1 // SPDX-License-Identifier: GPL-2.0+
3 * IBM eServer Hypervisor Virtual Console Server Device Driver
4 * Copyright (C) 2003, 2004 IBM Corp.
5 * Ryan S. Arnold (rsa@us.ibm.com)
7 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
9 * This is the device driver for the IBM Hypervisor Virtual Console Server,
10 * "hvcs". The IBM hvcs provides a tty driver interface to allow Linux
11 * user space applications access to the system consoles of logically
12 * partitioned operating systems, e.g. Linux, running on the same partitioned
13 * Power5 ppc64 system. Physical hardware consoles per partition are not
14 * practical on this hardware so system consoles are accessed by this driver
15 * using inter-partition firmware interfaces to virtual terminal devices.
17 * A vty is known to the HMC as a "virtual serial server adapter". It is a
18 * virtual terminal device that is created by firmware upon partition creation
19 * to act as a partitioned OS's console device.
21 * Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64
22 * Linux system upon their creation by the HMC or their exposure during boot.
23 * The non-user interactive backend of this driver is implemented as a vio
24 * device driver so that it can receive notification of vty-server lifetimes
25 * after it registers with the vio bus to handle vty-server probe and remove
28 * Many vty-servers can be configured to connect to one vty, but a vty can
29 * only be actively connected to by a single vty-server, in any manner, at one
30 * time. If the HMC is currently hosting the console for a target Linux
31 * partition; attempts to open the tty device to the partition's console using
32 * the hvcs on any partition will return -EBUSY with every open attempt until
33 * the HMC frees the connection between its vty-server and the desired
34 * partition's vty device. Conversely, a vty-server may only be connected to
35 * a single vty at one time even though it may have several configured vty
36 * partner possibilities.
38 * Firmware does not provide notification of vty partner changes to this
39 * driver. This means that an HMC Super Admin may add or remove partner vtys
40 * from a vty-server's partner list but the changes will not be signaled to
41 * the vty-server. Firmware only notifies the driver when a vty-server is
42 * added or removed from the system. To compensate for this deficiency, this
43 * driver implements a sysfs update attribute which provides a method for
44 * rescanning partner information upon a user's request.
46 * Each vty-server, prior to being exposed to this driver is reference counted
47 * using the 2.6 Linux kernel kref construct.
49 * For direction on installation and usage of this driver please reference
50 * Documentation/powerpc/hvcs.rst.
53 #include <linux/device.h>
54 #include <linux/init.h>
55 #include <linux/interrupt.h>
56 #include <linux/kernel.h>
57 #include <linux/kref.h>
58 #include <linux/kthread.h>
59 #include <linux/list.h>
60 #include <linux/major.h>
61 #include <linux/module.h>
62 #include <linux/moduleparam.h>
63 #include <linux/sched.h>
64 #include <linux/slab.h>
65 #include <linux/spinlock.h>
66 #include <linux/stat.h>
67 #include <linux/tty.h>
68 #include <linux/tty_flip.h>
69 #include <asm/hvconsole.h>
70 #include <asm/hvcserver.h>
71 #include <linux/uaccess.h>
75 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
76 * Removed braces around single statements following conditionals. Removed '=
77 * 0' after static int declarations since these default to zero. Removed
78 * list_for_each_safe() and replaced with list_for_each_entry() in
79 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
80 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
81 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
82 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
83 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
84 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
85 * list traversals from a deletion. Removed '= NULL' from pointer declaration
86 * statements since they are initialized NULL by default. Removed wmb()
87 * instances from hvcs_try_write(). They probably aren't needed with locking in
88 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
89 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
90 * the coupling between /dev/hvcs* and a vty-server can be automatically
91 * determined. Moved kobject_put() in hvcs_open outside of the
92 * spin_unlock_irqrestore().
94 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
95 * align with how the tty layer always assigns the lowest index available. This
96 * change resulted in a list of ints that denotes which indexes are available.
97 * Device additions and removals use the new hvcs_get_index() and
98 * hvcs_return_index() helper functions. The list is created with
99 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
100 * Without these fixes hotplug vty-server adapter support goes crazy with this
101 * driver if the user removes a vty-server adapter. Moved free_irq() outside of
102 * the hvcs_final_close() function in order to get it out of the spinlock.
103 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
104 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
105 * arch/powerepc/include/asm/hvcserver.h
107 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
108 * prevent possible lockup with realtime scheduling as similarly pointed out by
109 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
110 * to reorder cleanup operations and prevent discarding of pending data during
111 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
112 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
115 #define HVCS_DRIVER_VERSION "1.3.3"
117 MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
118 MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
119 MODULE_LICENSE("GPL");
120 MODULE_VERSION(HVCS_DRIVER_VERSION);
123 * Wait this long per iteration while trying to push buffered data to the
124 * hypervisor before allowing the tty to complete a close operation.
126 #define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
129 * Since the Linux TTY code does not currently (2-04-2004) support dynamic
130 * addition of tty derived devices and we shouldn't allocate thousands of
131 * tty_device pointers when the number of vty-server & vty partner connections
132 * will most often be much lower than this, we'll arbitrarily allocate
133 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
134 * register the tty_driver. This can be overridden using an insmod parameter.
