Re: [5/6] mvneta: implement SGMII-based in-band link state signaling

08.07.2015 19:30, Sebastien Rannou пишет:

Hi Stas,

On Fri, 27 Mar 2015, Stas Sergeev wrote:

quoted

When MDIO bus is unavailable (common setup for SGMII), the in-band
signaling must be used to correctly track link state.
This patch enables the in-band status delivery and interrupts for
links state changes, namely:
- link up/down
- link speed
- duplex full/half
Upon reciving the appropriate interrupt, the driver updates the
fixed_phy status to match the received status.

I'm seeing a regression with this patch when trying to netboot an Armada
XP board (by reverting this commit it is fine), the network
link stays down:

[    9.274492] mvneta d0070000.ethernet eth0: Link is Down

(I've added an extra call to phy_print_status() in mvneta_adjust_link() to
get this trace).

I've tried to dig a bit in the code, and it seems that the status.link flag
never gets set in mvneta_fixed_link_update(). If I try to force the
use_inband_status to 0 in mvneta_probe(), it boots properly so I'm not
sure that I need the in-band status/delivery in my case ; I'm using a
custom DTB with a fixed-link:

eth0: ethernet@70000 {
          status = "okay";
          fixed-link = <1 1 1000 0 0>;
          phy-mode = "sgmii";
};

Could there be something missing in the condition that initializes
pp->use_inband_status?

Hi, use_inband_status is set when fixed-link is used, which is
exactly your case. But it seems something on the other end
is not generating the inband status. What is there? A phy chip,
or something else?
Perhaps some DT property should be added to explicitly
enable the use of the inband status... I just thought in sgmii
protocol it is a mandatory.
I'll try to come up with the patch tomorrow that adds such
property.