OPAL_GET_MSG

#define OPAL_GET_MSG                         85

int64_t opal_get_msg(uint64_t *buffer, uint64_t size);

OPAL_GET_MSG will get the next pending OPAL Message (see OPAL_MESSAGE).

The maximum size of an opal message is specified in the device tree passed to the host OS:

ibm,opal {
          opal-msg-size = <0x48>;
}

It is ALWAYS at least 72 bytes. In the future, OPAL may have messages larger than 72 bytes. Naturally, a HOST OS will only be able to interpret these if it correctly uses opal-msg-size. Any OPAL message > 72 bytes, a host OS may safely ignore.

A host OS SHOULD always supply a buffer to OPAL_GET_MSG of either 72 bytes or opal-msg-size. It MUST NOT supply a buffer of < 72 bytes.

Return values

OPAL_RESOURCE
no available message.
OPAL_PARAMETER
buffer is NULL or size is < 72 bytes. If buffer size < 72 bytes, the message will NOT be discarded by OPAL.
OPAL_PARTIAL
If pending opal message is greater than supplied buffer. In this case the message is DISCARDED by OPAL. This is to keep compatibility with host Operating Systems with a hard coded opal-msg-size of 72 bytes. NOT CURRENTLY IMPLEMENTED. Specified so that host OS can prepare for the possible future with either a sensible error message or by gracefully ignoring such OPAL messages.
OPAL_SUCCESS
message successfully copied to buffer.