[PATCH] PPC64: EEH Recovery

[Linas Vepstas <linas@austin.ibm.com>]

[-- Attachment #1: Type: text/plain, Size: 407 bytes --]


Hi Paul,

The patch below implements hotplug style EEH error recovery. 
Its split into two pieces: a part that needs to be applied to the
PPC64 arch tree, and a part that needs to be applied to the 
RPA PHP hotplug tree.  The PPC64 part needs to go in first.

Assuming this doesn't generate a round of discussion, please
forward upstream to akpm/torvalds.

 Signed-off-by: Linas Vepstas <linas@linas.org>


[-- Attachment #2: eeh-recovery-bk-ppc64.patch --]
[-- Type: text/plain, Size: 15635 bytes --]

===== arch/ppc64/kernel/eeh.c 1.40 vs edited =====
--- 1.40/arch/ppc64/kernel/eeh.c	2004-10-25 14:47:50 -05:00
+++ edited/arch/ppc64/kernel/eeh.c	2004-11-17 17:31:41 -06:00
@@ -17,21 +17,19 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
-#include <linux/bootmem.h>
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/list.h>
-#include <linux/mm.h>
 #include <linux/notifier.h>
 #include <linux/pci.h>
 #include <linux/proc_fs.h>
 #include <linux/rbtree.h>
 #include <linux/seq_file.h>
-#include <linux/spinlock.h>
+#include <asm/atomic.h>
 #include <asm/eeh.h>
 #include <asm/io.h>
 #include <asm/machdep.h>
 #include <asm/rtas.h>
-#include <asm/atomic.h>
 #include "pci.h"
 
 #undef DEBUG
@@ -89,7 +87,6 @@ static struct notifier_block *eeh_notifi
  * attempts we allow before panicking.
  */
 #define EEH_MAX_FAILS	1000
-static atomic_t eeh_fail_count;
 
 /* RTAS tokens */
 static int ibm_set_eeh_option;
@@ -223,9 +220,9 @@ pci_addr_cache_insert(struct pci_dev *de
 	while (*p) {
 		parent = *p;
 		piar = rb_entry(parent, struct pci_io_addr_range, rb_node);
-		if (alo < piar->addr_lo) {
+		if (ahi < piar->addr_lo) {
 			p = &parent->rb_left;
-		} else if (ahi > piar->addr_hi) {
+		} else if (alo > piar->addr_hi) {
 			p = &parent->rb_right;
 		} else {
 			if (dev != piar->pcidev ||
@@ -243,6 +240,11 @@ pci_addr_cache_insert(struct pci_dev *de
 	piar->addr_hi = ahi;
 	piar->pcidev = dev;
 	piar->flags = flags;
+	
+#ifdef DEBUG 
+	printk (KERN_DEBUG "PIAR: insert range=[%lx:%lx] dev=%s\n", 
+	               alo, ahi, pci_name (dev));
+#endif
 
 	rb_link_node(&piar->rb_node, parent, p);
 	rb_insert_color(&piar->rb_node, &pci_io_addr_cache_root.rb_root);
@@ -377,6 +379,9 @@ void __init pci_addr_cache_build(void)
 			continue;
 		}
 		pci_addr_cache_insert_device(dev);
+		
+		/* Save the BAR's; firmware doesn't restore these after EEH reset */
+		pci_save_state (dev);
 	}
 
 #ifdef DEBUG
@@ -388,6 +393,32 @@ void __init pci_addr_cache_build(void)
 /* --------------------------------------------------------------- */
 /* Above lies the PCI Address Cache. Below lies the EEH event infrastructure */
 
+void eeh_slot_error_detail (struct device_node *dn, int severity)
+{
+	unsigned long flags;
+	int rc;
+
+	if (!dn) return;
+
+	/* Log the error with the rtas logger */
+	spin_lock_irqsave(&slot_errbuf_lock, flags);
+	memset(slot_errbuf, 0, eeh_error_buf_size);
+
+	rc = rtas_call(ibm_slot_error_detail,
+	               8, 1, NULL, dn->eeh_config_addr,
+	               BUID_HI(dn->phb->buid),
+	               BUID_LO(dn->phb->buid), NULL, 0,
+	               virt_to_phys(slot_errbuf),
+	               eeh_error_buf_size,
+	               severity);
+
+	if (rc == 0)
+		log_error(slot_errbuf, ERR_TYPE_RTAS_LOG, 0);
+	spin_unlock_irqrestore(&slot_errbuf_lock, flags);
+}
+
+EXPORT_SYMBOL(eeh_slot_error_detail);
+
 /**
  * eeh_register_notifier - Register to find out about EEH events.
  * @nb: notifier block to callback on events
@@ -462,11 +493,9 @@ static void eeh_event_handler(void *dumm
 		       "%s %s\n", event->reset_state,
 		       pci_name(event->dev), pci_pretty_name(event->dev));
 
