[SPARC64]: Refine Sabre wsync logic.

It is only needed when there is a PCI-PCI bridge sitting
between the device and the PCI host controller which is
not a Simba APB bridge.

Add logic to handle two special cases:

1) device behind EBUS, which sits on PCI
2) PCI controller interrupts

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 8 deletions

diff --git a/arch/sparc64/kernel/prom.c b/arch/sparc64/kernel/prom.c
index 86cdbd4dbad5..c86007a2aa3f 100644
--- a/arch/sparc64/kernel/prom.c
+++ b/arch/sparc64/kernel/prom.c
@@ -539,23 +539,43 @@ static unsigned long __sabre_onboard_imap_off[] = {
         ((ino & 0x20) ? (SABRE_ICLR_SCSI + (((ino) & 0x1f) << 3)) :  \
                         (SABRE_ICLR_A_SLOT0 + (((ino) & 0x1f)<<3)))
 
-static int parent_is_sabre_or_simba(struct device_node *dp)
+static int sabre_device_needs_wsync(struct device_node *dp)
 {
+        struct device_node *parent = dp->parent;
         char *parent_model, *parent_compat;
 
-        parent_model = of_get_property(dp->parent, "model", NULL);
+        /* This traversal up towards the root is meant to
+         * handle two cases:
+         *
+         * 1) non-PCI bus sitting under PCI, such as 'ebus'
+         * 2) the PCI controller interrupts themselves, which
+         *    will use the sabre_irq_build but do not need
+         *    the DMA synchronization handling
+         */
+        while (parent) {
+                if (!strcmp(parent->type, "pci"))
+                        break;
+                parent = parent->parent;
+        }
+
+        if (!parent)
+                return 0;
+
+        parent_model = of_get_property(parent,
+                                       "model", NULL);
         if (parent_model &&
             (!strcmp(parent_model, "SUNW,sabre") ||
              !strcmp(parent_model, "SUNW,simba")))
-                return 1;
+                return 0;
 
-        parent_compat = of_get_property(dp->parent, "compatible", NULL);
+        parent_compat = of_get_property(parent,
+                                        "compatible", NULL);
         if (parent_compat &&
             (!strcmp(parent_compat, "pci108e,a000") ||
              !strcmp(parent_compat, "pci108e,a001")))
-                return 1;
+                return 0;
 
-        return 0;
+        return 1;
 }
 
 static unsigned int sabre_irq_build(struct device_node *dp,
@@ -602,8 +622,7 @@ static unsigned int sabre_irq_build(struct device_node *dp,
          * is run.
          */
         regs = of_get_property(dp, "reg", NULL);
-        if (regs &&
-            !parent_is_sabre_or_simba(dp)) {
+        if (regs && sabre_device_needs_wsync(dp)) {
                 irq_install_pre_handler(virt_irq,
                                         sabre_wsync_handler,
                                         (void *) (long) regs->phys_hi,