Re: arm-lh7a40x IDE support in 2.6.6
From: Marc Singer
Date: Fri May 14 2004 - 16:34:45 EST
On Fri, May 14, 2004 at 11:23:19PM +0200, Bartlomiej Zolnierkiewicz wrote:
> On Friday 14 of May 2004 21:47, Marc Singer wrote:
> > > [ you used 'struct ide_hwif_s' in arch-lh7a40x/ide.h to workaround this
> > > 8) ]
> struct hwif_s actually
> > Copied from elsewhere.
> superio.h, superio.c
I don't think I ever looked at that code.
> EEK, added to TODO
> > Listen. It is not my intention to be clever. All I want to do is get
> > things working and to not break other people's code. I'm certain that
> > most people are working with the same assumptions. Aside from some
> > naive snippets I've see promulgated, the bulk of the kernel work I've
> > see is sane given limited information. Certainly, once one
> > understands a sybsystem completely then the quality rises. I hope
> > you'll admit that the IDE code is overly intricate.
> With changes like this nobody will ever be able to understand
> IDE subsystem completely. ;-)
I get the feeling that you're blaming me and others for making the IDE
code a mess. Might I suggest that this isn't a very productive tack?
The most helpful thing to do is to a) provide best-practice examples,
and b) to include some documentation. I'm not talking about anything
extensive, but statements like
"All references to linux/ide.h must reside in the ide tree."
Are pretty darn helpful.
> > > - you are setting IDE_NO_IRQ in ide_init_hwif_ports() which is used
> > > in many places in generic IDE code - anybody wanting to understand
> > > interactions with your code + generic code will have serious
> > > problems (especially if knows _nothing_ about lpd7a40x)
> > I don't know what you mean. I grep for that constant and found it
> > nowhere except for ide-io.c and in my code. It doesn't take much to
> > find the references.
> I'm talking about ide_init_hwif_ports() function.
Most of the ARM arch's use it. Perhaps all of them need a good once
> > What is it that you want changed?
> > > - hwif->mmio is set to 2 but resource handling is missed
> > Can you be more specific? Did you notice the comment? I didn't know
> > what it was for, but I set it because I thought that that was the
> > right way to go.
> > Are you talking about reserving the address space? At the moment,
> > this is done in the arch setup. I can certainly move it to the IDE
> > driver.
> > > > The OUTB breaks my interface because I don't really have byte-level
> > > > access to the resgisters. So, is selectproc a pre-select procedure or
> > > > should it be a substitute?
> > >
> > > pre-select but you can change it to be substitute if you need
> > > (just remember to update all users if you decide to do this)
> > I'll have to search the kernel to see what uses it. Maybe the better
> > way would be to define a new select proc that *is* a substitute.
So then we break anyone who is using the selectproc as a pre-select
proc? I don't understand what you mean here. There are several
drivers that use this function. How do you propose that we provide
both types of behavior with one entry point?
> > of the core code is fine. It is that core code that is necessary to
> > make the test possible.
> Stuff in arch-lh7a40x/ide.h is really a driver code but
> abuses subsystem code instead - that's my complain.
Right. We agree. I am talking about the core code. Not the ide
code. The core is what supports the CPU.
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