Re: [PATCH] drivers/ide: PATA driver for Celleb

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> > We use a drivers/ide driver because its design is more suitable for
> > SCC IDE controller than libata driver. Since SCC supports only 32bit
> > read/write, we must override many callbacks of ata_port_operations
> > by modifying generic helpers. Each time the libata common code is
> > updated, we must update those modified helpers. It is very hard for us.
> > But we will try to implement the libata driver as needed.
> > 
> > This patch set is intended to be merged to 2.6.20.
> > If you have any comment, please write to me.
> 
> Care to post libata version (even if it's not complete)?  Let's work 
> something out.

The main problem is error handling / reset code.

With the current libata, basically, you can only override the whole
thing pretty much at the toplevel. The problem is with things like
ata_std_prereset, ata_std_softreset and ata_std_postreset and callees.

We can either comletely re-implement them but that seems fairly dodgy to
me, or find a way to add hooks. At the end of the day, all they need is:

 - write to the control register
 - read & write of nsect_addr & lbal_addr

I wonder how much of these could be replaced by either a hook, or
taskfile accessors (possibly with a special flag).

Cheers,
Ben.