[IA64-SGI] Older PROM WAR for device flush code

Work-around to temporarily support older PROMs with new flush device code.

This code allows systems running older PROMs to continue to run on the new
kernel base until a new official PROM is released.
Signed-off-by: Prarit Bhargava <prarit@sgi.com>
Acked-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/sn/include/xtalk/hubdev.h

@@ -51,6 +51,15 @@ struct sn_flush_device_kernel {
 	struct sn_flush_device_common *common;
 };
 
+/* 01/16/06 This struct is the old PROM/kernel struct and needs to be included
+ * for older official PROMs to function on the new kernel base.  This struct
+ * will be removed when the next official PROM release occurs. */
+
+struct sn_flush_device_war {
+	struct sn_flush_device_common common;
+	u32 filler; /* older PROMs expect the default size of a spinlock_t */
+};
+
 /*
  * **widget_p - Used as an array[wid_num][device] of sn_flush_device_kernel.
  */

arch/ia64/sn/kernel/io_init.c

@@ -165,6 +165,43 @@ sn_pcidev_info_get(struct pci_dev *dev)
 	return NULL;
 }
 
+/* Older PROM flush WAR
+ *
+ * 01/16/06 -- This war will be in place until a new official PROM is released.
+ * Additionally note that the struct sn_flush_device_war also has to be
+ * removed from arch/ia64/sn/include/xtalk/hubdev.h
+ */
+static u8 war_implemented = 0;
+
+static void sn_device_fixup_war(u64 nasid, u64 widget, int device,
+				struct sn_flush_device_common *common)
+{
+	struct sn_flush_device_war *war_list;
+	struct sn_flush_device_war *dev_entry;
+	struct ia64_sal_retval isrv = {0,0,0,0};
+
+	if (!war_implemented) {
+		printk(KERN_WARNING "PROM version < 4.50 -- implementing old "
+		       "PROM flush WAR\n");
+		war_implemented = 1;
+	}
+
+	war_list = kzalloc(DEV_PER_WIDGET * sizeof(*war_list), GFP_KERNEL);
+	if (!war_list)
+		BUG();
+
+	SAL_CALL_NOLOCK(isrv, SN_SAL_IOIF_GET_WIDGET_DMAFLUSH_LIST,
+			nasid, widget, __pa(war_list), 0, 0, 0 ,0);
+	if (isrv.status)
+		panic("sn_device_fixup_war failed: %s\n",
+		      ia64_sal_strerror(isrv.status));
+
+	dev_entry = war_list + device;
+	memcpy(common,dev_entry, sizeof(*common));
+
+	kfree(war_list);
+}
+
 /*
  * sn_fixup_ionodes() - This routine initializes the HUB data strcuture for
  *	each node in the system.
@@ -246,8 +283,19 @@ static void sn_fixup_ionodes(void)
 									widget,
 								       	device,
 						      (u64)(dev_entry->common));
-				if (status)
+				if (status) {
+					if (sn_sal_rev() < 0x0450) {
+						/* shortlived WAR for older
+						 * PROM images
+						 */
+						sn_device_fixup_war(nasid,
+								    widget,
+								    device,
+							     dev_entry->common);
+					}
+					else
 						BUG();
+				}
 
 				spin_lock_init(&dev_entry->sfdl_flush_lock);
 			}