Re: [PATCH v2] net: mtk_sgmii: implement mtk_pcs_ops

["Bjørn Mork" <bjorn@mork.no>]

"Russell King (Oracle)" <linux@armlinux.org.uk> writes:

> On Mon, Jan 16, 2023 at 04:21:30PM +0100, Bjørn Mork wrote:
>> [   54.539438] mtk_soc_eth 15100000.ethernet wan: Link is Down
>> [   56.619937] mtk_sgmii_select_pcs: id=1
>> [   56.623690] mtk_pcs_config: interface=4
>> [   56.627511] offset:0 0x140
>> [   56.627513] offset:4 0x4d544950
>> [   56.630215] offset:8 0x20
>> [   56.633340] forcing AN
>> [   56.638292] mtk_pcs_config: rgc3=0x0, advertise=0x1 (changed), link_timer=1600000,  sgm_mode=0x103, bmcr=0x1000, use_an=1
>> [   56.649226] mtk_pcs_link_up: interface=4
>> [   56.653135] offset:0 0x81140
>> [   56.653137] offset:4 0x4d544950
>> [   56.656001] offset:8 0x1
>> [   56.659137] mtk_soc_eth 15100000.ethernet wan: Link is Up - 1Gbps/Full - flow control rx/tx
>
> Thanks - there seems to be something weird with the bmcr value printed
> above in the mtk_pcs_config line.
>
> You have bmcr=0x1000, but the code sets two bits - SGMII_AN_RESTART and
> SGMII_AN_ENABLE which are bits 9 and 12, so bmcr should be 0x1200, not
> 0x1000. Any ideas why?

No, not really

> Can you also hint at what the bits in the PHY register you quote mean
> please?

This could very well be a red herring.  It's the only difference I've
been able to spot, but I have no idea what it means.

This is an attempt at reformatting the pdf tables for email.  Hope it's
readable: 


VSPEC1_SGMII_STAT                                 Reset Value
Chip Level SGMII status register (Register 30.9)  0008 H

15        14..8   7     6     5     4     3     2    1 .. 0
MACSEC_*  Res     RES   Res   ANOK  RF    ANAB  LS   DR
ro                ro          ro    rolh  ro    roll ro


Field      Bits Type Description

MACSEC_CAP 15   RO   MACSEC Capability in the product
                     0 B DISABLED Product is not MACSEC capable
                     1 B ENABLED Product is MACSEC capable
RES        7    RO   Reserved
                     Ignore when read.
ANOK       5    RO   Auto-Negotiation Completed
                     Indicates whether the auto-negotiation process is completed or not.
                     0 B RUNNING Auto-negotiation process is in progress or not started
                     1 B COMPLETED Auto-negotiation process is completed
RF         4    ROLH Remote Fault
                     Indicates the detection of a remote fault event.
                     0 B INACTIVE No remote fault condition detected
                     1 B ACTIVE Remote fault condition detected
ANAB       3    RO   Auto-Negotiation Ability
                     Specifies the auto-negotiation ability.
                     0 B DISABLED PHY is not able to perform auto-negotiation
                     1 B ENABLED PHY is able to perform auto-negotiation
LS         2    ROLL Link Status
                     Indicates the link status of the SGMII
                     0 B INACTIVE The link is down. No communication with link partner possible.
                     1 B ACTIVE The link is up. Data communication with link partner is possible.
DR         1:0  RO   SGMII Data Rate
                     This field indicates the operating data rate of SGMII when link is up
                     00 B DR_10 SGMII link rate is 10 Mbit/s
                     01 B DR_100 SGMII link rate is 100 Mbit/s
                     10 B DR_1G SGMII link rate is 1000 Mbit/s
                     11 B DR_2G5 SGMII link rate is 2500 Mbit/s



Bjørn