• State TI Thinks Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 3 answers
  • Subscribers 99 subscribers
  • Views 3752 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Linux/DRA750: dra7xx evm doesn't generate eye diagram on usb port 2

shawn lin
Genius 3450 points
Part Number: DRA750


Tool/software: Linux

Hi all,

we are using DRA7xx_GLSDK_7.04.00.03 on dra7xx evm.

We need to measure the eye diagram on usb port2 (usb 2.0).
Refer to processors.wiki.ti.com/.../USB_General_Guide_Linux_v3.8,

# mount -t debugfs debugfs /mnt

# echo "test_packet" > /mnt/488d0000.usb/test_mode

but no pattern was generated after above sequence.

Is there any extra step need to make for generating eye diagram?

Thank you.

  • 0
    TI__Mastermind 42515 points
    Hi Shawn,

    I have forwarded your question to USB expert.

    Regards,
    Yordan
  • 0 in reply to Yordan Kamenov
    TI__Expert 7885 points
    Shawn lin

    Above mentioned steps are correct. Can you check once USB2 port is working in host/device mode. Once its working issue "test_packet" command. Capture the bus trace and check.

    Regards
    Ravi
  • 0 in reply to Ravi B
    Genius 3450 points

    Hi Ravi,
    thanks for your reply.
    We have checked these two situation, no difference between them.
    Nothing happened after test_packet command.

  • 0 in reply to shawn lin
    TI__Expert 7885 points
    Hi Shawn

    Before issuing "test_packet" command, whether the specific USB port X is functionally working in host or device mode ? Do you see SOF on the bus and enumeration sequence ?

    Regards
    Ravi
  • 0 in reply to Ravi B
    Genius 3450 points
    Hi Ravi,
    I'm sorry, could you please kindly tell me exactly how to perform this test?
    Something like step 1: connect a usb disk to check the host port is functionally working,
    step 2: issuing test_packet and capture the wave form,
    step3: ...

    I am afraid that i might misunderstand what you mean before.
    Sorry for my poor English and tank you again for your help.
  • 0 in reply to shawn lin
    TI__Expert 7885 points

    Yes, you are correct, i meant verify the USB host mode by connecting the USB disk and check USB disk is enumerated successfully.

    Are you using USB0 or USB1 port ?

    Regards

    Ravi

  • 0 in reply to Ravi B
    Genius 3450 points
    OK, if you mean USB0 is a USB 3.0 port and USB1 is a USB2.0 port, then I'm using USB1.
    (on dra7-evm board, there are only USB1(3.0) adn USB2(2.0)),
    The usb disk can be enumerated successfully and we can read/write files to it after we mount it.
    But after we send the "test_packet" command, nothing happened.
  • 0 in reply to shawn lin
    TI__Expert 7885 points

    Shawn

    Did you tried below sequence .

    1) Connect the USB disk to USB1 or USB2 port through analyzer and capture the bus trace and make sure you are able to capture the USB transaction & SOFs on the bus.

    2) Without disconnecting the USB disk, initiate test_packet generation.

    #mount -t debugfs debugfs /mnt

    #echo "test_packet" > /mnt/488<9 or d>0000.usb/test_mode

    3) You must see the test packet on the bus trace.

    Regards

    Ravi

  • 0 in reply to Ravi B
    Genius 3450 points
    Hi Ravi,
    1) yes we did.
    2) yes we did.
    3) nothing changed

    thanks for your reply,
    please give us some direction to debug this issue.
    Thanks again.
  • 0 in reply to shawn lin
    TI__Expert 7885 points

    Shawn

    Sorry for delayed response.

    Did you checked writing manually to USB_PORTMSC1 register ?

    Check with below sequence.

    1) boot the kernel and make sure host is working and SOF seen on USB bus trace.

    2) from kernel prompt

    #devmem2 0x488d0424 w 0x40000000

    The USB_PORTMSC1 register 0x488d0424 bit[31..28] is for Port Test controls.

    bit [31..28] = 1 - Test J STATE

    2 - TEST-K STATE

    3 - TEST-SE0 NAK

    4 -TEST PACKET 

    etc..

    refer to DRA7X TRM and XHCI specification for more details

    Regards

    Ravi

  • 0 in reply to Ravi B
    TI__Expert 7885 points
    Shawn

    The echo "test_packet" > /mnt/488<9 or d>0000.usb/testmode is supported only for device mode.
    Put the USB1 or USB2 port in device mode and issue the above command from kernel, the test_packet (53bytes) should be generated in device mode as well.

    For host mode, you can use above mentioned writing to USBPORTMS1 register from kernel.

    Regards
    Ravi