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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * IBM eServer Hypervisor Virtual Console Server Device Driver
4 * Copyright (C) 2003, 2004 IBM Corp.
5 * Ryan S. Arnold (rsa@us.ibm.com)
6 *
7 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
8 *
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.
16 *
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.
20 *
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
26 * callbacks.
27 *
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.
37 *
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.
45 *
46 * Each vty-server, prior to being exposed to this driver is reference counted
47 * using the 2.6 Linux kernel kref construct.
48 *
49 * For direction on installation and usage of this driver please reference
50 * Documentation/arch/powerpc/hvcs.rst.
51 */
52
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>
74#include <asm/vio.h>
75
76/*
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().
95 *
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
108 *
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.
115 */
116
117#define HVCS_DRIVER_VERSION "1.3.3"
118
119MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
120MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
121MODULE_LICENSE("GPL");
122MODULE_VERSION(HVCS_DRIVER_VERSION);
123
124/*
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.
127 */
128#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
129
130/*
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.
137 */
138#define HVCS_DEFAULT_SERVER_ADAPTERS 64
139
140/*
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.
144 */
145#define HVCS_MAX_SERVER_ADAPTERS 1024
146
147/*
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.
152 */
153#define HVCS_MINOR_START 0
154
155/*
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
160 * load.
161 */
162#define __ALIGNED__ __attribute__((__aligned__(8)))
163
164/*
165 * How much data can firmware send with each hvc_put_chars()? Maybe this
166 * should be moved into an architecture specific area.
167 */
168#define HVCS_BUFF_LEN 16
169
170/*
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.
173 */
174#define HVCS_MAX_FROM_USER 4096
175
176/*
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.
180 */
181static const struct ktermios hvcs_tty_termios = {
182 .c_iflag = IGNBRK | IGNPAR,
183 .c_oflag = OPOST,
184 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
185 .c_cc = INIT_C_CC,
186 .c_ispeed = 38400,
187 .c_ospeed = 38400
188};
189
190/*
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.
195 */
196static int hvcs_parm_num_devs = -1;
197module_param(hvcs_parm_num_devs, int, 0);
198
199static const char hvcs_driver_name[] = "hvcs";
200static const char hvcs_device_node[] = "hvcs";
201
202/* Status of partner info rescan triggered via sysfs. */
203static int hvcs_rescan_status;
204
205static struct tty_driver *hvcs_tty_driver;
206
207/*
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.
219 */
220static int *hvcs_index_list;
221
222/*
223 * How large is the list? This is kept for traversal since the list is
224 * dynamically created.
225 */
226static int hvcs_index_count;
227
228/*
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.
231 */
232static int hvcs_kicked;
233
234/*
235 * Use by the kthread construct for task operations like waking the sleeping
236 * thread and stopping the kthread.
237 */
238static struct task_struct *hvcs_task;
239
240/*
241 * We allocate this for the use of all of the hvcs_structs when they fetch
242 * partner info.
243 */
244static unsigned long *hvcs_pi_buff;
245
246/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
247static DEFINE_SPINLOCK(hvcs_pi_lock);
248
249/* One vty-server per hvcs_struct */
250struct hvcs_struct {
251 struct tty_port port;
252 spinlock_t lock;
253
254 /*
255 * This index identifies this hvcs device as the complement to a
256 * specific tty index.
257 */
258 unsigned int index;
259
260 /*
261 * Used to tell the driver kernel_thread what operations need to take
262 * place upon this hvcs_struct instance.
263 */
264 int todo_mask;
265
266 /*
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()].
273 */
274 char buffer[HVCS_BUFF_LEN];
275 int chars_in_buffer;
276
277 /*
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.
282 */
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;
290};
291
292static LIST_HEAD(hvcs_structs);
293static DEFINE_SPINLOCK(hvcs_structs_lock);
294static DEFINE_MUTEX(hvcs_init_mutex);
295
296static int hvcs_get_pi(struct hvcs_struct *hvcsd);
297static int hvcs_rescan_devices_list(void);
298
299static void hvcs_partner_free(struct hvcs_struct *hvcsd);
300
301static int hvcs_initialize(void);
302
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)
307
308static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
309{
310 return dev_get_drvdata(&viod->dev);
311}
312/* The sysfs interface for the driver and devices */
313
314static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
315{
316 struct vio_dev *viod = to_vio_dev(dev);
317 struct hvcs_struct *hvcsd = from_vio_dev(viod);
318 unsigned long flags;
319 int retval;
320
321 spin_lock_irqsave(&hvcsd->lock, flags);
322 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
323 spin_unlock_irqrestore(&hvcsd->lock, flags);
324 return retval;
325}
326static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
327
328static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
329{
330 struct vio_dev *viod = to_vio_dev(dev);
331 struct hvcs_struct *hvcsd = from_vio_dev(viod);
332 unsigned long flags;
333 int retval;
334
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);
338 return retval;
339}
340static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
341
342static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
343 size_t count)
344{
345 /*
346 * Don't need this feature at the present time because firmware doesn't
347 * yet support multiple partners.
348 */
349 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
350 return -EPERM;
351}
352
353static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
354{
355 struct vio_dev *viod = to_vio_dev(dev);
356 struct hvcs_struct *hvcsd = from_vio_dev(viod);
357 unsigned long flags;
358 int retval;
359
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);
363 return retval;
364}
365
366static DEVICE_ATTR(current_vty,
367 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
368
369static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
370 size_t count)
371{
372 struct vio_dev *viod = to_vio_dev(dev);
373 struct hvcs_struct *hvcsd = from_vio_dev(viod);
374 unsigned long flags;
375
376 /* writing a '0' to this sysfs entry will result in the disconnect. */
377 if (simple_strtol(buf, NULL, 0) != 0)
378 return -EINVAL;
379
380 spin_lock_irqsave(&hvcsd->lock, flags);
381
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");
386 return -EPERM;
387 }
388
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");
393 return -EPERM;
394 }
395
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);
402
403 spin_unlock_irqrestore(&hvcsd->lock, flags);
404 return count;
405}
406
407static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
408{
409 struct vio_dev *viod = to_vio_dev(dev);
410 struct hvcs_struct *hvcsd = from_vio_dev(viod);
411 unsigned long flags;
412 int retval;
413
414 spin_lock_irqsave(&hvcsd->lock, flags);
415 retval = sprintf(buf, "%d\n", hvcsd->connected);
416 spin_unlock_irqrestore(&hvcsd->lock, flags);
417 return retval;
418}
419static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
420 hvcs_vterm_state_show, hvcs_vterm_state_store);
421
422static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
423{
424 struct vio_dev *viod = to_vio_dev(dev);
425 struct hvcs_struct *hvcsd = from_vio_dev(viod);
426 unsigned long flags;
427 int retval;
428
429 spin_lock_irqsave(&hvcsd->lock, flags);
430 retval = sprintf(buf, "%d\n", hvcsd->index);
431 spin_unlock_irqrestore(&hvcsd->lock, flags);
432 return retval;
433}
434
435static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
436
437static 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,
443 NULL,
444};
445
446ATTRIBUTE_GROUPS(hvcs_dev);
447
448static ssize_t rescan_show(struct device_driver *ddp, char *buf)
449{
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);
452}
453
454static ssize_t rescan_store(struct device_driver *ddp, const char * buf,
455 size_t count)
456{
457 if ((simple_strtol(buf, NULL, 0) != 1)
458 && (hvcs_rescan_status != 0))
459 return -EINVAL;
460
461 hvcs_rescan_status = 1;
462 printk(KERN_INFO "HVCS: rescanning partner info for all"
463 " vty-servers.\n");
464 hvcs_rescan_devices_list();
465 hvcs_rescan_status = 0;
466 return count;
467}
468
469static DRIVER_ATTR_RW(rescan);
470
471static struct attribute *hvcs_attrs[] = {
472 &driver_attr_rescan.attr,
473 NULL,
474};
475
476ATTRIBUTE_GROUPS(hvcs);
477
478static void hvcs_kick(void)
479{
480 hvcs_kicked = 1;
481 wmb();
482 wake_up_process(hvcs_task);
483}
484
485static void hvcs_unthrottle(struct tty_struct *tty)
486{
487 struct hvcs_struct *hvcsd = tty->driver_data;
488 unsigned long flags;
489
490 spin_lock_irqsave(&hvcsd->lock, flags);
491 hvcsd->todo_mask |= HVCS_SCHED_READ;
492 spin_unlock_irqrestore(&hvcsd->lock, flags);
493 hvcs_kick();
494}
495
496static void hvcs_throttle(struct tty_struct *tty)
497{
498 struct hvcs_struct *hvcsd = tty->driver_data;
499 unsigned long flags;
500
501 spin_lock_irqsave(&hvcsd->lock, flags);
502 vio_disable_interrupts(hvcsd->vdev);
503 spin_unlock_irqrestore(&hvcsd->lock, flags);
504}
505
506/*
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.
