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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) STMicroelectronics 2022 - All Rights Reserved4 * 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 16struct 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 25static inline struct stm32_reset_data *26to_stm32_reset_data(struct reset_controller_dev *rcdev)27{28 return container_of(rcdev, struct stm32_reset_data, rcdev);29}30 31static 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 52static 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 else83 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 93static int stm32_reset_assert(struct reset_controller_dev *rcdev,94 unsigned long id)95{96 return stm32_reset_update(rcdev, id, true);97}98 99static int stm32_reset_deassert(struct reset_controller_dev *rcdev,100 unsigned long id)101{102 return stm32_reset_update(rcdev, id, false);103}104 105static 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 122static 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 128int 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