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/*
* Reset driver for Axxia devices
*
* Copyright (C) 2014 LSI
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/init.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#define SC_CRIT_WRITE_KEY 0x1000
#define SC_LATCH_ON_RESET 0x1004
#define SC_RESET_CONTROL 0x1008
#define RSTCTL_RST_ZERO (1<<3)
#define RSTCTL_RST_FAB (1<<2)
#define RSTCTL_RST_CHIP (1<<1)
#define RSTCTL_RST_SYS (1<<0)
#define SC_EFUSE_INT_STATUS 0x180c
#define EFUSE_READ_DONE (1<<31)
static struct regmap *syscon;
static int axxia_restart_handler(struct notifier_block *this,
unsigned long mode, void *cmd)
{
/* Access Key (0xab) */
regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
/* Select internal boot from 0xffff0000 */
regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
/* Assert ResetReadDone (to avoid hanging in boot ROM) */
regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
/* Assert chip reset */
regmap_update_bits(syscon, SC_RESET_CONTROL,
RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
return NOTIFY_DONE;
}
static struct notifier_block axxia_restart_nb = {
.notifier_call = axxia_restart_handler,
.priority = 128,
};
static int axxia_reset_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
int err;
syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
if (IS_ERR(syscon)) {
pr_err("%s: syscon lookup failed\n", dev->of_node->name);
return PTR_ERR(syscon);
}
err = register_restart_handler(&axxia_restart_nb);
if (err)
dev_err(dev, "cannot register restart handler (err=%d)\n", err);
return err;
}
static const struct of_device_id of_axxia_reset_match[] = {
{ .compatible = "lsi,axm55xx-reset", },
{},
};
MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
static struct platform_driver axxia_reset_driver = {
.probe = axxia_reset_probe,
.driver = {
.name = "axxia-reset",
.of_match_table = of_match_ptr(of_axxia_reset_match),
},
};
static int __init axxia_reset_init(void)
{
return platform_driver_register(&axxia_reset_driver);
}
device_initcall(axxia_reset_init);
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