510 */
511static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
512{
513 struct hvcs_struct *hvcsd = dev_instance;
514
515 spin_lock(&hvcsd->lock);
516 vio_disable_interrupts(hvcsd->vdev);
517 hvcsd->todo_mask |= HVCS_SCHED_READ;
518 spin_unlock(&hvcsd->lock);
519 hvcs_kick();
520
521 return IRQ_HANDLED;
522}
523
524/* This function must be called with the hvcsd->lock held */
525static void hvcs_try_write(struct hvcs_struct *hvcsd)
526{
527 uint32_t unit_address = hvcsd->vdev->unit_address;
528 struct tty_struct *tty = hvcsd->port.tty;
529 int sent;
530
531 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
532 /* won't send partial writes */
533 sent = hvc_put_chars(unit_address,
534 &hvcsd->buffer[0],
535 hvcsd->chars_in_buffer );
536 if (sent > 0) {
537 hvcsd->chars_in_buffer = 0;
538 /* wmb(); */
539 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
540 /* wmb(); */
541
542 /*
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.
547 */
548 if (tty) {
549 tty_wakeup(tty);
550 }
551 }
552 }
553}
554
555static int hvcs_io(struct hvcs_struct *hvcsd)
556{
557 uint32_t unit_address;
558 struct tty_struct *tty;
559 char buf[HVCS_BUFF_LEN] __ALIGNED__;
560 unsigned long flags;
561 int got = 0;
562
563 spin_lock_irqsave(&hvcsd->lock, flags);
564
565 unit_address = hvcsd->vdev->unit_address;
566 tty = hvcsd->port.tty;
567
568 hvcs_try_write(hvcsd);
569
570 if (!tty || tty_throttled(tty)) {
571 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
572 goto bail;
573 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
574 goto bail;
575
576 /* remove the read masks */
577 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
578
579 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
580 got = hvc_get_chars(unit_address,
581 &buf[0],
582 HVCS_BUFF_LEN);
583 tty_insert_flip_string(&hvcsd->port, buf, got);
584 }
585
586 /* Give the TTY time to process the data we just sent. */
587 if (got)
588 hvcsd->todo_mask |= HVCS_QUICK_READ;
589
590 spin_unlock_irqrestore(&hvcsd->lock, flags);
591 /* This is synch -- FIXME :js: it is not! */
592 if (got)
593 tty_flip_buffer_push(&hvcsd->port);
594 else {
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);
599 }
600
601 return hvcsd->todo_mask;
602
603 bail:
604 spin_unlock_irqrestore(&hvcsd->lock, flags);
605 return hvcsd->todo_mask;
606}
607
608static int khvcsd(void *unused)
609{
610 struct hvcs_struct *hvcsd;
611 int hvcs_todo_mask;
612
613 __set_current_state(TASK_RUNNING);
614
615 do {
616 hvcs_todo_mask = 0;
617 hvcs_kicked = 0;
618 wmb();
619
620 spin_lock(&hvcs_structs_lock);
621 list_for_each_entry(hvcsd, &hvcs_structs, next) {
622 hvcs_todo_mask |= hvcs_io(hvcsd);
623 }
624 spin_unlock(&hvcs_structs_lock);
625
626 /*
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.
630 */
631 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
632 yield();
633 continue;
634 }
635
636 set_current_state(TASK_INTERRUPTIBLE);
637 if (!hvcs_kicked)
638 schedule();
639 __set_current_state(TASK_RUNNING);
640 } while (!kthread_should_stop());
641
642 return 0;
643}
644
645static const struct vio_device_id hvcs_driver_table[] = {
646 {"serial-server", "hvterm2"},
647 { "", "" }
648};
649MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
650
651static void hvcs_return_index(int index)
652{
653 /* Paranoia check */
654 if (!hvcs_index_list)
655 return;
656 if (index < 0 || index >= hvcs_index_count)
657 return;
658 if (hvcs_index_list[index] == -1)
659 return;
660 else
661 hvcs_index_list[index] = -1;
662}
663
664static void hvcs_destruct_port(struct tty_port *p)
665{
666 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
667 struct completion *comp;
668 unsigned long flags;
669
670 spin_lock(&hvcs_structs_lock);
671 spin_lock_irqsave(&hvcsd->lock, flags);
672
673 comp = hvcsd->destroyed;
674 /* the list_del poisons the pointers */
675 list_del(&(hvcsd->next));
676
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);
684 }
685 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
686 hvcsd->vdev->unit_address);
687
688 hvcsd->vdev = NULL;
689
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);
695
696 spin_unlock_irqrestore(&hvcsd->lock, flags);
697 spin_unlock(&hvcs_structs_lock);
698
699 kfree(hvcsd);
700 if (comp)
701 complete(comp);
702}
703
704static const struct tty_port_operations hvcs_port_ops = {
705 .destruct = hvcs_destruct_port,
706};
707
708static int hvcs_get_index(void)
709{
710 int i;
711 /* Paranoia check */
712 if (!hvcs_index_list) {
713 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
714 return -EFAULT;
715 }
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;
720 return i;
721 }
722 }
723 return -1;
724}
725
726static int hvcs_probe(
727 struct vio_dev *dev,
728 const struct vio_device_id *id)
729{
730 struct hvcs_struct *hvcsd;
731 int index, rc;
732
733 if (!dev || !id) {
734 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
735 return -EPERM;
736 }
737
738 /* Make sure we are properly initialized */
739 rc = hvcs_initialize();
740 if (rc) {
741 pr_err("HVCS: Failed to initialize core driver.\n");
742 return rc;
743 }
744
745 /* early to avoid cleanup on failure */
746 index = hvcs_get_index();
747 if (index < 0) {
748 return -EFAULT;
749 }
750
751 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
752 if (!hvcsd)
753 return -ENODEV;
754
755 tty_port_init(&hvcsd->port);
756 hvcsd->port.ops = &hvcs_port_ops;
757 spin_lock_init(&hvcsd->lock);
758
759 hvcsd->vdev = dev;
760 dev_set_drvdata(&dev->dev, hvcsd);
761
762 hvcsd->index = index;
763
764 /* hvcsd->index = ++hvcs_struct_count; */
765 hvcsd->chars_in_buffer = 0;
766 hvcsd->todo_mask = 0;
767 hvcsd->connected = 0;
768
769 /*
770 * This will populate the hvcs_struct's partner info fields for the
771 * first time.
772 */
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);
777 }
778
779 /*
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
782 * will get -ENODEV.
783 */
784 spin_lock(&hvcs_structs_lock);
785 list_add_tail(&(hvcsd->next), &hvcs_structs);
786 spin_unlock(&hvcs_structs_lock);
787
788 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
789
790 /*
791 * DON'T enable interrupts here because there is no user to receive the
792 * data.
793 */
794 return 0;
795}
796
797static void hvcs_remove(struct vio_dev *dev)
798{
799 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
800 DECLARE_COMPLETION_ONSTACK(comp);
801 unsigned long flags;
802 struct tty_struct *tty;
803
804 /* By this time the vty-server won't be getting any more interrupts */
805
806 spin_lock_irqsave(&hvcsd->lock, flags);
807
808 hvcsd->destroyed = ∁
809 tty = tty_port_tty_get(&hvcsd->port);
810
811 spin_unlock_irqrestore(&hvcsd->lock, flags);
812
813 /*
814 * The tty should always be valid at this time unless a
815 * simultaneous tty close already cleaned up the hvcs_struct.
