From 3c7d9c81e1302c244180e62999a08ca95b175cf5 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Wed, 16 Apr 2008 00:15:20 +0100 Subject: [ARM] 4987/1: S3C24XX: Ensure watchdog reset initiated from cached code. There seems to be some problem with at-least the S3C2440 and bus traffic during an reset. It is unlikely, but still possible that the system will hang in such a way that the watchdog cannot get the system out of the state it is in. Change to making the code that calls the watchdog reset run from cached memory so that instruction fetches have quiesced before the watchdog fires. Signed-off-by: Ben Dooks Signed-off-by: Russell King --- include/asm-arm/arch-s3c2410/system-reset.h | 64 +++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 include/asm-arm/arch-s3c2410/system-reset.h (limited to 'include/asm-arm/arch-s3c2410/system-reset.h') diff --git a/include/asm-arm/arch-s3c2410/system-reset.h b/include/asm-arm/arch-s3c2410/system-reset.h new file mode 100644 index 000000000000..1615bce0c026 --- /dev/null +++ b/include/asm-arm/arch-s3c2410/system-reset.h @@ -0,0 +1,64 @@ +/* linux/include/asm-arm/arch-s3c2410/system-reset.h + * + * Copyright (c) 2008 Simtec Electronics + * Ben Dooks + * + * S3C2410 - System define for arch_reset() function + * + * 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 +#include + +#include +#include + +#include +#include + +extern void (*s3c24xx_reset_hook)(void); + +static void +arch_reset(char mode) +{ + struct clk *wdtclk; + + if (mode == 's') { + cpu_reset(0); + } + + if (s3c24xx_reset_hook) + s3c24xx_reset_hook(); + + printk("arch_reset: attempting watchdog reset\n"); + + __raw_writel(0, S3C2410_WTCON); /* disable watchdog, to be safe */ + + wdtclk = clk_get(NULL, "watchdog"); + if (!IS_ERR(wdtclk)) { + clk_enable(wdtclk); + } else + printk(KERN_WARNING "%s: warning: cannot get watchdog clock\n", __func__); + + /* put initial values into count and data */ + __raw_writel(0x80, S3C2410_WTCNT); + __raw_writel(0x80, S3C2410_WTDAT); + + /* set the watchdog to go and reset... */ + __raw_writel(S3C2410_WTCON_ENABLE|S3C2410_WTCON_DIV16|S3C2410_WTCON_RSTEN | + S3C2410_WTCON_PRESCALE(0x20), S3C2410_WTCON); + + /* wait for reset to assert... */ + mdelay(500); + + printk(KERN_ERR "Watchdog reset failed to assert reset\n"); + + /* delay to allow the serial port to show the message */ + mdelay(50); + + /* we'll take a jump through zero as a poor second */ + cpu_reset(0); +} -- cgit v1.2.3-59-g8ed1b