-		atomic_set(&eeh_fail_count, 0);
-		notifier_call_chain (&eeh_notifier_chain,
-				     EEH_NOTIFY_FREEZE, event);
-
 		__get_cpu_var(slot_resets)++;
+		notifier_call_chain (&eeh_notifier_chain,
+		           EEH_NOTIFY_FREEZE, event);
 
 		pci_dev_put(event->dev);
 		kfree(event);
@@ -510,7 +539,7 @@ int eeh_dn_check_failure(struct device_n
 	int ret;
 	int rets[2];
 	unsigned long flags;
-	int rc, reset_state;
+	int reset_state;
 	struct eeh_event  *event;
 
 	__get_cpu_var(total_mmio_ffs)++;
@@ -530,14 +559,15 @@ int eeh_dn_check_failure(struct device_n
 	if (!dn->eeh_config_addr) {
 		return 0;
 	}
-
+	
 	/*
 	 * If we already have a pending isolation event for this
 	 * slot, we know it's bad already, we don't need to check...
 	 */
 	if (dn->eeh_mode & EEH_MODE_ISOLATED) {
-		atomic_inc(&eeh_fail_count);
-		if (atomic_read(&eeh_fail_count) >= EEH_MAX_FAILS) {
+		dn->eeh_freeze_count ++;
+		if (dn->eeh_freeze_count >= EEH_MAX_FAILS) {
+			dump_stack();
 			/* re-read the slot reset state */
 			rets[0] = -1;
 			rtas_call(ibm_read_slot_reset_state, 3, 3, rets,
@@ -565,28 +595,17 @@ int eeh_dn_check_failure(struct device_n
 		return 0;
 	}
 
-	/* prevent repeated reports of this failure */
+	/* Prevent repeated reports of this failure */
 	dn->eeh_mode |= EEH_MODE_ISOLATED;
 
 	reset_state = rets[0];
+	/* Log the error with the rtas logger */
+	if (dn->eeh_freeze_count < EEH_MAX_ALLOWED_FREEZES) {
+		eeh_slot_error_detail (dn, 1 /* Temporary Error */);
+	} else {
+		eeh_slot_error_detail (dn, 2 /* Permanent Error */);
+   }
 
-	spin_lock_irqsave(&slot_errbuf_lock, flags);
-	memset(slot_errbuf, 0, eeh_error_buf_size);
-
-	rc = rtas_call(ibm_slot_error_detail,
-	               8, 1, NULL, dn->eeh_config_addr,
-	               BUID_HI(dn->phb->buid),
-	               BUID_LO(dn->phb->buid), NULL, 0,
-	               virt_to_phys(slot_errbuf),
-	               eeh_error_buf_size,
-	               1 /* Temporary Error */);
-
-	if (rc == 0)
-		log_error(slot_errbuf, ERR_TYPE_RTAS_LOG, 0);
-	spin_unlock_irqrestore(&slot_errbuf_lock, flags);
-
-	printk(KERN_INFO "EEH: MMIO failure (%d) on device: %s %s\n",
-	       rets[0], dn->name, dn->full_name);
 	event = kmalloc(sizeof(*event), GFP_ATOMIC);
 	if (event == NULL) {
 		eeh_panic(dev, reset_state);
@@ -618,7 +637,6 @@ EXPORT_SYMBOL(eeh_dn_check_failure);
  * @token i/o token, should be address in the form 0xA....
  * @val value, should be all 1's (XXX why do we need this arg??)
  *
- * Check for an eeh failure at the given token address.
  * Check for an EEH failure at the given token address.  Call this
  * routine if the result of a read was all 0xff's and you want to
  * find out if this is due to an EEH slot freeze event.  This routine
@@ -626,6 +644,7 @@ EXPORT_SYMBOL(eeh_dn_check_failure);
  *
  * Note this routine is safe to call in an interrupt context.
  */
+
 unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned long val)
 {
 	unsigned long addr;
@@ -635,7 +654,7 @@ unsigned long eeh_check_failure(const vo
 	/* Finding the phys addr + pci device; this is pretty quick. */
 	addr = eeh_token_to_phys((unsigned long __force) token);
 	dev = pci_get_device_by_addr(addr);
-	if (!dev)
+	if (!dev) 
 		return val;
 
 	dn = pci_device_to_OF_node(dev);
@@ -647,6 +666,174 @@ unsigned long eeh_check_failure(const vo
 
