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CodeConstruct / mctp

MCTP userspace tools
GNU General Public License v2.0
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MCTP over PCIe VDM #21

Closed Kendidi closed 12 months ago

Kendidi commented 12 months ago

Hi,

I wonder will there be driver support available for sending MCTP over PCIe VDM messages to device through BMC?

Many thanks! Ken

jk-ozlabs commented 12 months ago

This repo doesn't contain any transport drivers; that's all handled by the Linux kernel:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/mctp

- where the current drivers are for i2c, i3c and serial.

I don't have any plans for a PCIe VDM driver currently.

Kendidi commented 12 months ago

I see. Can you please point me to the right direction for what will need for sending MCTP over PCIe VDM messages to device?

jk-ozlabs commented 12 months ago

You'll need to write a driver along the same pattern as one of those above, but interacting with the AST2600's MCTP PCIe hardware block - see section 30 of the AST2600 datasheet.

Kendidi commented 12 months ago

Thank you very much for your direction! Where can I find the AST2600 datasheet? I tried "www.aspeedtech.com" but it required login.

Kendidi commented 12 months ago

By the way, will AST2500 work? Or only AST2600 will? Thanks!

jk-ozlabs commented 12 months ago

You will need to create an account with aspeed for that, yes, and possibly sign an agreement for access. Not sure about 2500; I'm not sure about the status of the MCTP/PCIe hardware there.

Kendidi commented 12 months ago

I see. Thank you! Beside that, do I need the ASpeed kernel driver, ast.ko?

jk-ozlabs commented 12 months ago

There is no single kernel driver for the aspeed hardware; there are all sorts of individual device drivers applicable to the platform. Some of those are common, some are ast-specific.

Which ones you need will depend on what your intended device usage is.

jk-ozlabs commented 12 months ago

Closing as not related to these mctp userspace tools, but feel free to get in touch if you need to discuss further.

Kendidi commented 12 months ago

Thank you Jeremy!!

Kendidi commented 11 months ago

Hi Jeremy,

I wonder can host submit MCTP PCIe VDM to AST2600's MCTP Controller registers through BAR X directly? Or does host need to go through PCIe Host to BMC Controller or its Mailbox? Please advise.

jk-ozlabs commented 11 months ago

Sorry, I have no idea how you would generate VDM messages on your host; I assume this is a matter of writing to the host's PCIe RC MMIO space to generate the appropriate VDM cycles (which sounds like the latter option there).

Kendidi commented 11 months ago

The VMD message bytes can be generated manually or by sw. The problem is how to send the message out to the PCIe device though AST2600, etc.