You can use the following boot parameters at the "boot: " prompt.
If you use hex numbers you have to use the 0x prefix (e.g. 0x300)

protect I/O port regions     reserve=iobase,extent[,...]
Adaptec 151x, 152x           aha152x=iobase[,irq[,scsi-id[,reconnect]]]
Adaptec 1542                 aha1542=iobase[,buson,busoff[,dmaspeed]]
Adaptec 274x, 284x           aic7xxx=extended,noreset (enabled if non-zero)
BusLogic SCSI Hosts          buslogic=iobase
Future Domain TMC-8xx/950    tmc8xx=mem_base,irq
Pro Audio Spectrum           pas16=iobase,irq
Seagate ST-0x                st0x=mem_base,irq
Trantor T128                 t128=mem_base,irq
Aztech CD-ROM                aztcd=iobase[,magic_number]
CDU-31A/CDU-33A Sony CD-ROM  cdu31a=iobase,[irq[,is_pas_card]]
CDU-535 Sony CD-ROM          sonycd535=iobase[,irq]
GoldStar CD-ROM              gscd=iobase
Mitsumi Standard CD-ROM      mcd=iobase,[irq[,wait_value]]
Optics Storage CD-ROM        optcd=iobase
Phillips CM206 CD-ROM        cm206=[iobase][,irq]
Sanyo CD-ROM                 sjcd=iobase[,irq[,dma_channel]]
SoundBlaster Pro CD-ROM      sbpcd=iobase,type
ATAPI/IDE CD-ROM             hd{a,b,c,d}=cdrom