1/*
2 * Reset driver for Axxia devices
3 *
4 * Copyright (C) 2014 LSI
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 */
16#include <linux/init.h>
17#include <linux/err.h>
18#include <linux/io.h>
19#include <linux/kernel.h>
20#include <linux/mfd/syscon.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/platform_device.h>
24#include <linux/reboot.h>
25#include <linux/regmap.h>
26
27#include <asm/system_misc.h>
28
29
30#define SC_CRIT_WRITE_KEY	0x1000
31#define SC_LATCH_ON_RESET	0x1004
32#define SC_RESET_CONTROL	0x1008
33#define   RSTCTL_RST_ZERO	(1<<3)
34#define   RSTCTL_RST_FAB	(1<<2)
35#define   RSTCTL_RST_CHIP	(1<<1)
36#define   RSTCTL_RST_SYS	(1<<0)
37#define SC_EFUSE_INT_STATUS	0x180c
38#define   EFUSE_READ_DONE	(1<<31)
39
40static struct regmap *syscon;
41
42static void do_axxia_restart(enum reboot_mode reboot_mode, const char *cmd)
43{
44	/* Access Key (0xab) */
45	regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
46	/* Select internal boot from 0xffff0000 */
47	regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
48	/* Assert ResetReadDone (to avoid hanging in boot ROM) */
49	regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
50	/* Assert chip reset */
51	regmap_update_bits(syscon, SC_RESET_CONTROL,
52			   RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
53}
54
55static int axxia_reset_probe(struct platform_device *pdev)
56{
57	struct device *dev = &pdev->dev;
58
59	syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
60	if (IS_ERR(syscon)) {
61		pr_err("%s: syscon lookup failed\n", dev->of_node->name);
62		return PTR_ERR(syscon);
63	}
64
65	arm_pm_restart = do_axxia_restart;
66
67	return 0;
68}
69
70static const struct of_device_id of_axxia_reset_match[] = {
71	{ .compatible = "lsi,axm55xx-reset", },
72	{},
73};
74MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
75
76static struct platform_driver axxia_reset_driver = {
77	.probe = axxia_reset_probe,
78	.driver = {
79		.name = "axxia-reset",
80		.of_match_table = of_match_ptr(of_axxia_reset_match),
81	},
82};
83
84static int __init axxia_reset_init(void)
85{
86	return platform_driver_register(&axxia_reset_driver);
87}
88device_initcall(axxia_reset_init);
89