hvcs.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,667 行 · 第 1/4 页

			hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
			/* wmb(); */

			/*
			 * We are still obligated to deliver the data to the
			 * hypervisor even if the tty has been closed because
			 * we commited to delivering it.  But don't try to wake
			 * a non-existent tty.
			 */
			if (tty) {
				tty_wakeup(tty);
			}
		}
	}
}

static int hvcs_io(struct hvcs_struct *hvcsd)
{
	uint32_t unit_address;
	struct tty_struct *tty;
	char buf[HVCS_BUFF_LEN] __ALIGNED__;
	unsigned long flags;
	int got = 0;
	int i;

	spin_lock_irqsave(&hvcsd->lock, flags);

	unit_address = hvcsd->vdev->unit_address;
	tty = hvcsd->tty;

	hvcs_try_write(hvcsd);

	if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
		hvcsd->todo_mask &= ~(HVCS_READ_MASK);
		goto bail;
	} else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
		goto bail;

	/* remove the read masks */
	hvcsd->todo_mask &= ~(HVCS_READ_MASK);

	if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) {
		got = hvc_get_chars(unit_address,
				&buf[0],
				HVCS_BUFF_LEN);
		for (i=0;got && i<got;i++)
			tty_insert_flip_char(tty, buf[i], TTY_NORMAL);
	}

	/* Give the TTY time to process the data we just sent. */
	if (got)
		hvcsd->todo_mask |= HVCS_QUICK_READ;

	spin_unlock_irqrestore(&hvcsd->lock, flags);
	if (tty->flip.count) {
		/* This is synch because tty->low_latency == 1 */
		tty_flip_buffer_push(tty);
	}

	if (!got) {
		/* Do this _after_ the flip_buffer_push */
		spin_lock_irqsave(&hvcsd->lock, flags);
		vio_enable_interrupts(hvcsd->vdev);
		spin_unlock_irqrestore(&hvcsd->lock, flags);
	}

	return hvcsd->todo_mask;

 bail:
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return hvcsd->todo_mask;
}

static int khvcsd(void *unused)
{
	struct hvcs_struct *hvcsd;
	int hvcs_todo_mask;

	__set_current_state(TASK_RUNNING);

	do {
		hvcs_todo_mask = 0;
		hvcs_kicked = 0;
		wmb();

		spin_lock(&hvcs_structs_lock);
		list_for_each_entry(hvcsd, &hvcs_structs, next) {
			hvcs_todo_mask |= hvcs_io(hvcsd);
		}
		spin_unlock(&hvcs_structs_lock);

		/*
		 * If any of the hvcs adapters want to try a write or quick read
		 * don't schedule(), yield a smidgen then execute the hvcs_io
		 * thread again for those that want the write.
		 */
		 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
			yield();
			continue;
		}

		set_current_state(TASK_INTERRUPTIBLE);
		if (!hvcs_kicked)
			schedule();
		__set_current_state(TASK_RUNNING);
	} while (!kthread_should_stop());

	return 0;
}

static struct vio_device_id hvcs_driver_table[] __devinitdata= {
	{"serial-server", "hvterm2"},
	{ 0, }
};
MODULE_DEVICE_TABLE(vio, hvcs_driver_table);

static void hvcs_return_index(int index)
{
	/* Paranoia check */
	if (!hvcs_index_list)
		return;
	if (index < 0 || index >= hvcs_index_count)
		return;
	if (hvcs_index_list[index] == -1)
		return;
	else
		hvcs_index_list[index] = -1;
}

/* callback when the kboject ref count reaches zero */
static void destroy_hvcs_struct(struct kobject *kobj)
{
	struct hvcs_struct *hvcsd = from_kobj(kobj);
	struct vio_dev *vdev;
	unsigned long flags;

	spin_lock(&hvcs_structs_lock);
	spin_lock_irqsave(&hvcsd->lock, flags);