816 */
817 if (tty) {
818 tty_vhangup(tty);
819 tty_kref_put(tty);
820 }
821
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);
826};
827
828static struct vio_driver hvcs_vio_driver = {
829 .id_table = hvcs_driver_table,
830 .probe = hvcs_probe,
831 .remove = hvcs_remove,
832 .name = hvcs_driver_name,
833 .driver = {
834 .groups = hvcs_groups,
835 .dev_groups = hvcs_dev_groups,
836 },
837};
838
839/* Only called from hvcs_get_pi please */
840static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
841{
842 hvcsd->p_unit_address = pi->unit_address;
843 hvcsd->p_partition_ID = pi->partition_ID;
844
845 /* copy the null-term char too */
846 strscpy(hvcsd->p_location_code, pi->location_code,
847 sizeof(hvcsd->p_location_code));
848}
849
850/*
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
859 * instances.
860 *
861 * This function must be called with the hvcsd->lock held.
862 */
863static int hvcs_get_pi(struct hvcs_struct *hvcsd)
864{
865 struct hvcs_partner_info *pi;
866 uint32_t unit_address = hvcsd->vdev->unit_address;
867 struct list_head head;
868 int retval;
869
870 spin_lock(&hvcs_pi_lock);
871 if (!hvcs_pi_buff) {
872 spin_unlock(&hvcs_pi_lock);
873 return -EFAULT;
874 }
875 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
876 spin_unlock(&hvcs_pi_lock);
877 if (retval) {
878 printk(KERN_ERR "HVCS: Failed to fetch partner"
879 " info for vty-server@%x.\n", unit_address);
880 return retval;
881 }
882
883 /* nixes the values if the partner vty went away */
884 hvcsd->p_unit_address = 0;
885 hvcsd->p_partition_ID = 0;
886
887 list_for_each_entry(pi, &head, node)
888 hvcs_set_pi(pi, hvcsd);
889
890 hvcs_free_partner_info(&head);
891 return 0;
892}
893
894/*
895 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
896 * be executed elsewhere, in order to prevent deadlock issues.
897 */
898static int hvcs_rescan_devices_list(void)
899{
900 struct hvcs_struct *hvcsd;
901 unsigned long flags;
902
903 spin_lock(&hvcs_structs_lock);
904
905 list_for_each_entry(hvcsd, &hvcs_structs, next) {
906 spin_lock_irqsave(&hvcsd->lock, flags);
907 hvcs_get_pi(hvcsd);
908 spin_unlock_irqrestore(&hvcsd->lock, flags);
909 }
910
911 spin_unlock(&hvcs_structs_lock);
912
913 return 0;
914}
915
916/*
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.
920 */
921static int hvcs_has_pi(struct hvcs_struct *hvcsd)
922{
923 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
924 return 0;
925 return 1;
926}
927
928/*
929 * NOTE: It is possible that the super admin removed a partner vty and then
930 * added a different vty as the new partner.
931 *
932 * This function must be called with the hvcsd->lock held.
933 */
934static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
935{
936 int retval;
937 unsigned int unit_address = hvcsd->vdev->unit_address;
938
939 /*
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.
945 */
946 retval = hvcs_register_connection(unit_address,
947 hvcsd->p_partition_ID,
948 hvcsd->p_unit_address);
949 if (!retval) {
950 hvcsd->connected = 1;
951 return 0;
952 } else if (retval != -EINVAL)
953 return retval;
954
955 /*
956 * As per the spec re-get the pi and try again if -EINVAL after the
957 * first connection attempt.
958 */
959 if (hvcs_get_pi(hvcsd))
960 return -ENOMEM;
961
962 if (!hvcs_has_pi(hvcsd))
963 return -ENODEV;
964
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;
970 return retval;
971 }
972
973 /*
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
977 * tell.
978 */
979 printk(KERN_INFO "HVCS: vty-server or partner"
980 " vty is busy. Try again later.\n");
981 return -EBUSY;
982}
983
984/* This function must be called with the hvcsd->lock held */
985static void hvcs_partner_free(struct hvcs_struct *hvcsd)
986{
987 int retval;
988 do {
989 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
990 } while (retval == -EBUSY);
991 hvcsd->connected = 0;
992}
993
994/* This helper function must be called WITHOUT the hvcsd->lock held */
995static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
996 unsigned int irq, struct vio_dev *vdev)
997{
998 unsigned long flags;
999 int rc;
1000
1001 /*
1002 * It is possible that the vty-server was removed between the time that
1003 * the conn was registered and now.
1004 */
1005 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd);
1006 if (!rc) {
1007 /*
1008 * It is possible the vty-server was removed after the irq was
1009 * requested but before we have time to enable interrupts.
1010 */
1011 if (vio_enable_interrupts(vdev) == H_SUCCESS)
1012 return 0;
1013 else {
1014 printk(KERN_ERR "HVCS: int enable failed for"
1015 " vty-server@%X.\n", unit_address);
1016 free_irq(irq, hvcsd);
1017 }
1018 } else
1019 printk(KERN_ERR "HVCS: irq req failed for"
1020 " vty-server@%X.\n", unit_address);
1021
1022 spin_lock_irqsave(&hvcsd->lock, flags);
1023 hvcs_partner_free(hvcsd);
1024 spin_unlock_irqrestore(&hvcsd->lock, flags);
1025
1026 return rc;
1027
1028}
1029
1030/*
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.
1033 *
1034 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
1035 * calling this function or you will get deadlock.
1036 */
1037static struct hvcs_struct *hvcs_get_by_index(int index)
1038{
1039 struct hvcs_struct *hvcsd;
1040 unsigned long flags;
1041
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);
1049 return hvcsd;
1050 }
1051 spin_unlock_irqrestore(&hvcsd->lock, flags);
1052 }
1053 spin_unlock(&hvcs_structs_lock);
1054
1055 return NULL;
1056}
1057
1058static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty)
1059{
1060 struct hvcs_struct *hvcsd;
1061 struct vio_dev *vdev;
1062 unsigned long unit_address, flags;
1063 unsigned int irq;
1064 int retval;
1065
1066 /*
1067 * Is there a vty-server that shares the same index?
1068 * This function increments the kref index.
1069 */
1070 hvcsd = hvcs_get_by_index(tty->index);
1071 if (!hvcsd) {
1072 printk(KERN_WARNING "HVCS: open failed, no device associated"
1073 " with tty->index %d.\n", tty->index);
1074 return -ENODEV;
1075 }
1076
1077 spin_lock_irqsave(&hvcsd->lock, flags);
1078
1079 if (hvcsd->connected == 0) {
1080 retval = hvcs_partner_connect(hvcsd);
1081 if (retval) {
1082 spin_unlock_irqrestore(&hvcsd->lock, flags);
1083 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1084 goto err_put;
1085 }
1086 }
1087
1088 hvcsd->port.count = 0;
1089 hvcsd->port.tty = tty;
1090 tty->driver_data = hvcsd;
1091
1092 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1093
1094 /*
1095 * Save these in the spinlock for the enable operations that need them
1096 * outside of the spinlock.
1097 */
1098 irq = hvcsd->vdev->irq;
1099 vdev = hvcsd->vdev;
1100 unit_address = hvcsd->vdev->unit_address;
1101
1102 hvcsd->todo_mask |= HVCS_SCHED_READ;
1103 spin_unlock_irqrestore(&hvcsd->lock, flags);
1104
1105 /*
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.
1108 */
1109 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev);
1110 if (retval) {
1111 printk(KERN_WARNING "HVCS: enable device failed.\n");
1112 goto err_put;
1113 }
1114
1115 retval = tty_port_install(&hvcsd->port, driver, tty);
1116 if (retval)
1117 goto err_irq;
1118
1119 return 0;
1120err_irq:
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);
1125err_put:
1126 tty_port_put(&hvcsd->port);
1127
1128 return retval;
1129}
1130
1131/*
1132 * This is invoked via the tty_open interface when a user app connects to the
1133 * /dev node.