136 #define HVCS_DEFAULT_SERVER_ADAPTERS 64
139 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
140 * nodes as a sanity check. Theoretically there can be over 1 Billion
141 * vty-server & vty partner connections.
143 #define HVCS_MAX_SERVER_ADAPTERS 1024
146 * We let Linux assign us a major number and we start the minors at zero. There
147 * is no intuitive mapping between minor number and the target vty-server
148 * adapter except that each new vty-server adapter is always assigned to the
149 * smallest minor number available.
151 #define HVCS_MINOR_START 0
154 * The hcall interface involves putting 8 chars into each of two registers.
155 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)
156 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a
157 * little (tiny) bit slower because an unaligned load is slower than aligned
160 #define __ALIGNED__ __attribute__((__aligned__(8)))
163 * How much data can firmware send with each hvc_put_chars()? Maybe this
164 * should be moved into an architecture specific area.
166 #define HVCS_BUFF_LEN 16
169 * This is the maximum amount of data we'll let the user send us (hvcs_write) at
170 * once in a chunk as a sanity check.
172 #define HVCS_MAX_FROM_USER 4096
175 * Be careful when adding flags to this line discipline. Don't add anything
176 * that will cause echoing or we'll go into recursive loop echoing chars back
177 * and forth with the console drivers.
179 static const struct ktermios hvcs_tty_termios = {
180 .c_iflag = IGNBRK | IGNPAR,
182 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
189 * This value is used to take the place of a command line parameter when the
190 * module is inserted. It starts as -1 and stays as such if the user doesn't
191 * specify a module insmod parameter. If they DO specify one then it is set to
192 * the value of the integer passed in.
194 static int hvcs_parm_num_devs = -1;
195 module_param(hvcs_parm_num_devs, int, 0);
197 static const char hvcs_driver_name[] = "hvcs";
198 static const char hvcs_device_node[] = "hvcs";
200 /* Status of partner info rescan triggered via sysfs. */
201 static int hvcs_rescan_status;
203 static struct tty_driver *hvcs_tty_driver;
206 * In order to be somewhat sane this driver always associates the hvcs_struct
207 * index element with the numerically equal tty->index. This means that a
208 * hotplugged vty-server adapter will always map to the lowest index valued
209 * device node. If vty-servers were hotplug removed from the system and then
210 * new ones added the new vty-server may have the largest slot number of all
211 * the vty-server adapters in the partition but it may have the lowest dev node
212 * index of all the adapters due to the hole left by the hotplug removed
213 * adapter. There are a set of functions provided to get the lowest index for
214 * a new device as well as return the index to the list. This list is allocated
215 * with a number of elements equal to the number of device nodes requested when
216 * the module was inserted.
218 static int *hvcs_index_list;
221 * How large is the list? This is kept for traversal since the list is
222 * dynamically created.
224 static int hvcs_index_count;
227 * Used by the khvcsd to pick up I/O operations when the kernel_thread is
228 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.
230 static int hvcs_kicked;
233 * Use by the kthread construct for task operations like waking the sleeping
234 * thread and stopping the kthread.
236 static struct task_struct *hvcs_task;
239 * We allocate this for the use of all of the hvcs_structs when they fetch
242 static unsigned long *hvcs_pi_buff;
244 /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
245 static DEFINE_SPINLOCK(hvcs_pi_lock);
247 /* One vty-server per hvcs_struct */
249 struct tty_port port;
253 * This index identifies this hvcs device as the complement to a
254 * specific tty index.
259 * Used to tell the driver kernel_thread what operations need to take
260 * place upon this hvcs_struct instance.
265 * This buffer is required so that when hvcs_write_room() reports that
266 * it can send HVCS_BUFF_LEN characters that it will buffer the full
267 * HVCS_BUFF_LEN characters if need be. This is essential for opost
268 * writes since they do not do high level buffering and expect to be
269 * able to send what the driver commits to sending buffering
270 * [e.g. tab to space conversions in n_tty.c opost()].
272 char buffer[HVCS_BUFF_LEN];
276 * Any variable below is valid before a tty is connected and
277 * stays valid after the tty is disconnected. These shouldn't be
278 * whacked until the kobject refcount reaches zero though some entries
279 * may be changed via sysfs initiatives.
