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/arch/powerpc/hvcs.rst.
53 #include <linux/device.h>
54 #include <linux/init.h>
55 #include <linux/completion.h>
56 #include <linux/interrupt.h>
57 #include <linux/kernel.h>
58 #include <linux/kref.h>
59 #include <linux/kthread.h>
60 #include <linux/list.h>
61 #include <linux/major.h>
62 #include <linux/module.h>
63 #include <linux/moduleparam.h>
64 #include <linux/sched.h>
65 #include <linux/slab.h>
66 #include <linux/spinlock.h>
67 #include <linux/stat.h>
68 #include <linux/tty.h>
69 #include <linux/tty_flip.h>
70 #include <asm/hvconsole.h>
71 #include <asm/hvcserver.h>
72 #include <linux/uaccess.h>
73 #include <linux/termios_internal.h>
77 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
78 * Removed braces around single statements following conditionals. Removed '=
79 * 0' after static int declarations since these default to zero. Removed
80 * list_for_each_safe() and replaced with list_for_each_entry() in
81 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
82 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
83 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
84 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
85 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
86 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
87 * list traversals from a deletion. Removed '= NULL' from pointer declaration
88 * statements since they are initialized NULL by default. Removed wmb()
89 * instances from hvcs_try_write(). They probably aren't needed with locking in
90 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
91 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
92 * the coupling between /dev/hvcs* and a vty-server can be automatically
93 * determined. Moved kobject_put() in hvcs_open outside of the
94 * spin_unlock_irqrestore().
96 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
97 * align with how the tty layer always assigns the lowest index available. This
98 * change resulted in a list of ints that denotes which indexes are available.
99 * Device additions and removals use the new hvcs_get_index() and
100 * hvcs_return_index() helper functions. The list is created with
101 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
102 * Without these fixes hotplug vty-server adapter support goes crazy with this
103 * driver if the user removes a vty-server adapter. Moved free_irq() outside of
104 * the hvcs_final_close() function in order to get it out of the spinlock.
105 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
106 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
107 * arch/powerepc/include/asm/hvcserver.h
109 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
110 * prevent possible lockup with realtime scheduling as similarly pointed out by
111 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
112 * to reorder cleanup operations and prevent discarding of pending data during
113 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
114 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
117 #define HVCS_DRIVER_VERSION "1.3.3"
119 MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
120 MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
121 MODULE_LICENSE("GPL");
122 MODULE_VERSION(HVCS_DRIVER_VERSION);
125 * Wait this long per iteration while trying to push buffered data to the
126 * hypervisor before allowing the tty to complete a close operation.
128 #define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
131 * Since the Linux TTY code does not currently (2-04-2004) support dynamic
132 * addition of tty derived devices and we shouldn't allocate thousands of
133 * tty_device pointers when the number of vty-server & vty partner connections
134 * will most often be much lower than this, we'll arbitrarily allocate
135 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
136 * register the tty_driver. This can be overridden using an insmod parameter.
138 #define HVCS_DEFAULT_SERVER_ADAPTERS 64
141 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
142 * nodes as a sanity check. Theoretically there can be over 1 Billion
143 * vty-server & vty partner connections.
145 #define HVCS_MAX_SERVER_ADAPTERS 1024
148 * We let Linux assign us a major number and we start the minors at zero. There
149 * is no intuitive mapping between minor number and the target vty-server
150 * adapter except that each new vty-server adapter is always assigned to the
151 * smallest minor number available.
153 #define HVCS_MINOR_START 0
156 * The hcall interface involves putting 8 chars into each of two registers.
157 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)
158 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a
159 * little (tiny) bit slower because an unaligned load is slower than aligned
162 #define __ALIGNED__ __attribute__((__aligned__(8)))
165 * How much data can firmware send with each hvc_put_chars()? Maybe this
166 * should be moved into an architecture specific area.
168 #define HVCS_BUFF_LEN 16
171 * This is the maximum amount of data we'll let the user send us (hvcs_write) at
172 * once in a chunk as a sanity check.
174 #define HVCS_MAX_FROM_USER 4096
177 * Be careful when adding flags to this line discipline. Don't add anything
178 * that will cause echoing or we'll go into recursive loop echoing chars back
179 * and forth with the console drivers.
181 static const struct ktermios hvcs_tty_termios = {
182 .c_iflag = IGNBRK | IGNPAR,
184 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
191 * This value is used to take the place of a command line parameter when the
192 * module is inserted. It starts as -1 and stays as such if the user doesn't
193 * specify a module insmod parameter. If they DO specify one then it is set to
194 * the value of the integer passed in.
