Modular ata chipsets data

[Søren Schmidt]

I found the devel tree with a modulerized ATA subsystem in it, and  
just upgraded it to the latest greatest from -current.
It can be found on http://deepcore.dk/pub/ATA as two files, ata- 
modules-diff that contains a diff for /sys/conf/files and ata- 
modules.tgz that is a replacement for /sys/dev/ata.
This turns the chipset parts into a module for each vendor, and they  
are all compiled in as is, however they can be left out on a pr vendor  
basis (there are a few interdependencies though).
I havn't written all the /sys/modules/ata/*/Makefiles that it would  
take to make it into loadable modules, but thats trivial todo.

Now what I'd like to find good generic solutions to is:

How to select the proper modules at config/compile time without  
drowning in "option ATA_BLA_BLA" in the config.

How to automagically load the right modules when device probing takes  
place. It could be loading them all in turn and unloading those that  
didnt catch anything. I'm not aware of any ways to do this in the  
kernel, but I've been unattentive for the last many months, so it  
might have crept in :)

Let me know how this works for you, I could very well be tempted to  
commit it to -current soonish as it makes some things easier to play  
with.

PS: please keep me CC'd  still, I dont read arch currently

-Søren

On 4Oct, 2008, at 19:57 , Oleksandr Tymoshenko wrote:

> Søren Schmidt wrote:
>> Hi
>> (Please keep me CC'd as I do not normally read the list)
>> Anyhow, what I would like to see is that the chipset support get  
>> moved into kernel modules, preferably auto-loadable when a given  
>> vendor is detected, but for starters that could be left out. This  
>> is the way to go for vendor supplied modules as well. I have a  
>> least 2 vendors that are looking into that way of providing support  
>> for new chipsets. For a small kernel you just load the module(s)  
>> you need and voila.
>> I have VIP in that direction, but its not finished yet, but  
>> spiitting up things is pretty trivial for the most part, except a  
>> few gotchas here and there that will make at least autoloading a  
>> wee bit tricky.
>> I guess the tedious part is to get all the code moved around into  
>> seperate files, how the actual compile/link/load should be done is  
>> a minor part that can be added when the seperaion is done.
>> However, I do have most of that in place in a tree here, so thats  
>> more or less done already, I just need to pull out the right tree  
>> here and that part should be dealt with more or less.
>    Great, I'll wait for results of your work to hit svn.
>
>> PS: in your patch you suddenly got exclusive Copyright on the Intel  
>> and AHCI code, that will get you bad karma :)
>    Ha! I cheated by helping old ladies across the street and got
> some extra karma to burn:) As I told - my vim is the one to be blamed,
> these copyrights wasn't going to make it into svn commit anyway :)
>
>
>> -Søren
>> On 4Oct, 2008, at 4:17 , Oleksandr Tymoshenko wrote:
>>> Hello -arch,
>>>
>>> I was playing with p4 mips2 branch catching up with recent  
>>> developments
>>> and trying to reduce kernel size for MALTA configuration. At some  
>>> point
>>> I ran into ata-chipset.c. This file contains all ATA chipsets  
>>> supported
>>> by FreeBSD so it was a natural candidate for axing. I hacked small
>>> proof-of-concept framework for pluggable ATA chipsets. The idea is  
>>> to
>>> move all vendor-related code to separated modules (.c, not .ko),
>>> register each during compile/link-time using ATA_CHIPSET macros
>>> (utilizes DATA_SET for this purpose) and provide each chipset with
>>> kernel config option.  Something like this Warner did to miibus/*phy
>>> about two years ago.
>>>
>>> So far I got only Intel vendor working (tested with Gxemul) and  
>>> would
>>> like to know if it's worth to keep moving in this direction and what
>>> possible pitfalls may appear.
>>>
>>> 90Kb is not that dramatical improvement :), but it's better then  
>>> nothing
>>> and code readability should be better after splitting 180K file into
>>> several, IMHO.
>>>
>>> Patch: http://people.freebsd.org/~gonzo/embedded/modular-ata.diff
>>> don't mind copyrights, they're automatically inserted by vim.
>>>
>>> -- 
>>> gonzo
>>>
>

-Søren