1134 */
1135static int hvcs_open(struct tty_struct *tty, struct file *filp)
1136{
1137 struct hvcs_struct *hvcsd = tty->driver_data;
1138 unsigned long flags;
1139
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);
1144
1145 hvcs_kick();
1146
1147 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1148 hvcsd->vdev->unit_address );
1149
1150 return 0;
1151}
1152
1153static void hvcs_close(struct tty_struct *tty, struct file *filp)
1154{
1155 struct hvcs_struct *hvcsd;
1156 unsigned long flags;
1157 int irq;
1158
1159 /*
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.
1162 */
1163 if (tty_hung_up_p(filp))
1164 return;
1165
1166 /*
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
1169 * exit cleanly.
1170 */
1171 if (!tty->driver_data)
1172 return;
1173
1174 hvcsd = tty->driver_data;
1175
1176 spin_lock_irqsave(&hvcsd->lock, flags);
1177 if (hvcsd->port.count == 0) {
1178 spin_unlock_irqrestore(&hvcsd->lock, flags);
1179 return;
1180 } else if (--hvcsd->port.count == 0) {
1181
1182 vio_disable_interrupts(hvcsd->vdev);
1183
1184 /*
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.
1188 */
1189 hvcsd->port.tty = NULL;
1190
1191 irq = hvcsd->vdev->irq;
1192 spin_unlock_irqrestore(&hvcsd->lock, flags);
1193
1194 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1195
1196 free_irq(irq, hvcsd);
1197 return;
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);
1201 }
1202
1203 spin_unlock_irqrestore(&hvcsd->lock, flags);
1204}
1205
1206static void hvcs_cleanup(struct tty_struct * tty)
1207{
1208 struct hvcs_struct *hvcsd = tty->driver_data;
1209
1210 /*
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
1213 * called.
1214 */
1215 tty->driver_data = NULL;
1216
1217 tty_port_put(&hvcsd->port);
1218}
1219
1220static void hvcs_hangup(struct tty_struct * tty)
1221{
1222 struct hvcs_struct *hvcsd = tty->driver_data;
1223 unsigned long flags;
1224 int irq;
1225
1226 spin_lock_irqsave(&hvcsd->lock, flags);
1227
1228 /*
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.
1232 */
1233 vio_disable_interrupts(hvcsd->vdev);
1234
1235 hvcsd->todo_mask = 0;
1236 hvcsd->port.tty = NULL;
1237 hvcsd->port.count = 0;
1238
1239 /* This will drop any buffered data on the floor which is OK in a hangup
1240 * scenario. */
1241 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1242 hvcsd->chars_in_buffer = 0;
1243
1244 irq = hvcsd->vdev->irq;
1245
1246 spin_unlock_irqrestore(&hvcsd->lock, flags);
1247
1248 free_irq(irq, hvcsd);
1249}
1250
1251/*
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.
1257 */
1258static ssize_t hvcs_write(struct tty_struct *tty, const u8 *buf, size_t count)
1259{
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;
1265 size_t tosend = 0;
1266 int result = 0;
1267
1268 /*
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.
1271 */
1272 if (!hvcsd)
1273 return -ENODEV;
1274
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;
1280 }
1281
1282 charbuf = buf;
1283
1284 spin_lock_irqsave(&hvcsd->lock, flags);
1285
1286 /*
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.
1291 */
1292 if (hvcsd->port.count <= 0) {
1293 spin_unlock_irqrestore(&hvcsd->lock, flags);
1294 return -ENODEV;
1295 }
1296
1297 unit_address = hvcsd->vdev->unit_address;
1298
1299 while (count > 0) {
1300 tosend = min_t(size_t, count,
1301 (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1302 /*
1303 * No more space, this probably means that the last call to
1304 * hvcs_write() didn't succeed and the buffer was filled up.
1305 */
1306 if (!tosend)
1307 break;
1308
1309 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1310 &charbuf[total_sent],
1311 tosend);
1312
1313 hvcsd->chars_in_buffer += tosend;
1314
1315 result = 0;
1316
1317 /*
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.
1321 */
1322 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1323 /* won't send partial writes */
1324 result = hvc_put_chars(unit_address,
1325 &hvcsd->buffer[0],
1326 hvcsd->chars_in_buffer);
1327
1328 /*
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.
1332 */
1333 total_sent+=tosend;
1334 count-=tosend;
1335 if (result == 0) {
1336 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1337 hvcs_kick();
1338 break;
1339 }
1340
1341 hvcsd->chars_in_buffer = 0;
1342 /*
1343 * Test after the chars_in_buffer reset otherwise this could
1344 * deadlock our writes if hvc_put_chars fails.
1345 */
1346 if (result < 0)
1347 break;
1348 }
1349
1350 spin_unlock_irqrestore(&hvcsd->lock, flags);
1351
1352 if (result == -1)
1353 return -EIO;
1354 else
1355 return total_sent;
1356}
1357
1358/*
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.
1362 */
1363static unsigned int hvcs_write_room(struct tty_struct *tty)
1364{
1365 struct hvcs_struct *hvcsd = tty->driver_data;
1366
1367 if (!hvcsd || hvcsd->port.count <= 0)
1368 return 0;
1369
1370 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1371}
1372
1373static unsigned int hvcs_chars_in_buffer(struct tty_struct *tty)
1374{
1375 struct hvcs_struct *hvcsd = tty->driver_data;
1376
1377 return hvcsd->chars_in_buffer;
1378}
1379
1380static const struct tty_operations hvcs_ops = {
1381 .install = hvcs_install,
1382 .open = hvcs_open,
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,
1391};
1392
1393static int hvcs_alloc_index_list(int n)
1394{
1395 int i;
1396
1397 hvcs_index_list = kmalloc_array(n, sizeof(hvcs_index_count),
1398 GFP_KERNEL);
1399 if (!hvcs_index_list)
1400 return -ENOMEM;
1401 hvcs_index_count = n;
1402 for (i = 0; i < hvcs_index_count; i++)
1403 hvcs_index_list[i] = -1;
1404 return 0;
1405}
1406
1407static void hvcs_free_index_list(void)
1408{
1409 /* Paranoia check to be thorough. */
1410 kfree(hvcs_index_list);
1411 hvcs_index_list = NULL;
1412 hvcs_index_count = 0;
1413}
1414
1415static int hvcs_initialize(void)
1416{
1417 int rc, num_ttys_to_alloc;
1418
1419 mutex_lock(&hvcs_init_mutex);
1420 if (hvcs_task) {
1421 mutex_unlock(&hvcs_init_mutex);
1422 return 0;
1423 }
1424
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;
1429 } else
1430 num_ttys_to_alloc = hvcs_parm_num_devs;
1431
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);
1437 }
1438
1439 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
1440 rc = -ENOMEM;
1441 goto index_fail;
1442 }
1443
1444 hvcs_tty_driver->driver_name = hvcs_driver_name;
1445 hvcs_tty_driver->name = hvcs_device_node;
1446
1447 /*
1448 * We'll let the system assign us a major number, indicated by leaving
1449 * it blank.
1450 */
1451
1452 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1453 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1454
1455 /*
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.
1459 */
1460 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1461
1462 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1463
1464 /*
1465 * The following call will result in sysfs entries that denote the
1466 * dynamically assigned major and minor numbers for our devices.
1467 */
1468 if (tty_register_driver(hvcs_tty_driver)) {
1469 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
1470 rc = -EIO;
1471 goto register_fail;
1472 }
1473
1474 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL);
1475 if (!hvcs_pi_buff) {
1476 rc = -ENOMEM;
1477 goto buff_alloc_fail;
1478 }
1479
1480 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1481 if (IS_ERR(hvcs_task)) {
1482 printk(KERN_ERR "HVCS: khvcsd creation failed.\n");
1483 rc = -EIO;
1484 goto kthread_fail;
1485 }
1486 mutex_unlock(&hvcs_init_mutex);
1487 return 0;
1488
1489kthread_fail:
1490 free_page((unsigned long)hvcs_pi_buff);
1491buff_alloc_fail:
1492 tty_unregister_driver(hvcs_tty_driver);
1493register_fail:
1494 hvcs_free_index_list();
1495index_fail:
1496 tty_driver_kref_put(hvcs_tty_driver);
1497 hvcs_tty_driver = NULL;
1498 mutex_unlock(&hvcs_init_mutex);
1499 return rc;
1500}
1501
1502static int __init hvcs_module_init(void)
1503{
1504 int rc = vio_register_driver(&hvcs_vio_driver);
1505 if (rc) {
1506 printk(KERN_ERR "HVCS: can't register vio driver\n");
1507 return rc;
1508 }
1509
1510 pr_info("HVCS: Driver registered.\n");
1511
1512 return 0;
1513}
1514
1515static void __exit hvcs_module_exit(void)
1516{
1517 /*
1518 * This driver receives hvcs_remove callbacks for each device upon
1519 * module removal.