196 static int hvcs_parm_num_devs = -1;
197 module_param(hvcs_parm_num_devs, int, 0);
199 static const char hvcs_driver_name[] = "hvcs";
200 static const char hvcs_device_node[] = "hvcs";
202 /* Status of partner info rescan triggered via sysfs. */
203 static int hvcs_rescan_status;
205 static struct tty_driver *hvcs_tty_driver;
208 * In order to be somewhat sane this driver always associates the hvcs_struct
209 * index element with the numerically equal tty->index. This means that a
210 * hotplugged vty-server adapter will always map to the lowest index valued
211 * device node. If vty-servers were hotplug removed from the system and then
212 * new ones added the new vty-server may have the largest slot number of all
213 * the vty-server adapters in the partition but it may have the lowest dev node
214 * index of all the adapters due to the hole left by the hotplug removed
215 * adapter. There are a set of functions provided to get the lowest index for
216 * a new device as well as return the index to the list. This list is allocated
217 * with a number of elements equal to the number of device nodes requested when
218 * the module was inserted.
220 static int *hvcs_index_list;
223 * How large is the list? This is kept for traversal since the list is
224 * dynamically created.
226 static int hvcs_index_count;
229 * Used by the khvcsd to pick up I/O operations when the kernel_thread is
230 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.
232 static int hvcs_kicked;
235 * Use by the kthread construct for task operations like waking the sleeping
236 * thread and stopping the kthread.
238 static struct task_struct *hvcs_task;
241 * We allocate this for the use of all of the hvcs_structs when they fetch
244 static unsigned long *hvcs_pi_buff;
246 /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
247 static DEFINE_SPINLOCK(hvcs_pi_lock);
249 /* One vty-server per hvcs_struct */
251 struct tty_port port;
255 * This index identifies this hvcs device as the complement to a
256 * specific tty index.
261 * Used to tell the driver kernel_thread what operations need to take
262 * place upon this hvcs_struct instance.
267 * This buffer is required so that when hvcs_write_room() reports that
268 * it can send HVCS_BUFF_LEN characters that it will buffer the full
269 * HVCS_BUFF_LEN characters if need be. This is essential for opost
270 * writes since they do not do high level buffering and expect to be
271 * able to send what the driver commits to sending buffering
272 * [e.g. tab to space conversions in n_tty.c opost()].
274 char buffer[HVCS_BUFF_LEN];
278 * Any variable below is valid before a tty is connected and
279 * stays valid after the tty is disconnected. These shouldn't be
280 * whacked until the kobject refcount reaches zero though some entries
281 * may be changed via sysfs initiatives.
283 int connected; /* is the vty-server currently connected to a vty? */
284 uint32_t p_unit_address; /* partner unit address */
285 uint32_t p_partition_ID; /* partner partition ID */
286 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
287 struct list_head next; /* list management */
288 struct vio_dev *vdev;
289 struct completion *destroyed;
292 static LIST_HEAD(hvcs_structs);
293 static DEFINE_SPINLOCK(hvcs_structs_lock);
294 static DEFINE_MUTEX(hvcs_init_mutex);
296 static int hvcs_get_pi(struct hvcs_struct *hvcsd);
297 static int hvcs_rescan_devices_list(void);
299 static void hvcs_partner_free(struct hvcs_struct *hvcsd);
301 static int hvcs_initialize(void);
303 #define HVCS_SCHED_READ 0x00000001
304 #define HVCS_QUICK_READ 0x00000002
305 #define HVCS_TRY_WRITE 0x00000004
306 #define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
308 static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
310 return dev_get_drvdata(&viod->dev);
312 /* The sysfs interface for the driver and devices */
314 static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
316 struct vio_dev *viod = to_vio_dev(dev);
317 struct hvcs_struct *hvcsd = from_vio_dev(viod);
321 spin_lock_irqsave(&hvcsd->lock, flags);
322 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
323 spin_unlock_irqrestore(&hvcsd->lock, flags);
326 static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
328 static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
330 struct vio_dev *viod = to_vio_dev(dev);
331 struct hvcs_struct *hvcsd = from_vio_dev(viod);
335 spin_lock_irqsave(&hvcsd->lock, flags);
336 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
337 spin_unlock_irqrestore(&hvcsd->lock, flags);
340 static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
342 static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
346 * Don't need this feature at the present time because firmware doesn't
347 * yet support multiple partners.
