Re: [Qemu-devel] Config file support

[Rob Landley <rob@landley.net>]

On Monday 23 October 2006 7:33 pm, Paul Brook wrote:

> My intention is that a machine config file would remove the "motherboard" 
bits 
> altogether. ie. the config file describes everything that pc_init_1 does. 
The 
> first half of pc.c would remain because that's device emulation.

Sounds highly cool.  I'm quite in favor of _that_ kind of config file.

> For things like network/serial/disks we need to figure out how to make the 
> machine description adapt to the config the user requested. Proably want to 
> replace the fixed tables eg. bs_table with some mechanism for 
> identifying/requesting disks by name.

If some of the hardware could be hotpluggable, that would be cool.  (I've 
hotpluged real IDE disks, ill-advised as that is.)  I dunno what has ordering 
requirements (or more specifically, dependencies on previous hardware) 
though.

> Take the Integrator/CP board as an example. I'd expect the machine config to 
> look something like:
> 
> ram {base=0; size=RAM_SIZE, physaddr=0}
> ram {base=0x80000000; size=RAM_SIZE, physaddr=0}
> integrator_core{ram_size=RAM_SIZE};
> arm_cpu_pic {cpu_index=0, pic_name="CPU0"}
> integrator_pic {pic_name="PRIMARY", base=0x14000000,parent="CPU0", 
> parent_irq=0, parent_fiq=1}
> integrator_pic {pic_name="SECONDARY", base=0xca000000, pic="PRIMARY",irq=0, 
> fiq=1}
> integrator_pit{base=0x13000000, pic="PRIMARY", irq=5}
> pl011{base=0x16000000, name="serial0", pic="PRIMARY", irq=1}
> etc.
> 
> The syntax I just made up, and there are the issues I mentioned above, but 
> hopefully you get the idea.

The syntax looks fine to me, and I can see where bits of that come from 
hw/integratorcp.c intergratorcp_init(), but when in that file I also see 
things like struct integratorcm_state and icp_pic_read() in there, and I 
don't know how they relate.  The "here's a new device: it's a DMA controller" 
and "here's a new motherboard that has all these chips and devices on it 
wired together this way" is all mixed together in the same files.  I have 
trouble figure out which bits belong to which categories.

Possibly I should be poking at application emulation first, rather than system 
emulation.  Easier to follow what's happening when you run "hello world"...

Rob
-- 
"Perfection is reached, not when there is no longer anything to add, but
when there is no longer anything to take away." - Antoine de Saint-Exupery