hvcs.c

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

		memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
				&charbuf[total_sent],
				tosend);

		hvcsd->chars_in_buffer += tosend;

		result = 0;

		/*
		 * If this is true then we don't want to try writing to the
		 * hypervisor because that is the kernel_threads job now.  We'll
		 * just add to the buffer.
		 */
		if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
			/* won't send partial writes */
			result = hvc_put_chars(unit_address,
					&hvcsd->buffer[0],
					hvcsd->chars_in_buffer);

		/*
		 * Since we know we have enough room in hvcsd->buffer for
		 * tosend we record that it was sent regardless of whether the
		 * hypervisor actually took it because we have it buffered.
		 */
		total_sent+=tosend;
		count-=tosend;
		if (result == 0) {
			hvcsd->todo_mask |= HVCS_TRY_WRITE;
			hvcs_kick();
			break;
		}

		hvcsd->chars_in_buffer = 0;
		/*
		 * Test after the chars_in_buffer reset otherwise this could
		 * deadlock our writes if hvc_put_chars fails.
		 */
		if (result < 0)
			break;
	}

	spin_unlock_irqrestore(&hvcsd->lock, flags);
	if (from_user)
		kfree(charbuf);

	if (result == -1)
		return -EIO;
	else
		return total_sent;
}

/*
 * This is really asking how much can we guarentee that we can send or that we
 * absolutely WILL BUFFER if we can't send it.  This driver MUST honor the
 * return value, hence the reason for hvcs_struct buffering.
 */
static int hvcs_write_room(struct tty_struct *tty)
{
	struct hvcs_struct *hvcsd = tty->driver_data;

	if (!hvcsd || hvcsd->open_count <= 0)
		return 0;

	return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
}

static int hvcs_chars_in_buffer(struct tty_struct *tty)
{
	struct hvcs_struct *hvcsd = tty->driver_data;

	return hvcsd->chars_in_buffer;
}

static struct tty_operations hvcs_ops = {
	.open = hvcs_open,
	.close = hvcs_close,
	.hangup = hvcs_hangup,
	.write = hvcs_write,
	.write_room = hvcs_write_room,
	.chars_in_buffer = hvcs_chars_in_buffer,
	.unthrottle = hvcs_unthrottle,
	.throttle = hvcs_throttle,
};

static int hvcs_alloc_index_list(int n)
{
	int i;
	hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL);
	if (!hvcs_index_list)
		return -ENOMEM;
	hvcs_index_count = n;
	for(i = 0; i < hvcs_index_count; i++)
		hvcs_index_list[i] = -1;
	return 0;
}

static void hvcs_free_index_list(void)
{
	/* Paranoia check to be thorough. */
	if (hvcs_index_list) {
		kfree(hvcs_index_list);
		hvcs_index_list = NULL;
		hvcs_index_count = 0;
	}
}

static int __init hvcs_module_init(void)
{
	int rc;
	int num_ttys_to_alloc;

	printk(KERN_INFO "Initializing %s\n", hvcs_driver_string);

	/* Has the user specified an overload with an insmod param? */
	if (hvcs_parm_num_devs <= 0 ||
		(hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
		num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
	} else
		num_ttys_to_alloc = hvcs_parm_num_devs;

	hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
	if (!hvcs_tty_driver)
		return -ENOMEM;

	if (hvcs_alloc_index_list(num_ttys_to_alloc))
		return -ENOMEM;

	hvcs_tty_driver->owner = THIS_MODULE;

	hvcs_tty_driver->driver_name = hvcs_driver_name;
	hvcs_tty_driver->name = hvcs_device_node;

	/*
	 * We'll let the system assign us a major number, indicated by leaving
	 * it blank.
	 */

	hvcs_tty_driver->minor_start = HVCS_MINOR_START;
	hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;

	/*
	 * We role our own so that we DONT ECHO.  We can't echo because the
	 * device we are connecting to already echoes by default and this would
	 * throw us into a horrible recursive echo-echo-echo loop.
	 */
	hvcs_tty_driver->init_termios = hvcs_tty_termios;
	hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;

	tty_set_operations(hvcs_tty_driver, &hvcs_ops);

	/*
	 * The following call will result in sysfs entries that denote the
	 * dynamically assigned major and minor numbers for our devices.
	 */
	if (tty_register_driver(hvcs_tty_driver)) {
		printk(KERN_ERR "HVCS: registration "
			" as a tty driver failed.\n");
		hvcs_free_index_list();
		put_tty_driver(hvcs_tty_driver);
		return -EIO;
	}

	hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!hvcs_pi_buff) {
		tty_unregister_driver(hvcs_tty_driver);
		hvcs_free_index_list();
		put_tty_driver(hvcs_tty_driver);
		return -ENOMEM;
	}

	hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
	if (IS_ERR(hvcs_task)) {
		printk(KERN_ERR "HVCS: khvcsd creation failed.  Driver not loaded.\n");
		kfree(hvcs_pi_buff);
		tty_unregister_driver(hvcs_tty_driver);
		hvcs_free_index_list();
		put_tty_driver(hvcs_tty_driver);
		return -EIO;
	}

	rc = vio_register_driver(&hvcs_vio_driver);

