[PATCH] shpchp: dont save PCI config for hotplug slots/devices

This patch eliminates saving the PCI config header for devices
in hotplug capable slots. We now use the PCI core to get the
specific parts of the config header as required.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/hotplug/shpchp.h

@@ -63,7 +63,6 @@ struct pci_func {
 	u8 switch_save;
 	u8 presence_save;
 	u8 pwr_save;
-	u32 config_space[0x20];
 	struct pci_dev* pci_dev;
 };
 

drivers/pci/hotplug/shpchp_core.c

@@ -424,13 +424,6 @@ static int shpc_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	first_device_num = ctrl->slot_device_offset;
 	num_ctlr_slots = ctrl->num_slots;
 
-	/* Store PCI Config Space for all devices on this bus */
-	rc = shpchp_save_config(ctrl, ctrl->slot_bus, num_ctlr_slots, first_device_num);
-	if (rc) {
-		err("%s: unable to save PCI configuration data, error %d\n", __FUNCTION__, rc);
-		goto err_out_free_ctrl_bus;
-	}
-
 	ctrl->add_support = 1;
 
 	/* Setup the slot information structures */

drivers/pci/hotplug/shpchp_ctrl.c

@@ -328,21 +328,20 @@ static int slot_remove(struct pci_func * old_slot)
 /**
  * bridge_slot_remove - Removes a node from the linked list of slots.
  * @bridge: bridge to remove
+ * @secondaryBus: secondary PCI bus number for bridge being removed
+ * @subordinateBus: subordinate PCI bus number for bridge being removed
  *
  * Returns 0 if successful, !0 otherwise.
  */
-static int bridge_slot_remove(struct pci_func *bridge)
+static int bridge_slot_remove(struct pci_func *bridge, u8 secondaryBus,
+		u8 subordinateBus)
 {
-	u8 subordinateBus, secondaryBus;
 	u8 tempBus;
 	struct pci_func *next;
 
 	if (bridge == NULL)
 		return(1);
 
-	secondaryBus = (bridge->config_space[0x06] >> 8) & 0xFF;
-	subordinateBus = (bridge->config_space[0x06] >> 16) & 0xFF;
-
 	for (tempBus = secondaryBus; tempBus <= subordinateBus; tempBus++) {
 		next = shpchp_slot_list[tempBus];
 
@@ -410,16 +409,23 @@ struct pci_func *shpchp_slot_find(u8 bus, u8 device, u8 index)
 	return(NULL);
 }
 
-static int is_bridge(struct pci_func * func)
+static int is_bridge(struct pci_func *func, struct controller *ctrl)
 {
-	/* Check the header type */
-	if (((func->config_space[0x03] >> 16) & 0xFF) == 0x01)
+	u8 hdr_type;
+	struct pci_bus *bus = ctrl->pci_dev->subordinate;
+
+	/*
+	 * Note: device may have just been hot-added and not yet scanned
+	 * by the pci core, so its pci_dev structure may not exist yet
+	 */
+	pci_bus_read_config_byte(bus, PCI_DEVFN(func->device, func->function),
+			PCI_HEADER_TYPE, &hdr_type);
+	if ((hdr_type & 0x7f) == PCI_HEADER_TYPE_BRIDGE)
 		return 1;
 	else
 		return 0;
 }
 
-
 /* The following routines constitute the bulk of the 
    hotplug controller logic
  */
@@ -709,8 +715,6 @@ static u32 board_added(struct pci_func * func, struct controller * ctrl)
 		goto err_exit;
 	}
 
-	shpchp_save_slot_config(ctrl, func);
-
 	func->status = 0;
 	func->switch_save = 0x10;
 	func->is_a_board = 0x01;
@@ -769,10 +773,18 @@ static u32 remove_board(struct pci_func *func, struct controller *ctrl)
 	u8 hp_slot;
 	u32 rc;
 	struct slot *p_slot;
+	u8 secondary = 0, subordinate = 0;
+	int remove_bridge;
 
 	if (func == NULL)
 		return(1);
 
+	if ((remove_bridge = is_bridge(func, ctrl))) {
+		/* Stash away bus information before we destroy it */
+		secondary = func->pci_dev->subordinate->secondary;
+		subordinate = func->pci_dev->subordinate->subordinate;
+	}
+
 	if (shpchp_unconfigure_device(func))
 		return(1);
 
@@ -825,10 +837,11 @@ static u32 remove_board(struct pci_func *func, struct controller *ctrl)
 
 	if (ctrl->add_support) {
 		while (func) {
-			if (is_bridge(func)) {
+			if (remove_bridge) {
 				dbg("PCI Bridge Hot-Remove s:b:d:f(%02x:%02x:%02x:%02x)\n", ctrl->seg, func->bus, 
 					func->device, func->function);
-				bridge_slot_remove(func);
+				bridge_slot_remove(func, secondary,
+						subordinate);
 			} else
 				dbg("PCI Function Hot-Remove s:b:d:f(%02x:%02x:%02x:%02x)\n", ctrl->seg, func->bus, 
 					func->device, func->function);
@@ -1185,9 +1198,12 @@ int shpchp_enable_slot (struct slot *p_slot)
 
 	rc = board_added(func, p_slot->ctrl);
 	if (rc) {
-		if (is_bridge(func))
-			bridge_slot_remove(func);
-		else
+		if (is_bridge(func, p_slot->ctrl)) {
+			u8 secondary = func->pci_dev->subordinate->secondary;
+			u8 subordinate =
+				func->pci_dev->subordinate->subordinate;
+			bridge_slot_remove(func, secondary, subordinate);
+		} else
 			slot_remove(func);
 
 		/* Setup slot structure with entry for empty slot */