	/* the list_del poisons the pointers */
	list_del(&(hvcsd->next));

	if (hvcsd->connected == 1) {
		hvcs_partner_free(hvcsd);
		printk(KERN_INFO "HVCS: Closed vty-server@%X and"
				" partner vty@%X:%d connection.\n",
				hvcsd->vdev->unit_address,
				hvcsd->p_unit_address,
				(uint32_t)hvcsd->p_partition_ID);
	}
	printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
			hvcsd->vdev->unit_address);

	vdev = hvcsd->vdev;
	hvcsd->vdev = NULL;

	hvcsd->p_unit_address = 0;
	hvcsd->p_partition_ID = 0;
	hvcs_return_index(hvcsd->index);
	memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);

	spin_unlock_irqrestore(&hvcsd->lock, flags);
	spin_unlock(&hvcs_structs_lock);

	hvcs_remove_device_attrs(vdev);

	kfree(hvcsd);
}

static struct kobj_type hvcs_kobj_type = {
	.release = destroy_hvcs_struct,
};

static int hvcs_get_index(void)
{
	int i;
	/* Paranoia check */
	if (!hvcs_index_list) {
		printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
		return -EFAULT;
	}
	/* Find the numerically lowest first free index. */
	for(i = 0; i < hvcs_index_count; i++) {
		if (hvcs_index_list[i] == -1) {
			hvcs_index_list[i] = 0;
			return i;
		}
	}
	return -1;
}

static int __devinit hvcs_probe(
	struct vio_dev *dev,
	const struct vio_device_id *id)
{
	struct hvcs_struct *hvcsd;
	int index;

	if (!dev || !id) {
		printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
		return -EPERM;
	}

	/* early to avoid cleanup on failure */
	index = hvcs_get_index();
	if (index < 0) {
		return -EFAULT;
	}

	hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL);
	if (!hvcsd)
		return -ENODEV;

	/* hvcsd->tty is zeroed out with the memset */
	memset(hvcsd, 0x00, sizeof(*hvcsd));

	hvcsd->lock = SPIN_LOCK_UNLOCKED;
	/* Automatically incs the refcount the first time */
	kobject_init(&hvcsd->kobj);
	/* Set up the callback for terminating the hvcs_struct's life */
	hvcsd->kobj.ktype = &hvcs_kobj_type;

	hvcsd->vdev = dev;
	dev->dev.driver_data = hvcsd;

	hvcsd->index = index;

	/* hvcsd->index = ++hvcs_struct_count; */
	hvcsd->chars_in_buffer = 0;
	hvcsd->todo_mask = 0;
	hvcsd->connected = 0;

	/*
	 * This will populate the hvcs_struct's partner info fields for the
	 * first time.
	 */
	if (hvcs_get_pi(hvcsd)) {
		printk(KERN_ERR "HVCS: Failed to fetch partner"
			" info for vty-server@%X on device probe.\n",
			hvcsd->vdev->unit_address);
	}

	/*
	 * If a user app opens a tty that corresponds to this vty-server before
	 * the hvcs_struct has been added to the devices list then the user app
	 * will get -ENODEV.
	 */

	spin_lock(&hvcs_structs_lock);

	list_add_tail(&(hvcsd->next), &hvcs_structs);

	spin_unlock(&hvcs_structs_lock);

	hvcs_create_device_attrs(hvcsd);

	printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);

	/*
	 * DON'T enable interrupts here because there is no user to receive the
	 * data.
	 */
	return 0;
}

static int __devexit hvcs_remove(struct vio_dev *dev)
{
	struct hvcs_struct *hvcsd = dev->dev.driver_data;
	unsigned long flags;
	struct kobject *kobjp;
	struct tty_struct *tty;

	if (!hvcsd)
		return -ENODEV;

	/* By this time the vty-server won't be getting any more interrups */

	spin_lock_irqsave(&hvcsd->lock, flags);

	tty = hvcsd->tty;

	kobjp = &hvcsd->kobj;

	spin_unlock_irqrestore(&hvcsd->lock, flags);

