This adds support for write protecting the RO code at boot, and the
entire flash on demand.
Implementation if WP# is not asserted is currently a little different
than STM32F and LM4; RO is still protected at boot if ro_at_boot, but
can be unprotected and the change will commit on the next reboot.
This saves the bank of flash which we use for pstate on LM4 and
STM32F. I think I can use one of the unused option bits (WRP2 bit 0)
to hold the RO-at-boot flag, in which case I can more closely match
the behavior of the other chips, but I'd like to do that (or give up
and implement pstate) in a separate CL so it's clearer what I'm doing.
BUG=chrome-os-partner:15613
BRANCH=none
TEST=manual
- flashinfo -> (no flags)
- enable WP (via screw or dut-control)
- flashinfo -> wp_gpio_asserted
- flashwp enable
- flashinfo -> wp_gpio_asserted ro_at_boot
- flashwp now
- flashinfo -> wp_gpio_asserted ro_at_boot all_now
- flashwp disable -> fails
- flashinfo -> wp_gpio_asserted ro_at_boot all_now
- flasherase 0x1fc00 0x400 -> fails
- reboot
- flashinfo -> wp_gpio_asserted ro_at_boot ro_now
- flasherase 0xfc00 0x400 -> fails
- flasherase 0x1fc00 0x400 -> succeeds
- disable WP (via screw or dut-control)
- reboot
- flashinfo -> ro_at_boot ro_now
- flashwp disable
- flashinfo -> ro_now
- reboot
- flashinfo -> (no flags)
- flasherase 0xfc00 0x400 -> succeeds
- flasherase 0x1fc00 0x400 -> succeeds
Change-Id: Id1b6b099a44a1985a5ab9387feb882a8f26e3aa1
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/55594
e8ecda5e8d