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kernel/linux-imx6_3.14.28/arch/arm/plat-samsung/watchdog-reset.c 2.28 KB
6b13f685e   김민수   BSP 최초 추가
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  /* arch/arm/plat-samsung/watchdog-reset.c
   *
   * Copyright (c) 2008 Simtec Electronics
   *	Ben Dooks <ben@simtec.co.uk>
   *
   * Coyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
   *
   * Watchdog reset support for Samsung SoCs.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
  */
  
  #include <linux/clk.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/delay.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  
  #define S3C2410_WTCON			0x00
  #define S3C2410_WTDAT			0x04
  #define S3C2410_WTCNT			0x08
  
  #define S3C2410_WTCON_ENABLE		(1 << 5)
  #define S3C2410_WTCON_DIV16		(0 << 3)
  #define S3C2410_WTCON_RSTEN		(1 << 0)
  #define S3C2410_WTCON_PRESCALE(x)	((x) << 8)
  
  static void __iomem *wdt_base;
  static struct clk *wdt_clock;
  
  void samsung_wdt_reset(void)
  {
  	if (!wdt_base) {
  		pr_err("%s: wdt reset not initialized
  ", __func__);
  		/* delay to allow the serial port to show the message */
  		mdelay(50);
  		return;
  	}
  
  	if (!IS_ERR(wdt_clock))
  		clk_prepare_enable(wdt_clock);
  
  	/* disable watchdog, to be safe  */
  	__raw_writel(0, wdt_base + S3C2410_WTCON);
  
  	/* put initial values into count and data */
  	__raw_writel(0x80, wdt_base + S3C2410_WTCNT);
  	__raw_writel(0x80, wdt_base + S3C2410_WTDAT);
  
  	/* set the watchdog to go and reset... */
  	__raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
  			S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
  			wdt_base + S3C2410_WTCON);
  
  	/* wait for reset to assert... */
  	mdelay(500);
  
  	pr_err("Watchdog reset failed to assert reset
  ");
  
  	/* delay to allow the serial port to show the message */
  	mdelay(50);
  }
  
  #ifdef CONFIG_OF
  static const struct of_device_id s3c2410_wdt_match[] = {
  	{ .compatible = "samsung,s3c2410-wdt" },
  	{},
  };
  
  void __init samsung_wdt_reset_of_init(void)
  {
  	struct device_node *np;
  
  	np = of_find_matching_node(NULL, s3c2410_wdt_match);
  	if (!np) {
  		pr_err("%s: failed to find watchdog node
  ", __func__);
  		return;
  	}
  
  	wdt_base = of_iomap(np, 0);
  	if (!wdt_base) {
  		pr_err("%s: failed to map watchdog registers
  ", __func__);
  		return;
  	}
  
  	wdt_clock = of_clk_get(np, 0);
  }
  #endif
  
  void __init samsung_wdt_reset_init(void __iomem *base)
  {
  	wdt_base = base;
  	wdt_clock = clk_get(NULL, "watchdog");
  }