Fix interrupt probing on E450 sparc64 systems

[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>

diff --git a/arch/sparc64/kernel/of_device.c b/arch/sparc64/kernel/of_device.c
index b0f3e0082a0da113fc31eedb484c44ae5c10a9b7..ad74e5e8778eb91932b55f3a4484f8f0bbc69cef 100644 (file)
--- a/arch/sparc64/kernel/of_device.c
+++ b/arch/sparc64/kernel/of_device.c
@@ -708,7 +708,7 @@ static unsigned int __init pci_irq_swizzle(struct device_node *dp,
                                           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_swizzle(struct device_node *dp,
        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;
 }