stm32h7/nocturne_fp: Enable RDP level 1, tie it to flash protection status

Prevent flash readout, using RDP field in option byte.

When RDP is defined, it makes no sense to be able to unlock
RO, as that'd allow flashing arbitrary RO that could read
back the rest of the flash, so we just tie
EC_FLASH_PROTECT_RO_AT_BOOT and RDP protection. This also
means we can't unlock the flash after it has been finalized
(without removing WP and using BOOT0/stm32mon to mass erase
the chip).

Also, in flash_mp_mcu, call stm32mon with -U, to unlock
flash for read-back first (which disables RDP and triggers
a mass erase if RDP was enabled). Finally, load spidev
before putting releasing reset, which makes reflashing
more reliable.

BRANCH=nocturne
BUG=b:111330723
TEST=cp flash_mp_mcu read_mp_mcu, replace stm32mon line with:
     "stm32mon -u -p -s ${SPIDEV} -r rb.bin"
  dut-control fw_wp_state:force_off
  => Check that read_mp_mcu works
  dut-control fw_wp_state:force_on
  ectool --name=cros_fp flashprotect enable
  ectool --name=cros_fp reboot_ec
  => RDP is now on
  dut-control fw_wp_state:force_off
  => Check that read_mp_mcu does not work anymore
TEST=Add -U to stm32mon line above in read_mp_mcu, check that
     readback only gets blank data.
TEST=In EC console, check that RDP bits are indeed not 0xaa:
     Before: rw 0x5200201c => 0x07d6aaf0
     After:  rw 0x5200201c => 0x07d600f0
TEST=flash_mp_mcu still works (does a flash erase that removes
     RDP protection)

Change-Id: Ifbe37ecafbf23f48d4a3cc17933130b7b104b728
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1222094
Commit-Ready: Nicolas Norvez <norvez@chromium.org>
Tested-by: Nicolas Norvez <norvez@chromium.org>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>

0 files changed, 0 insertions, 0 deletions