Re: [Qemu-devel] SCSI bus failures with qemu-arm in kernel 3.8+

[Guenter Roeck]

On Mon, Aug 12, 2013 at 11:12:50PM +0100, Russell King - ARM Linux wrote:
> On Mon, Aug 12, 2013 at 10:36:17PM +0100, Peter Maydell wrote:
> > On this point, yes. Equivalent bit from the PB926 TRM:
> > http://infocenter.arm.com/help/topic/com.arm.doc.dui0224i/Cacdijji.html
> > 
> > (There are differences between the PCI controllers on
> > the different boards. Differences I know of are:
> >  * size of the three memory mapped regions
> >  * whether the top bits of the PCI address come from the top
> >    or bottom of the IMAP* registers
> > I believe (based on some experimentation and an educated guess)
> > that these both changed at the same point, but some of the board
> > TRMs claim to be part one way part the other, presumably due to
> > copy and paste error. In particular PB1176's TRM has a mangled
> > description of the IMAP* registers which didn't match what the
> > h/w actually did in my testing.)
> 
> Bah, updated TRMs since my version.
> 
> Right, so if I've traced everything correctly, this should work:
> 
>         /*
>          * Slot INTA    INTB    INTC    INTD
>          *  31  PCI1    PCI2    PCI3    PCI0
>          *  30  PCI0    PCI1    PCI2    PCI3
>          *  29  PCI3    PCI0    PCI1    PCI2
>          */
>         return IRQ_SIC_PCI0 + ((slot + 2 + pin - 1) & 3);
> 
I tried the above with qemu 1.5.2. Success!

Hacked diff is below. Can I write that up as clean patch and submit it,
or do we need a test on real hardware ?

Thanks,
Guenter

---
diff --git a/arch/arm/mach-versatile/pci.c b/arch/arm/mach-versatile/pci.c
index e92e5e0..53b4208 100644
--- a/arch/arm/mach-versatile/pci.c
+++ b/arch/arm/mach-versatile/pci.c
@@ -333,7 +333,11 @@ static int __init versatile_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 	 *  26     1     IRQ_SIC_PCI2
 	 *  27     1     IRQ_SIC_PCI3
 	 */
+#if 0
 	irq = IRQ_SIC_PCI0 + ((slot - 24 + pin - 1) & 3);
+#else
+	irq = IRQ_SIC_PCI0 + ((slot + 2 + pin - 1) & 3);
+#endif
 
 	return irq;
 }
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