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Linux: AM57xx SDK 3.1.0.6 support uart soft flow control ?

Qing
Expert 1385 points
Other Parts Discussed in Thread: AM5718

Tool/software: Linux

HI,

I am on using TI SDK3.1.0.6 on AM5718 Customization board。

I test the soft flow control， but failed.  I want to know wether the SDK support the soft flow cntrol?

If yes, can you give me some test program ?

Thank you very much!

Best Regards

Qing

  • 0
    TI__Guru**** 161600 points
    Hi Qing,

    We're looking into this. Feedback will be posted here.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Expert 1385 points
    Thank you very much, Yoardan
  • 0 in reply to Yordan Kovachev
    Expert 1385 points
    Hello, yordon:
    I have seen this note in ($linux_dir)/driver/tty/serial/8250/8250_omap.c
    and the note as follow:
    "
    /*
    * OMAP rx s/w flow control is borked; the transmitter remains
    * stuck off even if rx flow control is subsequently disabled
    */
    "

    Is that the Omap RX sw flow control can't be used normally?
    Thank you very much!

    Best Regards
    Qing
  • 0 in reply to Qing
    TI__Guru**** 161600 points
    Hi Qing,

    Correct. I checked the configuration in TISDK (both u-boot & linux) and the serial driver uses hw flow control:
    Kernel
    root@am57xx-evm:~# devmem2 0x48020008
    /dev/mem opened.
    Memory mapped at address 0xb6f4a000.
    Read at address 0x48020008 (0xb6f4a008): 0x000000C1 //UART_EFR[ bit6]=1 [ bit7]=1 ==> AUTO-CTS & AUTO-RTS enabled ==> hw flow control
    root@am57xx-evm:~# devmem2 0x48020010
    /dev/mem opened.
    Memory mapped at address 0xb6fd9000.
    Read at address 0x48020010 (0xb6fd9010): 0x00000003 //UART_MCR[5]XON_EN = 0x0 -> Disable XON any function.

    Same results in u-boot:
    => md 0x48020008 1
    48020008: 000000c1 ....
    => md 0x48020010 1
    48020010: 00000003 ....

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Expert 1385 points

    Dear yordon:

    Thank you very much! And is this a H/W issue or S/W issue.  If this is a software issue, can you tell me when you will fix it ?


    Best Regards
    Qing