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Linux/AM5718: DP83822 support

Rakesh Muralidharan
Expert 2810 points

Part Number: AM5718
Other Parts Discussed in Thread: DP83822I, TLK105, AM3356,

Tool/software: Linux

Hi,

I have taken a deviation from EVM by choosing DP83822I Ethernet PHY for a custom board. EVM uses KSZ9031 (RGMII) PHY , interfaced to CPSW.

My requirement is to have 10/100 Ethernet port.

I guess Driver support is available for DP83822I in linux. https://e2e.ti.com/support/legacy_forums/embedded/linux/f/354/t/621288. Another thread points to issues with interfacing DP83822 to linux https://e2e.ti.com/support/legacy_forums/embedded/linux/f/354/t/621288.

In the custom board i need this Ethernet port active for uBOOT. Will there be driver support for uBoot?? I have a requirement to use this port for kernel update using TFTP.

If the implementation is going to be troublesome ,I have an alternate option of using KSZ9031 in 10/100 mode. KSZ9031 data sheet point to the mechanism that can be adopted for this. Does the linux driver support this scheme?? Can I adopt this scheme to uBOOT?? Will there be driver support ?? so that device will power up and auto negotiate for 10/100 rather than 1G port.

  • 0
    TI__Mastermind 45065 points

    Hello,

    I am wondering if you could please share your Uboot and Kernel versions.

    Regards,
    Krunal

  • 0 in reply to Krunal Bhargav34
    Expert 2810 points
    Hi,
    Kernel version:  4.14.79-ge669d52447
     
    Uboot version: U-Boot 2018.01-g825ac6e1ac 
  • 0 in reply to Rakesh Muralidharan
    TI__Mastermind 45065 points

    Hello,

    Based on my conversation with our experts, we do not support DP83822I Ethernet PHY.

    Regards,
    Krunal

  • 0 in reply to Krunal Bhargav34
    Expert 2810 points

    1. Does that mean that there will be no support for DP83822 in linux or there will be no support for DP83822 in uBoot??

    2. If I choose option 2 that is KSZ9031 will there be support in uBOOT & linux to operate it in 10/100 mode

    3. In the same board i have one more Ethernet port ( DP83822 interfaced to  PRU1) . EVM uses TLK105 for PRU . If there is no support in linux I may have to change chipset to TLK105.

  • 0 in reply to Rakesh Muralidharan
    Expert 2810 points

    TLK105 is in NRND category. Pls suggest a solution.

  • 0
    Prodigy 210 points

    Hello,

    I'm working on a customer project where we're using an AM3356 with DP83822 PHYs. Since (R)(G)MII and MDIO are standard interfaces I'd expect it to work out of the box without a special DP83822 driver. I'd expect the generic PHY driver to work, with U-Boot as well as Linux.
    Obviously it would not support all the feature of the PHY (cable testing, loopback modes, etc.).

    Rakesh, what kind of U-Boot support exactly would you expect?

    Krunal: is there a reason to why it shouldn't work with a generic U-Boot driver?

    Thanks & regards
    Ferdinand

  • 0 in reply to Ferdinand Grossmann
    Expert 2810 points

    In case of DP83822 

    1. We have limited experience in playing around with uBOOT. I was under the notion that PHY specific driver should be there in uBOOT.

    As you said if it is not needed well and good.  Now the concern is limited expertise in uBOOT . If we face some hurdles in waking up Ethernet we do not know where to look for in uBOOT and may need some handholding.

    CPSW in AM5718 EVM is connected via RGMII interface to Giga Bit PHY KSZ9031.

    In case of  KSZ9031 i need to operate it in 10/100 mode ie I will hardwire only 4 lines (Tx & Rx)

    1. here On wake up KSZ9031 is supposed to advertise 10/100 Mode . For this as i understand some changes are needed in uBOOT/Linux. Here I may need support to incorporate these features.

  • 0 in reply to Rakesh Muralidharan
    TI__Mastermind 41450 points

    Hi,

    U-Boot has had several PHYs integrated into them but currently only the TI DP83867 PHY has been integrated. Some PHYs such as the DP83867 require some parameters to be set that are outside of HW strapping and are critical to operation. The DP83867 requires setting RGMII timing parameters in the PHY extended mode area registers to get the PHY to function correctly, these timing parameters are read from the DTB file created as part of board development. Aside from specific interface settings as I just described I would agree with the other community member in this thread that basic PHY functionality should work. 

    Concerning the KSZ9031, the bit rate advertisement should be done as part of the HW strapping on the board. There should not have to be any software concerning the bit rate. The phy mode will need to set in the board DTS file.

    Best Regards,

    Schuyler

  • 0 in reply to Schuyler Patton
    Expert 2810 points

    Hi,

    In case of KSZ9031RN 

    1. For hardware bootstrap following schemes are available 

    I could not find a explicit means of forcing PHY  set link to 10/100 mode or advertise 10/100 mode 

    in their data sheet for 10/100 mode following procedure is recommended 

  • 0 in reply to Rakesh Muralidharan
    Expert 2810 points

    In case of KSZ9031

    if uBoot needs to advertise 10/100 mode i guess above configuration should be performed by uBOOT on device wakeup.

  • 0 in reply to Rakesh Muralidharan
    Expert 2810 points

    In case DP83822I

    i am using MII interface rather than  RGMII, so wont the generic ethernet  Uboot driver work for DP83822I. So i could use TFTP from uBoot.

    Once  linux is Up , using DP83822I linux drivers in http://www.ti.com/tool/ethernet-sw wont i be able work with DP83822I??

  • 0 in reply to Rakesh Muralidharan
    TI__Mastermind 41450 points

    Hi,

    In terms of u-boot the generic driver would probably work, just disable the TI driver from the u-boot menuconfig if it is enabled.

    If you are using the TI SDK there is a driver already in the kernel source tree provided. You will need to select the 83822 in the kernel menuconfig to make sure the driver is built into the kernel. 

    Best Regards,

    Schuyler