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 sys_off_data *data)
19{
20	/*
21	 * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
22	 * register. To write to that register we must first write the password
23	 * and the enable bit in the write access enable register.
24	 */
25	writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
26		RSTMGR_WR_ACCESS_ENABLE,
27		kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
28	writel(0, kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);
29
30	return NOTIFY_DONE;
31}
32
33static int kona_reset_probe(struct platform_device *pdev)
34{
35	kona_reset_base = devm_platform_ioremap_resource(pdev, 0);
36	if (IS_ERR(kona_reset_base))
37		return PTR_ERR(kona_reset_base);
38
39	return devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART,
40					     128, kona_reset_handler, NULL);
41}
42
43static const struct of_device_id of_match[] = {
44	{ .compatible = "brcm,bcm21664-resetmgr" },
45	{},
46};
47
48static struct platform_driver bcm_kona_reset_driver = {
49	.probe = kona_reset_probe,
50	.driver = {
51		.name = "brcm-kona-reset",
52		.of_match_table = of_match,
53	},
54};
55
56builtin_platform_driver(bcm_kona_reset_driver);
57