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Re: [Qemu-discuss] quick pointer on adding a new chardev

From: Herb Peyerl
Subject: Re: [Qemu-discuss] quick pointer on adding a new chardev
Date: Fri, 17 Feb 2017 09:49:05 -0700

[Thanks for your prompt and helpful reply.  I’m digesting it now.  I thought I 
would quickly respond to a couple of your points immediately.]

> On Feb 17, 2017, at 9:36 AM, Peter Maydell <address@hidden> wrote:
>> As a side note, it appears that the API has changed in recent
>> versions of qemu (CharBackend, and        DEFINE_PROP_CHR) but
>> the version of Qemu I’m using from the Xilinx Qemu tree hasn’t
>> been keeping up, as a result ‘CharBackend’ is not defined….
> I think this comes under the heading of "you should probably
> talk to Xilinx"…

Certainly.  I only mentioned it so it would be clear that I wasn’t on ‘master’ 
and was working on a different/older tree and not able to use the new style 

>>> qemu-system-aarch64: Option ‘-device myfoo’ cannot be handled by this 
>>> machine
> This is saying "I don't know about this device at all", and
> doesn't have anything to do with chardevs. I would
> start by checking that your code is really being built
> (ie you have the makefile syntax right and have specified
> in the right default-configs/ file that it should be
> built for this target architecture, and that you have
> the right syntax to register the device (the type_init
> macro and associated boilerplate).

My device is in there.  I can insmod my driver on the guest and I see my device 
registers being read/written do.  I can also ‘devmem’ to my emulated registers 
and see that the appropriate handlers are being called… When I do write(2) on 
the guest, the Qemu “Fifo” I have attached to the device is being filled.  It 
was once I had this stuff working that I wanted to bind my device to a TCP 
endpoint and how I got where I am now.

Again, thanks for your help.  I’m going to dig into the rest of your advice now.

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