_register(&reset_data->rcdev); 119 } 120