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authorBen Dooks <ben-linux@fluff.org>2008-04-16 00:15:20 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2008-04-17 17:04:41 +0100
commit3c7d9c81e1302c244180e62999a08ca95b175cf5 (patch)
treea67961f6c0435e0a1965df9770433c73cdfe1664
parentd96a980441a70168a8ead0a0f23c4c63725da5fa (diff)
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[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 <ben-linux@fluff.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/plat-s3c24xx/cpu.c27
-rw-r--r--include/asm-arm/arch-s3c2410/system-reset.h64
-rw-r--r--include/asm-arm/arch-s3c2410/system.h46
3 files changed, 92 insertions, 45 deletions
diff --git a/arch/arm/plat-s3c24xx/cpu.c b/arch/arm/plat-s3c24xx/cpu.c
index f513ab0..f5699ca 100644
--- a/arch/arm/plat-s3c24xx/cpu.c
+++ b/arch/arm/plat-s3c24xx/cpu.c
@@ -28,15 +28,19 @@
#include <linux/ioport.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h>
+#include <linux/delay.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/delay.h>
+#include <asm/cacheflush.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
+#include <asm/arch/system-reset.h>
+
#include <asm/arch/regs-gpio.h>
#include <asm/plat-s3c/regs-serial.h>
@@ -203,6 +207,27 @@ static unsigned long s3c24xx_read_idcode_v4(void)
#endif
}
+/* Hook for arm_pm_restart to ensure we execute the reset code
+ * with the caches enabled. It seems at least the S3C2440 has a problem
+ * resetting if there is bus activity interrupted by the reset.
+ */
+static void s3c24xx_pm_restart(char mode)
+{
+ if (mode != 's') {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __cpuc_flush_kern_all();
+ __cpuc_flush_user_all();
+
+ arch_reset(mode);
+ local_irq_restore(flags);
+ }
+
+ /* fallback, or unhandled */
+ arm_machine_restart(mode);
+}
+
void __init s3c24xx_init_io(struct map_desc *mach_desc, int size)
{
unsigned long idcode = 0x0;
@@ -230,6 +255,8 @@ void __init s3c24xx_init_io(struct map_desc *mach_desc, int size)
panic("Unsupported S3C24XX CPU");
}
+ arm_pm_restart = s3c24xx_pm_restart;
+
(cpu->map_io)(mach_desc, size);
}
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 0000000..1615bce
--- /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 <ben@simtec.co.uk>
+ *
+ * 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 <asm/hardware.h>
+#include <asm/io.h>
+
+#include <asm/plat-s3c/regs-watchdog.h>
+#include <asm/arch/regs-clock.h>
+
+#include <linux/clk.h>
+#include <linux/err.h>
+
+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);
+}
diff --git a/include/asm-arm/arch-s3c2410/system.h b/include/asm-arm/arch-s3c2410/system.h
index 14de4e5..ad25808 100644
--- a/include/asm-arm/arch-s3c2410/system.h
+++ b/include/asm-arm/arch-s3c2410/system.h
@@ -17,12 +17,8 @@
#include <asm/arch/idle.h>
#include <asm/arch/reset.h>
-#include <asm/plat-s3c/regs-watchdog.h>
#include <asm/arch/regs-clock.h>
-#include <linux/clk.h>
-#include <linux/err.h>
-
void (*s3c24xx_idle)(void);
void (*s3c24xx_reset_hook)(void);
@@ -59,44 +55,4 @@ static void arch_idle(void)
s3c24xx_default_idle();
}
-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);
-}
+#include <asm/arch/system-reset.h>