	/*
	 * This needs to be done AFTER the vio_register_driver() call or else
	 * the kobjects won't be initialized properly.
	 */
	hvcs_create_driver_attrs();

	printk(KERN_INFO "HVCS: driver module inserted.\n");

	return rc;
}

static void __exit hvcs_module_exit(void)
{
	/*
	 * This driver receives hvcs_remove callbacks for each device upon
	 * module removal.
	 */

	/*
	 * This synchronous operation  will wake the khvcsd kthread if it is
	 * asleep and will return when khvcsd has terminated.
	 */
	kthread_stop(hvcs_task);

	spin_lock(&hvcs_pi_lock);
	kfree(hvcs_pi_buff);
	hvcs_pi_buff = NULL;
	spin_unlock(&hvcs_pi_lock);

	hvcs_remove_driver_attrs();

	vio_unregister_driver(&hvcs_vio_driver);

	tty_unregister_driver(hvcs_tty_driver);

	hvcs_free_index_list();

	put_tty_driver(hvcs_tty_driver);

	printk(KERN_INFO "HVCS: driver module removed.\n");
}

module_init(hvcs_module_init);
module_exit(hvcs_module_exit);

static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
{
	return viod->dev.driver_data;
}
/* The sysfs interface for the driver and devices */

static ssize_t hvcs_partner_vtys_show(struct device *dev, char *buf)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&hvcsd->lock, flags);
	retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return retval;
}
static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);

static ssize_t hvcs_partner_clcs_show(struct device *dev, char *buf)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&hvcsd->lock, flags);
	retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return retval;
}
static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);

static ssize_t hvcs_current_vty_store(struct device *dev, const char * buf,
		size_t count)
{
	/*
	 * Don't need this feature at the present time because firmware doesn't
	 * yet support multiple partners.
	 */
	printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
	return -EPERM;
}

static ssize_t hvcs_current_vty_show(struct device *dev, char *buf)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&hvcsd->lock, flags);
	retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return retval;
}

static DEVICE_ATTR(current_vty,
	S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);

static ssize_t hvcs_vterm_state_store(struct device *dev, const char *buf,
		size_t count)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;

	/* writing a '0' to this sysfs entry will result in the disconnect. */
	if (simple_strtol(buf, NULL, 0) != 0)
		return -EINVAL;

	spin_lock_irqsave(&hvcsd->lock, flags);

	if (hvcsd->open_count > 0) {
		spin_unlock_irqrestore(&hvcsd->lock, flags);
		printk(KERN_INFO "HVCS: vterm state unchanged.  "
				"The hvcs device node is still in use.\n");
		return -EPERM;
	}

	if (hvcsd->connected == 0) {
		spin_unlock_irqrestore(&hvcsd->lock, flags);
		printk(KERN_INFO "HVCS: vterm state unchanged. The"
				" vty-server is not connected to a vty.\n");
		return -EPERM;
	}

	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);

	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return count;
}

static ssize_t hvcs_vterm_state_show(struct device *dev, char *buf)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&hvcsd->lock, flags);
	retval = sprintf(buf, "%d\n", hvcsd->connected);
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return retval;
}
static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
		hvcs_vterm_state_show, hvcs_vterm_state_store);

static ssize_t hvcs_index_show(struct device *dev, char *buf)
{
	struct vio_dev *viod = to_vio_dev(dev);
	struct hvcs_struct *hvcsd = from_vio_dev(viod);
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&hvcsd->lock, flags);
	retval = sprintf(buf, "%d\n", hvcsd->index);
	spin_unlock_irqrestore(&hvcsd->lock, flags);
	return retval;
}

static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);

static struct attribute *hvcs_attrs[] = {
	&dev_attr_partner_vtys.attr,
	&dev_attr_partner_clcs.attr,
	&dev_attr_current_vty.attr,
	&dev_attr_vterm_state.attr,
	&dev_attr_index.attr,
	NULL,
};

static struct attribute_group hvcs_attr_group = {
	.attrs = hvcs_attrs,
};

static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd)
{
	struct vio_dev *vdev = hvcsd->vdev;
	sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group);
}

static void hvcs_remove_device_attrs(struct vio_dev *vdev)
{
	sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
}

static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
{
	/* A 1 means it is updating, a 0 means it is done updating */
	return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
}

static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
		size_t count)
{
	if ((simple_strtol(buf, NULL, 0) != 1)
		&& (hvcs_rescan_status != 0))
		return -EINVAL;

	hvcs_rescan_status = 1;
	printk(KERN_INFO "HVCS: rescanning partner info for all"
		" vty-servers.\n");
	hvcs_rescan_devices_list();
	hvcs_rescan_status = 0;
	return count;
}
static DRIVER_ATTR(rescan,
	S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);

static void hvcs_create_driver_attrs(void)
{
	struct device_driver *driverfs = &(hvcs_vio_driver.driver);
	driver_create_file(driverfs, &driver_attr_rescan);
}

static void hvcs_remove_driver_attrs(void)
{
	struct device_driver *driverfs = &(hvcs_vio_driver.driver);
	driver_remove_file(driverfs, &driver_attr_rescan);
}