 EXPORT_SYMBOL(eeh_check_failure);
 
+/* ------------------------------------------------------------- */
+/* The code below deals with error recovery */
+
+void
+rtas_set_slot_reset(struct device_node *dn)
+{
+	int token = rtas_token ("ibm,set-slot-reset");
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return;
+	rc = rtas_call(token,4,1, NULL,
+	               dn->eeh_config_addr,
+	               BUID_HI(dn->phb->buid),
+	               BUID_LO(dn->phb->buid),
+	               1);
+	if (rc) {
+		printk (KERN_WARNING "EEH: Unable to reset the failed slot\n");
+		return;
+	}
+	
+	/* The PCI bus requires that the reset be held high for at least
+	 * a 100 milliseconds. We wait a bit longer 'just in case'.
+	 */
+   msleep (200);
+	
+	rc = rtas_call(token,4,1, NULL,
+	               dn->eeh_config_addr,
+	               BUID_HI(dn->phb->buid),
+	               BUID_LO(dn->phb->buid),
+	               0);
+}
+
+EXPORT_SYMBOL(rtas_set_slot_reset);
+
+void
+rtas_configure_bridge(struct device_node *dn)
+{
+	int token = rtas_token ("ibm,configure-bridge");
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return;
+	rc = rtas_call(token,3,1, NULL,
+	               dn->eeh_config_addr,
+	               BUID_HI(dn->phb->buid),
+	               BUID_LO(dn->phb->buid));
+	if (rc) {
+		printk (KERN_WARNING "EEH: Unable to configure device bridge\n");
+	}
+}
+
+EXPORT_SYMBOL(rtas_configure_bridge);
+
+/* ------------------------------------------------------- */
+/** Save and restore of PCI BARs
+ * 
+ * Although firmware will set up BARs during boot, it doesn't
+ * set up device BAR's after a device reset, although it will,
+ * if requested, set up bridge configuration. Thus, we need to 
+ * configure the PCI devices ourselves.  Config-space setup is 
+ * stored in the PCI structures which are normally deleted during
+ * device removal.  Thus, the "save" routine references the
+ * structures so that they aren't deleted. 
+ */
+
+
+struct eeh_cfg_tree
+{
+	struct eeh_cfg_tree *sibling;
+	struct eeh_cfg_tree *child;
+	struct pci_dev *dev;
+	struct device_node *dn;
+};
+
+static inline struct pci_dev * eeh_get_pci_dev(struct device_node *dn)
+{
+	struct pci_dev *dev = NULL;
+	char bus_id[BUS_ID_SIZE];
+
+	sprintf(bus_id, "%04x:%02x:%02x.%d",dn->phb->global_number,
+		dn->busno, PCI_SLOT(dn->devfn), PCI_FUNC(dn->devfn));
+
+	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+		if (!strcmp(pci_name(dev), bus_id)) 
+			return dev;
+	}
+	return NULL;
+}
+
+/** 
+ * eeh_save_bars - save the PCI config space info
+ */
+struct eeh_cfg_tree * eeh_save_bars(struct device_node *dn)
+{
+	struct eeh_cfg_tree *cnode;
+	struct pci_dev *dev;
+	
+	dev = eeh_get_pci_dev (dn);
+	if (!dev) 
+		return NULL;
+
+	cnode = kmalloc(sizeof(struct eeh_cfg_tree), GFP_KERNEL);
+	if (!cnode) 
+		return NULL;
+	
+	cnode->dev = dev;
+	
+	of_node_get(dn);
+	cnode->dn = dn;
+	
+	cnode->sibling = NULL;
+	cnode->child = NULL;
+
+	if (dn->child) {
+		cnode->child = eeh_save_bars (dn->child);
+	}
+	if (dn->sibling) {
+		cnode->sibling = eeh_save_bars (dn->sibling);
+	}
+
+	return cnode;
+}
+EXPORT_SYMBOL(eeh_save_bars);
+
+/**
+ * __restore_bars - Restore the Base Address Registers
+ * Loads the PCI configuration space base address registers 
+ * and the expansion ROM base address from the array 
+ * passed as the second argument.
+ */
+static inline void __restore_bars (struct device_node *dn, u32 *cfg_hdr)
+{
+	int i;
+	for (i=4; i<10; i++) {
+		rtas_write_config(dn, i*4, 4, cfg_hdr[i]);
+	}
+	rtas_write_config(dn, 12*4, 4, cfg_hdr[12]);
+}
+
+/** 
+ * eeh_restore_bars - restore the PCI config space info
+ */
+void eeh_restore_bars(struct eeh_cfg_tree *tree)
+{
+	if (tree->dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
+		__restore_bars (tree->dn, tree->dev->saved_config_space);
+	}
+	
+	if (tree->child) {
+		eeh_restore_bars (tree->child);
+	}
+	if (tree->sibling) {
+		eeh_restore_bars (tree->sibling);
+	}
+
+	of_node_put (tree->dn);
+	pci_dev_put (tree->dev);
+	kfree (tree);
+}
+EXPORT_SYMBOL(eeh_restore_bars);
+
+/* ------------------------------------------------------------- */
+/* The code below deals with enabling EEH for devices during  the
+ * early boot sequence.  EEH must be enabled before any PCI probing
+ * can be done.
+ */
+
 struct eeh_early_enable_info {
 	unsigned int buid_hi;
 	unsigned int buid_lo;
@@ -840,6 +1027,9 @@ void eeh_add_device_late(struct pci_dev 
 #endif
 
