Re: IBM Microdrive PCCard on TiBook (ide-cs module)

Ira Weiny wrote:

I have spent a little more time tracking down why the PCCard adapter for
my Microdrive causes the TiBook to shutdown.  But I need some help in
interpreting the information I have found.

Your symptoms sound similar to the ones i was seeing.
I recently did some work to get a PCMCIA ATA Flash card running on a
405GP (using a circa 2.4.0 kernel with some later pcmcia updates from
the 2.4-devel tree).  I ran into a large number of problems with
interrupts that would hang the system, but haven't figured out what to
do with them.  The basic issue i had was that the ide interrupt is
shared with the pc card controller and during drive probing the prober
issues a command which generates an interrupt with no ide interrupt
handler in place but the pccard interrupt handler gets flooded since it
is sharing the same line.  I 'fixed' the problem by disabling the
specific interrupt from ide-cs.c right before the call to ide_register()
and then (ughh) re-enabled it from inside init_irq() in ide-probe.c
(rather than re-enabling it right after the call to ide_register() to
avoid missing interrupts :(.  Additionally i did something to force the
SHIRQ flag when the irq was requested.  ide-cs differs from other card
service drivers in that the others usually install the interrupt handler
themselves, but ide-cs lets the rest of the ide susbsystem do it.
	david

1) I was able to catch with xmon a stack trace before it shutdown.  This
showed a stack trace as follows:

ide-cs.c:ide_config
ide.c:ide_register
ide.c:ide_register_hw
ide.c:ide_probe_module
ide-probe.c:ideprobe_init
ide-probe.c:probe_hwif
ide-probe.c:do_probe
ide-probe.c:try_to_identify
ide-probe.c:actual_try_to_identify  <== shutdown somewhere here??

2) I am assuming at this point it is writing to registers which are
mapped incorrectly (probably to the PMU) which cause it to shutdown.

3) I have found that the io_base addresses is 0x1000 (as set in my
config.opts file) and this is what is passed to the ide_register
function.  Changing this address does not seem to change it's behavior
though.  (??)

4) ide_register calls ide_init_hwif_ports with these addresses which
have a "pmac_" specific call.  So I am assuming that it would "ioremap"
these as appropriate.  (However, I don't see it modifying this address
at all?)

5) ide_register_hw calls "ide_probe_module" which takes me into the
ide-probe.c file.  But I see a specific "pmac_ide_probe" which is called
at init time.

My conclusion is that I should either be calling this pmac_ide_probe
rather than the generic ide_probe module (and making it _not_ an init
function).  OR I need to modify the ide_probe module to handle the
proper maping of the addresses such that I don't write to the PMU.

Unfortunatly I have not found any examples of the later in the pcmcia
drivers I have looked at so I am worried that I am totally off base.  If
I am "barking up the wrong tree" I hope someone can tell me such that I
can start looking elsewhere.

Thanks in advance,
Ira Weiny
iweiny@acm.org

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