fw_wr32
fw_wr32(fbd, FBNIC_IPC_MBX(mbx_idx, mbx->tail), 0);
fw_wr32(fbd, FBNIC_IPC_MBX(FBNIC_IPC_MBX_RX_IDX, head), 0);
fw_wr32(fbd, desc_offset + 1, upper_32_bits(desc));
fw_wr32(fbd, desc_offset, lower_32_bits(desc));
fw_wr32(fbd, desc_offset, desc);
fw_wr32(fbd, desc_offset + 1, 0);