281 int connected; /* is the vty-server currently connected to a vty? */
282 uint32_t p_unit_address; /* partner unit address */
283 uint32_t p_partition_ID; /* partner partition ID */
284 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
285 struct list_head next; /* list management */
286 struct vio_dev *vdev;
289 static LIST_HEAD(hvcs_structs);
290 static DEFINE_SPINLOCK(hvcs_structs_lock);
291 static DEFINE_MUTEX(hvcs_init_mutex);
293 static void hvcs_unthrottle(struct tty_struct *tty);
294 static void hvcs_throttle(struct tty_struct *tty);
295 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance);
297 static int hvcs_write(struct tty_struct *tty,
298 const unsigned char *buf, int count);
299 static int hvcs_write_room(struct tty_struct *tty);
300 static int hvcs_chars_in_buffer(struct tty_struct *tty);
302 static int hvcs_has_pi(struct hvcs_struct *hvcsd);
303 static void hvcs_set_pi(struct hvcs_partner_info *pi,
304 struct hvcs_struct *hvcsd);
305 static int hvcs_get_pi(struct hvcs_struct *hvcsd);
306 static int hvcs_rescan_devices_list(void);
308 static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
309 static void hvcs_partner_free(struct hvcs_struct *hvcsd);
311 static int hvcs_enable_device(struct hvcs_struct *hvcsd,
312 uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
314 static int hvcs_open(struct tty_struct *tty, struct file *filp);
315 static void hvcs_close(struct tty_struct *tty, struct file *filp);
316 static void hvcs_hangup(struct tty_struct * tty);
318 static int hvcs_probe(struct vio_dev *dev,
319 const struct vio_device_id *id);
320 static int __init hvcs_module_init(void);
321 static void __exit hvcs_module_exit(void);
322 static int hvcs_initialize(void);
324 #define HVCS_SCHED_READ 0x00000001
325 #define HVCS_QUICK_READ 0x00000002
326 #define HVCS_TRY_WRITE 0x00000004
327 #define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
329 static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
331 return dev_get_drvdata(&viod->dev);
333 /* The sysfs interface for the driver and devices */
335 static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
337 struct vio_dev *viod = to_vio_dev(dev);
338 struct hvcs_struct *hvcsd = from_vio_dev(viod);
342 spin_lock_irqsave(&hvcsd->lock, flags);
343 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
344 spin_unlock_irqrestore(&hvcsd->lock, flags);
347 static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
349 static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
351 struct vio_dev *viod = to_vio_dev(dev);
352 struct hvcs_struct *hvcsd = from_vio_dev(viod);
356 spin_lock_irqsave(&hvcsd->lock, flags);
357 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
358 spin_unlock_irqrestore(&hvcsd->lock, flags);
361 static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
363 static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
367 * Don't need this feature at the present time because firmware doesn't
368 * yet support multiple partners.
370 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
374 static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
376 struct vio_dev *viod = to_vio_dev(dev);
377 struct hvcs_struct *hvcsd = from_vio_dev(viod);
381 spin_lock_irqsave(&hvcsd->lock, flags);
382 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
383 spin_unlock_irqrestore(&hvcsd->lock, flags);
387 static DEVICE_ATTR(current_vty,
388 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
390 static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
393 struct vio_dev *viod = to_vio_dev(dev);
394 struct hvcs_struct *hvcsd = from_vio_dev(viod);
397 /* writing a '0' to this sysfs entry will result in the disconnect. */
398 if (simple_strtol(buf, NULL, 0) != 0)
401 spin_lock_irqsave(&hvcsd->lock, flags);
403 if (hvcsd->port.count > 0) {
404 spin_unlock_irqrestore(&hvcsd->lock, flags);
405 printk(KERN_INFO "HVCS: vterm state unchanged. "
406 "The hvcs device node is still in use.\n");
410 if (hvcsd->connected == 0) {
411 spin_unlock_irqrestore(&hvcsd->lock, flags);
412 printk(KERN_INFO "HVCS: vterm state unchanged. The"
413 " vty-server is not connected to a vty.\n");
417 hvcs_partner_free(hvcsd);
418 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
419 " partner vty@%X:%d connection.\n",
420 hvcsd->vdev->unit_address,
421 hvcsd->p_unit_address,
422 (uint32_t)hvcsd->p_partition_ID);
424 spin_unlock_irqrestore(&hvcsd->lock, flags);
428 static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
430 struct vio_dev *viod = to_vio_dev(dev);
431 struct hvcs_struct *hvcsd = from_vio_dev(viod);
435 spin_lock_irqsave(&hvcsd->lock, flags);
436 retval = sprintf(buf, "%d\n", hvcsd->connected);
437 spin_unlock_irqrestore(&hvcsd->lock, flags);
440 static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
441 hvcs_vterm_state_show, hvcs_vterm_state_store);
443 static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
445 struct vio_dev *viod = to_vio_dev(dev);
446 struct hvcs_struct *hvcsd = from_vio_dev(viod);
450 spin_lock_irqsave(&hvcsd->lock, flags);
451 retval = sprintf(buf, "%d\n", hvcsd->index);
452 spin_unlock_irqrestore(&hvcsd->lock, flags);
456 static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
458 static struct attribute *hvcs_attrs[] = {
459 &dev_attr_partner_vtys.attr,
460 &dev_attr_partner_clcs.attr,
461 &dev_attr_current_vty.attr,
462 &dev_attr_vterm_state.attr,
463 &dev_attr_index.attr,
467 static struct attribute_group hvcs_attr_group = {
471 static ssize_t rescan_show(struct device_driver *ddp, char *buf)
473 /* A 1 means it is updating, a 0 means it is done updating */
474 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
477 static ssize_t rescan_store(struct device_driver *ddp, const char * buf,
480 if ((simple_strtol(buf, NULL, 0) != 1)
481 && (hvcs_rescan_status != 0))
484 hvcs_rescan_status = 1;
485 printk(KERN_INFO "HVCS: rescanning partner info for all"
487 hvcs_rescan_devices_list();
488 hvcs_rescan_status = 0;
492 static DRIVER_ATTR_RW(rescan);
494 static void hvcs_kick(void)
498 wake_up_process(hvcs_task);
501 static void hvcs_unthrottle(struct tty_struct *tty)
503 struct hvcs_struct *hvcsd = tty->driver_data;
506 spin_lock_irqsave(&hvcsd->lock, flags);
507 hvcsd->todo_mask |= HVCS_SCHED_READ;
508 spin_unlock_irqrestore(&hvcsd->lock, flags);
512 static void hvcs_throttle(struct tty_struct *tty)
514 struct hvcs_struct *hvcsd = tty->driver_data;
517 spin_lock_irqsave(&hvcsd->lock, flags);
518 vio_disable_interrupts(hvcsd->vdev);
519 spin_unlock_irqrestore(&hvcsd->lock, flags);
523 * If the device is being removed we don't have to worry about this interrupt
524 * handler taking any further interrupts because they are disabled which means
525 * the hvcs_struct will always be valid in this handler.
