LXR linux/arch/arm/plat-samsung/watchdog-reset.c

   1// SPDX-License-Identifier: GPL-2.0
   2//
   3// Copyright (c) 2008 Simtec Electronics
   4//      Ben Dooks <ben@simtec.co.uk>
   5//
   6// Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
   7//
   8// Watchdog reset support for Samsung SoCs.
   9
  10#include <linux/clk.h>
  11#include <linux/err.h>
  12#include <linux/io.h>
  13#include <linux/delay.h>
  14#include <linux/of.h>
  15#include <linux/of_address.h>
  16
  17#define S3C2410_WTCON                   0x00
  18#define S3C2410_WTDAT                   0x04
  19#define S3C2410_WTCNT                   0x08
  20
  21#define S3C2410_WTCON_ENABLE            (1 << 5)
  22#define S3C2410_WTCON_DIV16             (0 << 3)
  23#define S3C2410_WTCON_RSTEN             (1 << 0)
  24#define S3C2410_WTCON_PRESCALE(x)       ((x) << 8)
  25
  26static void __iomem *wdt_base;
  27static struct clk *wdt_clock;
  28
  29void samsung_wdt_reset(void)
  30{
  31        if (!wdt_base) {
  32                pr_err("%s: wdt reset not initialized\n", __func__);
  33                /* delay to allow the serial port to show the message */
  34                mdelay(50);
  35                return;
  36        }
  37
  38        if (!IS_ERR(wdt_clock))
  39                clk_prepare_enable(wdt_clock);
  40
  41        /* disable watchdog, to be safe  */
  42        __raw_writel(0, wdt_base + S3C2410_WTCON);
  43
  44        /* put initial values into count and data */
  45        __raw_writel(0x80, wdt_base + S3C2410_WTCNT);
  46        __raw_writel(0x80, wdt_base + S3C2410_WTDAT);
  47
  48        /* set the watchdog to go and reset... */
  49        __raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
  50                        S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
  51                        wdt_base + S3C2410_WTCON);
  52
  53        /* wait for reset to assert... */
  54        mdelay(500);
  55
  56        pr_err("Watchdog reset failed to assert reset\n");
  57
  58        /* delay to allow the serial port to show the message */
  59        mdelay(50);
  60}
  61
  62#ifdef CONFIG_OF
  63static const struct of_device_id s3c2410_wdt_match[] = {
  64        { .compatible = "samsung,s3c2410-wdt" },
  65        { .compatible = "samsung,s3c6410-wdt" },
  66        {},
  67};
  68
  69void __init samsung_wdt_reset_of_init(void)
  70{
  71        struct device_node *np;
  72
  73        np = of_find_matching_node(NULL, s3c2410_wdt_match);
  74        if (!np) {
  75                pr_err("%s: failed to find watchdog node\n", __func__);
  76                return;
  77        }
  78
  79        wdt_base = of_iomap(np, 0);
  80        if (!wdt_base) {
  81                pr_err("%s: failed to map watchdog registers\n", __func__);
  82                return;
  83        }
  84
  85        wdt_clock = of_clk_get(np, 0);
  86}
  87#endif
  88
  89void __init samsung_wdt_reset_init(void __iomem *base)
  90{
  91        wdt_base = base;
  92        wdt_clock = clk_get(NULL, "watchdog");
  93}
  94