OPAL_CEC_POWER_DOWN

#define OPAL_CEC_POWER_DOWN                  5

int64 opal_cec_power_down(uint64 request)

As powering down the system is likely an asynchronous operation that we have to wait for a service processor to do, OPAL_CEC_POWER_DOWN should be called like the example code below:

int rc = OPAL_BUSY;

do {
  rc = opal_cec_power_down(0);
  if (rc == OPAL_BUSY_EVENT)
    opal_poll_events(NULL);
} while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT);

for (;;)
  opal_poll_events(NULL);

Arguments

uint64 request values as follows:

0
Power down normally
1
Power down immediately

This OPAL call requests OPAL to power down the system. The exact difference between a normal and immediate shutdown is platform specific.

Current Linux kernels just use power down normally (0). It is valid for a platform to only support some types of power down operations.

Return Values

OPAL_SUCCESS
the power down request was successful. This may/may not result in immediate power down. An OS should spin in a loop after getting OPAL_SUCCESS as it is likely that there will be a delay before instructions stop being executed.
OPAL_BUSY
unable to power down, try again later.
OPAL_BUSY_EVENT
Unable to power down, call OPAL_POLL_EVENTS and try again.
OPAL_PARAMETER
a parameter was incorrect
OPAL_INTERNAL_ERROR

Something went wrong, and waiting and trying again is unlikely to be successful. Although, considering that in a shutdown code path, there’s unlikely to be any other valid option to take, retrying is perfectly valid.

In older OPAL versions (prior to skiboot v5.9), on IBM FSP systems, this return code was returned erroneously instead of OPAL_BUSY_EVENT during an FSP Reset/Reload.

OPAL_UNSUPPORTED
this platform does not support being powered off. Practically speaking, this should never be returned, but in various simulation or bring-up situations, it’s plausible it is, so code should handle this gracefully.