Access Intel ME IPMB from BMC

[Vijay Khemka]

As i2c slave mqueue driver is not upstreamed and with already having same functionality in ipmb-dev driver which is already in uostream kernel, I don’t see any reason to use i2c slave mqueue driver. I highly incourage people to use ipmb-dev driver with latest ipmbbridge. If there are any issues, please let us know.

Regards
-Vijay

From: Oskar Senft <osk at google.com>
Date: Thursday, April 23, 2020 at 8:34 AM
To: Vijay Khemka <vijaykhemka at fb.com>
Cc: OpenBMC Maillist <openbmc at lists.ozlabs.org>
Subject: Re: Access Intel ME IPMB from BMC

On a side note regarding the ipmb-dev driver: It seems that the Documentation/IPMB.txt has gotten "lost". The only version I could find is this: https://github.com/openbmc/linux/blob/51bd6f291583684f495ea498984dfc22049d7fd2/Documentation/IPMB.txt. But it's not in any of the recent branches (dev-5.3 or dev-5.4).

Should this file be resurrected?

Oskar.

On Thu, Apr 23, 2020 at 11:31 AM Oskar Senft <osk at google.com<mailto:osk at google.com>> wrote:
Thanks again!

ipmbbridge solved my problem. I found that my version of OpenBMC (incl. kernel) used a slightly older version of ipmbbridge which still used the i2c slave mqueue, which worked fine. Reading a bit of source code made it clear how it worked. The key is to configure ipbm-channels.json with the correct i2c device and the rest "just works".

For the benefit of others: My understanding is that the current version of ipmbbridge no longer uses the i2c slave mqueue but requires the ipmb-dev driver in the kernel. It's not necessary to actually attach the driver to an i2c device as that can happen at runtime.

Oskar.


On Mon, Apr 20, 2020 at 4:34 PM Vijay Khemka <vijaykhemka at fb.com<mailto:vijaykhemka at fb.com>> wrote:
Hi Oskar,
You need to use ipmb-dev driver which is is being used by ipmbbridge. You don’t need ipmb-host as we are having ipmbbridge to replace that.

Regards
-Vijay

From: Oskar Senft <osk at google.com<mailto:osk at google.com>>
Date: Monday, April 20, 2020 at 11:35 AM
To: Vijay Khemka <vijaykhemka at fb.com<mailto:vijaykhemka at fb.com>>
Cc: OpenBMC Maillist <openbmc at lists.ozlabs.org<mailto:openbmc at lists.ozlabs.org>>
Subject: Re: Access Intel ME IPMB from BMC

Hi Vijay

Thanks for the pointer!

I also found both https://github.com/Mellanox/ipmb-host and https://github.com/openbmc/linux/blob/dev-5.4/drivers/char/ipmi/ipmb_dev_int.c.

Is it right that with ipmbbridge I don't need either of them since ipmbbridge uses the raw i2c dev?

Thanks
Oskar.

On Mon, Apr 20, 2020 at 2:12 PM Vijay Khemka <vijaykhemka at fb.com<mailto:vijaykhemka at fb.com>> wrote:
Hi Oskar,
You need to configure your ME channel in ipmb channel config file https://github.com/openbmc/ipmbbridge/blob/master/ipmb-channels.json
And make sure ipmbbridge is running. Then you can send get device id command to ME from command line itself to test if everything is working.



busctl call xyz.openbmc_project.Ipmi.Channel.Ipmb /xyz/openbmc_project/Ipmi/Channel/Ipmb org.openbmc.Ipmb sendRequest yyyyay 1 6 0 0x1 0

Regards
-Vijay

From: openbmc <openbmc-bounces+vijaykhemka=fb.com at lists.ozlabs.org<mailto:fb.com at lists.ozlabs.org>> on behalf of Oskar Senft <osk at google.com<mailto:osk at google.com>>
Date: Saturday, April 18, 2020 at 6:47 PM
To: OpenBMC Maillist <openbmc at lists.ozlabs.org<mailto:openbmc at lists.ozlabs.org>>
Subject: Access Intel ME IPMB from BMC

Hi everyone

I'm trying to find out how I can access the Intel ME via IPMB from the BMC (OpenBMC).

From what I gathered, Intel ME's IPMB is on the PCH's SMLink0. I know this is connected to one of the SMBus modules on my AST2500. But what I can't find out is how I actually send commands there? I'm sure I'm missing a document that makes this obvious.

Or is it as simple as dropping IPMI packets onto the bus?

Is this by any chance already implemented in OpenBMC?

Thanks for any hints!

Oskar
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