349 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
353 static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
355 struct vio_dev *viod = to_vio_dev(dev);
356 struct hvcs_struct *hvcsd = from_vio_dev(viod);
360 spin_lock_irqsave(&hvcsd->lock, flags);
361 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
362 spin_unlock_irqrestore(&hvcsd->lock, flags);
366 static DEVICE_ATTR(current_vty,
367 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
369 static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
372 struct vio_dev *viod = to_vio_dev(dev);
373 struct hvcs_struct *hvcsd = from_vio_dev(viod);
376 /* writing a '0' to this sysfs entry will result in the disconnect. */
377 if (simple_strtol(buf, NULL, 0) != 0)
380 spin_lock_irqsave(&hvcsd->lock, flags);
382 if (hvcsd->port.count > 0) {
383 spin_unlock_irqrestore(&hvcsd->lock, flags);
384 printk(KERN_INFO "HVCS: vterm state unchanged. "
385 "The hvcs device node is still in use.\n");
389 if (hvcsd->connected == 0) {
390 spin_unlock_irqrestore(&hvcsd->lock, flags);
391 printk(KERN_INFO "HVCS: vterm state unchanged. The"
392 " vty-server is not connected to a vty.\n");
396 hvcs_partner_free(hvcsd);
397 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
398 " partner vty@%X:%d connection.\n",
399 hvcsd->vdev->unit_address,
400 hvcsd->p_unit_address,
401 (uint32_t)hvcsd->p_partition_ID);
403 spin_unlock_irqrestore(&hvcsd->lock, flags);
407 static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
409 struct vio_dev *viod = to_vio_dev(dev);
410 struct hvcs_struct *hvcsd = from_vio_dev(viod);
414 spin_lock_irqsave(&hvcsd->lock, flags);
415 retval = sprintf(buf, "%d\n", hvcsd->connected);
416 spin_unlock_irqrestore(&hvcsd->lock, flags);
419 static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
420 hvcs_vterm_state_show, hvcs_vterm_state_store);
422 static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
424 struct vio_dev *viod = to_vio_dev(dev);
425 struct hvcs_struct *hvcsd = from_vio_dev(viod);
429 spin_lock_irqsave(&hvcsd->lock, flags);
430 retval = sprintf(buf, "%d\n", hvcsd->index);
431 spin_unlock_irqrestore(&hvcsd->lock, flags);
435 static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
437 static struct attribute *hvcs_dev_attrs[] = {
438 &dev_attr_partner_vtys.attr,
439 &dev_attr_partner_clcs.attr,
440 &dev_attr_current_vty.attr,
441 &dev_attr_vterm_state.attr,
442 &dev_attr_index.attr,
446 ATTRIBUTE_GROUPS(hvcs_dev);
448 static ssize_t rescan_show(struct device_driver *ddp, char *buf)
450 /* A 1 means it is updating, a 0 means it is done updating */
451 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
454 static ssize_t rescan_store(struct device_driver *ddp, const char * buf,
457 if ((simple_strtol(buf, NULL, 0) != 1)
458 && (hvcs_rescan_status != 0))
461 hvcs_rescan_status = 1;
462 printk(KERN_INFO "HVCS: rescanning partner info for all"
464 hvcs_rescan_devices_list();
465 hvcs_rescan_status = 0;
469 static DRIVER_ATTR_RW(rescan);
471 static struct attribute *hvcs_attrs[] = {
472 &driver_attr_rescan.attr,
476 ATTRIBUTE_GROUPS(hvcs);
478 static void hvcs_kick(void)
482 wake_up_process(hvcs_task);
485 static void hvcs_unthrottle(struct tty_struct *tty)
487 struct hvcs_struct *hvcsd = tty->driver_data;
490 spin_lock_irqsave(&hvcsd->lock, flags);
491 hvcsd->todo_mask |= HVCS_SCHED_READ;
492 spin_unlock_irqrestore(&hvcsd->lock, flags);
496 static void hvcs_throttle(struct tty_struct *tty)
498 struct hvcs_struct *hvcsd = tty->driver_data;
501 spin_lock_irqsave(&hvcsd->lock, flags);
502 vio_disable_interrupts(hvcsd->vdev);
503 spin_unlock_irqrestore(&hvcsd->lock, flags);
507 * If the device is being removed we don't have to worry about this interrupt
508 * handler taking any further interrupts because they are disabled which means
509 * the hvcs_struct will always be valid in this handler.
511 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
513 struct hvcs_struct *hvcsd = dev_instance;
515 spin_lock(&hvcsd->lock);
516 vio_disable_interrupts(hvcsd->vdev);
517 hvcsd->todo_mask |= HVCS_SCHED_READ;
518 spin_unlock(&hvcsd->lock);
524 /* This function must be called with the hvcsd->lock held */
525 static void hvcs_try_write(struct hvcs_struct *hvcsd)
527 uint32_t unit_address = hvcsd->vdev->unit_address;
528 struct tty_struct *tty = hvcsd->port.tty;
531 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
532 /* won't send partial writes */
533 sent = hvc_put_chars(unit_address,
535 hvcsd->chars_in_buffer );
537 hvcsd->chars_in_buffer = 0;
539 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
543 * We are still obligated to deliver the data to the
544 * hypervisor even if the tty has been closed because
545 * we committed to delivering it. But don't try to wake
546 * a non-existent tty.
