[U-Boot] [PATCH] Add CONFIG_GMAC_TX_DELAY=4 for OlinuXino Lime2

[Michael Haas <haas@computerlinguist.org>]

On 03/19/2016 10:32 AM, Hans de Goede wrote:
> Hi,
>
> On 19-03-16 09:39, Fran?ois-David Collin wrote:
>> Hi,
>>
>> As I?m banging my head on this too, please allow me to provide some
>> details
>> I got two stable situations :
>> The Lime2 is connected directly to the Gbit interface of my laptop,
>> speed are OK:
>
> Michael Haas' work to debug this by looking at the phy registers
> seems to be the most promising so-far, the clk reg and axp209
> registers all seem to be identical between good and bad setups.
>
> Can you try to:
>
> 1) Stop the boot in u-boot (press a key on the serial console)
> 2) Bring up the network, e.g. type "dhcp" then ctrl+c when it tries
> to tftp
> 3) Do: "mii read 1 0x11" in u-boot and record the output ?
>
> Regards,
>
> Hans

Hi all,

i have diffed and cross-compared logs of several working and broken tftp
downloads. The most significant
difference between working and broken was registers 0xa, 0x1c and 0x2a
in the first MII page.

These registers started making sense when I looked at the datasheet for
the RTL8211CL. Previously, I was looking at the RTL8211E.

0xA was set to 7800 for working runs and 3800 for broken runs. The
difference is bit 14 in the GBSR: 'MASTER/SLAVE Configuration
Resolution'. In the broken runs, the autonegotation configured the
OlinuXino to 'slave'. I have whipped up a quick patch which disable the
master/slave part of the autonegotiation and force master mode.

The patch itself is quite terrible as it's forcing the master mode bits
for every phy, not just for the RTL8211CL. It's good enough for testing,
however, and I seem to be getting consistent download speeds. There are
occasional hangs when booting the downloaded kernel, but that is
probably a different issue.

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 51b5746..484b2be 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -170,6 +170,7 @@ int genphy_restart_aneg(struct phy_device *phydev)
 int genphy_config_aneg(struct phy_device *phydev)
 {
        int result;
+       phy_write(phydev, MDIO_DEVAD_NONE, 0x09, 0x1A00);
 
        if (AUTONEG_ENABLE != phydev->autoneg)
                return genphy_setup_forced(phydev);

Please test this change and let me know. If it's successful, I will
submit a proper version.

Best

Michael


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