From: Govert Overgaauw <govert.overgaauw@prodrive-technologies.com>
To: Andrew Jeffery <andrew@aj.id.au>,
"openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>
Subject: Re: MCTP LPC FW binding
Date: Thu, 17 Mar 2022 15:42:38 +0000 [thread overview]
Message-ID: <AM9PR02MB64999E358D561C31D9B31060C1129@AM9PR02MB6499.eurprd02.prod.outlook.com> (raw)
>> Hello,
>>
>> I was wondering if anyone is/was successful in using the MCTP over LPC
>> binding with an intel platform? I read through the documents, it seems
>> to me the binding was designed to use LPC firmware cycles. To me it is
>> unclear if the ast2500 supports memory cycles on the LPC2AHB bridge
>> (datasheet seems to list it in the features, not much explanation).
>> The problem is that the C620 chipset doesn't support firmware cycles
>> (only memory and I/O cycles). And having a properly mapped window in
>> the C620 chipset and reserved memory in Linux. Writing and Reading to
>> it only returns ('1s').
>>
>> Writing a simple test on x86 that keeps writing a value to the mapped
>> registers, seems to trigger LAD[3:1] = 0xF readout on the BMC LPC host
>> controller register 0 (that has some debug registers to see the state
>> of the LPC bus). 0xF is the stop frame of a standard LPC memory cycle.
>
> As one of the authors of the binding, I just wanted to note that it was
> developed for IBM's Power systems (which support FW cycles). I haven't
> tried memory cycles, however there are other conditions under which you
> might get 0xF, such as if the LPC2AHB isn't enabled. The BMC
> aspeed-lpc-ctrl kernel driver should take care of this for you, however
> it only does so once you open the character device. From there you'll
> need to use the ioctl()s to switch the bridge to use the reserved
> memory rather than the default mapping of the host SPI-NOR.
>
> Andrew
I can confirm that the BMC works with memory cycles on the LPC bus using this binding. There was a misconfiguration on the x86 side resulting
in it not generating memory cycles on the bus.
Govert
next reply other threads:[~2022-03-18 2:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-17 15:42 Govert Overgaauw [this message]
2022-03-18 3:49 ` MCTP LPC FW binding Andrew Jeffery
-- strict thread matches above, loose matches on Subject: below --
2022-03-11 14:02 Govert Overgaauw
2022-03-15 22:42 ` Andrew Jeffery
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