1520 */
1521 vio_unregister_driver(&hvcs_vio_driver);
1522 if (!hvcs_task)
1523 return;
1524
1525 /*
1526 * This synchronous operation will wake the khvcsd kthread if it is
1527 * asleep and will return when khvcsd has terminated.
1528 */
1529 kthread_stop(hvcs_task);
1530
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);
1535
1536 tty_unregister_driver(hvcs_tty_driver);
1537
1538 hvcs_free_index_list();
1539
1540 tty_driver_kref_put(hvcs_tty_driver);
1541
1542 printk(KERN_INFO "HVCS: driver module removed.\n");
1543}
1544
1545module_init(hvcs_module_init);
1546module_exit(hvcs_module_exit);
1/*
2 * IBM eServer Hypervisor Virtual Console Server Device Driver
3 * Copyright (C) 2003, 2004 IBM Corp.
4 * Ryan S. Arnold (rsa@us.ibm.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
21 *
22 * This is the device driver for the IBM Hypervisor Virtual Console Server,
23 * "hvcs". The IBM hvcs provides a tty driver interface to allow Linux
24 * user space applications access to the system consoles of logically
25 * partitioned operating systems, e.g. Linux, running on the same partitioned
26 * Power5 ppc64 system. Physical hardware consoles per partition are not
27 * practical on this hardware so system consoles are accessed by this driver
28 * using inter-partition firmware interfaces to virtual terminal devices.
29 *
30 * A vty is known to the HMC as a "virtual serial server adapter". It is a
31 * virtual terminal device that is created by firmware upon partition creation
32 * to act as a partitioned OS's console device.
33 *
34 * Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64
35 * Linux system upon their creation by the HMC or their exposure during boot.
36 * The non-user interactive backend of this driver is implemented as a vio
37 * device driver so that it can receive notification of vty-server lifetimes
38 * after it registers with the vio bus to handle vty-server probe and remove
39 * callbacks.
40 *
41 * Many vty-servers can be configured to connect to one vty, but a vty can
42 * only be actively connected to by a single vty-server, in any manner, at one
43 * time. If the HMC is currently hosting the console for a target Linux
44 * partition; attempts to open the tty device to the partition's console using
45 * the hvcs on any partition will return -EBUSY with every open attempt until
46 * the HMC frees the connection between its vty-server and the desired
47 * partition's vty device. Conversely, a vty-server may only be connected to
48 * a single vty at one time even though it may have several configured vty
49 * partner possibilities.
50 *
51 * Firmware does not provide notification of vty partner changes to this
52 * driver. This means that an HMC Super Admin may add or remove partner vtys
53 * from a vty-server's partner list but the changes will not be signaled to
54 * the vty-server. Firmware only notifies the driver when a vty-server is
55 * added or removed from the system. To compensate for this deficiency, this
56 * driver implements a sysfs update attribute which provides a method for
57 * rescanning partner information upon a user's request.
58 *
59 * Each vty-server, prior to being exposed to this driver is reference counted
60 * using the 2.6 Linux kernel kref construct.
61 *
62 * For direction on installation and usage of this driver please reference
63 * Documentation/powerpc/hvcs.txt.
64 */
65
66#include <linux/device.h>
67#include <linux/init.h>
68#include <linux/interrupt.h>
69#include <linux/kernel.h>
70#include <linux/kref.h>
71#include <linux/kthread.h>
72#include <linux/list.h>
73#include <linux/major.h>
74#include <linux/module.h>
75#include <linux/moduleparam.h>
76#include <linux/sched.h>
77#include <linux/slab.h>
78#include <linux/spinlock.h>
79#include <linux/stat.h>
80#include <linux/tty.h>
81#include <linux/tty_flip.h>
82#include <asm/hvconsole.h>
83#include <asm/hvcserver.h>
84#include <linux/uaccess.h>
85#include <asm/vio.h>
86
87/*
88 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
89 * Removed braces around single statements following conditionals. Removed '=
90 * 0' after static int declarations since these default to zero. Removed
91 * list_for_each_safe() and replaced with list_for_each_entry() in
92 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
93 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
94 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
95 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
96 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
97 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
98 * list traversals from a deletion. Removed '= NULL' from pointer declaration
99 * statements since they are initialized NULL by default. Removed wmb()
100 * instances from hvcs_try_write(). They probably aren't needed with locking in
101 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
102 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
103 * the coupling between /dev/hvcs* and a vty-server can be automatically
104 * determined. Moved kobject_put() in hvcs_open outside of the
105 * spin_unlock_irqrestore().
106 *
107 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
108 * align with how the tty layer always assigns the lowest index available. This
109 * change resulted in a list of ints that denotes which indexes are available.
110 * Device additions and removals use the new hvcs_get_index() and
111 * hvcs_return_index() helper functions. The list is created with
112 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
113 * Without these fixes hotplug vty-server adapter support goes crazy with this
114 * driver if the user removes a vty-server adapter. Moved free_irq() outside of
115 * the hvcs_final_close() function in order to get it out of the spinlock.
116 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
117 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
118 * arch/powerepc/include/asm/hvcserver.h
119 *
120 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
121 * prevent possible lockup with realtime scheduling as similarly pointed out by
122 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
123 * to reorder cleanup operations and prevent discarding of pending data during
124 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
125 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
126 */
127
128#define HVCS_DRIVER_VERSION "1.3.3"
129
130MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
131MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
132MODULE_LICENSE("GPL");
133MODULE_VERSION(HVCS_DRIVER_VERSION);
134
135/*
136 * Wait this long per iteration while trying to push buffered data to the
137 * hypervisor before allowing the tty to complete a close operation.
138 */
139#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
140
141/*
142 * Since the Linux TTY code does not currently (2-04-2004) support dynamic
143 * addition of tty derived devices and we shouldn't allocate thousands of
144 * tty_device pointers when the number of vty-server & vty partner connections
145 * will most often be much lower than this, we'll arbitrarily allocate
146 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
147 * register the tty_driver. This can be overridden using an insmod parameter.
148 */
149#define HVCS_DEFAULT_SERVER_ADAPTERS 64
150
151/*
152 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
153 * nodes as a sanity check. Theoretically there can be over 1 Billion
154 * vty-server & vty partner connections.
155 */
156#define HVCS_MAX_SERVER_ADAPTERS 1024
157
158/*
159 * We let Linux assign us a major number and we start the minors at zero. There
160 * is no intuitive mapping between minor number and the target vty-server
161 * adapter except that each new vty-server adapter is always assigned to the
162 * smallest minor number available.
163 */
164#define HVCS_MINOR_START 0
165
166/*
167 * The hcall interface involves putting 8 chars into each of two registers.
168 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)
169 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a
170 * little (tiny) bit slower because an unaligned load is slower than aligned
171 * load.
172 */
173#define __ALIGNED__ __attribute__((__aligned__(8)))
174
175/*
176 * How much data can firmware send with each hvc_put_chars()? Maybe this
177 * should be moved into an architecture specific area.
178 */
179#define HVCS_BUFF_LEN 16
180
181/*
182 * This is the maximum amount of data we'll let the user send us (hvcs_write) at
183 * once in a chunk as a sanity check.
184 */
185#define HVCS_MAX_FROM_USER 4096
186
187/*
188 * Be careful when adding flags to this line discipline. Don't add anything
189 * that will cause echoing or we'll go into recursive loop echoing chars back
190 * and forth with the console drivers.
