From: Sean Anderson <sean.anderson@seco.com>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
linux-kernel@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [RFC net-next PATCH 16/16] net: sfp: Add quirk to ignore PHYs
Date: Tue, 5 Oct 2021 14:10:17 -0400 [thread overview]
Message-ID: <83797503-6459-c589-f7e5-63a4d83610cf@seco.com> (raw)
In-Reply-To: <66fd0680-a56b-a211-5f3e-ac7498f1ff9b@seco.com>
On 10/5/21 12:45 PM, Sean Anderson wrote:
>
>
> On 10/5/21 6:33 AM, Russell King (Oracle) wrote:
>> On Mon, Oct 04, 2021 at 03:15:27PM -0400, Sean Anderson wrote:
>>> Some modules have something at SFP_PHY_ADDR which isn't a PHY. If we try to
>>> probe it, we might attach genphy anyway if addresses 2 and 3 return
>>> something other than all 1s. To avoid this, add a quirk for these modules
>>> so that we do not probe their PHY.
>>>
>>> The particular module in this case is a Finisar SFP-GB-GE-T. This module is
>>> also worked around in xgbe_phy_finisar_phy_quirks() by setting the support
>>> manually. However, I do not believe that it has a PHY in the first place:
>>>
>>> $ i2cdump -y -r 0-31 $BUS 0x56 w
>>> 0,8 1,9 2,a 3,b 4,c 5,d 6,e 7,f
>>> 00: ff01 ff01 ff01 c20c 010c 01c0 0f00 0120
>>> 08: fc48 000e ff78 0000 0000 0000 0000 00f0
>>> 10: 7800 00bc 0000 401c 680c 0300 0000 0000
>>> 18: ff41 0000 0a00 8890 0000 0000 0000 0000
>>
>> Actually, I think that is a PHY. It's byteswapped (which is normal using
>> i2cdump in this way).The real contents of the registers are:
>>
>> 00: 01ff 01ff 01ff 0cc2 0c01 c001 000f 2001
>> 08: 48fc 0e00 78ff 0000 0000 0000 0000 f000
>> 10: 0078 bc00 0000 1c40 0c68 0003 0000 0000
>> 18: 41ff 0000 000a 9088 0000 0000 0000 0000
>
> Ah, thanks for catching this.
>
>> It's advertising pause + asym pause, 1000BASE-T FD, link partner is also
>> advertising 1000BASE-T FD but no pause abilities.
>>
>> When comparing this with a Marvell 88e1111:
>>
>> 00: 1140 7949 0141 0cc2 05e1 0000 0004 2001
>> 08: 0000 0e00 4000 0000 0000 0000 0000 f000
>> 10: 0078 8100 0000 0040 0568 0000 0000 0000
>> 18: 4100 0000 0002 8084 0000 0000 0000 0000
>>
>> It looks remarkably similar. However, The first few reads seem to be
>> corrupted with 0x01ff. It may be that the module is slow to allow the
>> PHY to start responding - we've had similar with Champion One SFPs.
>
> Do you have an an example of how to work around this? Even reading one
> register at a time I still get the bogus 0x01ff. Reading bytewise, a
> reasonable-looking upper byte is returned every other read, but the
> lower byte is 0xff every time.
Ok, upon further experimentation, I can read out something reasonable by using the "consecutive byte" mode
# i2cdump -y -r 0-0x3f 2 0x56 c
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 01 40 01 6d 01 41 0c c2 0c 01 c5 e1 00 0d 20 01 ?@?m?A??????.? ?
10: 59 f9 0e 00 78 00 00 00 00 00 00 00 00 00 f0 00 Y??.x.........?.
20: 00 78 ac 40 00 00 00 00 0c 68 00 00 00 00 00 00 .x?@....?h......
30: 41 00 00 00 00 0a 90 88 00 00 00 00 00 00 00 00 A....???........
I believe this is just doing i2c_smbus_write_byte+i2c_smbus_read_byte
S Addr Wr [A] Phyaddr [A] P
S Addr Rd [A] [DataHigh] NA P
S Addr Rd [A] [DataLow] NA P
as opposed to i2c_smbus_read_word_data
S Addr Wr [A] Phyaddr [A]
S Addr Rd [A] [DataHigh] A [DataLow] NA P
or i2c_smbus_read_word_data
S Addr Wr [A] Phyaddr [A]
S Addr Rd [A] [DataHigh] NA P
S Addr Wr [A] Phyaddr [A]
S Addr Rd [A] [DataLow] NA P
So now I suppose the question is whether replacing the existing i2c
logic with something like
i2c_smbus_write_byte(i2c, i2c_mii_phy_addr(phy_id));
i2c_smbus_read_byte(i2c);
i2c_smbus_read_byte(i2c);
will break everyone else's SFP phys. If it does, this could be difficult
to do as a quirk because the MII-I2C bus is created before we read the
SFP EEPROM.
