Re: [lwip-users] how to set the link up

[massimiliano cialdi]

On 07/07/2017 18:04, Noam Weissman wrote:
> Speed, duplex, link etc... is low level handling and the TCP stack is 
> not aware of that.
>
>
> This is why you call the set_link_up/down in your task, informing the 
> stack !.
Yes, of course

> The MDIO interface between your micro and PHY has no relation with 
> netif so why do you
>
> pass it as argument ?
because, in our implementation (NXP), netif->state is pointer to 
structure containing information to interface with PHY.

> You several options to get the link state. You can connect the link 
> led in the ETH connector
>
> to your micro and read it as a simple IO.
>
>
> If your PHY supports MII and it is connected as an MII you can hook an 
> interrupt to the link line.
We are compliant to RMII, except interrupt signal that is not routed, so 
we have to poll PHY.

> The third option is what I suggested to read the PHY basic register 
> and check for the link bit.
Is what I do.

> Your link task should not only check if link is up or down but also 
> know if it has changed !!. In your
>
> code is constantly calling the netifapi functions unless I missed 
> something ?
Yes, I have further modified the task:

static void PhyStatus_Task( struct netif *netif )
{
    enum { link_up, link_down } linkstatus = link_down;
    phy_speed_t physpeed;
    phy_duplex_t phyduplex;
    bool link;
    status_t result;

    ETHSPDOFF();
    netifapi_netif_set_link_down(netif);
    while(1)
    {
        result = ethernetif_GetLinkStatus(netif, &link);
        if(result == kStatus_Success)
        {
            switch(linkstatus)
            {
            case link_down:
                if(true == link)
                {
                    linkstatus = link_up;
                    netifapi_netif_set_link_up(netif);
                }
                break;
            case link_up:
                if(false == link)
                {
                    linkstatus = link_down;
                    netifapi_netif_set_link_down(netif);
                    ETHSPDOFF();
                }
                else
                {
                    result = ethernetif_GetLinkSpeedDuplex(netif, 
&physpeed, &phyduplex);
                    if(result == kStatus_Success)
                    {
                        ETHSPD(physpeed);
                    }
                }
                break;
            }
        }
        vTaskDelay(100);
    }
}


I have investigated the problems: netifapi_netif_set_link_up() is called 
and it cause call to link callback, in this function I call another 
function in netifapi (netifapi_dhcp_start()), so I have a deadlock.

best regards
Max