imx53 WinCE7 UART DMA bug

[sunajiang]

Hi

  I'm working on iMX53 SMD board(WinCE7 OS)  and find a UART DMA  bug , I don't know how to fix it and look for help.

  The problem is : When I use UART3 DMA  transmission  mode ,  if the PC send bytes (count number is multiple of 16), the mx53 RX dma chanel doesn't raise any interupt until the rx fifo buffer is full ,this will cause UART's ReadFile operation hang until DMA interupts raised .

  However if I send 1byte or any number of bytes which is not multiple of 16, rx DMA channel works well .

  I have changed the RX DMA channel watermark level to 32, howerver this will cause the 32nd、 64th、...(32*n th) character lost in single transmission if the PC sends more than 32bytes everytime.

  So, Can anyone help to fix this ?? I'd really preciate that, thanks all!

  @adeneoengineeringteam Qiang_FSL 

[Yuri · Accepted solution]

Please refer to the following:

i.MX53 UART DMA problem under WEC7/WEC2013 | Freescale Community

It is recommended to apply "SDMA script fix from the Linux repo : linux-2.6-imx.git - Freescale i.MX Linux Tree
[ENGR40066538-1 MX53: UART: update the DMA script for UART ,  "When enable the DMA for UART, the ATDMAEN(cr1) does not work]"

Have a great day,
Yuri

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