527 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
529 struct hvcs_struct *hvcsd = dev_instance;
531 spin_lock(&hvcsd->lock);
532 vio_disable_interrupts(hvcsd->vdev);
533 hvcsd->todo_mask |= HVCS_SCHED_READ;
534 spin_unlock(&hvcsd->lock);
540 /* This function must be called with the hvcsd->lock held */
541 static void hvcs_try_write(struct hvcs_struct *hvcsd)
543 uint32_t unit_address = hvcsd->vdev->unit_address;
544 struct tty_struct *tty = hvcsd->port.tty;
547 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
548 /* won't send partial writes */
549 sent = hvc_put_chars(unit_address,
551 hvcsd->chars_in_buffer );
553 hvcsd->chars_in_buffer = 0;
555 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
559 * We are still obligated to deliver the data to the
560 * hypervisor even if the tty has been closed because
561 * we committed to delivering it. But don't try to wake
562 * a non-existent tty.
571 static int hvcs_io(struct hvcs_struct *hvcsd)
573 uint32_t unit_address;
574 struct tty_struct *tty;
575 char buf[HVCS_BUFF_LEN] __ALIGNED__;
579 spin_lock_irqsave(&hvcsd->lock, flags);
581 unit_address = hvcsd->vdev->unit_address;
582 tty = hvcsd->port.tty;
584 hvcs_try_write(hvcsd);
586 if (!tty || tty_throttled(tty)) {
587 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
589 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
592 /* remove the read masks */
593 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
595 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
596 got = hvc_get_chars(unit_address,
599 tty_insert_flip_string(&hvcsd->port, buf, got);
602 /* Give the TTY time to process the data we just sent. */
604 hvcsd->todo_mask |= HVCS_QUICK_READ;
606 spin_unlock_irqrestore(&hvcsd->lock, flags);
607 /* This is synch -- FIXME :js: it is not! */
609 tty_flip_buffer_push(&hvcsd->port);
612 /* Do this _after_ the flip_buffer_push */
613 spin_lock_irqsave(&hvcsd->lock, flags);
614 vio_enable_interrupts(hvcsd->vdev);
615 spin_unlock_irqrestore(&hvcsd->lock, flags);
618 return hvcsd->todo_mask;
621 spin_unlock_irqrestore(&hvcsd->lock, flags);
622 return hvcsd->todo_mask;
625 static int khvcsd(void *unused)
627 struct hvcs_struct *hvcsd;
630 __set_current_state(TASK_RUNNING);
637 spin_lock(&hvcs_structs_lock);
638 list_for_each_entry(hvcsd, &hvcs_structs, next) {
639 hvcs_todo_mask |= hvcs_io(hvcsd);
641 spin_unlock(&hvcs_structs_lock);
644 * If any of the hvcs adapters want to try a write or quick read
645 * don't schedule(), yield a smidgen then execute the hvcs_io
646 * thread again for those that want the write.
648 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
653 set_current_state(TASK_INTERRUPTIBLE);
656 __set_current_state(TASK_RUNNING);
657 } while (!kthread_should_stop());
662 static const struct vio_device_id hvcs_driver_table[] = {
663 {"serial-server", "hvterm2"},
666 MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
668 static void hvcs_return_index(int index)
671 if (!hvcs_index_list)
673 if (index < 0 || index >= hvcs_index_count)
675 if (hvcs_index_list[index] == -1)
678 hvcs_index_list[index] = -1;
681 static void hvcs_destruct_port(struct tty_port *p)
683 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
684 struct vio_dev *vdev;
687 spin_lock(&hvcs_structs_lock);
688 spin_lock_irqsave(&hvcsd->lock, flags);
690 /* the list_del poisons the pointers */
691 list_del(&(hvcsd->next));
693 if (hvcsd->connected == 1) {
694 hvcs_partner_free(hvcsd);
695 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
696 " partner vty@%X:%d connection.\n",
697 hvcsd->vdev->unit_address,
698 hvcsd->p_unit_address,
699 (uint32_t)hvcsd->p_partition_ID);
701 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
702 hvcsd->vdev->unit_address);
707 hvcsd->p_unit_address = 0;
708 hvcsd->p_partition_ID = 0;
709 hvcs_return_index(hvcsd->index);
710 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
712 spin_unlock_irqrestore(&hvcsd->lock, flags);
713 spin_unlock(&hvcs_structs_lock);
715 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
720 static const struct tty_port_operations hvcs_port_ops = {
721 .destruct = hvcs_destruct_port,
724 static int hvcs_get_index(void)
728 if (!hvcs_index_list) {
729 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
732 /* Find the numerically lowest first free index. */
733 for(i = 0; i < hvcs_index_count; i++) {
734 if (hvcs_index_list[i] == -1) {
735 hvcs_index_list[i] = 0;
742 static int hvcs_probe(
744 const struct vio_device_id *id)
746 struct hvcs_struct *hvcsd;
751 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
755 /* Make sure we are properly initialized */
756 rc = hvcs_initialize();
758 pr_err("HVCS: Failed to initialize core driver.\n");
