pciehp: Event handling rework

The event handler of PCIEHP driver is unnecessarily very complex. In
addition, current event handler can only a fixed number of events at
the same time, and some of events would be lost if several number of
events happened at the same time.

This patch simplify the event handler using 'work queue', and it also
fix the above-mentioned issue.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/hotplug/pciehp.h

@@ -43,6 +43,7 @@ extern int pciehp_poll_mode;
 extern int pciehp_poll_time;
 extern int pciehp_debug;
 extern int pciehp_force;
+extern struct workqueue_struct *pciehp_wq;
 
 #define dbg(format, arg...)						\
 	do {								\
@@ -70,14 +71,16 @@ struct slot {
 	struct list_head	slot_list;
 	char name[SLOT_NAME_SIZE];
 	unsigned long last_emi_toggle;
+	struct delayed_work work;	/* work for button event */
+	struct mutex lock;
 };
 
 struct event_info {
 	u32 event_type;
-	u8 hp_slot;
+	struct slot *p_slot;
+	struct work_struct work;
 };
 
-#define MAX_EVENTS		10
 struct controller {
 	struct controller *next;
 	struct mutex crit_sect;		/* critical section mutex */
@@ -86,11 +89,9 @@ struct controller {
 	int slot_num_inc;		/* 1 or -1 */
 	struct pci_dev *pci_dev;
 	struct list_head slot_list;
-	struct event_info event_queue[MAX_EVENTS];
 	struct slot *slot;
 	struct hpc_ops *hpc_ops;
 	wait_queue_head_t queue;	/* sleep & wake process */
-	u8 next_event;
 	u8 bus;
 	u8 device;
 	u8 function;
@@ -149,16 +150,15 @@ struct controller {
 #define HP_SUPR_RM(cap)		(cap & HP_SUPR_RM_SUP)
 #define EMI(cap)		(cap & EMI_PRSN)
 
-extern int pciehp_event_start_thread(void);
-extern void pciehp_event_stop_thread(void);
-extern int pciehp_enable_slot(struct slot *slot);
-extern int pciehp_disable_slot(struct slot *slot);
+extern int pciehp_sysfs_enable_slot(struct slot *slot);
+extern int pciehp_sysfs_disable_slot(struct slot *slot);
 extern u8 pciehp_handle_attention_button(u8 hp_slot, struct controller *ctrl);
 extern u8 pciehp_handle_switch_change(u8 hp_slot, struct controller *ctrl);
 extern u8 pciehp_handle_presence_change(u8 hp_slot, struct controller *ctrl);
 extern u8 pciehp_handle_power_fault(u8 hp_slot, struct controller *ctrl);
 extern int pciehp_configure_device(struct slot *p_slot);
 extern int pciehp_unconfigure_device(struct slot *p_slot);
+extern void queue_pushbutton_work(struct work_struct *work);
 int pcie_init(struct controller *ctrl, struct pcie_device *dev);
 
 /* Global variables */

drivers/pci/hotplug/pciehp_core.c

@@ -41,6 +41,7 @@ int pciehp_debug;
 int pciehp_poll_mode;
 int pciehp_poll_time;
 int pciehp_force;
+struct workqueue_struct *pciehp_wq;
 struct controller *pciehp_ctrl_list;
 
 #define DRIVER_VERSION	"0.4"
@@ -62,7 +63,6 @@ MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if _OSC and OSHP are missing"
 
 #define PCIE_MODULE_NAME "pciehp"
 
-static int pcie_start_thread (void);
 static int set_attention_status (struct hotplug_slot *slot, u8 value);
 static int enable_slot		(struct hotplug_slot *slot);
 static int disable_slot		(struct hotplug_slot *slot);
@@ -229,6 +229,8 @@ static int init_slots(struct controller *ctrl)
 		slot->device = ctrl->slot_device_offset + i;
 		slot->hpc_ops = ctrl->hpc_ops;
 		slot->number = ctrl->first_slot;
+		mutex_init(&slot->lock);
+		INIT_DELAYED_WORK(&slot->work, queue_pushbutton_work);
 
 		/* register this slot with the hotplug pci core */
 		hotplug_slot->private = slot;
@@ -286,6 +288,9 @@ static void cleanup_slots(struct controller *ctrl)
 		if (EMI(ctrl->ctrlcap))
 			sysfs_remove_file(&slot->hotplug_slot->kobj,
 				&hotplug_slot_attr_lock.attr);
+		cancel_delayed_work(&slot->work);
+		flush_scheduled_work();
+		flush_workqueue(pciehp_wq);
 		pci_hp_deregister(slot->hotplug_slot);
 	}
 }
@@ -314,7 +319,7 @@ static int enable_slot(struct hotplug_slot *hotplug_slot)
 
 	dbg("%s - physical_slot = %s\n", __FUNCTION__, hotplug_slot->name);
 
-	return pciehp_enable_slot(slot);
+	return pciehp_sysfs_enable_slot(slot);
 }
 
 
@@ -324,7 +329,7 @@ static int disable_slot(struct hotplug_slot *hotplug_slot)
 
 	dbg("%s - physical_slot = %s\n", __FUNCTION__, hotplug_slot->name);
 
-	return pciehp_disable_slot(slot);
+	return pciehp_sysfs_disable_slot(slot);
 }
 
 static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
@@ -466,9 +471,6 @@ static int pciehp_probe(struct pcie_device *dev, const struct pcie_port_service_
 
 	t_slot = pciehp_find_slot(ctrl, ctrl->slot_device_offset);
 
-	/*	Finish setting up the hot plug ctrl device */
-	ctrl->next_event = 0;
-
 	if (!pciehp_ctrl_list) {
 		pciehp_ctrl_list = ctrl;
 		ctrl->next = NULL;
@@ -496,22 +498,6 @@ err_out_none:
 	return -ENODEV;
 }
 
