uint32_t rcar_trigger_scmi(uint64_t chan_id)
{
	uint32_t ret;
	struct scmi_shared_mem *shmem;
	uint32_t payload_size;
	scmi_msg_header_t hdr;

	if (chan_id >= RCAR_SCMI_CHAN_COUNT)
		return SMC_ARCH_CALL_INVAL_PARAM;
	shmem = (struct scmi_shared_mem *)(RCAR_SCMI_SHMEM_BASE + chan_id * PAGE_SIZE);
	payload_size = MAX((uint32_t)sizeof(shmem->msg_header),
			mmio_read_32((uintptr_t)&shmem->length));
	payload_size -= sizeof(shmem->msg_header);
	hdr.v = mmio_read_32((uintptr_t)&shmem->msg_header);
	ret = scmi_handle_cmd(  hdr.u.protocol, hdr.u.id,
				(uint8_t*)mmio_read_64((uintptr_t)&shmem->msg_payload),
				payload_size);
	INFO("BL31-SCMI: channel: %#llx, protocol: %#x, command: %#x\n",
		chan_id, hdr.u.protocol, hdr.u.id);
	mmio_write_32((uintptr_t)&shmem->channel_status, BIT(0)); /* mark free */
	return ret;
}