762 /* early to avoid cleanup on failure */
763 index = hvcs_get_index();
768 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
772 tty_port_init(&hvcsd->port);
773 hvcsd->port.ops = &hvcs_port_ops;
774 spin_lock_init(&hvcsd->lock);
777 dev_set_drvdata(&dev->dev, hvcsd);
779 hvcsd->index = index;
781 /* hvcsd->index = ++hvcs_struct_count; */
782 hvcsd->chars_in_buffer = 0;
783 hvcsd->todo_mask = 0;
784 hvcsd->connected = 0;
787 * This will populate the hvcs_struct's partner info fields for the
790 if (hvcs_get_pi(hvcsd)) {
791 printk(KERN_ERR "HVCS: Failed to fetch partner"
792 " info for vty-server@%X on device probe.\n",
793 hvcsd->vdev->unit_address);
797 * If a user app opens a tty that corresponds to this vty-server before
798 * the hvcs_struct has been added to the devices list then the user app
801 spin_lock(&hvcs_structs_lock);
802 list_add_tail(&(hvcsd->next), &hvcs_structs);
803 spin_unlock(&hvcs_structs_lock);
805 retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group);
807 printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n",
808 hvcsd->vdev->unit_address);
812 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
815 * DON'T enable interrupts here because there is no user to receive the
821 static void hvcs_remove(struct vio_dev *dev)
823 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
825 struct tty_struct *tty;
827 /* By this time the vty-server won't be getting any more interrupts */
829 spin_lock_irqsave(&hvcsd->lock, flags);
831 tty = hvcsd->port.tty;
833 spin_unlock_irqrestore(&hvcsd->lock, flags);
836 * Let the last holder of this object cause it to be removed, which
837 * would probably be tty_hangup below.
839 tty_port_put(&hvcsd->port);
842 * The hangup is a scheduled function which will auto chain call
843 * hvcs_hangup. The tty should always be valid at this time unless a
844 * simultaneous tty close already cleaned up the hvcs_struct.
849 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
850 " vio bus.\n", dev->unit_address);
853 static struct vio_driver hvcs_vio_driver = {
854 .id_table = hvcs_driver_table,
856 .remove = hvcs_remove,
857 .name = hvcs_driver_name,
860 /* Only called from hvcs_get_pi please */
861 static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
863 hvcsd->p_unit_address = pi->unit_address;
864 hvcsd->p_partition_ID = pi->partition_ID;
866 /* copy the null-term char too */
867 strlcpy(hvcsd->p_location_code, pi->location_code,
868 sizeof(hvcsd->p_location_code));
872 * Traverse the list and add the partner info that is found to the hvcs_struct
873 * struct entry. NOTE: At this time I know that partner info will return a
874 * single entry but in the future there may be multiple partner info entries per
875 * vty-server and you'll want to zero out that list and reset it. If for some
876 * reason you have an old version of this driver but there IS more than one
877 * partner info then hvcsd->p_* will hold the last partner info data from the
878 * firmware query. A good way to update this code would be to replace the three
879 * partner info fields in hvcs_struct with a list of hvcs_partner_info
882 * This function must be called with the hvcsd->lock held.
884 static int hvcs_get_pi(struct hvcs_struct *hvcsd)
886 struct hvcs_partner_info *pi;
887 uint32_t unit_address = hvcsd->vdev->unit_address;
888 struct list_head head;
891 spin_lock(&hvcs_pi_lock);
893 spin_unlock(&hvcs_pi_lock);
896 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
897 spin_unlock(&hvcs_pi_lock);
899 printk(KERN_ERR "HVCS: Failed to fetch partner"
900 " info for vty-server@%x.\n", unit_address);
904 /* nixes the values if the partner vty went away */
905 hvcsd->p_unit_address = 0;
906 hvcsd->p_partition_ID = 0;
908 list_for_each_entry(pi, &head, node)
909 hvcs_set_pi(pi, hvcsd);
911 hvcs_free_partner_info(&head);
916 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
917 * be executed elsewhere, in order to prevent deadlock issues.
919 static int hvcs_rescan_devices_list(void)
921 struct hvcs_struct *hvcsd;
924 spin_lock(&hvcs_structs_lock);
926 list_for_each_entry(hvcsd, &hvcs_structs, next) {
927 spin_lock_irqsave(&hvcsd->lock, flags);
929 spin_unlock_irqrestore(&hvcsd->lock, flags);
932 spin_unlock(&hvcs_structs_lock);
938 * Farm this off into its own function because it could be more complex once
939 * multiple partners support is added. This function should be called with
940 * the hvcsd->lock held.
942 static int hvcs_has_pi(struct hvcs_struct *hvcsd)
944 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
950 * NOTE: It is possible that the super admin removed a partner vty and then
951 * added a different vty as the new partner.
953 * This function must be called with the hvcsd->lock held.