191 */
192static struct ktermios hvcs_tty_termios = {
193 .c_iflag = IGNBRK | IGNPAR,
194 .c_oflag = OPOST,
195 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
196 .c_cc = INIT_C_CC,
197 .c_ispeed = 38400,
198 .c_ospeed = 38400
199};
200
201/*
202 * This value is used to take the place of a command line parameter when the
203 * module is inserted. It starts as -1 and stays as such if the user doesn't
204 * specify a module insmod parameter. If they DO specify one then it is set to
205 * the value of the integer passed in.
206 */
207static int hvcs_parm_num_devs = -1;
208module_param(hvcs_parm_num_devs, int, 0);
209
210static const char hvcs_driver_name[] = "hvcs";
211static const char hvcs_device_node[] = "hvcs";
212static const char hvcs_driver_string[]
213 = "IBM hvcs (Hypervisor Virtual Console Server) Driver";
214
215/* Status of partner info rescan triggered via sysfs. */
216static int hvcs_rescan_status;
217
218static struct tty_driver *hvcs_tty_driver;
219
220/*
221 * In order to be somewhat sane this driver always associates the hvcs_struct
222 * index element with the numerically equal tty->index. This means that a
223 * hotplugged vty-server adapter will always map to the lowest index valued
224 * device node. If vty-servers were hotplug removed from the system and then
225 * new ones added the new vty-server may have the largest slot number of all
226 * the vty-server adapters in the partition but it may have the lowest dev node
227 * index of all the adapters due to the hole left by the hotplug removed
228 * adapter. There are a set of functions provided to get the lowest index for
229 * a new device as well as return the index to the list. This list is allocated
230 * with a number of elements equal to the number of device nodes requested when
231 * the module was inserted.
232 */
233static int *hvcs_index_list;
234
235/*
236 * How large is the list? This is kept for traversal since the list is
237 * dynamically created.
238 */
239static int hvcs_index_count;
240
241/*
242 * Used by the khvcsd to pick up I/O operations when the kernel_thread is
243 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.
244 */
245static int hvcs_kicked;
246
247/*
248 * Use by the kthread construct for task operations like waking the sleeping
249 * thread and stopping the kthread.
250 */
251static struct task_struct *hvcs_task;
252
253/*
254 * We allocate this for the use of all of the hvcs_structs when they fetch
255 * partner info.
256 */
257static unsigned long *hvcs_pi_buff;
258
259/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
260static DEFINE_SPINLOCK(hvcs_pi_lock);
261
262/* One vty-server per hvcs_struct */
263struct hvcs_struct {
264 struct tty_port port;
265 spinlock_t lock;
266
267 /*
268 * This index identifies this hvcs device as the complement to a
269 * specific tty index.
270 */
271 unsigned int index;
272
273 /*
274 * Used to tell the driver kernel_thread what operations need to take
275 * place upon this hvcs_struct instance.
276 */
277 int todo_mask;
278
279 /*
280 * This buffer is required so that when hvcs_write_room() reports that
281 * it can send HVCS_BUFF_LEN characters that it will buffer the full
282 * HVCS_BUFF_LEN characters if need be. This is essential for opost
283 * writes since they do not do high level buffering and expect to be
284 * able to send what the driver commits to sending buffering
285 * [e.g. tab to space conversions in n_tty.c opost()].
286 */
287 char buffer[HVCS_BUFF_LEN];
288 int chars_in_buffer;
289
290 /*
291 * Any variable below is valid before a tty is connected and
292 * stays valid after the tty is disconnected. These shouldn't be
293 * whacked until the kobject refcount reaches zero though some entries
294 * may be changed via sysfs initiatives.
295 */
296 int connected; /* is the vty-server currently connected to a vty? */
297 uint32_t p_unit_address; /* partner unit address */
298 uint32_t p_partition_ID; /* partner partition ID */
299 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
300 struct list_head next; /* list management */
301 struct vio_dev *vdev;
302};
303
304static LIST_HEAD(hvcs_structs);
305static DEFINE_SPINLOCK(hvcs_structs_lock);
306static DEFINE_MUTEX(hvcs_init_mutex);
307
308static void hvcs_unthrottle(struct tty_struct *tty);
309static void hvcs_throttle(struct tty_struct *tty);
310static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance);
311
312static int hvcs_write(struct tty_struct *tty,
313 const unsigned char *buf, int count);
314static int hvcs_write_room(struct tty_struct *tty);
315static int hvcs_chars_in_buffer(struct tty_struct *tty);
316
317static int hvcs_has_pi(struct hvcs_struct *hvcsd);
318static void hvcs_set_pi(struct hvcs_partner_info *pi,
319 struct hvcs_struct *hvcsd);
320static int hvcs_get_pi(struct hvcs_struct *hvcsd);
321static int hvcs_rescan_devices_list(void);
322
323static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
324static void hvcs_partner_free(struct hvcs_struct *hvcsd);
325
326static int hvcs_enable_device(struct hvcs_struct *hvcsd,
327 uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
328
329static int hvcs_open(struct tty_struct *tty, struct file *filp);
330static void hvcs_close(struct tty_struct *tty, struct file *filp);
331static void hvcs_hangup(struct tty_struct * tty);
332
333static int hvcs_probe(struct vio_dev *dev,
334 const struct vio_device_id *id);
335static int hvcs_remove(struct vio_dev *dev);
336static int __init hvcs_module_init(void);
337static void __exit hvcs_module_exit(void);
338static int hvcs_initialize(void);
339
340#define HVCS_SCHED_READ 0x00000001
341#define HVCS_QUICK_READ 0x00000002
342#define HVCS_TRY_WRITE 0x00000004
343#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
344
345static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
346{
347 return dev_get_drvdata(&viod->dev);
348}
349/* The sysfs interface for the driver and devices */
350
351static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
352{
353 struct vio_dev *viod = to_vio_dev(dev);
354 struct hvcs_struct *hvcsd = from_vio_dev(viod);
355 unsigned long flags;
356 int retval;
357
358 spin_lock_irqsave(&hvcsd->lock, flags);
359 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
360 spin_unlock_irqrestore(&hvcsd->lock, flags);
361 return retval;
362}
363static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
364
365static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
366{
367 struct vio_dev *viod = to_vio_dev(dev);
368 struct hvcs_struct *hvcsd = from_vio_dev(viod);
369 unsigned long flags;
370 int retval;
371
372 spin_lock_irqsave(&hvcsd->lock, flags);
373 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
374 spin_unlock_irqrestore(&hvcsd->lock, flags);
375 return retval;
376}
377static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
378
379static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
380 size_t count)
381{
382 /*
383 * Don't need this feature at the present time because firmware doesn't
384 * yet support multiple partners.
