RE: [PATCH net-next v1 2/4] r8169: add sfp mode for RTL8116af

[Javen]

>On 17.03.2026 04:14, Javen wrote:
>>> On 13.03.2026 08:25, Javen wrote:
>>>>> On 02.03.2026 07:32, javen wrote:
>>>>>> From: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
>>>>>>
>>>>>> RTL8116af is a variation of RTL8168fp. It uses SerDes instead of PHY.
>>>>>> But SerDes status will not relect to PHY. So it needs to add sfp
>>>>>> mode for quirk to help reflect SerDes status during PHY read.
>>>>>>
>>>>>
>>>>> Is there any mass market device using this chip version? As far as
>>>>> possible I'd like to avoid adding support for chip versions that
>>>>> never make it to the mass market. This just makes driver
>>>>> maintenance
>>> harder.
>>>>>
>>>>> The patch includes support for 100Mbps fiber mode. Is there any use
>>>>> case for such legacy modes?
>>>>>
>>>>>
>>>>>> Signed-off-by: Javen Xu <javen_xu@xxxxxxxxxxxxxx>
>>>>>> ---
>>>>>>  drivers/net/ethernet/realtek/r8169_main.c | 71
>>>>>> ++++++++++++++++++++---
>>>>>>  1 file changed, 62 insertions(+), 9 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
>>>>>> b/drivers/net/ethernet/realtek/r8169_main.c
>>>>>> index fb2247a20c36..a5c0d3995328 100644
>>>>>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>>>>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>>>>>> @@ -726,6 +726,12 @@ enum rtl_dash_type {
>>>>>>       RTL_DASH_25_BP,
>>>>>>  };
>>>>>>
>>>>>> +enum rtl_sfp_mode {
>>>>>> +     RTL_SFP_NONE,
>>>>>> +     RTL_SFP_8168_AF,
>>>>>> +     RTL_SFP_8127_ATF,
>>>>>> +};
>>>>>> +
>>>>>>  struct rtl8169_private {
>>>>>>       void __iomem *mmio_addr;        /* memory map physical address
>*/
>>>>>>       struct pci_dev *pci_dev;
>>>>>> @@ -734,6 +740,7 @@ struct rtl8169_private {
>>>>>>       struct napi_struct napi;
>>>>>>       enum mac_version mac_version;
>>>>>>       enum rtl_dash_type dash_type;
>>>>>> +     enum rtl_sfp_mode sfp_mode;
>>>>>>       u32 cur_rx; /* Index into the Rx descriptor buffer of next Rx pkt. */
>>>>>>       u32 cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */
>>>>>>       u32 dirty_tx;
>>>>>> @@ -760,7 +767,6 @@ struct rtl8169_private {
>>>>>>       unsigned supports_gmii:1;
>>>>>>       unsigned aspm_manageable:1;
>>>>>>       unsigned dash_enabled:1;
>>>>>> -     bool sfp_mode:1;
>>>>>>       dma_addr_t counters_phys_addr;
>>>>>>       struct rtl8169_counters *counters;
>>>>>>       struct rtl8169_tc_offsets tc_offset; @@ -1126,7 +1132,7 @@
>>>>>> static int r8168_phy_ocp_read(struct rtl8169_private *tp, u32 reg)
>>>>>>               return 0;
>>>>>>
>>>>>>       /* Return dummy MII_PHYSID2 in SFP mode to match SFP PHY
