/* * 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("%pOFn: syscon lookup failed\n", dev->of_node); 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);