385 */
386 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
387 return -EPERM;
388}
389
390static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
391{
392 struct vio_dev *viod = to_vio_dev(dev);
393 struct hvcs_struct *hvcsd = from_vio_dev(viod);
394 unsigned long flags;
395 int retval;
396
397 spin_lock_irqsave(&hvcsd->lock, flags);
398 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
399 spin_unlock_irqrestore(&hvcsd->lock, flags);
400 return retval;
401}
402
403static DEVICE_ATTR(current_vty,
404 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
405
406static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
407 size_t count)
408{
409 struct vio_dev *viod = to_vio_dev(dev);
410 struct hvcs_struct *hvcsd = from_vio_dev(viod);
411 unsigned long flags;
412
413 /* writing a '0' to this sysfs entry will result in the disconnect. */
414 if (simple_strtol(buf, NULL, 0) != 0)
415 return -EINVAL;
416
417 spin_lock_irqsave(&hvcsd->lock, flags);
418
419 if (hvcsd->port.count > 0) {
420 spin_unlock_irqrestore(&hvcsd->lock, flags);
421 printk(KERN_INFO "HVCS: vterm state unchanged. "
422 "The hvcs device node is still in use.\n");
423 return -EPERM;
424 }
425
426 if (hvcsd->connected == 0) {
427 spin_unlock_irqrestore(&hvcsd->lock, flags);
428 printk(KERN_INFO "HVCS: vterm state unchanged. The"
429 " vty-server is not connected to a vty.\n");
430 return -EPERM;
431 }
432
433 hvcs_partner_free(hvcsd);
434 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
435 " partner vty@%X:%d connection.\n",
436 hvcsd->vdev->unit_address,
437 hvcsd->p_unit_address,
438 (uint32_t)hvcsd->p_partition_ID);
439
440 spin_unlock_irqrestore(&hvcsd->lock, flags);
441 return count;
442}
443
444static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
445{
446 struct vio_dev *viod = to_vio_dev(dev);
447 struct hvcs_struct *hvcsd = from_vio_dev(viod);
448 unsigned long flags;
449 int retval;
450
451 spin_lock_irqsave(&hvcsd->lock, flags);
452 retval = sprintf(buf, "%d\n", hvcsd->connected);
453 spin_unlock_irqrestore(&hvcsd->lock, flags);
454 return retval;
455}
456static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
457 hvcs_vterm_state_show, hvcs_vterm_state_store);
458
459static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
460{
461 struct vio_dev *viod = to_vio_dev(dev);
462 struct hvcs_struct *hvcsd = from_vio_dev(viod);
463 unsigned long flags;
464 int retval;
465
466 spin_lock_irqsave(&hvcsd->lock, flags);
467 retval = sprintf(buf, "%d\n", hvcsd->index);
468 spin_unlock_irqrestore(&hvcsd->lock, flags);
469 return retval;
470}
471
472static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
473
474static struct attribute *hvcs_attrs[] = {
475 &dev_attr_partner_vtys.attr,
476 &dev_attr_partner_clcs.attr,
477 &dev_attr_current_vty.attr,
478 &dev_attr_vterm_state.attr,
479 &dev_attr_index.attr,
480 NULL,
481};
482
483static struct attribute_group hvcs_attr_group = {
484 .attrs = hvcs_attrs,
485};
486
487static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
488{
489 /* A 1 means it is updating, a 0 means it is done updating */
490 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
491}
492
493static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
494 size_t count)
495{
496 if ((simple_strtol(buf, NULL, 0) != 1)
497 && (hvcs_rescan_status != 0))
498 return -EINVAL;
499
500 hvcs_rescan_status = 1;
501 printk(KERN_INFO "HVCS: rescanning partner info for all"
502 " vty-servers.\n");
503 hvcs_rescan_devices_list();
504 hvcs_rescan_status = 0;
505 return count;
506}
507
508static DRIVER_ATTR(rescan,
509 S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
510
511static void hvcs_kick(void)
512{
513 hvcs_kicked = 1;
514 wmb();
515 wake_up_process(hvcs_task);
516}
517
518static void hvcs_unthrottle(struct tty_struct *tty)
519{
520 struct hvcs_struct *hvcsd = tty->driver_data;
521 unsigned long flags;
522
523 spin_lock_irqsave(&hvcsd->lock, flags);
524 hvcsd->todo_mask |= HVCS_SCHED_READ;
525 spin_unlock_irqrestore(&hvcsd->lock, flags);
526 hvcs_kick();
527}
528
529static void hvcs_throttle(struct tty_struct *tty)
530{
531 struct hvcs_struct *hvcsd = tty->driver_data;
532 unsigned long flags;
533
534 spin_lock_irqsave(&hvcsd->lock, flags);
535 vio_disable_interrupts(hvcsd->vdev);
536 spin_unlock_irqrestore(&hvcsd->lock, flags);
537}
538
539/*
540 * If the device is being removed we don't have to worry about this interrupt
541 * handler taking any further interrupts because they are disabled which means
542 * the hvcs_struct will always be valid in this handler.
543 */
544static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
545{
546 struct hvcs_struct *hvcsd = dev_instance;
547
548 spin_lock(&hvcsd->lock);
549 vio_disable_interrupts(hvcsd->vdev);
550 hvcsd->todo_mask |= HVCS_SCHED_READ;
551 spin_unlock(&hvcsd->lock);
552 hvcs_kick();
553
554 return IRQ_HANDLED;
555}
556
557/* This function must be called with the hvcsd->lock held */
558static void hvcs_try_write(struct hvcs_struct *hvcsd)
559{
560 uint32_t unit_address = hvcsd->vdev->unit_address;
561 struct tty_struct *tty = hvcsd->port.tty;
562 int sent;
563
564 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
565 /* won't send partial writes */
566 sent = hvc_put_chars(unit_address,
567 &hvcsd->buffer[0],
568 hvcsd->chars_in_buffer );
569 if (sent > 0) {
570 hvcsd->chars_in_buffer = 0;
571 /* wmb(); */
572 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
573 /* wmb(); */
574
575 /*
576 * We are still obligated to deliver the data to the
577 * hypervisor even if the tty has been closed because
578 * we committed to delivering it. But don't try to wake
579 * a non-existent tty.
580 */
581 if (tty) {
582 tty_wakeup(tty);
583 }
584 }
585 }
586}
587
588static int hvcs_io(struct hvcs_struct *hvcsd)
589{
590 uint32_t unit_address;
591 struct tty_struct *tty;
592 char buf[HVCS_BUFF_LEN] __ALIGNED__;
593 unsigned long flags;
594 int got = 0;
595
596 spin_lock_irqsave(&hvcsd->lock, flags);
597
598 unit_address = hvcsd->vdev->unit_address;
599 tty = hvcsd->port.tty;
600
601 hvcs_try_write(hvcsd);
602
603 if (!tty || tty_throttled(tty)) {
604 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
605 goto bail;
606 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
607 goto bail;
608
609 /* remove the read masks */
610 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
611
612 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
613 got = hvc_get_chars(unit_address,
614 &buf[0],
615 HVCS_BUFF_LEN);
616 tty_insert_flip_string(&hvcsd->port, buf, got);
617 }
618
619 /* Give the TTY time to process the data we just sent. */
620 if (got)
621 hvcsd->todo_mask |= HVCS_QUICK_READ;
622
623 spin_unlock_irqrestore(&hvcsd->lock, flags);
624 /* This is synch because tty->low_latency == 1 */
625 if(got)
626 tty_flip_buffer_push(&hvcsd->port);
627
628 if (!got) {
629 /* Do this _after_ the flip_buffer_push */
630 spin_lock_irqsave(&hvcsd->lock, flags);
631 vio_enable_interrupts(hvcsd->vdev);
632 spin_unlock_irqrestore(&hvcsd->lock, flags);
633 }
634
635 return hvcsd->todo_mask;
636
637 bail:
638 spin_unlock_irqrestore(&hvcsd->lock, flags);
639 return hvcsd->todo_mask;
640}
641
642static int khvcsd(void *unused)
643{
644 struct hvcs_struct *hvcsd;
645 int hvcs_todo_mask;
646
647 __set_current_state(TASK_RUNNING);
648
649 do {
650 hvcs_todo_mask = 0;
651 hvcs_kicked = 0;
652 wmb();
653
654 spin_lock(&hvcs_structs_lock);
655 list_for_each_entry(hvcsd, &hvcs_structs, next) {
656 hvcs_todo_mask |= hvcs_io(hvcsd);
657 }
658 spin_unlock(&hvcs_structs_lock);
659
660 /*
661 * If any of the hvcs adapters want to try a write or quick read
662 * don't schedule(), yield a smidgen then execute the hvcs_io
663 * thread again for those that want the write.
