From: Florian Fainelli <f.fainelli@gmail.com>
To: Vladimir Oltean <vladimir.oltean@nxp.com>, netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Claudiu Manoil <claudiu.manoil@nxp.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
Colin Foster <colin.foster@in-advantage.com>,
Lee Jones <lee@kernel.org>,
Maksim Kiselev <bigunclemax@gmail.com>,
Maxim Kochetkov <fido_max@inbox.ru>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH net 1/3] net: dsa: seville: ignore mscc-miim read errors from Lynx PCS
Date: Fri, 24 Feb 2023 10:37:37 -0800 [thread overview]
Message-ID: <413b0b3f-4afa-a99c-33b5-341278656415@gmail.com> (raw)
In-Reply-To: <20230224155235.512695-2-vladimir.oltean@nxp.com>
On 2/24/23 07:52, Vladimir Oltean wrote:
> During the refactoring in the commit below, vsc9953_mdio_read() was
> replaced with mscc_miim_read(), which has one extra step: it checks for
> the MSCC_MIIM_DATA_ERROR bits before returning the result.
>
> On T1040RDB, there are 8 QSGMII PCSes belonging to the switch, and they
> are organized in 2 groups. First group responds to MDIO addresses 4-7
> because QSGMIIACR1[MDEV_PORT] is 1, and the second group responds to
> MDIO addresses 8-11 because QSGMIIBCR1[MDEV_PORT] is 2. I have double
> checked that these values are correctly set in the SERDES, as well as
> PCCR1[QSGMA_CFG] and PCCR1[QSGMB_CFG] are both 0b01.
>
> mscc_miim_read: phyad 8 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 8 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 8 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 8 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 9 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 9 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 9 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 9 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 10 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 10 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 10 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 10 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 11 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 11 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 11 reg 0x1 MIIM_DATA 0x2d
> mscc_miim_read: phyad 11 reg 0x5 MIIM_DATA 0x5801
> mscc_miim_read: phyad 4 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 4 reg 0x5 MIIM_DATA 0x3da01, ERROR
> mscc_miim_read: phyad 5 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 5 reg 0x5 MIIM_DATA 0x35801, ERROR
> mscc_miim_read: phyad 5 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 5 reg 0x5 MIIM_DATA 0x35801, ERROR
> mscc_miim_read: phyad 6 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 6 reg 0x5 MIIM_DATA 0x35801, ERROR
> mscc_miim_read: phyad 6 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 6 reg 0x5 MIIM_DATA 0x35801, ERROR
> mscc_miim_read: phyad 7 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 7 reg 0x5 MIIM_DATA 0x35801, ERROR
> mscc_miim_read: phyad 7 reg 0x1 MIIM_DATA 0x3002d, ERROR
> mscc_miim_read: phyad 7 reg 0x5 MIIM_DATA 0x35801, ERROR
>
> As can be seen, the data in MIIM_DATA is still valid despite having the
> MSCC_MIIM_DATA_ERROR bits set. The driver as introduced in commit
> 84705fc16552 ("net: dsa: felix: introduce support for Seville VSC9953
> switch") was ignoring these bits, perhaps deliberately (although
> unbeknownst to me).
>
> This is an old IP and the hardware team cannot seem to be able to help
> me track down a plausible reason for these failures. I'll keep
> investigating, but in the meantime, this is a direct regression which
> must be restored to a working state.
>
> The only thing I can do is keep ignoring the errors as before.
>
> Fixes: b99658452355 ("net: dsa: ocelot: felix: utilize shared mscc-miim driver for indirect MDIO access")
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
--
Florian
next prev parent reply other threads:[~2023-02-24 18:37 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 15:52 [PATCH net 0/3] Regressions in Ocelot switch drivers Vladimir Oltean
2023-02-24 15:52 ` [PATCH net 1/3] net: dsa: seville: ignore mscc-miim read errors from Lynx PCS Vladimir Oltean
2023-02-24 18:37 ` Florian Fainelli [this message]
2023-02-24 15:52 ` [PATCH net 2/3] net: dsa: felix: fix internal MDIO controller resource length Vladimir Oltean
2023-02-24 18:37 ` Florian Fainelli
2023-02-24 15:52 ` [PATCH net 3/3] net: mscc: ocelot: fix duplicate driver name error Vladimir Oltean
2023-02-24 15:58 ` Russell King (Oracle)
2023-02-24 16:09 ` Vladimir Oltean
2023-02-24 16:14 ` Russell King (Oracle)
2023-02-24 16:16 ` Vladimir Oltean
2023-02-24 16:45 ` Russell King (Oracle)
2023-02-24 18:38 ` Florian Fainelli
2023-02-27 10:52 ` Lee Jones
2023-02-27 19:40 ` [PATCH net 0/3] Regressions in Ocelot switch drivers Jakub Kicinski
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