Blinking the SGI Indy Power Light

I figured out what broke in netbsd to make the R5000SC I have here poweroff during startup.

In any case, the hack for blinking the front panel LED, inspired from their BLINKY driver, shouldn't be lost when i clean up my tree.

 

So, I give you all:

+void
+blink_led(void)
+{
+       uint32_t reg;
+       uint32_t i;
+
+       reg = *(volatile uint32_t *)MIPS_PHYS_TO_KSEG1(0x1fbd9870) & 0xff;
+       reg = reg ^ 0x10; /* toggle? */
+       *(volatile uint32_t *)MIPS_PHYS_TO_KSEG1(0x1fbd9870) = reg;
+       asm(".set mips3; sync");
+
+       for (i = 0; i < 20 * 1000 * 1000; i++)
+               asm(".set mips3; nop ; nop");
+}

It's terrible but it works!

Also, amusingly, the ARC BIOS console IO was available at this point but nothing was being printed early enough for it to be seen! Debugging was quite a bit faster once I realised I was getting far enough for the ARC BIOS entrypoint to be initialised so I could printf().