555 static int hvcs_io(struct hvcs_struct *hvcsd)
557 uint32_t unit_address;
558 struct tty_struct *tty;
559 char buf[HVCS_BUFF_LEN] __ALIGNED__;
563 spin_lock_irqsave(&hvcsd->lock, flags);
565 unit_address = hvcsd->vdev->unit_address;
566 tty = hvcsd->port.tty;
568 hvcs_try_write(hvcsd);
570 if (!tty || tty_throttled(tty)) {
571 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
573 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
576 /* remove the read masks */
577 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
579 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
580 got = hvc_get_chars(unit_address,
583 tty_insert_flip_string(&hvcsd->port, buf, got);
586 /* Give the TTY time to process the data we just sent. */
588 hvcsd->todo_mask |= HVCS_QUICK_READ;
590 spin_unlock_irqrestore(&hvcsd->lock, flags);
591 /* This is synch -- FIXME :js: it is not! */
593 tty_flip_buffer_push(&hvcsd->port);
595 /* Do this _after_ the flip_buffer_push */
596 spin_lock_irqsave(&hvcsd->lock, flags);
597 vio_enable_interrupts(hvcsd->vdev);
598 spin_unlock_irqrestore(&hvcsd->lock, flags);
601 return hvcsd->todo_mask;
604 spin_unlock_irqrestore(&hvcsd->lock, flags);
605 return hvcsd->todo_mask;
608 static int khvcsd(void *unused)
610 struct hvcs_struct *hvcsd;
613 __set_current_state(TASK_RUNNING);
620 spin_lock(&hvcs_structs_lock);
621 list_for_each_entry(hvcsd, &hvcs_structs, next) {
622 hvcs_todo_mask |= hvcs_io(hvcsd);
624 spin_unlock(&hvcs_structs_lock);
627 * If any of the hvcs adapters want to try a write or quick read
628 * don't schedule(), yield a smidgen then execute the hvcs_io
629 * thread again for those that want the write.
631 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
636 set_current_state(TASK_INTERRUPTIBLE);
639 __set_current_state(TASK_RUNNING);
640 } while (!kthread_should_stop());
645 static const struct vio_device_id hvcs_driver_table[] = {
646 {"serial-server", "hvterm2"},
649 MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
651 static void hvcs_return_index(int index)
654 if (!hvcs_index_list)
656 if (index < 0 || index >= hvcs_index_count)
658 if (hvcs_index_list[index] == -1)
661 hvcs_index_list[index] = -1;
664 static void hvcs_destruct_port(struct tty_port *p)
666 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
667 struct completion *comp;
670 spin_lock(&hvcs_structs_lock);
671 spin_lock_irqsave(&hvcsd->lock, flags);
673 comp = hvcsd->destroyed;
674 /* the list_del poisons the pointers */
675 list_del(&(hvcsd->next));
677 if (hvcsd->connected == 1) {
678 hvcs_partner_free(hvcsd);
679 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
680 " partner vty@%X:%d connection.\n",
681 hvcsd->vdev->unit_address,
682 hvcsd->p_unit_address,
683 (uint32_t)hvcsd->p_partition_ID);
685 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
686 hvcsd->vdev->unit_address);
690 hvcsd->p_unit_address = 0;
691 hvcsd->p_partition_ID = 0;
692 hvcsd->destroyed = NULL;
693 hvcs_return_index(hvcsd->index);
694 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
696 spin_unlock_irqrestore(&hvcsd->lock, flags);
697 spin_unlock(&hvcs_structs_lock);
704 static const struct tty_port_operations hvcs_port_ops = {
705 .destruct = hvcs_destruct_port,
708 static int hvcs_get_index(void)
712 if (!hvcs_index_list) {
713 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
716 /* Find the numerically lowest first free index. */
717 for(i = 0; i < hvcs_index_count; i++) {
718 if (hvcs_index_list[i] == -1) {
719 hvcs_index_list[i] = 0;
726 static int hvcs_probe(
728 const struct vio_device_id *id)
730 struct hvcs_struct *hvcsd;
734 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
738 /* Make sure we are properly initialized */
739 rc = hvcs_initialize();
741 pr_err("HVCS: Failed to initialize core driver.\n");
745 /* early to avoid cleanup on failure */
746 index = hvcs_get_index();
751 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
755 tty_port_init(&hvcsd->port);
756 hvcsd->port.ops = &hvcs_port_ops;
757 spin_lock_init(&hvcsd->lock);
760 dev_set_drvdata(&dev->dev, hvcsd);
762 hvcsd->index = index;
764 /* hvcsd->index = ++hvcs_struct_count; */
765 hvcsd->chars_in_buffer = 0;
766 hvcsd->todo_mask = 0;
767 hvcsd->connected = 0;
770 * This will populate the hvcs_struct's partner info fields for the
773 if (hvcs_get_pi(hvcsd)) {
774 printk(KERN_ERR "HVCS: Failed to fetch partner"
775 " info for vty-server@%X on device probe.\n",
776 hvcsd->vdev->unit_address);
780 * If a user app opens a tty that corresponds to this vty-server before
781 * the hvcs_struct has been added to the devices list then the user app
784 spin_lock(&hvcs_structs_lock);
785 list_add_tail(&(hvcsd->next), &hvcs_structs);
786 spin_unlock(&hvcs_structs_lock);
788 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
791 * DON'T enable interrupts here because there is no user to receive the
797 static void hvcs_remove(struct vio_dev *dev)
799 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
800 DECLARE_COMPLETION_ONSTACK(comp);
802 struct tty_struct *tty;
804 /* By this time the vty-server won't be getting any more interrupts */
806 spin_lock_irqsave(&hvcsd->lock, flags);
808 hvcsd->destroyed = ∁
809 tty = tty_port_tty_get(&hvcsd->port);
811 spin_unlock_irqrestore(&hvcsd->lock, flags);
814 * The tty should always be valid at this time unless a
815 * simultaneous tty close already cleaned up the hvcs_struct.