-
-static int pcie_start_thread(void)
-{
-	int retval = 0;
-	
-	dbg("Initialize + Start the notification/polling mechanism \n");
-
-	retval = pciehp_event_start_thread();
-	if (retval) {
-		dbg("pciehp_event_start_thread() failed\n");
-		return retval;
-	}
-
-	return retval;
-}
-
 static void __exit unload_pciehpd(void)
 {
 	struct controller *ctrl;
@@ -529,10 +515,6 @@ static void __exit unload_pciehpd(void)
 
 		kfree(tctrl);
 	}
-
-	/* Stop the notification mechanism */
-	pciehp_event_stop_thread();
-
 }
 
 static void pciehp_remove (struct pcie_device *device)
@@ -585,21 +567,11 @@ static int __init pcied_init(void)
 	pciehp_poll_mode = 1;
 #endif
 
-	retval = pcie_start_thread();
-	if (retval)
-		goto error_hpc_init;
-
 	retval = pcie_port_service_register(&hpdriver_portdrv);
  	dbg("pcie_port_service_register = %d\n", retval);
   	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
  	if (retval)
 		dbg("%s: Failure to register service\n", __FUNCTION__);
-
-error_hpc_init:
-	if (retval) {
-		pciehp_event_stop_thread();
-	};
-
 	return retval;
 }
 

drivers/pci/hotplug/pciehp_hpc.c

@@ -71,6 +71,8 @@
 #define DBG_LEAVE_ROUTINE
 #endif				/* DEBUG */
 
+static atomic_t pciehp_num_controllers = ATOMIC_INIT(0);
+
 struct ctrl_reg {
 	u8 cap_id;
 	u8 nxt_ptr;
@@ -219,10 +221,7 @@ static inline int pciehp_writel(struct controller *ctrl, int reg, u32 value)
 #define EMI_STATE		0x0080
 #define EMI_STATUS_BIT		7
 
-static spinlock_t hpc_event_lock;
-
 DEFINE_DBG_BUFFER		/* Debug string buffer for entire HPC defined here */
-static int ctlr_seq_num = 0;	/* Controller sequence # */
 
 static irqreturn_t pcie_isr(int irq, void *dev_id);
 static void start_int_poll_timer(struct controller *ctrl, int sec);
@@ -656,6 +655,13 @@ static void hpc_release_ctlr(struct controller *ctrl)
 	else
 		free_irq(ctrl->pci_dev->irq, ctrl);
 
+	/*
+	 * If this is the last controller to be released, destroy the
+	 * pciehp work queue
+	 */
+	if (atomic_dec_and_test(&pciehp_num_controllers))
+		destroy_workqueue(pciehp_wq);
+
 	DBG_LEAVE_ROUTINE
 }
 
@@ -1152,7 +1158,6 @@ int pciehp_acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev)
 int pcie_init(struct controller * ctrl, struct pcie_device *dev)
 {
 	int rc;
-	static int first = 1;
 	u16 temp_word;
 	u16 cap_reg;
 	u16 intr_enable = 0;
@@ -1221,11 +1226,6 @@ int pcie_init(struct controller * ctrl, struct pcie_device *dev)
 	dbg("%s: SLOTCTRL offset %x slot_ctrl %x\n",
 	    __FUNCTION__, ctrl->cap_base + SLOTCTRL, slot_ctrl);
 
-	if (first) {
-		spin_lock_init(&hpc_event_lock);
-		first = 0;
-	}
-
 	for ( rc = 0; rc < DEVICE_COUNT_RESOURCE; rc++)
 		if (pci_resource_len(pdev, rc) > 0)
 			dbg("pci resource[%d] start=0x%llx(len=0x%llx)\n", rc,
@@ -1286,7 +1286,8 @@ int pcie_init(struct controller * ctrl, struct pcie_device *dev)
 		rc = request_irq(ctrl->pci_dev->irq, pcie_isr, IRQF_SHARED,
 				 MY_NAME, (void *)ctrl);
 		dbg("%s: request_irq %d for hpc%d (returns %d)\n",
-		    __FUNCTION__, ctrl->pci_dev->irq, ctlr_seq_num, rc);
+		    __FUNCTION__, ctrl->pci_dev->irq,
+		    atomic_read(&pciehp_num_controllers), rc);
 		if (rc) {
 			err("Can't get irq %d for the hotplug controller\n",
 			    ctrl->pci_dev->irq);
@@ -1296,6 +1297,18 @@ int pcie_init(struct controller * ctrl, struct pcie_device *dev)
 	dbg("pciehp ctrl b:d:f:irq=0x%x:%x:%x:%x\n", pdev->bus->number,
 		PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn), dev->irq);
 
+	/*
+	 * If this is the first controller to be initialized,
+	 * initialize the pciehp work queue
+	 */
+	if (atomic_add_return(1, &pciehp_num_controllers) == 1) {
+		pciehp_wq = create_singlethread_workqueue("pciehpd");
+		if (!pciehp_wq) {
+			rc = -ENOMEM;
+			goto abort_free_irq;
+		}
+	}
+
 	rc = pciehp_readw(ctrl, SLOTCTRL, &temp_word);
 	if (rc) {
 		err("%s: Cannot read SLOTCTRL register\n", __FUNCTION__);
@@ -1349,7 +1362,6 @@ int pcie_init(struct controller * ctrl, struct pcie_device *dev)
 			goto abort_disable_intr;
 	}
 
-	ctlr_seq_num++;
 	ctrl->hpc_ops = &pciehp_hpc_ops;
 
 	DBG_LEAVE_ROUTINE