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Subject[patch 064/101] Fix interrupt probing on E450 sparc64 systems
From: David Miller <davem@davemloft.net>

[SPARC64]: Fix PCI interrupts on E450 et al.

When the PCI controller OBP node lacks an interrupt-map
and interrupt-map-mask property, we need to form the
INO by hand. The PCI swizzle logic was not doing that
properly.

This was a regression added by the of_device code.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/sparc64/kernel/of_device.c | 40 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 38 insertions(+), 2 deletions(-)
--- linux-2.6.20.1.orig/arch/sparc64/kernel/of_device.c
+++ linux-2.6.20.1/arch/sparc64/kernel/of_device.c
@@ -708,7 +708,7 @@ static unsigned int __init pci_irq_swizz
unsigned int irq)
{
struct linux_prom_pci_registers *regs;
- unsigned int devfn, slot, ret;
+ unsigned int bus, devfn, slot, ret;

if (irq < 1 || irq > 4)
return irq;
@@ -717,10 +717,46 @@ static unsigned int __init pci_irq_swizz
if (!regs)
return irq;

+ bus = (regs->phys_hi >> 16) & 0xff;
devfn = (regs->phys_hi >> 8) & 0xff;
slot = (devfn >> 3) & 0x1f;

- ret = ((irq - 1 + (slot & 3)) & 3) + 1;
+ if (pp->irq_trans) {
+ /* Derived from Table 8-3, U2P User's Manual. This branch
+ * is handling a PCI controller that lacks a proper set of
+ * interrupt-map and interrupt-map-mask properties. The
+ * Ultra-E450 is one example.
+ *
+ * The bit layout is BSSLL, where:
+ * B: 0 on bus A, 1 on bus B
+ * D: 2-bit slot number, derived from PCI device number as
+ * (dev - 1) for bus A, or (dev - 2) for bus B
+ * L: 2-bit line number
+ *
+ * Actually, more "portable" way to calculate the funky
+ * slot number is to subtract pbm->pci_first_slot from the
+ * device number, and that's exactly what the pre-OF
+ * sparc64 code did, but we're building this stuff generically
+ * using the OBP tree, not in the PCI controller layer.
+ */
+ if (bus & 0x80) {
+ /* PBM-A */
+ bus = 0x00;
+ slot = (slot - 1) << 2;
+ } else {
+ /* PBM-B */
+ bus = 0x10;
+ slot = (slot - 2) << 2;
+ }
+ irq -= 1;
+
+ ret = (bus | slot | irq);
+ } else {
+ /* Going through a PCI-PCI bridge that lacks a set of
+ * interrupt-map and interrupt-map-mask properties.
+ */
+ ret = ((irq - 1 + (slot & 3)) & 3) + 1;
+ }

return ret;
}
--
-
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