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(val: (RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
26 RSTMGR_WR_ACCESS_ENABLE,
27 addr: kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
28 writel(val: 0, addr: 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, index: 0);
36 if (IS_ERR(ptr: kona_reset_base))
37 return PTR_ERR(ptr: kona_reset_base);
38
39 return devm_register_sys_off_handler(dev: &pdev->dev, mode: SYS_OFF_MODE_RESTART,
40 priority: 128, callback: 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

source code of linux/drivers/power/reset/brcm-kona-reset.c