	/*
	 * Let the last holder of this object cause it to be removed, which
	 * would probably be tty_hangup below.
	 */
	kobject_put (kobjp);

	/*
	 * The hangup is a scheduled function which will auto chain call
	 * hvcs_hangup.  The tty should always be valid at this time unless a
	 * simultaneous tty close already cleaned up the hvcs_struct.
	 */
	if (tty)
		tty_hangup(tty);

	printk(KERN_INFO "HVCS: vty-server@%X removed from the"
			" vio bus.\n", dev->unit_address);
	return 0;
};

static struct vio_driver hvcs_vio_driver = {
	.name		= hvcs_driver_name,
	.id_table	= hvcs_driver_table,
	.probe		= hvcs_probe,
	.remove		= hvcs_remove,
};

/* Only called from hvcs_get_pi please */
static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
{
	int clclength;

	hvcsd->p_unit_address = pi->unit_address;
	hvcsd->p_partition_ID  = pi->partition_ID;
	clclength = strlen(&pi->location_code[0]);
	if (clclength > HVCS_CLC_LENGTH)
		clclength = HVCS_CLC_LENGTH;

	/* copy the null-term char too */
	strncpy(&hvcsd->p_location_code[0],
			&pi->location_code[0], clclength + 1);
}

/*
 * Traverse the list and add the partner info that is found to the hvcs_struct
 * struct entry. NOTE: At this time I know that partner info will return a
 * single entry but in the future there may be multiple partner info entries per
 * vty-server and you'll want to zero out that list and reset it.  If for some
 * reason you have an old version of this driver but there IS more than one
 * partner info then hvcsd->p_* will hold the last partner info data from the
 * firmware query.  A good way to update this code would be to replace the three
 * partner info fields in hvcs_struct with a list of hvcs_partner_info
 * instances.
 *
 * This function must be called with the hvcsd->lock held.
 */
static int hvcs_get_pi(struct hvcs_struct *hvcsd)
{
	struct hvcs_partner_info *pi;
	uint32_t unit_address = hvcsd->vdev->unit_address;
	struct list_head head;
	int retval;

	spin_lock(&hvcs_pi_lock);
	if (!hvcs_pi_buff) {
		spin_unlock(&hvcs_pi_lock);
		return -EFAULT;
	}
	retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
	spin_unlock(&hvcs_pi_lock);
	if (retval) {
		printk(KERN_ERR "HVCS: Failed to fetch partner"
			" info for vty-server@%x.\n", unit_address);
		return retval;
	}

	/* nixes the values if the partner vty went away */
	hvcsd->p_unit_address = 0;
	hvcsd->p_partition_ID = 0;

	list_for_each_entry(pi, &head, node)
		hvcs_set_pi(pi, hvcsd);

	hvcs_free_partner_info(&head);
	return 0;
}

/*
 * This function is executed by the driver "rescan" sysfs entry.  It shouldn't
 * be executed elsewhere, in order to prevent deadlock issues.
 */
static int hvcs_rescan_devices_list(void)
{
	struct hvcs_struct *hvcsd;
	unsigned long flags;

	spin_lock(&hvcs_structs_lock);

	list_for_each_entry(hvcsd, &hvcs_structs, next) {
		spin_lock_irqsave(&hvcsd->lock, flags);
		hvcs_get_pi(hvcsd);
		spin_unlock_irqrestore(&hvcsd->lock, flags);
	}

	spin_unlock(&hvcs_structs_lock);

	return 0;
}

/*
 * Farm this off into its own function because it could be more complex once
 * multiple partners support is added. This function should be called with
 * the hvcsd->lock held.
 */
static int hvcs_has_pi(struct hvcs_struct *hvcsd)
{
	if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
		return 0;
	return 1;
}

/*
 * NOTE: It is possible that the super admin removed a partner vty and then
 * added a different vty as the new partner.
 *
 * This function must be called with the hvcsd->lock held.
 */
static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
{
	int retval;
	unsigned int unit_address = hvcsd->vdev->unit_address;

	/*