Re: [PATCH 2/4] acpi: add aml/asl parsing script

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Sep 21, 2011 at 05:27:32PM +0300, Gleb Natapov wrote:
> On Wed, Sep 21, 2011 at 03:44:29PM +0300, Michael S. Tsirkin wrote:
> > script ./src/find_ej0.pl finds all instances of
> > method named EJ0_ and the matching _ADR information,
> > and outputs the AML offset and slot mask of each.
> > 
> There is tools/ directory for such kind of scripts. Most (if not all) of
> scripts there are in python though.

OK, rewriting that in python should be easy.
I'll wait a bit for more comments on the design though.

> Perl should die painful death.
> 
> This approach delivers nice result, but since the script does not really
> decodes AML, but tries to match ASL source code with regular expressions,
> it introduces some assumptions to the code that make DSDT code less
> hackable. I'll hate to be the one who will have to change PCI device
> definitions in DSDT next time.

There are three requirements now:
1. don't use the name EJ0_ anywhere if you don't want it patches
2. _ADR must be an integer constant
3. put _ADR name immediately before EJ0_ method
I tried to make it easy to obey these rules
by adding comments in source code.

I don't believe a generic mechanism that does not place
any restrictions on language use is possible without adding an
AML interpreter in bios.

> Generally speaking finding an offset of some scope in AML is useful not
> only for PCI hotplug. For instance we want to make S3/S4 capability
> configurable by a command line switch, but this also requires DSDT
> patching and having automatic way to find _S3_/_S4_ offset is required
> for that too (we do not what to find it by hand each time DSDT is
> recompiled).

Right. So that would be an easy extension.
We could also add some directives for the tool
(e.g. in C comments) so that you can e.g. find more names
just by adding such a directive in dsl.

I'll be happy to work on that preferably
after we merge a simple version of the tool first.