netdev - Re: mv88e6xxx: Timeout waiting for EEPROM done

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Message-ID: <CAOMZO5D-F+V+5LFGqiw_N8tNPtAVMANGQjUnUW9_WeTj6sBN5g@mail.gmail.com>
Date: Tue, 19 Sep 2023 16:23:01 -0300
From: Fabio Estevam <festevam@...il.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: Vladimir Oltean <olteanv@...il.com>, l00g33k@...il.com, netdev <netdev@...r.kernel.org>, 
	Jakub Kicinski <kuba@...nel.org>, sashal@...nel.org
Subject: Re: mv88e6xxx: Timeout waiting for EEPROM done

Hi Andrew,

On Fri, Sep 15, 2023 at 3:23 PM Andrew Lunn <andrew@...n.ch> wrote:

> The problem with this is that the way to read the contests of the
> EEPROM depend on the switch family.
>
> linux/drivers/net/dsa/mv88e6xxx$ grep \.get_eeprom chip.c
>         .get_eeprom = mv88e6xxx_g2_get_eeprom8,
>         .get_eeprom = mv88e6xxx_g2_get_eeprom16,

Indeed, there are two methods for reading the EEPROM.

> And how do you know the EEPROM does not in fact contain 0xffff?

The functional spec doc says:

"If the just read in Command is all one’s, terminate the serial EEPROM
reading process, go to 8."

> What i found interesting in the datasheet for the 6352:
>
>      The EEInt indicates the processing of the EEPROM contents is
>      complete and the I/O registers are now available for CPU
>      access. A CPU can use this interrupt to know it is OK to start
>      accessing the device’s registers. The EEInt will assert the
>      device’s INT pin even if not EEPROM is attached unless the EEPROM
>      changes the contents of the EEIntMast register (Global 1, offset
>      0x04) or if the Test SW_MODE has been configured (see 8888E6352,
>      88E6240, 88E6176, and 88E6172 Functional Specification Datasheet,
>      Part 1 of 3: Overview, Pinout, Applications, Mechanical and
>      Electrical Specifications for details).  The StatsDone, VTUDone
>      and ATUDone interrupts de-assert after the Switch Globa
>
> So i would expect that EEInt is set when there is no EEPROM.
>
> What strapping do you have for SW_MODE? Is the switch actually in
> standalone mode?

Pardon my ignorance, but I don't know the answer to these.

I do have access to the schematics. How can I tell?

Thanks