Limitations of entity-manager:FruDevice

[James Feist]

On 7/29/19 9:11 AM, Patrick Venture wrote:
> Hi;
> 
> I don't know much about FRUs.  However, I know that for some eeproms
> on the device-tree for my platform, the default eeprom driver instance
> isn't correct and I need to explicitly use 24c64.
> 
> root at semitruck:~# echo "eeprom 0x50" > /sys/bus/i2c/devices/i2c-14/new_device
> i2c i2c-14: new_device: Instantiated device eeprom at 0x50
> root at semitruck:~#
> root at semitruck:~# ls -l /sys/bus/i2c/devices/14-0050/
> -r--r--r--    1 root     root          4096 Jul 29 15:20 modalias
> -r--r--r--    1 root     root          4096 Jul 29 15:20 name
> drwxr-xr-x    2 root     root             0 Jul 29 15:20 power
> lrwxrwxrwx    1 root     root             0 Jul 29 15:20 subsystem ->
> ../../../../../../../bus/i2c
> -rw-r--r--    1 root     root          4096 Jul 29 15:20 uevent
> 
> root at semitruck:~# echo "24c64 0x50" > /sys/bus/i2c/devices/i2c-14/new_device
> at24 14-0050: 8192 byte 24c64 EEPROM, writable, 1 bytes/write
> i2c i2c-14: new_device: Instantiated device 24c64 at 0x50
> root at semitruck:~# ls -l /sys/bus/i2c/devices/14-0050/
> drwxr-xr-x    3 root     root             0 Jul 29 15:46 14-00500
> lrwxrwxrwx    1 root     root             0 Jul 29 15:46 driver ->
> ../../../../../../../bus/i2c/drivers/at24
> -rw-------    1 root     root          8192 Jul 29 15:46 eeprom
> -r--r--r--    1 root     root          4096 Jul 29 15:46 modalias
> -r--r--r--    1 root     root          4096 Jul 29 15:46 name
> drwxr-xr-x    2 root     root             0 Jul 29 15:46 power
> lrwxrwxrwx    1 root     root             0 Jul 29 15:46 subsystem ->
> ../../../../../../../bus/i2c
> -rw-r--r--    1 root     root          4096 Jul 29 15:46 uevent
> 
> For entity-manager, I can add the type and it'll do the right thing.
> However, when FruDevice runs first and populates the FRUs, it doesn't
> seem to detect the difference in the eeproms.  I don't know enough (as
> previously stated) to jump into fixing this, so I wanted to check if
> this was a known limitation (presumably) and whether there was a plan
> to fix it?

FruDevice basically does a i2cdetect, i2cdump, then reads the fru data 
and sees if it looks like a fru. Do i2cdetect and i2cdump work with this 
eeprom?

I know for 16 bit eeproms, that it doesn't work correctly, as in this 
thread:
https://lists.ozlabs.org/pipermail/openbmc/2019-July/017134.html

There's also a issue: https://github.com/openbmc/entity-manager/issues/1 
with a link to using device tree.

I don't have any of these eeproms available to try that don't work, I 
can't comment on others attempts to get them going.

-James

> 
> Patrick
>