Subject: Re: Oops in IDE probing on ppc_440 when PCI is enabled in strapping

From: Benjamin Herrenschmidt <[email-masked]>
Date: Tue, 15 Sep 2009 10:42:21 +1000

On Mon, 2009-09-14 at 15:08 +0200, Ludo Van Put wrote:
> 2009/9/14 Josh Boyer <[email-masked]>:
> > On Mon, Sep 14, 2009 at 02:36:15PM +0200, Ludo Van Put wrote:
> >>Hi,
> >>
> >>we're working with a PPC440GX on a board that has a.o. a compact flash slot.
> >>We had the PCI subsystem of the ppc disabled in strapping for quite a while,
> >>until we wanted to start using it.
> >>However, when we enabled PCI in the strapping and in the (patched 2.6.10)
> >
> > 2.6.10?  Really?  If that is truly the case, you probably aren't going to get
> > a whole lot of help from the list, since that kernel is pretty ancient.
> >
> I can only acknowledge that, but we're stuck to that kernel for now...
> 
> >>kernel configuration, we triggered an oops when probing for IDE devices (to
> >>read out the first 512 bytes of the CF). I can see that the ioremap64 call
> >>in the driver code for our CF returns a different address (compared to PCI
> >>disabled in strapping), but using this address later on for accessing the CF
> >>goes wrong.
> >
> > Posting the oops output would perhaps help.  Or maybe not.
> >
> > josh
> >
> 
> Here it goes, you never know:
> 
> Oops: kernel access of bad area, sig: 11 [#1]
> PREEMPT
> NIP: C0148050 LR: C013BC64 SP: C07CFEA0 REGS: c07cfdf0 TRAP: 0300    Not tainted
> MSR: 00021000 EE: 0 PR: 0 FP: 0 ME: 1 IR/DR: 00
> DAR: E3093000, DSISR: 00000000
> TASK = c07cdb70[1] 'swapper' THREAD: c07ce000
> Last syscall: 120
> GPR00: 00000000 C07CFEA0 C07CDB70 E3093000 DFE829FE 00000100 C01184E8 C021B270
> GPR08: C0220000 C02D0F60 C07CDEF8 C07CDEF8 00000000 70000000 1FFF6400 00000001
> GPR16: 00000001 FFFFFFFF 1FFF06C0 00000000 00000001 C0220000 C0280000 00029000
> GPR24: 00000000 C02D0F60 C01F0000 C0148040 00000080 00000000 DFE82A00 C02D0FF0
> NIP [c0148050] ide_insw+0x10/0x24
> LR [c013bc64] ata_input_data+0x74/0x114
> Call backtrace:
>  c013e6a4 try_to_identify+0x2ec/0x5ec
>  c013eaa8 do_probe+0x104/0x304
>  c013f0c4 probe_hwif+0x358/0x6c4
>  c0140068 ideprobe_init+0xa8/0x1a0
>  c02a4ef8 ide_generic_init+0x10/0x28
>  c0001324 init+0xc4/0x244
>  c0004254 kernel_thread+0x44/0x60
> Kernel panic - not syncing: Attempted to kill init!
>  <0>Rebooting in 180 seconds..
> 
> 
> ide_insw is a asm routine to read in 16bit words and swap them. Copied
> from arch/ppc/kernel/misc.S. Works fine when PCI is disabled.

Probably because ide_insw uses isnw which offsets everything from
_IO_BASE which changes value when you have a PCI bus with an IO space...
If your IDE isn't PCI IO space based you shouldn't use ide_insw but the
MMIO variants instead.

Ben.

> KR, Ludo
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