HP Jornada 6xx PCMCIA driver

[Kristoffer Ericson]

On Mon, 19 Nov 2007 09:49:41 +0100
Dominik Brodowski <linux at dominikbrodowski.net> wrote:

> Hi,
> 
> On Mon, Nov 19, 2007 at 01:19:00AM -0800, Kristoffer Ericson wrote:
> > > Actually, why do you bother? The PCMCIA subsystem is capable of working with
> > > shared IRQs...
> > > 
> > So I should have same interrupt for both? Isn't it important to know
> > where the IRQ came from? Thats what puzzles me.
> 
> Well, each IRQ handler needs to check whether it is indeed the one which was
> called. So, inside hd6441_interrupt() you'd need to do the following
> 
> 	cscr = inb(cscr_reg);
> 	if !(cscr & HD64461_PCCCSCR_IRQ)
> 		return IRQ_NONE;
> 
> to avoid handling ("IRQ_HANDLED") an interrupt which wasn't caused by this
> device.
>
Oki, sounds logical. But do I need to setup io_irq "IRQ's" or does PCMCIA code register one for me? From what I've read so far
I believe I need to register the "slot IRQ" and handler, while pcmcia setups the pcmcia_card handler. Correct?
> > > > int hd64461_init_socket(int sock, int irq, int io_irq, unsigned long mem_base,unsigned long io_offset)
> > > > {
> > > > 	sp->irq = irq;
> > > ...
> > > > 	sp->socket.pci_irq = io_irq;
> > > ...
> > > > 	if ((request_irq(irq, hd64461_interrupt, IRQF_DISABLED, "hd64461_ss-irq", sp)) < 0) {
> > > 
> > > I think this should be io_irq here -- the "socket" IRQ which is demuxed to 79
> > > is io_irq; and the "card" one stays at 78. (Better use these terms than
> > > "pcmcia" interrupt -- which is ambiguous).
> > >
> > Oki, so basicly IRQ 78 for socket IRQ? I'll changed the
> > IRQF_DISABLED -> IRQF_SHARED then.
> 
> Yes, you have two alternatives: either fix up the demux by requesting io_irq
> here, or not bothering about demux and using IRQF_SHARED.
Considering how much trouble the demux is giving me, I would much rather go for IRQF_SHARED.
> 
> > It does, thx! Btw, do you have any good suggestion on which drivers to look
> > at for good reference?
> 
> Not really, but pd6729.c may be a good place to look at, for Komuro knows
> really much about the PCMCIA subsystem.
Oki, I'll take a look at that.
> 
> 	Dominik