Need help EHCI host driver on Linux 2.6.29

Dear Experts, I am developing a EHCI host driver for Linux kernel 2.6.29 on a proprietary SoC. But for weeks now, I am troubleshooting a time out error from khubd. I believe it's related to the client device not being able to update the qtd struct which has been set at some Dma addresses, say 0x87xxxxxx. Is this possible? The main issue is the register address for chip lies in 0x5a800000 range, so is the on-chip memory. If I set the qtd structs to on chip memory(internal sram), kernel paging error will occur. So I am at a loss of what I can. Please kindly advise. Best regards, CL