When you are booting up, the BIOS will report the card's firmware version during POST. Some cards do not have their BIOS ROM flashed; I think that's a bad idea, because it lets you safely check on versions and connectivity outside of the UNIX environment. But opinions vary.
When the OS boots, it will also report it in the file /var/run/dmesg.boot, such as
mps0: <Avago Technologies (LSI) SAS2008> port 0x4000-0x40ff mem 0xfd3f0000-0xfd3fffff,0xfd380000-0xfd3bffff irq 18 at device 0.0 on pci3
mps0: Firmware: 20.00.07.00, Driver: 21.02.00.00-fbsd
mps0: IOCCapabilities: 1285c<ScsiTaskFull,DiagTrace,SnapBuf,EEDP,TransRetry,EventReplay,HostDisc>
You can also check at the FreeNAS CLI.
# mpsutil show adapter
mps0 Adapter:
Board Name: SAS9211-8i
Board Assembly:
Chip Name: LSISAS2008
Chip Revision: ALL
BIOS Revision: 7.31.00.00
Firmware Revision: 20.00.07.00
Integrated RAID: no
PhyNum CtlrHandle DevHandle Disabled Speed Min Max Device
0 0003 000b N 6.0 1.5 6.0 SAS Initiator
1 0006 000e N 6.0 1.5 6.0 SAS Initiator
2 0008 0010 N 6.0 1.5 6.0 SAS Initiator
3 0002 000a N 6.0 1.5 6.0 SAS Initiator
4 0005 000d N 6.0 1.5 6.0 SAS Initiator
5 0007 000f N 6.0 1.5 6.0 SAS Initiator
6 0001 0009 N 6.0 1.5 6.0 SAS Initiator
7 0004 000c N 6.0 1.5 6.0 SAS Initiator