FreeCalypso > hg > freecalypso-tools
view target-utils/compalstage/compalstage.S @ 497:74610c4f10f7
target-utils: added 10 ms delay at the end of abb_power_off()
The deosmification of the ABB access code (replacement of osmo_delay_ms()
bogus delays with correctly-timed ones, which are significantly shorter)
had one annoying side effect: when executing the poweroff command from
any of the programs, one last '=' prompt character was being sent (and
received by the x86 host) as the Calypso board powers off. With delays
being shorter now, the abb_power_off() function was returning and the
standalone program's main loop was printing its prompt before the Iota chip
fully executed the switch-off sequence!
I thought about inserting an endless tight loop at the end of the
abb_power_off() function, but the implemented solution of a 10 ms delay
is a little nicer IMO because if the DEVOFF operation doesn't happen for
some reason in a manual hacking scenario, there won't be an artificial
blocker in the form of a tight loop keeping us from further poking around.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 25 May 2019 20:44:05 +0000 |
| parents | 21eec7569eb8 |
| children |
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.text .org 0 #if THUMB_ENTRY .code 16 bx pc nop #endif .code 32 /* delay loop like OsmocomBB does */ mov r1, #0xa0000 1: subs r1, r1, #1 bne 1b /* enable the Calypso boot ROM */ ldr r1, reg_addr mov r2, #0x0100 strh r2, [r1] /* jump to it! */ mov pc, #0 reg_addr: .word 0xFFFFFB10 #if PAD_TO_1003 /* * The older and most familiar versions of C139/140 boot code expect the * signature bytes to be "1003" or greater, but a recently encountered * newer version expects them to be "1004" or greater instead. As the * actual comparison check in all currently known boot code versions is * an inequality (the signature bytes in the downloaded image need to be * greater than or equal to the hard-coded reference values), always * putting "1004" in our compalstage image instead of "1003" should satisfy * all existing C1xx boot code versions, or at least all currently known * ones. However, having an image named compalstage-1003.bin with the * corresponding -c 1003 loadtools option that is actually "1004" inside * feels a little "wrong" in some sense, while getting rid of the -c 1003 * option would break old user instructions, hence let's go ahead and do the * silly exercise of building both "1003" and "1004" versions. */ .org 0x3be0 #if MAGIC_1004 .ascii "1004" #else .ascii "1003" #endif #endif