822 tty_port_put(&hvcsd->port);
823 wait_for_completion(&comp);
824 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
825 " vio bus.\n", dev->unit_address);
828 static struct vio_driver hvcs_vio_driver = {
829 .id_table = hvcs_driver_table,
831 .remove = hvcs_remove,
832 .name = hvcs_driver_name,
834 .groups = hvcs_groups,
835 .dev_groups = hvcs_dev_groups,
839 /* Only called from hvcs_get_pi please */
840 static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
842 hvcsd->p_unit_address = pi->unit_address;
843 hvcsd->p_partition_ID = pi->partition_ID;
845 /* copy the null-term char too */
846 strscpy(hvcsd->p_location_code, pi->location_code,
847 sizeof(hvcsd->p_location_code));
851 * Traverse the list and add the partner info that is found to the hvcs_struct
852 * struct entry. NOTE: At this time I know that partner info will return a
853 * single entry but in the future there may be multiple partner info entries per
854 * vty-server and you'll want to zero out that list and reset it. If for some
855 * reason you have an old version of this driver but there IS more than one
856 * partner info then hvcsd->p_* will hold the last partner info data from the
857 * firmware query. A good way to update this code would be to replace the three
858 * partner info fields in hvcs_struct with a list of hvcs_partner_info
861 * This function must be called with the hvcsd->lock held.
863 static int hvcs_get_pi(struct hvcs_struct *hvcsd)
865 struct hvcs_partner_info *pi;
866 uint32_t unit_address = hvcsd->vdev->unit_address;
867 struct list_head head;
870 spin_lock(&hvcs_pi_lock);
872 spin_unlock(&hvcs_pi_lock);
875 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
876 spin_unlock(&hvcs_pi_lock);
878 printk(KERN_ERR "HVCS: Failed to fetch partner"
879 " info for vty-server@%x.\n", unit_address);
883 /* nixes the values if the partner vty went away */
884 hvcsd->p_unit_address = 0;
885 hvcsd->p_partition_ID = 0;
887 list_for_each_entry(pi, &head, node)
888 hvcs_set_pi(pi, hvcsd);
890 hvcs_free_partner_info(&head);
895 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
896 * be executed elsewhere, in order to prevent deadlock issues.
898 static int hvcs_rescan_devices_list(void)
900 struct hvcs_struct *hvcsd;
903 spin_lock(&hvcs_structs_lock);
905 list_for_each_entry(hvcsd, &hvcs_structs, next) {
906 spin_lock_irqsave(&hvcsd->lock, flags);
908 spin_unlock_irqrestore(&hvcsd->lock, flags);
911 spin_unlock(&hvcs_structs_lock);
917 * Farm this off into its own function because it could be more complex once
918 * multiple partners support is added. This function should be called with
919 * the hvcsd->lock held.
921 static int hvcs_has_pi(struct hvcs_struct *hvcsd)
923 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
929 * NOTE: It is possible that the super admin removed a partner vty and then
930 * added a different vty as the new partner.
932 * This function must be called with the hvcsd->lock held.
934 static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
937 unsigned int unit_address = hvcsd->vdev->unit_address;
940 * If there wasn't any pi when the device was added it doesn't meant
941 * there isn't any now. This driver isn't notified when a new partner
942 * vty is added to a vty-server so we discover changes on our own.
943 * Please see comments in hvcs_register_connection() for justification
944 * of this bizarre code.
946 retval = hvcs_register_connection(unit_address,
947 hvcsd->p_partition_ID,
948 hvcsd->p_unit_address);
950 hvcsd->connected = 1;
952 } else if (retval != -EINVAL)
956 * As per the spec re-get the pi and try again if -EINVAL after the
957 * first connection attempt.
