include/asm-arm/arch-s3c2410/system.h

   1 /* linux/include/asm-arm/arch-s3c2410/system.h
   2  *
   3  * Copyright (c) 2003 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 - System function defines and includes
   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 version 2 as
  10  * published by the Free Software Foundation.
  11 */
  12
  13 #include <asm/hardware.h>
  14 #include <asm/io.h>
  15
  16 #include <asm/arch/map.h>
  17 #include <asm/arch/idle.h>
  18 #include <asm/arch/reset.h>
  19
  20 #include <asm/plat-s3c/regs-watchdog.h>
  21 #include <asm/arch/regs-clock.h>
  22
  23 #include <linux/clk.h>
  24 #include <linux/err.h>
  25
  26 void (*s3c24xx_idle)(void);
  27 void (*s3c24xx_reset_hook)(void);
  28
  29 void s3c24xx_default_idle(void)
  30 {
  31         unsigned long tmp;
  32         int i;
  33
  34         /* idle the system by using the idle mode which will wait for an
  35          * interrupt to happen before restarting the system.
  36          */
  37
  38         /* Warning: going into idle state upsets jtag scanning */
  39
  40         __raw_writel(__raw_readl(S3C2410_CLKCON) | S3C2410_CLKCON_IDLE,
  41                      S3C2410_CLKCON);
  42
  43         /* the samsung port seems to do a loop and then unset idle.. */
  44         for (i = 0; i < 50; i++) {
  45                 tmp += __raw_readl(S3C2410_CLKCON); /* ensure loop not optimised out */
  46         }
  47
  48         /* this bit is not cleared on re-start... */
  49
  50         __raw_writel(__raw_readl(S3C2410_CLKCON) & ~S3C2410_CLKCON_IDLE,
  51                      S3C2410_CLKCON);
  52 }
  53
  54 static void arch_idle(void)
  55 {
  56         if (s3c24xx_idle != NULL)
  57                 (s3c24xx_idle)();
  58         else
  59                 s3c24xx_default_idle();
  60 }
  61
  62 static void
  63 arch_reset(char mode)
  64 {
  65         struct clk *wdtclk;
  66
  67         if (mode == 's') {
  68                 cpu_reset(0);
  69         }
  70
  71         if (s3c24xx_reset_hook)
  72                 s3c24xx_reset_hook();
  73
  74         printk("arch_reset: attempting watchdog reset\n");
  75
  76         __raw_writel(0, S3C2410_WTCON);   /* disable watchdog, to be safe  */
  77
  78         wdtclk = clk_get(NULL, "watchdog");
  79         if (!IS_ERR(wdtclk)) {
  80                 clk_enable(wdtclk);
  81         } else
  82                 printk(KERN_WARNING "%s: warning: cannot get watchdog clock\n", __func__);
  83
  84         /* put initial values into count and data */
  85         __raw_writel(0x80, S3C2410_WTCNT);
  86         __raw_writel(0x80, S3C2410_WTDAT);
  87
  88         /* set the watchdog to go and reset... */
  89         __raw_writel(S3C2410_WTCON_ENABLE|S3C2410_WTCON_DIV16|S3C2410_WTCON_RSTEN |
  90                      S3C2410_WTCON_PRESCALE(0x20), S3C2410_WTCON);
  91
  92         /* wait for reset to assert... */
  93         mdelay(500);
  94
  95         printk(KERN_ERR "Watchdog reset failed to assert reset\n");
  96
  97         /* delay to allow the serial port to show the message */
  98         mdelay(50);
  99
 100         /* we'll take a jump through zero as a poor second */
 101         cpu_reset(0);
 102 }