iMX53 DMA Issues

fraserwinters — Wed, 10 Jun 2015 13:51:07 GMT

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.

Thanks

Fraser

Re: iMX53 DMA Issues

Yuri — Thu, 11 Jun 2015 05:00:59 GMT

Perhaps, it may be useful to look at the following patches

from the git, linked below.

ENGR00252150 Fix MX53 IOMUX setup for all UARTsimx_2.6.35_11.09.01

ENGR40066538-3 MX53: UART: enable the hardware flow control

ENGR40066538-2 MX53: UART: fix the wrong CTS pinmux macro

ENGR40066538-1 MX53: UART: update the DMA script for UART

http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/log/?h=imx_2.6.35_11.09.01

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

topic iMX53 DMA Issues in i.MX Processors

iMX53 DMA Issues

Re: iMX53 DMA Issues