959 if (hvcs_get_pi(hvcsd))
962 if (!hvcs_has_pi(hvcsd))
965 retval = hvcs_register_connection(unit_address,
966 hvcsd->p_partition_ID,
967 hvcsd->p_unit_address);
968 if (retval != -EINVAL) {
969 hvcsd->connected = 1;
974 * EBUSY is the most likely scenario though the vty could have been
975 * removed or there really could be an hcall error due to the parameter
976 * data but thanks to ambiguous firmware return codes we can't really
979 printk(KERN_INFO "HVCS: vty-server or partner"
980 " vty is busy. Try again later.\n");
984 /* This function must be called with the hvcsd->lock held */
985 static void hvcs_partner_free(struct hvcs_struct *hvcsd)
989 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
990 } while (retval == -EBUSY);
991 hvcsd->connected = 0;
994 /* This helper function must be called WITHOUT the hvcsd->lock held */
995 static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
996 unsigned int irq, struct vio_dev *vdev)
1002 * It is possible that the vty-server was removed between the time that
1003 * the conn was registered and now.
1005 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd);
1008 * It is possible the vty-server was removed after the irq was
1009 * requested but before we have time to enable interrupts.
1011 if (vio_enable_interrupts(vdev) == H_SUCCESS)
1014 printk(KERN_ERR "HVCS: int enable failed for"
1015 " vty-server@%X.\n", unit_address);
1016 free_irq(irq, hvcsd);
1019 printk(KERN_ERR "HVCS: irq req failed for"
1020 " vty-server@%X.\n", unit_address);
1022 spin_lock_irqsave(&hvcsd->lock, flags);
1023 hvcs_partner_free(hvcsd);
1024 spin_unlock_irqrestore(&hvcsd->lock, flags);
1031 * This always increments the kref ref count if the call is successful.
1032 * Please remember to dec when you are done with the instance.
1034 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
1035 * calling this function or you will get deadlock.
1037 static struct hvcs_struct *hvcs_get_by_index(int index)
1039 struct hvcs_struct *hvcsd;
1040 unsigned long flags;
1042 spin_lock(&hvcs_structs_lock);
1043 list_for_each_entry(hvcsd, &hvcs_structs, next) {
1044 spin_lock_irqsave(&hvcsd->lock, flags);
1045 if (hvcsd->index == index) {
1046 tty_port_get(&hvcsd->port);
1047 spin_unlock_irqrestore(&hvcsd->lock, flags);
1048 spin_unlock(&hvcs_structs_lock);
1051 spin_unlock_irqrestore(&hvcsd->lock, flags);
1053 spin_unlock(&hvcs_structs_lock);
1058 static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty)
1060 struct hvcs_struct *hvcsd;
1061 struct vio_dev *vdev;
1062 unsigned long unit_address, flags;
1067 * Is there a vty-server that shares the same index?
1068 * This function increments the kref index.
1070 hvcsd = hvcs_get_by_index(tty->index);
1072 printk(KERN_WARNING "HVCS: open failed, no device associated"
1073 " with tty->index %d.\n", tty->index);
1077 spin_lock_irqsave(&hvcsd->lock, flags);
1079 if (hvcsd->connected == 0) {
1080 retval = hvcs_partner_connect(hvcsd);
1082 spin_unlock_irqrestore(&hvcsd->lock, flags);
1083 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1088 hvcsd->port.count = 0;
1089 hvcsd->port.tty = tty;
1090 tty->driver_data = hvcsd;
1092 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1095 * Save these in the spinlock for the enable operations that need them
1096 * outside of the spinlock.
1098 irq = hvcsd->vdev->irq;
1100 unit_address = hvcsd->vdev->unit_address;
1102 hvcsd->todo_mask |= HVCS_SCHED_READ;
1103 spin_unlock_irqrestore(&hvcsd->lock, flags);
1106 * This must be done outside of the spinlock because it requests irqs
1107 * and will grab the spinlock and free the connection if it fails.
1109 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev);
1111 printk(KERN_WARNING "HVCS: enable device failed.\n");
1115 retval = tty_port_install(&hvcsd->port, driver, tty);
1121 spin_lock_irqsave(&hvcsd->lock, flags);
1122 vio_disable_interrupts(hvcsd->vdev);
1123 spin_unlock_irqrestore(&hvcsd->lock, flags);
1124 free_irq(irq, hvcsd);
1126 tty_port_put(&hvcsd->port);
1132 * This is invoked via the tty_open interface when a user app connects to the
1135 static int hvcs_open(struct tty_struct *tty, struct file *filp)
1137 struct hvcs_struct *hvcsd = tty->driver_data;
1138 unsigned long flags;
1140 spin_lock_irqsave(&hvcsd->lock, flags);
1141 hvcsd->port.count++;
1142 hvcsd->todo_mask |= HVCS_SCHED_READ;
1143 spin_unlock_irqrestore(&hvcsd->lock, flags);
1147 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1148 hvcsd->vdev->unit_address );
1153 static void hvcs_close(struct tty_struct *tty, struct file *filp)
1155 struct hvcs_struct *hvcsd;
1156 unsigned long flags;
1160 * Is someone trying to close the file associated with this device after
1161 * we have hung up? If so tty->driver_data wouldn't be valid.
