| Tomasz Figa | a4658e5 | 2013-06-17 23:45:33 +0900 | [diff] [blame] | 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 | } |