1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Reset driver for Axxia devices |
4 | * |
5 | * Copyright (C) 2014 LSI |
6 | */ |
7 | #include <linux/init.h> |
8 | #include <linux/err.h> |
9 | #include <linux/io.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/mfd/syscon.h> |
12 | #include <linux/module.h> |
13 | #include <linux/notifier.h> |
14 | #include <linux/of.h> |
15 | #include <linux/platform_device.h> |
16 | #include <linux/reboot.h> |
17 | #include <linux/regmap.h> |
18 | |
19 | #define SC_CRIT_WRITE_KEY 0x1000 |
20 | #define SC_LATCH_ON_RESET 0x1004 |
21 | #define SC_RESET_CONTROL 0x1008 |
22 | #define RSTCTL_RST_ZERO (1<<3) |
23 | #define RSTCTL_RST_FAB (1<<2) |
24 | #define RSTCTL_RST_CHIP (1<<1) |
25 | #define RSTCTL_RST_SYS (1<<0) |
26 | #define SC_EFUSE_INT_STATUS 0x180c |
27 | #define EFUSE_READ_DONE (1<<31) |
28 | |
29 | static struct regmap *syscon; |
30 | |
31 | static int axxia_restart_handler(struct notifier_block *this, |
32 | unsigned long mode, void *cmd) |
33 | { |
34 | /* Access Key (0xab) */ |
35 | regmap_write(map: syscon, SC_CRIT_WRITE_KEY, val: 0xab); |
36 | /* Select internal boot from 0xffff0000 */ |
37 | regmap_write(map: syscon, SC_LATCH_ON_RESET, val: 0x00000040); |
38 | /* Assert ResetReadDone (to avoid hanging in boot ROM) */ |
39 | regmap_write(map: syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE); |
40 | /* Assert chip reset */ |
41 | regmap_update_bits(map: syscon, SC_RESET_CONTROL, |
42 | RSTCTL_RST_CHIP, RSTCTL_RST_CHIP); |
43 | |
44 | return NOTIFY_DONE; |
45 | } |
46 | |
47 | static struct notifier_block axxia_restart_nb = { |
48 | .notifier_call = axxia_restart_handler, |
49 | .priority = 128, |
50 | }; |
51 | |
52 | static int axxia_reset_probe(struct platform_device *pdev) |
53 | { |
54 | struct device *dev = &pdev->dev; |
55 | int err; |
56 | |
57 | syscon = syscon_regmap_lookup_by_phandle(np: dev->of_node, property: "syscon" ); |
58 | if (IS_ERR(ptr: syscon)) { |
59 | pr_err("%pOFn: syscon lookup failed\n" , dev->of_node); |
60 | return PTR_ERR(ptr: syscon); |
61 | } |
62 | |
63 | err = register_restart_handler(&axxia_restart_nb); |
64 | if (err) |
65 | dev_err(dev, "cannot register restart handler (err=%d)\n" , err); |
66 | |
67 | return err; |
68 | } |
69 | |
70 | static const struct of_device_id of_axxia_reset_match[] = { |
71 | { .compatible = "lsi,axm55xx-reset" , }, |
72 | {}, |
73 | }; |
74 | MODULE_DEVICE_TABLE(of, of_axxia_reset_match); |
75 | |
76 | static 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 | builtin_platform_driver(axxia_reset_driver); |
84 | |