 	pci_addr_cache_insert_device (dev);
+
+	/* Save the BAR's; firmware doesn't restore these after EEH reset */
+	pci_save_state (dev);
 }
 EXPORT_SYMBOL(eeh_add_device_late);
 
@@ -885,10 +1075,8 @@ static int proc_eeh_show(struct seq_file
 		seq_printf(m, "eeh_total_mmio_ffs=%ld\n"
 			   "eeh_false_positives=%ld\n"
 			   "eeh_ignored_failures=%ld\n"
-			   "eeh_slot_resets=%ld\n"
-				"eeh_fail_count=%d\n",
-			   ffs, positives, failures, resets,
-				eeh_fail_count.counter);
+			   "eeh_slot_resets=%ld\n",
+			   ffs, positives, failures, resets);
 	}
 
 	return 0;
===== arch/ppc64/kernel/pSeries_pci.c 1.59 vs edited =====
--- 1.59/arch/ppc64/kernel/pSeries_pci.c	2004-11-15 21:29:10 -06:00
+++ edited/arch/ppc64/kernel/pSeries_pci.c	2004-11-17 16:18:02 -06:00
@@ -102,7 +102,7 @@ static int rtas_pci_read_config(struct p
 	return PCIBIOS_DEVICE_NOT_FOUND;
 }
 
-static int rtas_write_config(struct device_node *dn, int where, int size, u32 val)
+int rtas_write_config(struct device_node *dn, int where, int size, u32 val)
 {
 	unsigned long buid, addr;
 	int ret;
@@ -125,6 +125,7 @@ static int rtas_write_config(struct devi
 
 	return PCIBIOS_SUCCESSFUL;
 }
+EXPORT_SYMBOL(rtas_write_config);
 
 static int rtas_pci_write_config(struct pci_bus *bus,
 				 unsigned int devfn,
===== include/asm-ppc64/eeh.h 1.23 vs edited =====
--- 1.23/include/asm-ppc64/eeh.h	2004-10-25 18:17:38 -05:00
+++ edited/include/asm-ppc64/eeh.h	2004-11-17 16:10:58 -06:00
@@ -22,8 +22,8 @@
 
 #include <linux/init.h>
 #include <linux/list.h>
-#include <linux/string.h>
 #include <linux/notifier.h>
+#include <linux/string.h>
 
 struct pci_dev;
 struct device_node;
@@ -33,6 +33,10 @@ struct device_node;
 #define EEH_MODE_NOCHECK	(1<<1)
 #define EEH_MODE_ISOLATED	(1<<2)
 
+/* Max number of EEH freezes allowed before we consider the device
+ * to be permanently disabled. */
+#define EEH_MAX_ALLOWED_FREEZES 5
+
 #ifdef CONFIG_PPC_PSERIES
 extern void __init eeh_init(void);
 unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned long val);
@@ -57,6 +61,34 @@ void eeh_add_device_early(struct device_
 void eeh_add_device_late(struct pci_dev *);
 
