[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>

3 files changed, 25 insertions, 7 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);
 
diff --git a/arch/powerpc/kernel/prom_parse.c b/arch/powerpc/kernel/prom_parse.c
index 11052c212ad5..a10825a5dfe6 100644
--- a/arch/powerpc/kernel/prom_parse.c
+++ b/arch/powerpc/kernel/prom_parse.c
@@ -639,14 +639,17 @@ void of_irq_map_init(unsigned int flags)
 
 }
 
-int of_irq_map_raw(struct device_node *parent, u32 *intspec, u32 *addr,
-                   struct of_irq *out_irq)
+int of_irq_map_raw(struct device_node *parent, u32 *intspec, u32 ointsize,
+                   u32 *addr, struct of_irq *out_irq)
 {
         struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
         u32 *tmp, *imap, *imask;
         u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
         int imaplen, match, i;
 
+        DBG("of_irq_map_raw: par=%s,intspec=[0x%08x 0x%08x...],ointsize=%d\n",
+            parent->full_name, intspec[0], intspec[1], ointsize);
+
         ipar = of_node_get(parent);
 
         /* First get the #interrupt-cells property of the current cursor
@@ -670,6 +673,9 @@ int of_irq_map_raw(struct device_node *parent, u32 *intspec, u32 *addr,
 
         DBG("of_irq_map_raw: ipar=%s, size=%d\n", ipar->full_name, intsize);
 
+        if (ointsize != intsize)
+                return -EINVAL;
+
         /* Look for this #address-cells. We have to implement the old linux
          * trick of looking for the parent here as some device-trees rely on it
          */
@@ -875,12 +881,15 @@ int of_irq_map_one(struct device_node *device, int index, struct of_irq *out_irq
         }
         intsize = *tmp;
 
+        DBG(" intsize=%d intlen=%d\n", intsize, intlen);
+
         /* Check index */
         if ((index + 1) * intsize > intlen)
                 return -EINVAL;
 
         /* Get new specifier and map it */
-        res = of_irq_map_raw(p, intspec + index * intsize, addr, out_irq);
+        res = of_irq_map_raw(p, intspec + index * intsize, intsize,
+                             addr, out_irq);
         of_node_put(p);
         return res;
 }
@@ -965,7 +974,7 @@ int of_irq_map_pci(struct pci_dev *pdev, struct of_irq *out_irq)
         laddr[0] = (pdev->bus->number << 16)
                 | (pdev->devfn << 8);
         laddr[1]  = laddr[2] = 0;
-        return of_irq_map_raw(ppnode, &lspec, laddr, out_irq);
+        return of_irq_map_raw(ppnode, &lspec, 1, laddr, out_irq);
 }
 EXPORT_SYMBOL_GPL(of_irq_map_pci);
 #endif /* CONFIG_PCI */
diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index b095a285c84b..d0fa1b9aed35 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -276,6 +276,7 @@ extern void of_irq_map_init(unsigned int flags);
  * of_irq_map_raw - Low level interrupt tree parsing
  * @parent:     the device interrupt parent
  * @intspec:    interrupt specifier ("interrupts" property of the device)
+ * @ointsize:   size of the passed in interrupt specifier
  * @addr:       address specifier (start of "reg" property of the device)
  * @out_irq:    structure of_irq filled by this function
  *
@@ -288,7 +289,8 @@ extern void of_irq_map_init(unsigned int flags);
  *
  */
 
-extern int of_irq_map_raw(struct device_node *parent, u32 *intspec, u32 *addr,
+extern int of_irq_map_raw(struct device_node *parent, u32 *intspec,
+                          u32 ointsize, u32 *addr,
                           struct of_irq *out_irq);