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 | |
16 | static void __iomem *kona_reset_base; |
17 | |
18 | static 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(val: (RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) | |
27 | RSTMGR_WR_ACCESS_ENABLE, |
28 | addr: kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET); |
29 | writel(val: 0, addr: kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET); |
30 | |
31 | return NOTIFY_DONE; |
32 | } |
33 | |
34 | static struct notifier_block kona_reset_nb = { |
35 | .notifier_call = kona_reset_handler, |
36 | .priority = 128, |
37 | }; |
38 | |
39 | static int kona_reset_probe(struct platform_device *pdev) |
40 | { |
41 | kona_reset_base = devm_platform_ioremap_resource(pdev, index: 0); |
42 | if (IS_ERR(ptr: kona_reset_base)) |
43 | return PTR_ERR(ptr: kona_reset_base); |
44 | |
45 | return register_restart_handler(&kona_reset_nb); |
46 | } |
47 | |
48 | static const struct of_device_id of_match[] = { |
49 | { .compatible = "brcm,bcm21664-resetmgr" }, |
50 | {}, |
51 | }; |
52 | |
53 | static 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 | |
61 | builtin_platform_driver(bcm_kona_reset_driver); |
62 | |