On Friday 12 June 2009 21:07:34 Sergei Shtylyov wrote:
> Hello.
>
> Bartlomiej Zolnierkiewicz wrote:
>
> >>>> There are now two methods that clear the port interrupt: ack_intr() method,
> >>>> implemented only on M680x0 machines, that is called at the start of ide_intr(),
> >>>> and clear_irq() method, that is called somewhat later in this function. In
> >>>> order to stop this duplication, delegate the task of clearing the interrupt
> >>>> to clear_irq() method, only leaving to ack_intr() the task of testing for the
> >>>> port interrupt. This involves moving clear_irq() method call in ide_intr()
> >>>> closer to the beginning of the function and removing ack_intr() method call
> >>>> in ide_timer_expiry(), now becoming useless...
> >>>>
> >>>> Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
> >>>>
> >>>> ---
> >>>> The patch is atop of ide-2.6.git 'for-next' branch.
> >>>>
> >>>> drivers/ide/gayle.c | 23 +++++++++++------------
> >>>> drivers/ide/ide-io.c | 11 ++++-------
> >>>> drivers/ide/macide.c | 18 ++++++++++++++----
> >>>> 3 files changed, 29 insertions(+), 23 deletions(-)
> >>>>
> >>>> Index: ide-2.6/drivers/ide/gayle.c
> >>>> ===================================================================
> >>>> --- ide-2.6.orig/drivers/ide/gayle.c
> >>>> +++ ide-2.6/drivers/ide/gayle.c
> >>>> @@ -66,7 +66,7 @@ MODULE_PARM_DESC(doubler, "enable suppor
> >>>> * Check and acknowledge the interrupt status
> >>>> */
> >>>>
> >>>> -static int gayle_ack_intr_a4000(ide_hwif_t *hwif)
> >>>> +static int gayle_ack_intr(ide_hwif_t *hwif)
> >>>> {
> >>>> unsigned char ch;
> >>>>
> >>>> @@ -76,16 +76,12 @@ static int gayle_ack_intr_a4000(ide_hwif
> >>>> return 1;
> >>>> }
> >>>>
> >>>> -static int gayle_ack_intr_a1200(ide_hwif_t *hwif)
> >>>> +static void gayle_a1200_clear_irq(ide_drive_t *drive)
> >>>> {
> >>>> - unsigned char ch;
> >>>> + ide_hwif_t *hwif = drive->hwif;
> >>>>
> >>>> - ch = z_readb(hwif->io_ports.irq_addr);
> >>>> - if (!(ch & GAYLE_IRQ_IDE))
> >>>> - return 0;
> >>>> (void)z_readb(hwif->io_ports.status_addr);
> >>>> z_writeb(0x7c, hwif->io_ports.irq_addr);
> >>>> - return 1;
> >>>> }
> >>>>
> >>>>
> >>> buddha.c needs a similar treatment
> >>>
> >>>
> >> Do you mean this fragment of xsurf_ack_intr()?
> >>
> >
> > Yes.
> >
>
> OK, I'm taking your word for it.
Don't take my word on it, jut cc: m68k guys. :)
> >> /* X-Surf needs a 0 written to IRQ register to ensure ISA bit A11 stays at 0 */
> >> z_writeb(0, hwif->io_ports.irq_addr);
> >>
>
> Ah, that's "A11", not "All"
lol
> >>
> >> I felt doubtful about it and decided to leave it as is.
> >>
> >>
> >>>> --- ide-2.6.orig/drivers/ide/ide-io.c
> >>>> +++ ide-2.6/drivers/ide/ide-io.c
> >>>>
> >>>>
> >>>
> >>>
> >>>> @@ -791,6 +789,10 @@ irqreturn_t ide_intr (int irq, void *dev
> >>>> goto out;
> >>>>
> >>>> handler = hwif->handler;
> >>>> + drive = hwif->cur_dev;
> >>>> +
> >>>> + if (hwif->port_ops && hwif->port_ops->clear_irq)
> >>>> + hwif->port_ops->clear_irq(drive);
> >>>>
> >>>>
> >>> We need to check for valid ->handler before using ->cur_dev
> >>> (it may contain a stale value otherwise).
> >>>
> >>>
> >> Hm...
> >>
>
> Do we really care about the valid 'drive' here? Ah, we do, for the
> sake of piix.c's implementation of clear_irq(); otherwise, we really
> don't...
We want a good and maintainable design/code. Not WorksForMeToday one.
> >>> Moreover I somehow miss the point of moving ->clear_irq call here
> >>>
> >>>
> >> I moved it here because ack_intr() was clearing the interrupt at
> >> exactly *this* point.
> >>
> >
> > ack_intr() is a m68k-specific thing -- please take a look at things from
> > this perspective.
> >
>
> I'm not sure what you mean by "this perspective". I've been looked at
> it from the more common perspective from which clearing IRQ earlier also
> made sense. When the handler is missing, we always "whack" the status
> register to clear the interrupt, so it seemed consistent to also clear
> it in the controller before doing this.
>
> >>> (it should be done after we know that it is really our IRQ).
> >>>
> >> I don't think that really matters much...
> >>
> >
> > We can have ->clear_irq without ->test_irq (i.e. piix) and thus end up
> > incorrectly clearing IRQ in case of shared IRQs..
> >
>
> I doubt that you really can clear IRQ "incorrectly"... speaking of
> existing clear_irq() implementation, I should have added test_irq()
> handler to piix.c...
Depends on the low-level hardware implementation.
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
