cpci_hotplug_core.c

底层驱动开发

	list_for_each_entry(slot, &slot_list, slot_list) {
		dbg("%s - looking at slot %s",
		    __FUNCTION__, slot->hotplug_slot->name);
		if (clear_ins && cpci_check_and_clear_ins(slot))
			dbg("%s - cleared INS for slot %s",
			    __FUNCTION__, slot->hotplug_slot->name);
		dev = pci_get_slot(slot->bus, PCI_DEVFN(slot->number, 0));
		if (dev) {
			if (update_adapter_status(slot->hotplug_slot, 1))
				warn("failure to update adapter file");
			if (update_latch_status(slot->hotplug_slot, 1))
				warn("failure to update latch file");
			slot->dev = dev;
		}
	}
	up_read(&list_rwsem);
	dbg("%s - exit", __FUNCTION__);
	return 0;
}

static int
check_slots(void)
{
	struct slot *slot;
	int extracted;
	int inserted;
	u16 hs_csr;

	down_read(&list_rwsem);
	if (!slots) {
		up_read(&list_rwsem);
		err("no slots registered, shutting down");
		return -1;
	}
	extracted = inserted = 0;
	list_for_each_entry(slot, &slot_list, slot_list) {
		dbg("%s - looking at slot %s",
		    __FUNCTION__, slot->hotplug_slot->name);
		if (cpci_check_and_clear_ins(slot)) {
			/*
			 * Some broken hardware (e.g. PLX 9054AB) asserts
			 * ENUM# twice...
			 */
			if (slot->dev) {
				warn("slot %s already inserted",
				     slot->hotplug_slot->name);
				inserted++;
				continue;
			}

			/* Process insertion */
			dbg("%s - slot %s inserted",
			    __FUNCTION__, slot->hotplug_slot->name);

			/* GSM, debug */
			hs_csr = cpci_get_hs_csr(slot);
			dbg("%s - slot %s HS_CSR (1) = %04x",
			    __FUNCTION__, slot->hotplug_slot->name, hs_csr);

			/* Configure device */
			dbg("%s - configuring slot %s",
			    __FUNCTION__, slot->hotplug_slot->name);
			if (cpci_configure_slot(slot)) {
				err("%s - could not configure slot %s",
				    __FUNCTION__, slot->hotplug_slot->name);
				continue;
			}
			dbg("%s - finished configuring slot %s",
			    __FUNCTION__, slot->hotplug_slot->name);

			/* GSM, debug */
			hs_csr = cpci_get_hs_csr(slot);
			dbg("%s - slot %s HS_CSR (2) = %04x",
			    __FUNCTION__, slot->hotplug_slot->name, hs_csr);

			if (update_latch_status(slot->hotplug_slot, 1))
				warn("failure to update latch file");

			if (update_adapter_status(slot->hotplug_slot, 1))
				warn("failure to update adapter file");

			cpci_led_off(slot);

			/* GSM, debug */
			hs_csr = cpci_get_hs_csr(slot);
			dbg("%s - slot %s HS_CSR (3) = %04x",
			    __FUNCTION__, slot->hotplug_slot->name, hs_csr);

			inserted++;
		} else if (cpci_check_ext(slot)) {
			/* Process extraction request */
			dbg("%s - slot %s extracted",
			    __FUNCTION__, slot->hotplug_slot->name);

			/* GSM, debug */
			hs_csr = cpci_get_hs_csr(slot);
			dbg("%s - slot %s HS_CSR = %04x",
			    __FUNCTION__, slot->hotplug_slot->name, hs_csr);

			if (!slot->extracting) {
				if (update_latch_status(slot->hotplug_slot, 0)) {
					warn("failure to update latch file");
				}
				slot->extracting = 1;
				atomic_inc(&extracting);
			}
			extracted++;
		} else if (slot->extracting) {
			hs_csr = cpci_get_hs_csr(slot);
			if (hs_csr == 0xffff) {
				/*
				 * Hmmm, we're likely hosed at this point, should we
				 * bother trying to tell the driver or not?
				 */
				err("card in slot %s was improperly removed",
				    slot->hotplug_slot->name);
				if (update_adapter_status(slot->hotplug_slot, 0))
					warn("failure to update adapter file");
				slot->extracting = 0;
				atomic_dec(&extracting);
			}
		}
	}
	up_read(&list_rwsem);
	dbg("inserted=%d, extracted=%d, extracting=%d",
	    inserted, extracted, atomic_read(&extracting));
	if (inserted || extracted)
		return extracted;
	else if (!atomic_read(&extracting)) {
		err("cannot find ENUM# source, shutting down");
		return -1;
	}
	return 0;
}

/* This is the interrupt mode worker thread body */
static int
event_thread(void *data)
{
	int rc;

	lock_kernel();
	daemonize("cpci_hp_eventd");
	unlock_kernel();

	dbg("%s - event thread started", __FUNCTION__);
	while (1) {
		dbg("event thread sleeping");
		down_interruptible(&event_semaphore);
		dbg("event thread woken, thread_finished = %d",
		    thread_finished);
		if (thread_finished || signal_pending(current))
			break;
		do {
			rc = check_slots();
			if (rc > 0) {
				/* Give userspace a chance to handle extraction */
				msleep(500);
			} else if (rc < 0) {
				dbg("%s - error checking slots", __FUNCTION__);
				thread_finished = 1;
				break;
			}
		} while (atomic_read(&extracting) && !thread_finished);
		if (thread_finished)
			break;

