AM335X with 2 ethernet interface can't be pingable if only one cable is plugged

This may well be hardware related. If you repeated the Starter Kit schematics, you should notice that the second Ethernet PHY there uses the clock that is sourced from the first PHY. If the first PHY cable is unplugged the PHY goes to sleep and stops the clock to the second PHY, making it unusable.

This can be overcome if you configure the PHY's never to go to sleep mode. However I'm not a software expert and cannot say how this is done. There have been posts on this topic on the forum. You can use the Search Community tool (located on top right of the forum page) to find similar topics.

Hello

thanks for the reply

i haven't founf topics on this subject : can you give me a link  please? thanks

regards

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/345275.aspx

Hello

thanks !

yes this a good link, but drivers/net/phy/smsc.c is not compiled for my kernel. I have a 88E3018 and 88E1118 PHY ; do you know where could be set the power saving for these PHY ?

regards

No, you should look in the PHY datasheet.

Hello

thanks,

what should i look for in the data sheet  (a function that power down PHY if deconnected) ?

The initialize function is :

static int m88e3018_config_init(struct phy_device *phydev)
{
    int err;
    /* Change Page Number */

    phy_write(phydev,  MIIM_88E3018_PHY_PAGE, 0x0000);
    /* Adjust LED control avec LED2 = Interrupt, LED1 = Link, LED0 = Colx */
    phy_write(phydev,  0x16, 0x0e50);
    /* Change Page Number */
    phy_write(phydev,  MIIM_88E3018_PHY_PAGE, 0x0000);

    genphy_config_aneg(phydev);

    err = phy_write(phydev, MII_MARVELL_PHY_PAGE, 0x0);
    if (err < 0)
        return err;

    err = phy_write(phydev, MII_BMCR, BMCR_RESET);
    if (err < 0)
        return err;

    /* Change Page Number */
    phy_write(phydev,  MIIM_88E3018_PHY_PAGE, 0x0000);

    genphy_update_link(phydev);
//    genphy_read_status(phydev);
marvell_read_status(phydev);
    return 0;
}

I don't have any documentation for these PHY's so cannot tell how they are configured. Generally this is done with bootstrap resistors at boot time and can later be modified by writing in PHY registers via MDIO, but I don't have details for these particular PHY's.

I am not sure this is a PHY problem, both ethernet ports cannot be on the same subnet, in this case both ports are on the same 213 subnet.

Right, should have seen that. Thanks for the post!

Hello

i don't think it isa problem of different subnet : the 2 interfces can be pingable if both cable ethernet are plugged.

If one is not plugged on the target, i can't ping the interface that is still plugged !!!

Any idea ?

thanks

regards

Hello

The problem is also true under u-boot :

eth0=192.168.0.2 plugged on the same switch of linux PC (192.168.0.44)

eth1 plugged on a hub with no network connected on it

Ping of 192.168.0.44 is OK; but if i unplugged the eth1, ping doesn't work

What may oblige us to have the eth1 plugged physically to ping on eth0 ?

Thanks

regards

U-boot only sets up one ethernet port, so you should not have to have the second port hooked up to work.

Do you have an the am335x evm-sk, does it behave the same way using the TI-SDK prebuilt images with the network setup you have?

another thing to try is to use wireshark on the linux PC and see which MAC address is showing up as part of the ARP process at the beginning of the ping sequence.