On Sun, Jul 26, 2015 at 5:02 PM, AYAN KUMAR HALDER <[email protected]> wrote:
> 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. > > There could be multiple issues like - In buffers allocations, is the buffer used for to-device DMA is physically contiguous? - Caching issue, buffer should be un-cacheable. - Any other programming error. - Chetan Nanda Regards, > Ayan Kumar Halder > > _______________________________________________ > Kernelnewbies mailing list > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >
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