view loadtools/scripts/compal.init @ 501:7a6eba04c1bb

CHANGES: target-utils poweroff VRPCAUX addition documented
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 27 May 2019 01:12:43 +0000
parents ac48ed111d6a
children b0f9d38bfd9e
line wrap: on
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# Set WS=3 for both nCS0 and nCS1.  This configuration is used by all official
# C11x, C139/140 and SE J100 firmwares that have been examined, i.e., by the
# official firmwares for all Compal models to which this init script applies.

w16 fffffb00 00A3
w16 fffffb02 00A3

# On most targets we use the alternate nCS0 mapping at 0x03000000 to access
# the full flash bank even though the boot ROM is mapped at 0, overlapping
# the first 8 KiB of flash.  However, the Calypso chip (all versions we work
# with) has a little design bug in this part of the silicon: the alternate
# nCS0 mapping at 0x03000000 works only when the debug visibility bit in the
# API-RHEA control register (bit 6 in the FFFF:FB0E register) is set, and
# does not work otherwise.  This bit is initially set as the Calypso comes
# out of reset, and on most platforms we gain loadtool access via the boot ROM,
# hence the problem does not occur - but on these Compal targets we gain
# loadtool access either through Compal's bootloader or via tfc139, and in
# both cases Compal's fw (either the full fw or the bootloader part) has
# already set the register in question to the runtime operational value of
# 0x2A (unchanged from TI's TCS211 reference fw), with the debug visibility
# bit cleared, hence the 0x03000000 flash mapping no longer works.
#
# We could write into the FFFF:FB0E register here, restore the Calypso power-up
# state and use the 0x03000000 mapping like on other platforms, but the problem
# of the mapping not working as expected was first encountered in 2014 when we
# started working on Compal targets, whereas the root cause described above was
# only discovered in 2019.  For now we are keeping the original workaround from
# 2014: we set the FFFF:FB10 register to map the flash (not the boot ROM)
# to address 0, and use that "main" mapping instead of the alternate one.

w16 fffffb10 0300