--Sean
next prev parent reply other threads:[~2021-10-05 18:10 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 19:15 [RFC net-next PATCH 00/16] Add support for Xilinx PCS Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 01/16] dt-bindings: net: Add pcs property Sean Anderson
2021-10-05 9:39 ` Russell King (Oracle)
2021-10-05 16:18 ` Sean Anderson
2021-10-12 13:16 ` Rob Herring
2021-10-12 16:18 ` Sean Anderson
2021-10-12 16:44 ` Rob Herring
2021-10-12 17:01 ` Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 02/16] dt-bindings: net: Add binding for Xilinx PCS Sean Anderson
2021-10-05 12:26 ` Rob Herring
2021-10-04 19:15 ` [RFC net-next PATCH 03/16] net: sfp: Fix typo in state machine debug string Sean Anderson
2021-10-04 21:31 ` Andrew Lunn
2021-10-04 19:15 ` [RFC net-next PATCH 04/16] net: phylink: Move phylink_set_pcs before phylink_create Sean Anderson
2021-10-05 9:43 ` Russell King (Oracle)
2021-10-04 19:15 ` [RFC net-next PATCH 05/16] net: phylink: Automatically attach PCS devices Sean Anderson
2021-10-05 9:48 ` Russell King (Oracle)
2021-10-05 16:42 ` Sean Anderson
2021-10-07 10:23 ` Russell King (Oracle)
2021-10-08 0:14 ` Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 06/16] net: phylink: Add function for optionally adding a PCS Sean Anderson
2021-10-05 9:51 ` Russell King (Oracle)
2021-10-05 13:43 ` Andrew Lunn
2021-10-05 16:17 ` Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 07/16] net: phylink: Add helpers for c22 registers without MDIO Sean Anderson
2021-10-22 12:33 ` Russell King (Oracle)
2021-10-04 19:15 ` [RFC net-next PATCH 08/16] net: macb: Clean up macb_validate Sean Anderson
2021-10-04 23:04 ` Russell King (Oracle)
2021-10-04 23:09 ` Sean Anderson
2021-10-07 13:22 ` Nicolas Ferre
2021-10-08 0:20 ` Sean Anderson
2021-10-08 8:12 ` Nicolas Ferre
2021-10-04 19:15 ` [RFC net-next PATCH 09/16] net: macb: Move most of mac_prepare to mac_config Sean Anderson
2021-10-04 23:05 ` Russell King (Oracle)
2021-10-04 23:09 ` Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 10/16] net: macb: Move PCS settings to PCS callbacks Sean Anderson
2021-10-05 10:06 ` Russell King (Oracle)
2021-10-05 16:03 ` Sean Anderson
2021-10-05 18:53 ` Russell King (Oracle)
2021-10-05 21:44 ` Sean Anderson
2021-10-05 22:19 ` Russell King (Oracle)
2021-10-07 10:34 ` Russell King (Oracle)
2021-10-07 11:29 ` Russell King (Oracle)
2021-10-07 16:23 ` Russell King (Oracle)
2021-10-07 17:04 ` Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 11/16] net: macb: Support restarting PCS autonegotiation Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 12/16] net: macb: Support external PCSs Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 13/16] net: phy: Export get_phy_c22_id Sean Anderson
2021-10-05 10:12 ` Russell King (Oracle)
2021-10-04 19:15 ` [RFC net-next PATCH 14/16] net: mdio: Add helper functions for accessing MDIO devices Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 15/16] net: pcs: Add Xilinx PCS driver Sean Anderson
2021-10-04 19:15 ` [RFC net-next PATCH 16/16] net: sfp: Add quirk to ignore PHYs Sean Anderson
2021-10-04 22:01 ` Andrew Lunn
2021-10-05 10:33 ` Russell King (Oracle)
2021-10-05 16:45 ` Sean Anderson
2021-10-05 18:10 ` Sean Anderson [this message]
2021-10-05 19:12 ` Russell King (Oracle)
2021-10-05 20:38 ` Sean Anderson
2021-10-05 22:17 ` Russell King (Oracle)
2021-10-05 23:16 ` Sean Anderson
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