1// SPDX-License-Identifier: GPL-2.0-only
2// Copyright (C) 2016 Broadcom
3
4#include <linux/io.h>
5#include <linux/mod_devicetable.h>
6#include <linux/platform_device.h>
7#include <linux/reboot.h>
8
9#define RSTMGR_REG_WR_ACCESS_OFFSET	0
10#define RSTMGR_REG_CHIP_SOFT_RST_OFFSET	4
11
12#define RSTMGR_WR_PASSWORD		0xa5a5
13#define RSTMGR_WR_PASSWORD_SHIFT	8
14#define RSTMGR_WR_ACCESS_ENABLE		1
15
16static void __iomem *kona_reset_base;
17
18static int kona_reset_handler(struct notifier_block *this,
19				unsigned long mode, void *cmd)
20{
21	/*
22	 * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
23	 * register. To write to that register we must first write the password
24	 * and the enable bit in the write access enable register.
25	 */
26	writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
27		RSTMGR_WR_ACCESS_ENABLE,
28		kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
29	writel(0, kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);
30
31	return NOTIFY_DONE;
32}
33
34static struct notifier_block kona_reset_nb = {
35	.notifier_call = kona_reset_handler,
36	.priority = 128,
37};
38
39static int kona_reset_probe(struct platform_device *pdev)
40{
41	kona_reset_base = devm_platform_ioremap_resource(pdev, 0);
42	if (IS_ERR(kona_reset_base))
43		return PTR_ERR(kona_reset_base);
44
45	return register_restart_handler(&kona_reset_nb);
46}
47
48static const struct of_device_id of_match[] = {
49	{ .compatible = "brcm,bcm21664-resetmgr" },
50	{},
51};
52
53static struct platform_driver bcm_kona_reset_driver = {
54	.probe = kona_reset_probe,
55	.driver = {
56		.name = "brcm-kona-reset",
57		.of_match_table = of_match,
58	},
59};
60
61builtin_platform_driver(bcm_kona_reset_driver);
62