 /**
+ * eeh_slot_error_detail -- record and EEH error condition to the log
+ * @severity: 1 if temporary, 2 if permanent failure.
+ *
+ * Obtains the the EEH error details from the RTAS subsystem, 
+ * and then logs these details with the RTAS error log system.
+ */
+void eeh_slot_error_detail (struct device_node *dn, int severity);
+
+/** 
+ * rtas_set_slot_reset -- unfreeze a frozen slot
+ *
+ * Clear the EEH-frozen condition on a slot.  This routine
+ * does this by asserting the PCI #RST line for 1/8th of 
+ * a second; this routine will sleep while the adapter is 
+ * being reset.
+ */
+void rtas_set_slot_reset (struct device_node *dn);
+
+/**
+ * rtas_configure_bridge -- firmware initialization of pci bridge
+ * 
+ * Ask the firmware to configure any PCI bridge devices 
+ * located behind the indicated node. Required after a 
+ * pci device reset.
+ */
+void rtas_configure_bridge(struct device_node *dn);
+
+/**
  * eeh_remove_device - undo EEH setup for the indicated pci device
  * @dev: pci device to be removed
  *
@@ -91,6 +123,13 @@ struct eeh_event {
 /** Register to find out about EEH events. */
 int eeh_register_notifier(struct notifier_block *nb);
 int eeh_unregister_notifier(struct notifier_block *nb);
+
+/** Save and restore device configuration info across
+ *  device resets
+ */
+struct eeh_cfg_tree;
+struct eeh_cfg_tree * eeh_save_bars(struct device_node *dn);
+void eeh_restore_bars(struct eeh_cfg_tree *tree);
 
 /**
  * EEH_POSSIBLE_ERROR() -- test for possible MMIO failure.
===== include/asm-ppc64/prom.h 1.23 vs edited =====
--- 1.23/include/asm-ppc64/prom.h	2004-10-24 20:55:43 -05:00
+++ edited/include/asm-ppc64/prom.h	2004-11-17 16:00:37 -06:00
@@ -162,6 +162,7 @@ struct device_node {
 	int	status;			/* Current device status (non-zero is bad) */
 	int	eeh_mode;		/* See eeh.h for possible EEH_MODEs */
 	int	eeh_config_addr;
+	int	eeh_freeze_count;   /* number of times this device froze up. */
 	struct  pci_controller *phb;	/* for pci devices */
 	struct	iommu_table *iommu_table;	/* for phb's or bridges */
 
===== include/asm-ppc64/rtas.h 1.24 vs edited =====
--- 1.24/include/asm-ppc64/rtas.h	2004-09-22 00:42:53 -05:00
+++ edited/include/asm-ppc64/rtas.h	2004-11-17 16:00:37 -06:00
@@ -241,4 +241,6 @@ extern void rtas_stop_self(void);
 /* RMO buffer reserved for user-space RTAS use */
 extern unsigned long rtas_rmo_buf;
 
+extern int rtas_write_config(struct device_node *dn, int where, int size, u32 val);
+
 #endif /* _PPC64_RTAS_H */

[-- Attachment #3: eeh-recovery-bk-hotplug.patch --]
[-- Type: text/plain, Size: 7784 bytes --]

===== drivers/pci/hotplug/rpaphp.h 1.11 vs edited =====
--- 1.11/drivers/pci/hotplug/rpaphp.h	2004-10-06 11:43:44 -05:00
+++ edited/drivers/pci/hotplug/rpaphp.h	2004-11-17 16:00:37 -06:00
@@ -126,6 +126,8 @@ extern int register_pci_slot(struct slot
 extern int rpaphp_unconfig_pci_adapter(struct slot *slot);
 extern int rpaphp_get_pci_adapter_status(struct slot *slot, int is_init, u8 * value);
 extern struct hotplug_slot *rpaphp_find_hotplug_slot(struct pci_dev *dev);
+extern void init_eeh_handler (void);
+extern void exit_eeh_handler (void);
 
