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iMX53 DMA Issues

Question asked by Fraser Winters on Jun 10, 2015
Latest reply on Jun 10, 2015 by Yuri Muhin

I am currently developing a new system based on the iMX53 device and using Linux 2.6.35. We have three UART connections to this system running at a relatively high speed (921kbaud) and have issues trying to get this running with DMA enabled for the three UARTS. We have inconsistent results in DMA mode with what appears to be bytes dropped, delayed interrupts depending on the message and channel and various other issues.

I have tried applying the patch for the DMA micro code which did not appear to resolve the issues. On a post I found there was mention of Freescale support having an updated mxc_uart.c with updates for DMA operation. Does anyone know where this update is available or do they have it and could supply a copy?


At present we are running without DMA which is obviously not ideal due to high number of interrupts and the occassional OE error we encounter...


Is anyone aware of any further updates for DMA microcode.


For reference we are not using a Freescale BSP due to the board we are using although obviously most of the files for the driver layer are the Freescale versions.