955 static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
958 unsigned int unit_address = hvcsd->vdev->unit_address;
961 * If there wasn't any pi when the device was added it doesn't meant
962 * there isn't any now. This driver isn't notified when a new partner
963 * vty is added to a vty-server so we discover changes on our own.
964 * Please see comments in hvcs_register_connection() for justification
965 * of this bizarre code.
967 retval = hvcs_register_connection(unit_address,
968 hvcsd->p_partition_ID,
969 hvcsd->p_unit_address);
971 hvcsd->connected = 1;
973 } else if (retval != -EINVAL)
977 * As per the spec re-get the pi and try again if -EINVAL after the
978 * first connection attempt.
980 if (hvcs_get_pi(hvcsd))
983 if (!hvcs_has_pi(hvcsd))
986 retval = hvcs_register_connection(unit_address,
987 hvcsd->p_partition_ID,
988 hvcsd->p_unit_address);
989 if (retval != -EINVAL) {
990 hvcsd->connected = 1;
995 * EBUSY is the most likely scenario though the vty could have been
996 * removed or there really could be an hcall error due to the parameter
997 * data but thanks to ambiguous firmware return codes we can't really
1000 printk(KERN_INFO "HVCS: vty-server or partner"
1001 " vty is busy. Try again later.\n");
1005 /* This function must be called with the hvcsd->lock held */
1006 static void hvcs_partner_free(struct hvcs_struct *hvcsd)
1010 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
1011 } while (retval == -EBUSY);
1012 hvcsd->connected = 0;
1015 /* This helper function must be called WITHOUT the hvcsd->lock held */
1016 static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
1017 unsigned int irq, struct vio_dev *vdev)
1019 unsigned long flags;
1023 * It is possible that the vty-server was removed between the time that
1024 * the conn was registered and now.
1026 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd);
1029 * It is possible the vty-server was removed after the irq was
1030 * requested but before we have time to enable interrupts.
1032 if (vio_enable_interrupts(vdev) == H_SUCCESS)
1035 printk(KERN_ERR "HVCS: int enable failed for"
1036 " vty-server@%X.\n", unit_address);
1037 free_irq(irq, hvcsd);
1040 printk(KERN_ERR "HVCS: irq req failed for"
1041 " vty-server@%X.\n", unit_address);
1043 spin_lock_irqsave(&hvcsd->lock, flags);
1044 hvcs_partner_free(hvcsd);
1045 spin_unlock_irqrestore(&hvcsd->lock, flags);
1052 * This always increments the kref ref count if the call is successful.
1053 * Please remember to dec when you are done with the instance.
1055 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
1056 * calling this function or you will get deadlock.
1058 static struct hvcs_struct *hvcs_get_by_index(int index)
1060 struct hvcs_struct *hvcsd;
1061 unsigned long flags;
1063 spin_lock(&hvcs_structs_lock);
1064 list_for_each_entry(hvcsd, &hvcs_structs, next) {
1065 spin_lock_irqsave(&hvcsd->lock, flags);
1066 if (hvcsd->index == index) {
1067 tty_port_get(&hvcsd->port);
1068 spin_unlock_irqrestore(&hvcsd->lock, flags);
1069 spin_unlock(&hvcs_structs_lock);
1072 spin_unlock_irqrestore(&hvcsd->lock, flags);
1074 spin_unlock(&hvcs_structs_lock);
1079 static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty)
1081 struct hvcs_struct *hvcsd;
1082 struct vio_dev *vdev;
1083 unsigned long unit_address, flags;
1088 * Is there a vty-server that shares the same index?
1089 * This function increments the kref index.
1091 hvcsd = hvcs_get_by_index(tty->index);
1093 printk(KERN_WARNING "HVCS: open failed, no device associated"
1094 " with tty->index %d.\n", tty->index);
1098 spin_lock_irqsave(&hvcsd->lock, flags);
1100 if (hvcsd->connected == 0) {
1101 retval = hvcs_partner_connect(hvcsd);
1103 spin_unlock_irqrestore(&hvcsd->lock, flags);
1104 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1109 hvcsd->port.count = 0;
1110 hvcsd->port.tty = tty;
1111 tty->driver_data = hvcsd;
1113 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1116 * Save these in the spinlock for the enable operations that need them
1117 * outside of the spinlock.
1119 irq = hvcsd->vdev->irq;
1121 unit_address = hvcsd->vdev->unit_address;
1123 hvcsd->todo_mask |= HVCS_SCHED_READ;
1124 spin_unlock_irqrestore(&hvcsd->lock, flags);
1127 * This must be done outside of the spinlock because it requests irqs
1128 * and will grab the spinlock and free the connection if it fails.
1130 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev);
1132 printk(KERN_WARNING "HVCS: enable device failed.\n");
1136 retval = tty_port_install(&hvcsd->port, driver, tty);
1142 spin_lock_irqsave(&hvcsd->lock, flags);
1143 vio_disable_interrupts(hvcsd->vdev);
1144 spin_unlock_irqrestore(&hvcsd->lock, flags);
1145 free_irq(irq, hvcsd);
1147 tty_port_put(&hvcsd->port);
1153 * This is invoked via the tty_open interface when a user app connects to the
1156 static int hvcs_open(struct tty_struct *tty, struct file *filp)
1158 struct hvcs_struct *hvcsd = tty->driver_data;
1159 unsigned long flags;
1161 spin_lock_irqsave(&hvcsd->lock, flags);
1162 hvcsd->port.count++;
1163 hvcsd->todo_mask |= HVCS_SCHED_READ;
1164 spin_unlock_irqrestore(&hvcsd->lock, flags);
1168 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1169 hvcsd->vdev->unit_address );
1174 static void hvcs_close(struct tty_struct *tty, struct file *filp)
1176 struct hvcs_struct *hvcsd;
1177 unsigned long flags;
1181 * Is someone trying to close the file associated with this device after
1182 * we have hung up? If so tty->driver_data wouldn't be valid.
