introduce-panic-blink-led-not-using-userspace-omfg.patch

A panic is silent on GTA02, it would be good if we got a little hint
if we are crashing (eg, in suspend / resume) from a panic instead of
a deadlock, etc.  On a normal PC i8042 blinks the keyboard lights if
we panic, this patch causes AUX to flash at 5Hz in event of a panic.

Tested by giving kernel fake root= that didn't exist.

Signed-off-by: Andy Green <andy@openmoko.com>

diff --git a/arch/arm/mach-s3c2440/mach-gta02.c b/arch/arm/mach-s3c2440/mach-gta02.c
index fd746fd..c32bb2a 100644 (file)
--- a/arch/arm/mach-s3c2440/mach-gta02.c
+++ b/arch/arm/mach-s3c2440/mach-gta02.c
@@ -328,6 +328,27 @@ FIQ_HANDLER_ENTRY(256, 512)
 FIQ_HANDLER_END()
 
 
+/*
+ * this gets called every 1ms when we paniced.
+ */
+
+static long gta02_panic_blink(long count)
+{
+       long delay = 0;
+       static long last_blink;
+       static char led;
+
+       if (count - last_blink < 100) /* 200ms period, fast blink */
+               return 0;
+
+       led ^= 1;
+       s3c2410_gpio_cfgpin(GTA02_GPIO_AUX_LED, S3C2410_GPIO_OUTPUT);
+       neo1973_gpb_setpin(GTA02_GPIO_AUX_LED, led);
+
+       last_blink = count;
+       return delay;
+}
+
 
 /**
  * returns PCB revision information in b9,b8 and b2,b1,b0
@@ -1476,6 +1497,9 @@ static void __init gta02_machine_init(void)
 {
        int rc;
 
+       /* set the panic callback to make AUX blink fast */
+       panic_blink = gta02_panic_blink;
+
        switch (system_rev) {
        case GTA02v6_SYSTEM_REV:
                /* we need push-pull interrupt from motion sensors */