 /* rpaphp_core.c */
 extern int rpaphp_add_slot(struct device_node *dn);
===== drivers/pci/hotplug/rpaphp_core.c 1.18 vs edited =====
--- 1.18/drivers/pci/hotplug/rpaphp_core.c	2004-10-06 11:43:44 -05:00
+++ edited/drivers/pci/hotplug/rpaphp_core.c	2004-11-17 16:00:37 -06:00
@@ -443,12 +443,18 @@ static int __init rpaphp_init(void)
 {
 	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 
+	/* Get set to handle EEH events. */
+	init_eeh_handler();
+
 	/* read all the PRA info from the system */
 	return init_rpa();
 }
 
 static void __exit rpaphp_exit(void)
 {
+	/* Let EEH know we are going away. */
+	exit_eeh_handler();
+
 	cleanup_slots();
 }
 
===== drivers/pci/hotplug/rpaphp_pci.c 1.16 vs edited =====
--- 1.16/drivers/pci/hotplug/rpaphp_pci.c	2004-10-19 11:54:38 -05:00
+++ edited/drivers/pci/hotplug/rpaphp_pci.c	2004-11-17 17:23:39 -06:00
@@ -22,8 +22,12 @@
  * Send feedback to <lxie@us.ibm.com>
  *
  */
+#include <linux/delay.h>
+#include <linux/notifier.h>
 #include <linux/pci.h>
+#include <asm/eeh.h>
 #include <asm/pci-bridge.h>
+#include <asm/prom.h>
 #include <asm/rtas.h>
 #include "../pci.h"		/* for pci_add_new_bus */
 
@@ -63,6 +67,7 @@ int rpaphp_claim_resource(struct pci_dev
 		    root ? "Address space collision on" :
 		    "No parent found for",
 		    resource, dtype, pci_name(dev), res->start, res->end);
+		dump_stack();
 	}
 	return err;
 }
@@ -185,6 +190,19 @@ rpaphp_fixup_new_pci_devices(struct pci_
 
 static int rpaphp_pci_config_bridge(struct pci_dev *dev);
 
+static void rpaphp_eeh_add_bus_device(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		eeh_add_device_late(dev);
+		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+			struct pci_bus *subbus = dev->subordinate;
+			if (bus)
+				rpaphp_eeh_add_bus_device (subbus);
+		}
+	}
+}
+
 /*****************************************************************************
  rpaphp_pci_config_slot() will  configure all devices under the 
  given slot->dn and return the the first pci_dev.
@@ -212,6 +230,8 @@ rpaphp_pci_config_slot(struct device_nod
 		}
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) 
 			rpaphp_pci_config_bridge(dev);
+
+		rpaphp_eeh_add_bus_device(bus);
 	}
 	return dev;
 }
@@ -220,7 +240,6 @@ static int rpaphp_pci_config_bridge(stru
 {
 	u8 sec_busno;
 	struct pci_bus *child_bus;
-	struct pci_dev *child_dev;
 
 	dbg("Enter %s:  BRIDGE dev=%s\n", __FUNCTION__, pci_name(dev));
 
@@ -237,11 +256,7 @@ static int rpaphp_pci_config_bridge(stru
 	/* do pci_scan_child_bus */
 	pci_scan_child_bus(child_bus);
 
-	list_for_each_entry(child_dev, &child_bus->devices, bus_list) {
-		eeh_add_device_late(child_dev);
-	}
-
-	 /* fixup new pci devices without touching bus struct */
+	/* Fixup new pci devices without touching bus struct */
 	rpaphp_fixup_new_pci_devices(child_bus, 0);
 
 	/* Make the discovered devices available */
@@ -279,7 +294,7 @@ static void print_slot_pci_funcs(struct 
 	return;
 }
 #else
-static void print_slot_pci_funcs(struct slot *slot)
+static inline void print_slot_pci_funcs(struct slot *slot)
 {
 	return;
 }
@@ -361,7 +376,6 @@ static void rpaphp_eeh_remove_bus_device
 			if (pdev)
 				rpaphp_eeh_remove_bus_device(pdev);
 		}
-
 	}
 	return;
 }
@@ -563,10 +577,14 @@ exit:
 	return retval;
 }
 
