mbox series

[0/3] Make WDOGCONTROL.INTEN the counter enable of the CMSDK APB Watchdog

Message ID 20241108191024.2931097-1-roqueh@google.com (mailing list archive)
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Series Make WDOGCONTROL.INTEN the counter enable of the CMSDK APB Watchdog | expand

Message

Roque Arcudia Hernandez Nov. 8, 2024, 7:10 p.m. UTC 
The following patchset tries to address an issue where the watchdog
counter was running as soon as the device is out of reset. This
created a few problems with the firmware under test. It was pointed
out that the firmware under test was already working on an emulator
using the real RTL. Further review showed that the WDOGCONTROL.INTEN
is also expected to be the counter enable as it is defined in this
page from ARM:

https://developer.arm.com/documentation/ddi0479/d/apb-components/apb-watchdog/programmers-model?lang=en

     |       | Enable the interrupt event, WDOGINT. Set to 1 to
     |       | enable the counter and the interrupt, or to 0 to
 [0] | INTEN | disable the counter and interrupt. Reloads the
     |       | counter from the value in WDOGLOAD when the interrupt
     |       | is enabled, after previously being disabled.

The second half of the patch is focused on adding tests for this
behavior. It was required to modify the test to be able to run some
test cases in the MPS2 since the the stellaris machine had 2 issues:

  - The stellaris machine did not run the counter out of reset
    because of the way it is reset. The function
    ssys_calculate_system_clock is not called until the reset phase
    stellaris_sys_reset_hold which is after the watchdog executes its
    reset, so the watchdog would not start the counter due to the
    clock not being set up at the time of reset.

  - The Stellaris machine uses a derived watchdog and not the
    original CMSDK one which has a special behavior where it cannot
    be stopped.

The MPS2 machine on the other hand uses the standard CMSDK watchdog
and could expose the problems we were dealing with.

Roque Arcudia Hernandez (3):
  hw/watchdog/cmsdk_apb_watchdog: Fix INTEN issues
  tests/qtest/cmsdk-apb-watchdog-test: Parameterize tests
  tests/qtest/cmsdk-apb-watchdog-test: Test INTEN as counter enable

 hw/watchdog/cmsdk-apb-watchdog.c      |  29 ++-
 tests/qtest/cmsdk-apb-watchdog-test.c | 327 +++++++++++++++++++++++---
 tests/qtest/meson.build               |   3 +-
 3 files changed, 325 insertions(+), 34 deletions(-)