1163 if (tty_hung_up_p(filp))
1167 * No driver_data means that this close was probably issued after a
1168 * failed hvcs_open by the tty layer's release_dev() api and we can just
1171 if (!tty->driver_data)
1174 hvcsd = tty->driver_data;
1176 spin_lock_irqsave(&hvcsd->lock, flags);
1177 if (hvcsd->port.count == 0) {
1178 spin_unlock_irqrestore(&hvcsd->lock, flags);
1180 } else if (--hvcsd->port.count == 0) {
1182 vio_disable_interrupts(hvcsd->vdev);
1185 * NULL this early so that the kernel_thread doesn't try to
1186 * execute any operations on the TTY even though it is obligated
1187 * to deliver any pending I/O to the hypervisor.
1189 hvcsd->port.tty = NULL;
1191 irq = hvcsd->vdev->irq;
1192 spin_unlock_irqrestore(&hvcsd->lock, flags);
1194 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1196 free_irq(irq, hvcsd);
1198 } else if (hvcsd->port.count < 0) {
1199 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n",
1200 hvcsd->vdev->unit_address, hvcsd->port.count);
1203 spin_unlock_irqrestore(&hvcsd->lock, flags);
1206 static void hvcs_cleanup(struct tty_struct * tty)
1208 struct hvcs_struct *hvcsd = tty->driver_data;
1211 * This line is important because it tells hvcs_open that this
1212 * device needs to be re-configured the next time hvcs_open is
1215 tty->driver_data = NULL;
1217 tty_port_put(&hvcsd->port);
1220 static void hvcs_hangup(struct tty_struct * tty)
1222 struct hvcs_struct *hvcsd = tty->driver_data;
1223 unsigned long flags;
1226 spin_lock_irqsave(&hvcsd->lock, flags);
1229 * Don't kref put inside the spinlock because the destruction
1230 * callback may use the spinlock and it may get called before the
1231 * spinlock has been released.
1233 vio_disable_interrupts(hvcsd->vdev);
1235 hvcsd->todo_mask = 0;
1236 hvcsd->port.tty = NULL;
1237 hvcsd->port.count = 0;
1239 /* This will drop any buffered data on the floor which is OK in a hangup
1241 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1242 hvcsd->chars_in_buffer = 0;
1244 irq = hvcsd->vdev->irq;
1246 spin_unlock_irqrestore(&hvcsd->lock, flags);
1248 free_irq(irq, hvcsd);
1252 * NOTE: This is almost always from_user since user level apps interact with the
1253 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1254 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1255 * tty_hangup will allow hvcs_write time to complete execution before it
1256 * terminates our device.
1258 static ssize_t hvcs_write(struct tty_struct *tty, const u8 *buf, size_t count)
1260 struct hvcs_struct *hvcsd = tty->driver_data;
1261 unsigned int unit_address;
1262 const unsigned char *charbuf;
1263 unsigned long flags;
1264 size_t total_sent = 0;
1269 * If they don't check the return code off of their open they may
1270 * attempt this even if there is no connected device.
1275 /* Reasonable size to prevent user level flooding */
1276 if (count > HVCS_MAX_FROM_USER) {
1277 printk(KERN_WARNING "HVCS write: count being truncated to"
1278 " HVCS_MAX_FROM_USER.\n");
1279 count = HVCS_MAX_FROM_USER;
1284 spin_lock_irqsave(&hvcsd->lock, flags);
1287 * Somehow an open succeeded but the device was removed or the
1288 * connection terminated between the vty-server and partner vty during
1289 * the middle of a write operation? This is a crummy place to do this
1290 * but we want to keep it all in the spinlock.
1292 if (hvcsd->port.count <= 0) {
1293 spin_unlock_irqrestore(&hvcsd->lock, flags);
1297 unit_address = hvcsd->vdev->unit_address;
1300 tosend = min_t(size_t, count,
1301 (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1303 * No more space, this probably means that the last call to
1304 * hvcs_write() didn't succeed and the buffer was filled up.
1309 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1310 &charbuf[total_sent],
1313 hvcsd->chars_in_buffer += tosend;
1318 * If this is true then we don't want to try writing to the
1319 * hypervisor because that is the kernel_threads job now. We'll
1320 * just add to the buffer.
1322 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1323 /* won't send partial writes */
1324 result = hvc_put_chars(unit_address,
1326 hvcsd->chars_in_buffer);
1329 * Since we know we have enough room in hvcsd->buffer for
1330 * tosend we record that it was sent regardless of whether the
1331 * hypervisor actually took it because we have it buffered.
1336 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1341 hvcsd->chars_in_buffer = 0;
1343 * Test after the chars_in_buffer reset otherwise this could
1344 * deadlock our writes if hvc_put_chars fails.