1184 if (tty_hung_up_p(filp))
1188 * No driver_data means that this close was probably issued after a
1189 * failed hvcs_open by the tty layer's release_dev() api and we can just
1192 if (!tty->driver_data)
1195 hvcsd = tty->driver_data;
1197 spin_lock_irqsave(&hvcsd->lock, flags);
1198 if (--hvcsd->port.count == 0) {
1200 vio_disable_interrupts(hvcsd->vdev);
1203 * NULL this early so that the kernel_thread doesn't try to
1204 * execute any operations on the TTY even though it is obligated
1205 * to deliver any pending I/O to the hypervisor.
1207 hvcsd->port.tty = NULL;
1209 irq = hvcsd->vdev->irq;
1210 spin_unlock_irqrestore(&hvcsd->lock, flags);
1212 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1214 free_irq(irq, hvcsd);
1216 } else if (hvcsd->port.count < 0) {
1217 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n",
1218 hvcsd->vdev->unit_address, hvcsd->port.count);
1221 spin_unlock_irqrestore(&hvcsd->lock, flags);
1224 static void hvcs_cleanup(struct tty_struct * tty)
1226 struct hvcs_struct *hvcsd = tty->driver_data;
1229 * This line is important because it tells hvcs_open that this
1230 * device needs to be re-configured the next time hvcs_open is
1233 tty->driver_data = NULL;
1235 tty_port_put(&hvcsd->port);
1238 static void hvcs_hangup(struct tty_struct * tty)
1240 struct hvcs_struct *hvcsd = tty->driver_data;
1241 unsigned long flags;
1242 int temp_open_count;
1245 spin_lock_irqsave(&hvcsd->lock, flags);
1246 /* Preserve this so that we know how many kref refs to put */
1247 temp_open_count = hvcsd->port.count;
1250 * Don't kref put inside the spinlock because the destruction
1251 * callback may use the spinlock and it may get called before the
1252 * spinlock has been released.
1254 vio_disable_interrupts(hvcsd->vdev);
1256 hvcsd->todo_mask = 0;
1258 /* I don't think the tty needs the hvcs_struct pointer after a hangup */
1259 tty->driver_data = NULL;
1260 hvcsd->port.tty = NULL;
1262 hvcsd->port.count = 0;
1264 /* This will drop any buffered data on the floor which is OK in a hangup
1266 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1267 hvcsd->chars_in_buffer = 0;
1269 irq = hvcsd->vdev->irq;
1271 spin_unlock_irqrestore(&hvcsd->lock, flags);
1273 free_irq(irq, hvcsd);
1276 * We need to kref_put() for every open_count we have since the
1277 * tty_hangup() function doesn't invoke a close per open connection on a
1278 * non-console device.
1280 while(temp_open_count) {
1283 * The final put will trigger destruction of the hvcs_struct.
1284 * NOTE: If this hangup was signaled from user space then the
1285 * final put will never happen.
1287 tty_port_put(&hvcsd->port);
1292 * NOTE: This is almost always from_user since user level apps interact with the
1293 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1294 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1295 * tty_hangup will allow hvcs_write time to complete execution before it
1296 * terminates our device.
1298 static int hvcs_write(struct tty_struct *tty,
1299 const unsigned char *buf, int count)
1301 struct hvcs_struct *hvcsd = tty->driver_data;
1302 unsigned int unit_address;
1303 const unsigned char *charbuf;
1304 unsigned long flags;
1310 * If they don't check the return code off of their open they may
1311 * attempt this even if there is no connected device.
1316 /* Reasonable size to prevent user level flooding */
1317 if (count > HVCS_MAX_FROM_USER) {
1318 printk(KERN_WARNING "HVCS write: count being truncated to"
1319 " HVCS_MAX_FROM_USER.\n");
1320 count = HVCS_MAX_FROM_USER;
1325 spin_lock_irqsave(&hvcsd->lock, flags);
1328 * Somehow an open succeeded but the device was removed or the
1329 * connection terminated between the vty-server and partner vty during
1330 * the middle of a write operation? This is a crummy place to do this
1331 * but we want to keep it all in the spinlock.
1333 if (hvcsd->port.count <= 0) {
1334 spin_unlock_irqrestore(&hvcsd->lock, flags);
1338 unit_address = hvcsd->vdev->unit_address;
1341 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1343 * No more space, this probably means that the last call to
1344 * hvcs_write() didn't succeed and the buffer was filled up.
1349 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1350 &charbuf[total_sent],
1353 hvcsd->chars_in_buffer += tosend;
1358 * If this is true then we don't want to try writing to the
1359 * hypervisor because that is the kernel_threads job now. We'll
1360 * just add to the buffer.
