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1 | /* arch/arm/plat-samsung/watchdog-reset.c |
2 | * | |
3 | * Copyright (c) 2008 Simtec Electronics | |
4 | * Ben Dooks <ben@simtec.co.uk> | |
5 | * | |
6 | * Coyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com> | |
7 | * | |
8 | * Watchdog reset support for Samsung SoCs. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | #include <linux/clk.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/delay.h> | |
19 | #include <linux/of.h> | |
20 | #include <linux/of_address.h> | |
21 | ||
22 | #define S3C2410_WTCON 0x00 | |
23 | #define S3C2410_WTDAT 0x04 | |
24 | #define S3C2410_WTCNT 0x08 | |
25 | ||
26 | #define S3C2410_WTCON_ENABLE (1 << 5) | |
27 | #define S3C2410_WTCON_DIV16 (0 << 3) | |
28 | #define S3C2410_WTCON_RSTEN (1 << 0) | |
29 | #define S3C2410_WTCON_PRESCALE(x) ((x) << 8) | |
30 | ||
31 | static void __iomem *wdt_base; | |
32 | static struct clk *wdt_clock; | |
33 | ||
34 | void samsung_wdt_reset(void) | |
35 | { | |
36 | if (!wdt_base) { | |
37 | pr_err("%s: wdt reset not initialized\n", __func__); | |
38 | /* delay to allow the serial port to show the message */ | |
39 | mdelay(50); | |
40 | return; | |
41 | } | |
42 | ||
43 | if (!IS_ERR(wdt_clock)) | |
44 | clk_prepare_enable(wdt_clock); | |
45 | ||
46 | /* disable watchdog, to be safe */ | |
47 | __raw_writel(0, wdt_base + S3C2410_WTCON); | |
48 | ||
49 | /* put initial values into count and data */ | |
50 | __raw_writel(0x80, wdt_base + S3C2410_WTCNT); | |
51 | __raw_writel(0x80, wdt_base + S3C2410_WTDAT); | |
52 | ||
53 | /* set the watchdog to go and reset... */ | |
54 | __raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 | | |
55 | S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20), | |
56 | wdt_base + S3C2410_WTCON); | |
57 | ||
58 | /* wait for reset to assert... */ | |
59 | mdelay(500); | |
60 | ||
61 | pr_err("Watchdog reset failed to assert reset\n"); | |
62 | ||
63 | /* delay to allow the serial port to show the message */ | |
64 | mdelay(50); | |
65 | } | |
66 | ||
67 | #ifdef CONFIG_OF | |
68 | static const struct of_device_id s3c2410_wdt_match[] = { | |
69 | { .compatible = "samsung,s3c2410-wdt" }, | |
70 | {}, | |
71 | }; | |
72 | ||
73 | void __init samsung_wdt_reset_of_init(void) | |
74 | { | |
75 | struct device_node *np; | |
76 | ||
77 | np = of_find_matching_node(NULL, s3c2410_wdt_match); | |
78 | if (!np) { | |
79 | pr_err("%s: failed to find watchdog node\n", __func__); | |
80 | return; | |
81 | } | |
82 | ||
83 | wdt_base = of_iomap(np, 0); | |
84 | if (!wdt_base) { | |
85 | pr_err("%s: failed to map watchdog registers\n", __func__); | |
86 | return; | |
87 | } | |
88 | ||
89 | wdt_clock = of_clk_get(np, 0); | |
90 | } | |
91 | #endif | |
92 | ||
93 | void __init samsung_wdt_reset_init(void __iomem *base) | |
94 | { | |
95 | wdt_base = base; | |
96 | wdt_clock = clk_get(NULL, "watchdog"); | |
97 | } |