>>>>>> driver
>>> */
>>>>>> -     if (tp->sfp_mode && reg == (OCP_STD_PHY_BASE + 2 *
>MII_PHYSID2))
>>>>>> +     if (tp->sfp_mode == RTL_SFP_8127_ATF && reg ==
>>>>> (OCP_STD_PHY_BASE
>>>>>> + + 2 * MII_PHYSID2))
>>>>>>               return PHY_ID_RTL_DUMMY_SFP & 0xffff;
>>>>>>
>>>>>>       RTL_W32(tp, GPHY_OCP, reg << 15); @@ -1270,6 +1276,34 @@
>>>>>> static int r8168g_mdio_read(struct rtl8169_private *tp, int reg)
>>>>>>       return r8168_phy_ocp_read(tp, tp->ocp_base + reg * 2);  }
>>>>>>
>>>>>> +/* The quirk reflects RTL8116af SerDes status. */ static int
>>>>>> +r8116af_mdio_read_quirk(struct rtl8169_private *tp, int reg) {
>>>>>> +     u8 phyStatus = RTL_R8(tp, PHYstatus);
>>>>>> +
>>>>>> +     if (!(phyStatus & LinkStatus))
>>>>>> +             return 0;
>>>>>> +
>>>>>> +     /* BMSR */
>>>>>> +     if (tp->ocp_base == OCP_STD_PHY_BASE && reg == MII_BMSR)
>>>>>> +             return BMSR_ANEGCOMPLETE | BMSR_LSTATUS;
>>>>>> +
>>>>>> +     /* PHYSR */
>>>>>> +     if (tp->ocp_base == 0xa430 && reg == 0x12) {
>>>>>> +             if (phyStatus & _1000bpsF)
>>>>>> +                     return 0x0028;
>>>>>> +             else if (phyStatus & _100bps)
>>>>>> +                     return 0x0018;
>>>>>
>>>>> This is a complete hack. Any means to access the SerDes directly?
>>>>
>>>> Hi, Heiner
>>>> Now we find a indirect access to serdes reg. The serdes reg is
>>>> designed
>>> according to IEEE 802.3.
>>>> BIT 2 means Link Status and BIT 5 means ANEGCOMPLETE. We can access
>>>> it through read mac ocp 0xeb14, I wonder whether this indirect
>>>> access can be
>>> accepted?
>>>>
>>> Based on the bit numbers this seems to be the BMSR register. Can all
>>> clause
>>> 22 registers be accessed in a similar way so that a MII bus can be
>>> implemented for accessing the SerDes?
>>
>> We checked our chip documentation and confirmed that the SerDes
>> register file maps all clause 22 registers(e.g. WR 0xeb10<reg_addr>,
>> RD 0xeb14. reg_addr 0x40 is for BMCR,
>> 0x41 for BMSR, 0x42 for PHYSID1, 0x43 for PHYSID2, etc.) As you
>> suggested, I wonder whether the proper approach is to implement a
>> virtual mii_bus and map the standard serdes reg in the new map.
>>
>We'd need to know how the internal PHY and the SerDes play together.
>Whether the usual internal PHY plays any role in communication between
>MAC and SerDes.
>How interface modes are controlled on MAC and SerDes side, etc.
>If Realtek doesn't implement proper layering in hw, and doesn't have enough
>knowledge about mainline network driver structures, and on the other hand
>doesn't want to provide chip documentation, then the situation somewhat
>deadlocks.
>

