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204 lines
5.5 KiB
204 lines
5.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Simple Reset Controller Driver |
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* |
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* Copyright (C) 2017 Pengutronix, Philipp Zabel <[email protected]> |
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* |
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* Based on Allwinner SoCs Reset Controller driver |
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* |
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* Copyright 2013 Maxime Ripard |
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* |
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* Maxime Ripard <[email protected]> |
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*/ |
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#include <linux/delay.h> |
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#include <linux/device.h> |
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#include <linux/err.h> |
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#include <linux/io.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/reset-controller.h> |
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#include <linux/reset/reset-simple.h> |
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#include <linux/spinlock.h> |
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static inline struct reset_simple_data * |
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to_reset_simple_data(struct reset_controller_dev *rcdev) |
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{ |
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return container_of(rcdev, struct reset_simple_data, rcdev); |
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} |
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static int reset_simple_update(struct reset_controller_dev *rcdev, |
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unsigned long id, bool assert) |
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{ |
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struct reset_simple_data *data = to_reset_simple_data(rcdev); |
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int reg_width = sizeof(u32); |
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int bank = id / (reg_width * BITS_PER_BYTE); |
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int offset = id % (reg_width * BITS_PER_BYTE); |
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unsigned long flags; |
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u32 reg; |
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spin_lock_irqsave(&data->lock, flags); |
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reg = readl(data->membase + (bank * reg_width)); |
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if (assert ^ data->active_low) |
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reg |= BIT(offset); |
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else |
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reg &= ~BIT(offset); |
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writel(reg, data->membase + (bank * reg_width)); |
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spin_unlock_irqrestore(&data->lock, flags); |
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return 0; |
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} |
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static int reset_simple_assert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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return reset_simple_update(rcdev, id, true); |
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} |
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static int reset_simple_deassert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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return reset_simple_update(rcdev, id, false); |
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} |
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static int reset_simple_reset(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct reset_simple_data *data = to_reset_simple_data(rcdev); |
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int ret; |
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if (!data->reset_us) |
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return -ENOTSUPP; |
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ret = reset_simple_assert(rcdev, id); |
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if (ret) |
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return ret; |
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usleep_range(data->reset_us, data->reset_us * 2); |
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return reset_simple_deassert(rcdev, id); |
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} |
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static int reset_simple_status(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct reset_simple_data *data = to_reset_simple_data(rcdev); |
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int reg_width = sizeof(u32); |
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int bank = id / (reg_width * BITS_PER_BYTE); |
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int offset = id % (reg_width * BITS_PER_BYTE); |
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u32 reg; |
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reg = readl(data->membase + (bank * reg_width)); |
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return !(reg & BIT(offset)) ^ !data->status_active_low; |
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} |
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const struct reset_control_ops reset_simple_ops = { |
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.assert = reset_simple_assert, |
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.deassert = reset_simple_deassert, |
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.reset = reset_simple_reset, |
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.status = reset_simple_status, |
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}; |
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EXPORT_SYMBOL_GPL(reset_simple_ops); |
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/** |
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* struct reset_simple_devdata - simple reset controller properties |
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* @reg_offset: offset between base address and first reset register. |
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* @nr_resets: number of resets. If not set, default to resource size in bits. |
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* @active_low: if true, bits are cleared to assert the reset. Otherwise, bits |
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* are set to assert the reset. |
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* @status_active_low: if true, bits read back as cleared while the reset is |
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* asserted. Otherwise, bits read back as set while the |
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* reset is asserted. |
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*/ |
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struct reset_simple_devdata { |
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u32 reg_offset; |
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u32 nr_resets; |
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bool active_low; |
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bool status_active_low; |
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}; |
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#define SOCFPGA_NR_BANKS 8 |
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static const struct reset_simple_devdata reset_simple_socfpga = { |
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.reg_offset = 0x20, |
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.nr_resets = SOCFPGA_NR_BANKS * 32, |
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.status_active_low = true, |
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}; |
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static const struct reset_simple_devdata reset_simple_active_low = { |
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.active_low = true, |
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.status_active_low = true, |
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}; |
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static const struct of_device_id reset_simple_dt_ids[] = { |
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{ .compatible = "altr,stratix10-rst-mgr", |
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.data = &reset_simple_socfpga }, |
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{ .compatible = "st,stm32-rcc", }, |
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{ .compatible = "allwinner,sun6i-a31-clock-reset", |
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.data = &reset_simple_active_low }, |
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{ .compatible = "zte,zx296718-reset", |
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.data = &reset_simple_active_low }, |
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{ .compatible = "aspeed,ast2400-lpc-reset" }, |
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{ .compatible = "aspeed,ast2500-lpc-reset" }, |
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{ .compatible = "bitmain,bm1880-reset", |
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.data = &reset_simple_active_low }, |
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{ .compatible = "brcm,bcm4908-misc-pcie-reset", |
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.data = &reset_simple_active_low }, |
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{ .compatible = "snps,dw-high-reset" }, |
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{ .compatible = "snps,dw-low-reset", |
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.data = &reset_simple_active_low }, |
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{ /* sentinel */ }, |
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}; |
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static int reset_simple_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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const struct reset_simple_devdata *devdata; |
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struct reset_simple_data *data; |
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void __iomem *membase; |
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struct resource *res; |
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u32 reg_offset = 0; |
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devdata = of_device_get_match_data(dev); |
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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membase = devm_ioremap_resource(dev, res); |
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if (IS_ERR(membase)) |
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return PTR_ERR(membase); |
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spin_lock_init(&data->lock); |
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data->membase = membase; |
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data->rcdev.owner = THIS_MODULE; |
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data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE; |
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data->rcdev.ops = &reset_simple_ops; |
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data->rcdev.of_node = dev->of_node; |
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if (devdata) { |
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reg_offset = devdata->reg_offset; |
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if (devdata->nr_resets) |
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data->rcdev.nr_resets = devdata->nr_resets; |
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data->active_low = devdata->active_low; |
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data->status_active_low = devdata->status_active_low; |
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} |
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data->membase += reg_offset; |
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return devm_reset_controller_register(dev, &data->rcdev); |
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} |
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static struct platform_driver reset_simple_driver = { |
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.probe = reset_simple_probe, |
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.driver = { |
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.name = "simple-reset", |
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.of_match_table = reset_simple_dt_ids, |
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}, |
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}; |
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builtin_platform_driver(reset_simple_driver);
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