Simultaneous Tx and Rx data transfer using USB

Vineet,

There is an errata that addresses the concurrent Rx Tx DMA transaction issue on OMAP35xx w.r.t MUSB controller.

I would recommend that you use PIO mode in one of the direction in the MUSB driver.  In the mean time let me look around to see if this modification is already done so that you can use that patch.

regards

swmi

Thanks a lot for the reply.

Do I need to change the usb driver code for changing the mode in one direction?

Will use of PIO mode slow down the data transfer?

Thanks and regards,

Vineet

PIO would not slow down the transfer but ARM will be occupied.  You would have to change the USB driver at this point in time as the official patch is not available yet.

regards

swami

I believe changes have to be done in drivers/usb/musb folder.

I see some use_dma flags in the code which can be used  during runtime to disable DMA. Will making this flags to "n" in tx related function solve the purpose?

Thanks and regards,

Vineet

Simple solution is to force the IO to use PIO say in Tx path in the musb_ep_program function.

regards

swami