Data inconsistency observed while performing to-device DMA with spi-nor (m25p80)

Hi, I am doing a DMA transfer (to device) using pl330 driver from memory(DDR) to device(m25p80, spi- nor). I am sending data in chunks of 256 bytes ( m25p80 - writesize) using scatter-gather mechanism. I see that when I try to write 8K of data, one or the other 256 bytes(or lesser) are not written or are partially written with 0s. This problem is observed only when I perform a to-device DMA transfer. When I perform a from-device DMA transfer, I am able to read correct data. Regards, Ayan Kumar Halder