[ixp1200] [Q] How do I request a command to another PCI device?

Hello. I installed IXP1200EB on the Linux machine with vera driver. And I want to send a command from IXP1200EB to another device. (Especially, SCSI controller or IDE HDD for DMA data transfer from there to IXP1200 SDRAM unti) Is it possible? And if possible, please let me know how I can. Thanks.