[POWERPC] Make OF irq map code detect more error cases

Device-tree bugs on js20 with some versions of SLOF were causing the
interrupt for IDE to not be parsed correctly and fail to boot. This
patch adds a bit more sanity checking to the parser to detect some of
those errors and fail instead of returning bogus information.  The
powerpc PCI code can then trigger a fallback that works on those
machines.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 9 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 2fce7738e9e2..138134c8c17d 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -1289,6 +1289,9 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
 
         DBG("Try to map irq for %s...\n", pci_name(pci_dev));
 
+#ifdef DEBUG
+        memset(&oirq, 0xff, sizeof(oirq));
+#endif
         /* Try to get a mapping from the device-tree */
         if (of_irq_map_pci(pci_dev, &oirq)) {
                 u8 line, pin;
@@ -1314,8 +1317,9 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
                 if (virq != NO_IRQ)
                         set_irq_type(virq, IRQ_TYPE_LEVEL_LOW);
         } else {
-                DBG(" -> got one, spec %d cells (0x%08x...) on %s\n",
-                    oirq.size, oirq.specifier[0], oirq.controller->full_name);
+                DBG(" -> got one, spec %d cells (0x%08x 0x%08x...) on %s\n",
+                    oirq.size, oirq.specifier[0], oirq.specifier[1],
+                    oirq.controller->full_name);
 
                 virq = irq_create_of_mapping(oirq.controller, oirq.specifier,
                                              oirq.size);
@@ -1324,6 +1328,9 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
                 DBG(" -> failed to map !\n");
                 return -1;
         }
+
+        DBG(" -> mapped to linux irq %d\n", virq);
+
         pci_dev->irq = virq;
         pci_write_config_byte(pci_dev, PCI_INTERRUPT_LINE, virq);