		/* Re-enable ENUM# interrupt */
		dbg("%s - re-enabling irq", __FUNCTION__);
		controller->ops->enable_irq();
	}
	dbg("%s - event thread signals exit", __FUNCTION__);
	up(&thread_exit);
	return 0;
}

/* This is the polling mode worker thread body */
static int
poll_thread(void *data)
{
	int rc;

	lock_kernel();
	daemonize("cpci_hp_polld");
	unlock_kernel();

	while (1) {
		if (thread_finished || signal_pending(current))
			break;
		if (controller->ops->query_enum()) {
			do {
				rc = check_slots();
				if (rc > 0) {
					/* Give userspace a chance to handle extraction */
					msleep(500);
				} else if (rc < 0) {
					dbg("%s - error checking slots", __FUNCTION__);
					thread_finished = 1;
					break;
				}
			} while (atomic_read(&extracting) && !thread_finished);
		}
		msleep(100);
	}
	dbg("poll thread signals exit");
	up(&thread_exit);
	return 0;
}

static int
cpci_start_thread(void)
{
	int pid;

	/* initialize our semaphores */
	init_MUTEX_LOCKED(&event_semaphore);
	init_MUTEX_LOCKED(&thread_exit);
	thread_finished = 0;

	if (controller->irq)
		pid = kernel_thread(event_thread, NULL, 0);
	else
		pid = kernel_thread(poll_thread, NULL, 0);
	if (pid < 0) {
		err("Can't start up our thread");
		return -1;
	}
	dbg("Our thread pid = %d", pid);
	return 0;
}

static void
cpci_stop_thread(void)
{
	thread_finished = 1;
	dbg("thread finish command given");
	if (controller->irq)
		up(&event_semaphore);
	dbg("wait for thread to exit");
	down(&thread_exit);
}

int
cpci_hp_register_controller(struct cpci_hp_controller *new_controller)
{
	int status = 0;

	if (controller)
		return -1;
	if (!(new_controller && new_controller->ops))
		return -EINVAL;
	if (new_controller->irq) {
		if (!(new_controller->ops->enable_irq &&
		     new_controller->ops->disable_irq))
			status = -EINVAL;
		if (request_irq(new_controller->irq,
			       cpci_hp_intr,
			       new_controller->irq_flags,
			       MY_NAME,
			       new_controller->dev_id)) {
			err("Can't get irq %d for the hotplug cPCI controller",
			    new_controller->irq);
			status = -ENODEV;
		}
		dbg("%s - acquired controller irq %d",
		    __FUNCTION__, new_controller->irq);
	}
	if (!status)
		controller = new_controller;
	return status;
}

static void
cleanup_slots(void)
{
	struct slot *slot;
	struct slot *tmp;

	/*
	 * Unregister all of our slots with the pci_hotplug subsystem,
	 * and free up all memory that we had allocated.
	 */
	down_write(&list_rwsem);
	if (!slots)
		goto cleanup_null;
	list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
		list_del(&slot->slot_list);
		pci_hp_deregister(slot->hotplug_slot);
	}
cleanup_null:
	up_write(&list_rwsem);
	return;
}

int
cpci_hp_unregister_controller(struct cpci_hp_controller *old_controller)
{
	int status = 0;

	if (controller) {
		if (!thread_finished)
			cpci_stop_thread();
		if (controller->irq)
			free_irq(controller->irq, controller->dev_id);
		controller = NULL;
		cleanup_slots();
	} else
		status = -ENODEV;
	return status;
}

int
cpci_hp_start(void)
{
	static int first = 1;
	int status;

	dbg("%s - enter", __FUNCTION__);
	if (!controller)
		return -ENODEV;

	down_read(&list_rwsem);
	if (list_empty(&slot_list)) {
		up_read(&list_rwsem);
		return -ENODEV;
	}
	up_read(&list_rwsem);

	status = init_slots(first);
	if (first)
		first = 0;
	if (status)
		return status;

	status = cpci_start_thread();
	if (status)
		return status;
	dbg("%s - thread started", __FUNCTION__);

	if (controller->irq) {
		/* Start enum interrupt processing */
		dbg("%s - enabling irq", __FUNCTION__);
		controller->ops->enable_irq();
	}
	dbg("%s - exit", __FUNCTION__);
	return 0;
}

int
cpci_hp_stop(void)
{
	if (!controller)
		return -ENODEV;
	if (controller->irq) {
		/* Stop enum interrupt processing */
		dbg("%s - disabling irq", __FUNCTION__);
		controller->ops->disable_irq();
	}
	cpci_stop_thread();
	return 0;
}

int __init
cpci_hotplug_init(int debug)
{
	cpci_debug = debug;
	return 0;
}

void __exit
cpci_hotplug_exit(void)
{
	/*
	 * Clean everything up.
	 */
	cpci_hp_stop();
	cpci_hp_unregister_controller(controller);
}

EXPORT_SYMBOL_GPL(cpci_hp_register_controller);
EXPORT_SYMBOL_GPL(cpci_hp_unregister_controller);
EXPORT_SYMBOL_GPL(cpci_hp_register_bus);
EXPORT_SYMBOL_GPL(cpci_hp_unregister_bus);
EXPORT_SYMBOL_GPL(cpci_hp_start);
EXPORT_SYMBOL_GPL(cpci_hp_stop);