// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Reset driver for Axxia devices
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*
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* Copyright (C) 2014 LSI
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*/
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/reboot.h>
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#include <linux/regmap.h>
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#define SC_CRIT_WRITE_KEY 0x1000
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#define SC_LATCH_ON_RESET 0x1004
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#define SC_RESET_CONTROL 0x1008
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#define RSTCTL_RST_ZERO (1<<3)
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#define RSTCTL_RST_FAB (1<<2)
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#define RSTCTL_RST_CHIP (1<<1)
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#define RSTCTL_RST_SYS (1<<0)
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#define SC_EFUSE_INT_STATUS 0x180c
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#define EFUSE_READ_DONE (1<<31)
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static struct regmap *syscon;
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static int axxia_restart_handler(struct notifier_block *this,
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unsigned long mode, void *cmd)
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{
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/* Access Key (0xab) */
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regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
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/* Select internal boot from 0xffff0000 */
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regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
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/* Assert ResetReadDone (to avoid hanging in boot ROM) */
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regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
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/* Assert chip reset */
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regmap_update_bits(syscon, SC_RESET_CONTROL,
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RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
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return NOTIFY_DONE;
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}
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static struct notifier_block axxia_restart_nb = {
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.notifier_call = axxia_restart_handler,
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.priority = 128,
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};
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static int axxia_reset_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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int err;
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syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
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if (IS_ERR(syscon)) {
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pr_err("%pOFn: syscon lookup failed\n", dev->of_node);
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return PTR_ERR(syscon);
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}
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err = register_restart_handler(&axxia_restart_nb);
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if (err)
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dev_err(dev, "cannot register restart handler (err=%d)\n", err);
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return err;
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}
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static const struct of_device_id of_axxia_reset_match[] = {
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{ .compatible = "lsi,axm55xx-reset", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
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static struct platform_driver axxia_reset_driver = {
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.probe = axxia_reset_probe,
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.driver = {
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.name = "axxia-reset",
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.of_match_table = of_match_ptr(of_axxia_reset_match),
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},
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};
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static int __init axxia_reset_init(void)
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{
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return platform_driver_register(&axxia_reset_driver);
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}
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device_initcall(axxia_reset_init);
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