iMX8QXP LP-UART Linux driver has problem

[thepnimit]

Hi NXP

    We are using iMX8QXP and currently we are having the problem when we enable uart1 baud rate 9600. The problem is about transfer data is too slow than it suppose to be. (By using python code in attached file) 

    In linux-imx version imx_4.14.98_2.0.0_ga, we are having the problem that when we transfer data it took 0.13 second, but when we change the version to imx_4.14.98_2.3.0 the problem is:

1. Data with odd number of byte (1, 3, 5 byte etc..) it took the same 0.13 second.

2. Data with even number of byte ( 2,4,6 byte etc...) it faster and took around 0.002 second.

Our Target is we want to transfer the 1 byte data about 300kb and it took 40 mins which is too slow,
so we would like to know if this is the problem of linux driver ?

Best regards.

Thepnimit 

[thepnimit]

Hi Igor

On https://source.codeaurora.org/external/imx/linux-imx 

In branch imx_4.14.98_2.3.0, from arch/arm64/boot/dts/freescale/

fsl-imx8qxp.dtsi include fsl-imx8dxp.dtsi

fsl-imx8dxp.dtsi include fsl-imx8dx.dtsi

and fsl-imx8dx.dtsi include dt-bindings/clock/imx8qxp-clock.h (1)

In branch imx_5.4.47_2.2.0, from arch/arm64/boot/dts/freescale/

imx8qxp.dtsi include dt-bindings/clock/imx8-clock.h (2)

I would like to know if we can use (2) instead of (1) ?

Best regards.

Thepnimit 

[igorpadykov]

Hi Thepnimit

for this issue may be recommended to try latest L5.4 kernels and use rev.C0

of silicon. Check if issue persists on i.MX8QXP MEK board with Demo Image:

i.MX 8QuadXPlus(C0) MEK, i.MX 8DualX MEK​

Best regards
igor

[thepnimit]

Hi Igor

I have tried the latest L5.4 kernels that you told me from the link you sent, UART still having the same problem with version imx_4.14.98_2.0.0_ga

I would like to know if this is the hardware problem or software driver. 

Best regards