1350 spin_unlock_irqrestore(&hvcsd->lock, flags);
1359 * This is really asking how much can we guarantee that we can send or that we
1360 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1361 * return value, hence the reason for hvcs_struct buffering.
1363 static unsigned int hvcs_write_room(struct tty_struct *tty)
1365 struct hvcs_struct *hvcsd = tty->driver_data;
1367 if (!hvcsd || hvcsd->port.count <= 0)
1370 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1373 static unsigned int hvcs_chars_in_buffer(struct tty_struct *tty)
1375 struct hvcs_struct *hvcsd = tty->driver_data;
1377 return hvcsd->chars_in_buffer;
1380 static const struct tty_operations hvcs_ops = {
1381 .install = hvcs_install,
1383 .close = hvcs_close,
1384 .cleanup = hvcs_cleanup,
1385 .hangup = hvcs_hangup,
1386 .write = hvcs_write,
1387 .write_room = hvcs_write_room,
1388 .chars_in_buffer = hvcs_chars_in_buffer,
1389 .unthrottle = hvcs_unthrottle,
1390 .throttle = hvcs_throttle,
1393 static int hvcs_alloc_index_list(int n)
1397 hvcs_index_list = kmalloc_array(n, sizeof(hvcs_index_count),
1399 if (!hvcs_index_list)
1401 hvcs_index_count = n;
1402 for (i = 0; i < hvcs_index_count; i++)
1403 hvcs_index_list[i] = -1;
1407 static void hvcs_free_index_list(void)
1409 /* Paranoia check to be thorough. */
1410 kfree(hvcs_index_list);
1411 hvcs_index_list = NULL;
1412 hvcs_index_count = 0;
1415 static int hvcs_initialize(void)
1417 int rc, num_ttys_to_alloc;
1419 mutex_lock(&hvcs_init_mutex);
1421 mutex_unlock(&hvcs_init_mutex);
1425 /* Has the user specified an overload with an insmod param? */
1426 if (hvcs_parm_num_devs <= 0 ||
1427 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1428 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1430 num_ttys_to_alloc = hvcs_parm_num_devs;
1432 hvcs_tty_driver = tty_alloc_driver(num_ttys_to_alloc,
1433 TTY_DRIVER_REAL_RAW);
1434 if (IS_ERR(hvcs_tty_driver)) {
1435 mutex_unlock(&hvcs_init_mutex);
1436 return PTR_ERR(hvcs_tty_driver);
1439 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
1444 hvcs_tty_driver->driver_name = hvcs_driver_name;
1445 hvcs_tty_driver->name = hvcs_device_node;
1448 * We'll let the system assign us a major number, indicated by leaving
1452 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1453 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1456 * We role our own so that we DONT ECHO. We can't echo because the
1457 * device we are connecting to already echoes by default and this would
1458 * throw us into a horrible recursive echo-echo-echo loop.
1460 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1462 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1465 * The following call will result in sysfs entries that denote the
1466 * dynamically assigned major and minor numbers for our devices.
1468 if (tty_register_driver(hvcs_tty_driver)) {
1469 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
1474 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL);
1475 if (!hvcs_pi_buff) {
1477 goto buff_alloc_fail;
1480 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1481 if (IS_ERR(hvcs_task)) {
1482 printk(KERN_ERR "HVCS: khvcsd creation failed.\n");
1486 mutex_unlock(&hvcs_init_mutex);
1490 free_page((unsigned long)hvcs_pi_buff);
1492 tty_unregister_driver(hvcs_tty_driver);
1494 hvcs_free_index_list();
1496 tty_driver_kref_put(hvcs_tty_driver);
1497 hvcs_tty_driver = NULL;
1498 mutex_unlock(&hvcs_init_mutex);
1502 static int __init hvcs_module_init(void)
1504 int rc = vio_register_driver(&hvcs_vio_driver);
1506 printk(KERN_ERR "HVCS: can't register vio driver\n");
1510 pr_info("HVCS: Driver registered.\n");
1515 static void __exit hvcs_module_exit(void)
1518 * This driver receives hvcs_remove callbacks for each device upon
1521 vio_unregister_driver(&hvcs_vio_driver);
1526 * This synchronous operation will wake the khvcsd kthread if it is
1527 * asleep and will return when khvcsd has terminated.
1529 kthread_stop(hvcs_task);
1531 spin_lock(&hvcs_pi_lock);
1532 free_page((unsigned long)hvcs_pi_buff);
1533 hvcs_pi_buff = NULL;
1534 spin_unlock(&hvcs_pi_lock);
1536 tty_unregister_driver(hvcs_tty_driver);
1538 hvcs_free_index_list();
1540 tty_driver_kref_put(hvcs_tty_driver);
1542 printk(KERN_INFO "HVCS: driver module removed.\n");
1545 module_init(hvcs_module_init);
1546 module_exit(hvcs_module_exit);