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 const struct stm32_reset_cfg **reset_lines; 23 }; 24 25 static inline struct stm32_reset_data * 26 to_stm32_reset_data(struct reset_controller_dev *rcdev) 27 { 28 return container_of(rcdev, struct stm32_reset_data, rcdev); 29 } 30 31 static const struct stm32_reset_cfg *stm32_get_reset_line(struct reset_controller_dev *rcdev, 32 unsigned long id, 33 struct stm32_reset_cfg *line) 34 { 35 struct stm32_reset_data *data = to_stm32_reset_data(rcdev); 36 37 if (!data->reset_lines) { 38 int reg_width = sizeof(u32); 39 int bank = id / (reg_width * BITS_PER_BYTE); 40 int offset = id % (reg_width * BITS_PER_BYTE); 41 42 line->offset = bank * reg_width; 43 line->bit_idx = offset; 44 line->set_clr = (data->clear_offset ? true : false); 45 46 return line; 47 } 48 49 return data->reset_lines[id]; 50 } 51 52 static int stm32_reset_update(struct reset_controller_dev *rcdev, 53 unsigned long id, bool assert) 54 { 55 struct stm32_reset_data *data = to_stm32_reset_data(rcdev); 56 struct stm32_reset_cfg line_reset; 57 const struct stm32_reset_cfg *ptr_line; 58 59 ptr_line = stm32_get_reset_line(rcdev, id, &line_reset); 60 if (!ptr_line) 61 return -EPERM; 62 63 if (ptr_line->set_clr) { 64 void __iomem *addr; 65 66 addr = data->membase + ptr_line->offset; 67 if (!assert) 68 addr += data->clear_offset; 69 70 writel(BIT(ptr_line->bit_idx), addr); 71 72 } else { 73 unsigned long flags; 74 u32 reg; 75 76 spin_lock_irqsave(&data->lock, flags); 77 78 reg = readl(data->membase + ptr_line->offset); 79 80 if (assert) 81 reg |= BIT(ptr_line->bit_idx); 82 else 83 reg &= ~BIT(ptr_line->bit_idx); 84 85 writel(reg, data->membase + ptr_line->offset); 86 87 spin_unlock_irqrestore(&data->lock, flags); 88 } 89 90 return 0; 91 } 92 93 static int stm32_reset_assert(struct reset_controller_dev *rcdev, 94 unsigned long id) 95 { 96 return stm32_reset_update(rcdev, id, true); 97 } 98 99 static int stm32_reset_deassert(struct reset_controller_dev *rcdev, 100 unsigned long id) 101 { 102 return stm32_reset_update(rcdev, id, false); 103 } 104 105 static int stm32_reset_status(struct reset_controller_dev *rcdev, 106 unsigned long id) 107 { 108 struct stm32_reset_data *data = to_stm32_reset_data(rcdev); 109 struct stm32_reset_cfg line_reset; 110 const struct stm32_reset_cfg *ptr_line; 111 u32 reg; 112 113 ptr_line = stm32_get_reset_line(rcdev, id, &line_reset); 114 if (!ptr_line) 115 return -EPERM; 116 117 reg = readl(data->membase + ptr_line->offset); 118 119 return !!(reg & BIT(ptr_line->bit_idx)); 120 } 121 122 static const struct reset_control_ops stm32_reset_ops = { 123 .assert = stm32_reset_assert, 124 .deassert = stm32_reset_deassert, 125 .status = stm32_reset_status, 126 }; 127 128 int stm32_rcc_reset_init(struct device *dev, struct clk_stm32_reset_data *data, 129 void __iomem *base) 130 { 131 struct stm32_reset_data *reset_data; 132 133 reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL); 134 if (!reset_data) 135 return -ENOMEM; 136 137 spin_lock_init(&reset_data->lock); 138 139 reset_data->membase = base; 140 reset_data->rcdev.owner = THIS_MODULE; 141 reset_data->rcdev.ops = &stm32_reset_ops; 142 reset_data->rcdev.of_node = dev_of_node(dev); 143 reset_data->rcdev.nr_resets = data->nr_lines; 144 reset_data->reset_lines = data->reset_lines; 145 reset_data->clear_offset = data->clear_offset; 146 147 return reset_controller_register(&reset_data->rcdev); 148 } 149