arch/arm/mach-imx/system.c

   1 /*
   2  * Copyright (C) 1999 ARM Limited
   3  * Copyright (C) 2000 Deep Blue Solutions Ltd
   4  * Copyright 2006-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   5  * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   6  * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/clk.h>
  21 #include <linux/io.h>
  22 #include <linux/err.h>
  23 #include <linux/delay.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26
  27 #include <asm/system_misc.h>
  28 #include <asm/proc-fns.h>
  29 #include <asm/mach-types.h>
  30
  31 #include "common.h"
  32 #include "hardware.h"
  33
  34 static void __iomem *wdog_base;
  35 static struct clk *wdog_clk;
  36
  37 /*
  38  * Reset the system. It is called by machine_restart().
  39  */
  40 void mxc_restart(enum reboot_mode mode, const char *cmd)
  41 {
  42         unsigned int wcr_enable;
  43
  44         if (wdog_clk)
  45                 clk_enable(wdog_clk);
  46
  47         if (cpu_is_mx1())
  48                 wcr_enable = (1 << 0);
  49         else
  50                 wcr_enable = (1 << 2);
  51
  52         /* Assert SRS signal */
  53         __raw_writew(wcr_enable, wdog_base);
  54
  55         /* wait for reset to assert... */
  56         mdelay(500);
  57
  58         pr_err("%s: Watchdog reset failed to assert reset\n", __func__);
  59
  60         /* delay to allow the serial port to show the message */
  61         mdelay(50);
  62
  63         /* we'll take a jump through zero as a poor second */
  64         soft_restart(0);
  65 }
  66
  67 void __init mxc_arch_reset_init(void __iomem *base)
  68 {
  69         wdog_base = base;
  70
  71         wdog_clk = clk_get_sys("imx2-wdt.0", NULL);
  72         if (IS_ERR(wdog_clk)) {
  73                 pr_warn("%s: failed to get wdog clock\n", __func__);
  74                 wdog_clk = NULL;
  75                 return;
  76         }
  77
  78         clk_prepare(wdog_clk);
  79 }
  80
  81 void __init mxc_arch_reset_init_dt(void)
  82 {
  83         struct device_node *np;
  84
  85         np = of_find_compatible_node(NULL, NULL, "fsl,imx21-wdt");
  86         wdog_base = of_iomap(np, 0);
  87         WARN_ON(!wdog_base);
  88
  89         wdog_clk = of_clk_get(np, 0);
  90         if (IS_ERR(wdog_clk)) {
  91                 pr_warn("%s: failed to get wdog clock\n", __func__);
  92                 wdog_clk = NULL;
  93                 return;
  94         }
  95
  96         clk_prepare(wdog_clk);
  97 }