Re: [Qemu-devel] [PATCH v1 1/3] e1000: emulate auto-negotiation during external link status change

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jun 16, 2014 at 01:29:09PM -0400, Gabriel L. Somlo wrote:
> This patch emulates auto-negotiation when the network link status
> is modified externally (i.e. via "set_link <id> off/on").
> 
> Also, a couple of cleanup items regarding the PHY status register:
>   - unset AUTONEG_COMPLETE during link_down()
>   - set AUTONEG_COMPLETE during autoneg_timer() only if we actually
>     brought the link up.
> 
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> ---
>  hw/net/e1000.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> index 57bdffd..f0070ca 100644
> --- a/hw/net/e1000.c
> +++ b/hw/net/e1000.c
> @@ -175,6 +175,7 @@ e1000_link_down(E1000State *s)
>  {
>      s->mac_reg[STATUS] &= ~E1000_STATUS_LU;
>      s->phy_reg[PHY_STATUS] &= ~MII_SR_LINK_STATUS;
> +    s->phy_reg[PHY_STATUS] &= ~MII_SR_AUTONEG_COMPLETE;
>  }
>  
>  static void
> @@ -197,7 +198,6 @@ set_phy_ctrl(E1000State *s, int index, uint16_t val)
>      }
>      if ((val & MII_CR_AUTO_NEG_EN) && (val & MII_CR_RESTART_AUTO_NEG)) {
>          e1000_link_down(s);
> -        s->phy_reg[PHY_STATUS] &= ~MII_SR_AUTONEG_COMPLETE;
>          DBGOUT(PHY, "Start link auto negotiation\n");
>          timer_mod(s->autoneg_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
>      }
> @@ -209,9 +209,9 @@ e1000_autoneg_timer(void *opaque)
>      E1000State *s = opaque;
>      if (!qemu_get_queue(s->nic)->link_down) {
>          e1000_link_up(s);
> +        s->phy_reg[PHY_STATUS] |= MII_SR_AUTONEG_COMPLETE;
> +        DBGOUT(PHY, "Auto negotiation is completed\n");
>      }
> -    s->phy_reg[PHY_STATUS] |= MII_SR_AUTONEG_COMPLETE;
> -    DBGOUT(PHY, "Auto negotiation is completed\n");
>  }
>  
>  static void (*phyreg_writeops[])(E1000State *, int, uint16_t) = {
> @@ -853,7 +853,15 @@ e1000_set_link_status(NetClientState *nc)
>      if (nc->link_down) {
>          e1000_link_down(s);
>      } else {
> -        e1000_link_up(s);
> +        if (s->phy_reg[PHY_CTRL] & MII_CR_AUTO_NEG_EN &&
> +            s->phy_reg[PHY_CTRL] & MII_CR_RESTART_AUTO_NEG &&
> +            !(s->phy_reg[PHY_STATUS] & MII_SR_AUTONEG_COMPLETE)) {

I think we also must test E1000_FLAG_AUTONEG in s->compat_flags.
No?


> +            /* emulate auto-negotiation if supported */
> +            timer_mod(s->autoneg_timer,
> +                      qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
> +        } else {
> +            e1000_link_up(s);
> +        }
>      }
>  
>      if (s->mac_reg[STATUS] != old_status)
> -- 
> 1.9.3