Add function to send mailbox command via SMC to get usercode from SDM.
Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>
invoke_smc() allow U-Boot proper running in non-secure mode (EL2)
to invoke SMC call to ATF's PSCI runtime services such as
System Manager's registers access, 2nd phase bitstream FPGA
reconfiguration, Remote System Update (RSU) and etc.
smc_send_mailbox() is a send mailbox command helper function which invokes
the ATF's PSCI runtime service (function ID: INTEL_SIP_SMC_MBOX_SEND_CMD)
to send mailbox messages to Secure Device Manager (SDM).
Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