-struct hotplug_slot *rpaphp_find_hotplug_slot(struct pci_dev *dev)
+/**
+ * rpaphp_find_slot - find and return the slot holding the device
+ * @dev: pci device for which we want the slot structure.
+ */
+static struct slot *rpaphp_find_slot(struct pci_dev *dev)
 {
-	struct list_head	*tmp, *n;
-	struct slot		*slot;
+	struct list_head *tmp, *n;
+	struct slot	*slot;
 
 	list_for_each_safe(tmp, n, &rpaphp_slot_head) {
 		struct pci_bus *bus;
@@ -585,14 +603,109 @@ struct hotplug_slot *rpaphp_find_hotplug
 		if (!bus) {
 			continue;  /* should never happen? */
 		}
+
 		for (ln = bus->devices.next; ln != &bus->devices; ln = ln->next) {
-                                struct pci_dev *pdev = pci_dev_b(ln);
-				if (pdev == dev)
-					return slot->hotplug_slot;
+			struct pci_dev *pdev = pci_dev_b(ln);
+			if (pdev == dev)
+				return slot;
 		}
 	}
 
 	return NULL;
 }
 
-EXPORT_SYMBOL_GPL(rpaphp_find_hotplug_slot);
+/* ------------------------------------------------------- */
+/**
+ * handle_eeh_events -- reset a PCI device after hard lockup.
+ *
+ * pSeries systems will isolate a PCI slot if the PCI-Host
+ * bridge detects address or data parity errors, DMA's 
+ * occuring to wild addresses (which usually happen due to
+ * bugs in device drivers or in PCI adapter firmware).
+ * Slot isolations also occur if #SERR, #PERR or other misc
+ * PCI-related errors are detected.
+ * 
+ * Recovery process consists of unplugging the device driver
+ * (which generated hotplug events to userspace), then issuing
+ * a PCI #RST to the device, then reconfiguring the PCI config 
+ * space for all bridges & devices under this slot, and then 
+ * finally restarting the device drivers (which cause a second
+ * set of hotplug events to go out to userspace).
+ */
+int handle_eeh_events (struct notifier_block *self, 
+                       unsigned long reason, void *ev)
+{
+	struct eeh_event *event = ev;
+	struct slot *frozen_slot;
+	struct eeh_cfg_tree * saved_bars;
+
+	frozen_slot = rpaphp_find_slot(event->dev);
+	if (!frozen_slot)
+	{
+		printk (KERN_ERR 
+			"EEH: Cannot find PCI slot for EEH error! dev=%p dn=%p\n", 
+			event->dev, event->dn);
+		return 1;
+	}
+
+	/* Keep a copy of the config space registers */
+	saved_bars = eeh_save_bars(frozen_slot->dn);
+	of_node_get(event->dn);
+	pci_dev_get(event->dev);
+
+	rpaphp_unconfig_pci_adapter (frozen_slot);
+
+	event->dn->eeh_freeze_count ++;
+	if (event->dn->eeh_freeze_count > EEH_MAX_ALLOWED_FREEZES) {
+		/* 
+		 * About 90% of all real-life EEH failures in the field
+		 * are due to poorly seated PCI cards. Only 10% or so are
+		 * due to actual, failed cards 
+		 */
+		printk (KERN_ERR
+		   "EEH: device %s:%s has failed %d times \n"
+			"and has been permanently disabled.  Please try reseating\n"
+		   "this device or replacing it.\n",
+			pci_name (event->dev),
+			pci_pretty_name (event->dev),
+			EEH_MAX_ALLOWED_FREEZES);
+		goto rdone;
+	}
+
+	/* Reset the pci controller. (Asserts RST#; resets config space). 
+	 * Reconfigure bridges and devices */
+	rtas_set_slot_reset (event->dn);
+	rtas_configure_bridge(event->dn);
+	eeh_restore_bars(saved_bars);
+
+	/* Give the system 5 seconds to finish running the user-space
+	 * hotplug scripts, e.g. ifdown for ethernet.  Yes, this is a hack, 
+	 * but if we don't do this, weird things happen.
+	 */
+	ssleep (5);
+
+	rpaphp_enable_pci_slot (frozen_slot);
+
+	/* The new device node is different than the old one; 
+	 * copy over the freeze count, so that we don't loose track of it.
+	 */
+	frozen_slot->dn->eeh_freeze_count = event->dn->eeh_freeze_count;
+rdone:
+	of_node_put(event->dn);
+	pci_dev_put(event->dev);
+	return 0;
+}
+
+static struct notifier_block eeh_block;
+
+void __init init_eeh_handler (void)
+{
+	eeh_block.notifier_call = handle_eeh_events;
+	eeh_register_notifier (&eeh_block);
+}
+
+void __exit exit_eeh_handler (void)
+{
+	eeh_unregister_notifier (&eeh_block);
+}
+