Re: [RFC] Inter-processor Mailboxes Drivers

On 02/15/2011 01:58 PM, Meador Inge wrote:

On 02/14/2011 04:01 AM, Jamie Iles wrote:

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On Fri, Feb 11, 2011 at 03:19:51PM -0600, Meador Inge wrote:

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     1. Hardware specific bits somewhere under '.../arch/*'.  =

Drivers

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        for the MPIC message registers on Power and OMAP4 mailboxes, =

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for
        example.
     2. A higher level driver under '.../drivers/mailbox/*'.  That =

the

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        pieces in (1) would register with.  This piece would expose =

the

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        main kernel API.
     3. Userspace interfaces for accessing the mailboxes.  A
        '/dev/mailbox1', '/dev/mailbox2', etc... mapping, for =

example.

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How about using virtio for all of this and having the mailbox as a
notification/message passing driver for the virtio backend?  There =

are

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already virtio console and network drivers that could be useful for =

the

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userspace part of it.  drivers/virtio/virtio_ring.c might be a good
starting point if you thought there was some mileage in this =

approach.

To be honest, I am not that familiar with 'virtio', but I will take a=20
look.  Thanks for the pointer.  Maybe Hollis can speak to this idea =

more.
My opinion is that virtio is (over?) complicated.

I've looked into it in the past, and I'm definitely open to using it if=20
somebody can demonstrate how easy it is, but adopting it wouldn't have=20
helped OpenMCAPI with our use cases, and would have incurred extra pain, =

so we didn't.

Hollis Blanchard
Mentor Graphics, Embedded Systems Division