1362 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1363 /* won't send partial writes */
1364 result = hvc_put_chars(unit_address,
1366 hvcsd->chars_in_buffer);
1369 * Since we know we have enough room in hvcsd->buffer for
1370 * tosend we record that it was sent regardless of whether the
1371 * hypervisor actually took it because we have it buffered.
1376 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1381 hvcsd->chars_in_buffer = 0;
1383 * Test after the chars_in_buffer reset otherwise this could
1384 * deadlock our writes if hvc_put_chars fails.
1390 spin_unlock_irqrestore(&hvcsd->lock, flags);
1399 * This is really asking how much can we guarantee that we can send or that we
1400 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1401 * return value, hence the reason for hvcs_struct buffering.
1403 static int hvcs_write_room(struct tty_struct *tty)
1405 struct hvcs_struct *hvcsd = tty->driver_data;
1407 if (!hvcsd || hvcsd->port.count <= 0)
1410 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1413 static int hvcs_chars_in_buffer(struct tty_struct *tty)
1415 struct hvcs_struct *hvcsd = tty->driver_data;
1417 return hvcsd->chars_in_buffer;
1420 static const struct tty_operations hvcs_ops = {
1421 .install = hvcs_install,
1423 .close = hvcs_close,
1424 .cleanup = hvcs_cleanup,
1425 .hangup = hvcs_hangup,
1426 .write = hvcs_write,
1427 .write_room = hvcs_write_room,
1428 .chars_in_buffer = hvcs_chars_in_buffer,
1429 .unthrottle = hvcs_unthrottle,
1430 .throttle = hvcs_throttle,
1433 static int hvcs_alloc_index_list(int n)
1437 hvcs_index_list = kmalloc_array(n, sizeof(hvcs_index_count),
1439 if (!hvcs_index_list)
1441 hvcs_index_count = n;
1442 for (i = 0; i < hvcs_index_count; i++)
1443 hvcs_index_list[i] = -1;
1447 static void hvcs_free_index_list(void)
1449 /* Paranoia check to be thorough. */
1450 kfree(hvcs_index_list);
1451 hvcs_index_list = NULL;
1452 hvcs_index_count = 0;
1455 static int hvcs_initialize(void)
1457 int rc, num_ttys_to_alloc;
1459 mutex_lock(&hvcs_init_mutex);
1461 mutex_unlock(&hvcs_init_mutex);
1465 /* Has the user specified an overload with an insmod param? */
1466 if (hvcs_parm_num_devs <= 0 ||
1467 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1468 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1470 num_ttys_to_alloc = hvcs_parm_num_devs;
1472 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
1473 if (!hvcs_tty_driver) {
1474 mutex_unlock(&hvcs_init_mutex);
1478 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
1483 hvcs_tty_driver->driver_name = hvcs_driver_name;
1484 hvcs_tty_driver->name = hvcs_device_node;
1487 * We'll let the system assign us a major number, indicated by leaving
1491 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1492 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1495 * We role our own so that we DONT ECHO. We can't echo because the
1496 * device we are connecting to already echoes by default and this would
1497 * throw us into a horrible recursive echo-echo-echo loop.
1499 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1500 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;
1502 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1505 * The following call will result in sysfs entries that denote the
1506 * dynamically assigned major and minor numbers for our devices.
1508 if (tty_register_driver(hvcs_tty_driver)) {
1509 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
1514 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL);
1515 if (!hvcs_pi_buff) {
1517 goto buff_alloc_fail;
1520 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1521 if (IS_ERR(hvcs_task)) {
1522 printk(KERN_ERR "HVCS: khvcsd creation failed.\n");
1526 mutex_unlock(&hvcs_init_mutex);
1530 free_page((unsigned long)hvcs_pi_buff);
1532 tty_unregister_driver(hvcs_tty_driver);
1534 hvcs_free_index_list();
1536 put_tty_driver(hvcs_tty_driver);
1537 hvcs_tty_driver = NULL;
1538 mutex_unlock(&hvcs_init_mutex);
1542 static int __init hvcs_module_init(void)
1544 int rc = vio_register_driver(&hvcs_vio_driver);
1546 printk(KERN_ERR "HVCS: can't register vio driver\n");
1550 pr_info("HVCS: Driver registered.\n");
1552 /* This needs to be done AFTER the vio_register_driver() call or else
1553 * the kobjects won't be initialized properly.
1555 rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan);
1557 pr_warn("HVCS: Failed to create rescan file (err %d)\n", rc);
1562 static void __exit hvcs_module_exit(void)
1565 * This driver receives hvcs_remove callbacks for each device upon
1568 vio_unregister_driver(&hvcs_vio_driver);
1573 * This synchronous operation will wake the khvcsd kthread if it is
1574 * asleep and will return when khvcsd has terminated.
1576 kthread_stop(hvcs_task);
1578 spin_lock(&hvcs_pi_lock);
1579 free_page((unsigned long)hvcs_pi_buff);
1580 hvcs_pi_buff = NULL;
1581 spin_unlock(&hvcs_pi_lock);
1583 driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
1585 tty_unregister_driver(hvcs_tty_driver);
1587 hvcs_free_index_list();
1589 put_tty_driver(hvcs_tty_driver);
1591 printk(KERN_INFO "HVCS: driver module removed.\n");
1594 module_init(hvcs_module_init);
1595 module_exit(hvcs_module_exit);