Hi, Heiner
For RTL8116af, the datapath is structured as MAC->PCS->SerDes.
However, PCS block does not have a standard MDIO interface. Instead, we have to 
access the standard reg via MAC OCP.These standard registers are exactly the standard 
IEEE 802.3 Clause 22 PHY registers.
Given hardware information above, I would like to ask for your advice on the recommended 
approach to support RTL8116af. Or any other information do I need to provide?

Thanks,
Javen Xu

>>> In general it's hard to provide a statement w/o knowing the internal
>>> layout of the IP blocks.
>>> Can you provide any chip documentation / datasheet?
>>> For proper support of such a component chain between MAC and SFP port
>>> the driver would have to be converted to use phylink, what requires
>>> access to the involved components, incl. the SFP I2C bus.
>>>
>>>
>>>> Thanks,
>>>> Javen Xu
>>>>
>>>>>
>>>>>> +     }
>>>>>> +
>>>>>> +     return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static int r8116af_mdio_read(struct rtl8169_private *tp, int reg) {
>>>>>> +     return r8168g_mdio_read(tp, reg) |
>>>>>> +r8116af_mdio_read_quirk(tp, reg); }
>>>>>> +
>>>>>>  static void mac_mcu_write(struct rtl8169_private *tp, int reg,
>>>>>> int
>>>>>> value)  {
>>>>>>       if (reg == 0x1f) {
>>>>>> @@ -1280,6 +1314,13 @@ static void mac_mcu_write(struct
>>>>>> rtl8169_private
>>>>> *tp, int reg, int value)
>>>>>>       r8168_mac_ocp_write(tp, tp->ocp_base + reg, value);  }
>>>>>>
>>>>>> +static bool rtl_is_8116af(struct rtl8169_private *tp) {
>>>>>> +     return tp->mac_version == RTL_GIGA_MAC_VER_52 &&
>>>>>> +             (r8168_mac_ocp_read(tp, 0xdc00) & 0x0078) == 0x0030 &&
>>>>>> +             (r8168_mac_ocp_read(tp, 0xd006) & 0x00ff) == 0x0000;
>>>>>> +}
>>>>>> +
>>>>>>  static int mac_mcu_read(struct rtl8169_private *tp, int reg)  {
>>>>>>       return r8168_mac_ocp_read(tp, tp->ocp_base + reg); @@
>>>>>> -1386,7
>>>>>> +1427,10 @@ static int rtl_readphy(struct rtl8169_private *tp, int
>>>>>> +location)
>>>>>>       case RTL_GIGA_MAC_VER_31:
>>>>>>               return r8168dp_2_mdio_read(tp, location);
>>>>>>       case RTL_GIGA_MAC_VER_40 ... RTL_GIGA_MAC_VER_LAST:
>>>>>> -             return r8168g_mdio_read(tp, location);
>>>>>> +             if (tp->sfp_mode == RTL_SFP_8168_AF)
>>>>>> +                     return r8116af_mdio_read(tp, location);
>>>>>> +             else
>>>>>> +                     return r8168g_mdio_read(tp, location);
>>>>>>       default:
>>>>>>               return r8169_mdio_read(tp, location);
>>>>>>       }
>>>>>> @@ -1575,6 +1619,20 @@ static bool rtl_dash_is_enabled(struct
>>>>> rtl8169_private *tp)
>>>>>>       }
>>>>>>  }
>>>>>>
>>>>>> +static enum rtl_sfp_mode rtl_get_sfp_mode(struct rtl8169_private
>>>>>> +*tp) {
>>>>>> +     if (rtl_is_8125(tp)) {
>>>>>> +             u16 data = r8168_mac_ocp_read(tp, 0xd006);
>>>>>> +
>>>>>> +             if ((data & 0xff) == 0x07)
>>>>>> +                     return RTL_SFP_8127_ATF;
>>>>>> +     } else if (rtl_is_8116af(tp)) {
>>>>>> +             return RTL_SFP_8168_AF;
>>>>>> +     }
>>>>>> +
>>>>>> +     return RTL_SFP_NONE;
>>>>>> +}
>>>>>> +
>>>>>>  static enum rtl_dash_type rtl_get_dash_type(struct
>>>>>> rtl8169_private
>>>>>> *tp)  {
>>>>>>       switch (tp->mac_version) {
>>>>>> @@ -5693,12 +5751,7 @@ static int rtl_init_one(struct pci_dev
>>>>>> *pdev, const
>>>>> struct pci_device_id *ent)
>>>>>>       }
>>>>>>       tp->aspm_manageable = !rc;
>>>>>>
>>>>>> -     if (rtl_is_8125(tp)) {
>>>>>> -             u16 data = r8168_mac_ocp_read(tp, 0xd006);
>>>>>> -
>>>>>> -             if ((data & 0xff) == 0x07)
>>>>>> -                     tp->sfp_mode = true;
>>>>>> -     }
>>>>>> +     tp->sfp_mode = rtl_get_sfp_mode(tp);
>>>>>>
>>>>>>       tp->dash_type = rtl_get_dash_type(tp);
>>>>>>       tp->dash_enabled = rtl_dash_is_enabled(tp);
>>>>
>>