664 */
665 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
666 yield();
667 continue;
668 }
669
670 set_current_state(TASK_INTERRUPTIBLE);
671 if (!hvcs_kicked)
672 schedule();
673 __set_current_state(TASK_RUNNING);
674 } while (!kthread_should_stop());
675
676 return 0;
677}
678
679static struct vio_device_id hvcs_driver_table[] = {
680 {"serial-server", "hvterm2"},
681 { "", "" }
682};
683MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
684
685static void hvcs_return_index(int index)
686{
687 /* Paranoia check */
688 if (!hvcs_index_list)
689 return;
690 if (index < 0 || index >= hvcs_index_count)
691 return;
692 if (hvcs_index_list[index] == -1)
693 return;
694 else
695 hvcs_index_list[index] = -1;
696}
697
698static void hvcs_destruct_port(struct tty_port *p)
699{
700 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
701 struct vio_dev *vdev;
702 unsigned long flags;
703
704 spin_lock(&hvcs_structs_lock);
705 spin_lock_irqsave(&hvcsd->lock, flags);
706
707 /* the list_del poisons the pointers */
708 list_del(&(hvcsd->next));
709
710 if (hvcsd->connected == 1) {
711 hvcs_partner_free(hvcsd);
712 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
713 " partner vty@%X:%d connection.\n",
714 hvcsd->vdev->unit_address,
715 hvcsd->p_unit_address,
716 (uint32_t)hvcsd->p_partition_ID);
717 }
718 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
719 hvcsd->vdev->unit_address);
720
721 vdev = hvcsd->vdev;
722 hvcsd->vdev = NULL;
723
724 hvcsd->p_unit_address = 0;
725 hvcsd->p_partition_ID = 0;
726 hvcs_return_index(hvcsd->index);
727 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
728
729 spin_unlock_irqrestore(&hvcsd->lock, flags);
730 spin_unlock(&hvcs_structs_lock);
731
732 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
733
734 kfree(hvcsd);
735}
736
737static const struct tty_port_operations hvcs_port_ops = {
738 .destruct = hvcs_destruct_port,
739};
740
741static int hvcs_get_index(void)
742{
743 int i;
744 /* Paranoia check */
745 if (!hvcs_index_list) {
746 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
747 return -EFAULT;
748 }
749 /* Find the numerically lowest first free index. */
750 for(i = 0; i < hvcs_index_count; i++) {
751 if (hvcs_index_list[i] == -1) {
752 hvcs_index_list[i] = 0;
753 return i;
754 }
755 }
756 return -1;
757}
758
759static int hvcs_probe(
760 struct vio_dev *dev,
761 const struct vio_device_id *id)
762{
763 struct hvcs_struct *hvcsd;
764 int index, rc;
765 int retval;
766
767 if (!dev || !id) {
768 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
769 return -EPERM;
770 }
771
772 /* Make sure we are properly initialized */
773 rc = hvcs_initialize();
774 if (rc) {
775 pr_err("HVCS: Failed to initialize core driver.\n");
776 return rc;
777 }
778
779 /* early to avoid cleanup on failure */
780 index = hvcs_get_index();
781 if (index < 0) {
782 return -EFAULT;
783 }
784
785 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
786 if (!hvcsd)
787 return -ENODEV;
788
789 tty_port_init(&hvcsd->port);
790 hvcsd->port.ops = &hvcs_port_ops;
791 spin_lock_init(&hvcsd->lock);
792
793 hvcsd->vdev = dev;
794 dev_set_drvdata(&dev->dev, hvcsd);
795
796 hvcsd->index = index;
797
798 /* hvcsd->index = ++hvcs_struct_count; */
799 hvcsd->chars_in_buffer = 0;
800 hvcsd->todo_mask = 0;
801 hvcsd->connected = 0;
802
803 /*
804 * This will populate the hvcs_struct's partner info fields for the
805 * first time.
806 */
807 if (hvcs_get_pi(hvcsd)) {
808 printk(KERN_ERR "HVCS: Failed to fetch partner"
809 " info for vty-server@%X on device probe.\n",
810 hvcsd->vdev->unit_address);
811 }
812
813 /*
814 * If a user app opens a tty that corresponds to this vty-server before
815 * the hvcs_struct has been added to the devices list then the user app
816 * will get -ENODEV.
817 */
818 spin_lock(&hvcs_structs_lock);
819 list_add_tail(&(hvcsd->next), &hvcs_structs);
820 spin_unlock(&hvcs_structs_lock);
821
822 retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group);
823 if (retval) {
824 printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n",
825 hvcsd->vdev->unit_address);
826 return retval;
827 }
828
829 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
830
831 /*
832 * DON'T enable interrupts here because there is no user to receive the
833 * data.
834 */
835 return 0;
836}
837
838static int hvcs_remove(struct vio_dev *dev)
839{
840 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
841 unsigned long flags;
842 struct tty_struct *tty;
843
844 if (!hvcsd)
845 return -ENODEV;
846
847 /* By this time the vty-server won't be getting any more interrupts */
848
849 spin_lock_irqsave(&hvcsd->lock, flags);
850
851 tty = hvcsd->port.tty;
852
853 spin_unlock_irqrestore(&hvcsd->lock, flags);
854
855 /*
856 * Let the last holder of this object cause it to be removed, which
857 * would probably be tty_hangup below.
858 */
859 tty_port_put(&hvcsd->port);
860
861 /*
862 * The hangup is a scheduled function which will auto chain call
863 * hvcs_hangup. The tty should always be valid at this time unless a
864 * simultaneous tty close already cleaned up the hvcs_struct.
865 */
866 if (tty)
867 tty_hangup(tty);
868
869 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
870 " vio bus.\n", dev->unit_address);
871 return 0;
872};
873
874static struct vio_driver hvcs_vio_driver = {
875 .id_table = hvcs_driver_table,
876 .probe = hvcs_probe,
877 .remove = hvcs_remove,
878 .name = hvcs_driver_name,
879};
880
881/* Only called from hvcs_get_pi please */
882static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
883{
884 hvcsd->p_unit_address = pi->unit_address;
885 hvcsd->p_partition_ID = pi->partition_ID;
886
887 /* copy the null-term char too */
888 strlcpy(&hvcsd->p_location_code[0],
889 &pi->location_code[0], sizeof(hvcsd->p_location_code));
890}
891
892/*
893 * Traverse the list and add the partner info that is found to the hvcs_struct
894 * struct entry. NOTE: At this time I know that partner info will return a
895 * single entry but in the future there may be multiple partner info entries per
896 * vty-server and you'll want to zero out that list and reset it. If for some
897 * reason you have an old version of this driver but there IS more than one
898 * partner info then hvcsd->p_* will hold the last partner info data from the
899 * firmware query. A good way to update this code would be to replace the three
900 * partner info fields in hvcs_struct with a list of hvcs_partner_info
901 * instances.
902 *
903 * This function must be called with the hvcsd->lock held.
904 */
905static int hvcs_get_pi(struct hvcs_struct *hvcsd)
906{
907 struct hvcs_partner_info *pi;
908 uint32_t unit_address = hvcsd->vdev->unit_address;
909 struct list_head head;
910 int retval;
911
912 spin_lock(&hvcs_pi_lock);
913 if (!hvcs_pi_buff) {
914 spin_unlock(&hvcs_pi_lock);
915 return -EFAULT;
916 }
917 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
918 spin_unlock(&hvcs_pi_lock);
919 if (retval) {
920 printk(KERN_ERR "HVCS: Failed to fetch partner"
921 " info for vty-server@%x.\n", unit_address);
922 return retval;
923 }
924
925 /* nixes the values if the partner vty went away */
926 hvcsd->p_unit_address = 0;
927 hvcsd->p_partition_ID = 0;
928
929 list_for_each_entry(pi, &head, node)
930 hvcs_set_pi(pi, hvcsd);
931
932 hvcs_free_partner_info(&head);
933 return 0;
934}
935
936/*
937 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
938 * be executed elsewhere, in order to prevent deadlock issues.
939 */
940static int hvcs_rescan_devices_list(void)
941{
942 struct hvcs_struct *hvcsd;
943 unsigned long flags;
944
945 spin_lock(&hvcs_structs_lock);
946
947 list_for_each_entry(hvcsd, &hvcs_structs, next) {
948 spin_lock_irqsave(&hvcsd->lock, flags);
949 hvcs_get_pi(hvcsd);
950 spin_unlock_irqrestore(&hvcsd->lock, flags);
951 }
952
953 spin_unlock(&hvcs_structs_lock);
954
955 return 0;
956}
957
958/*
959 * Farm this off into its own function because it could be more complex once
960 * multiple partners support is added. This function should be called with
961 * the hvcsd->lock held.
962 */
963static int hvcs_has_pi(struct hvcs_struct *hvcsd)
964{
965 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
966 return 0;
967 return 1;
968}
969
970/*
971 * NOTE: It is possible that the super admin removed a partner vty and then
972 * added a different vty as the new partner.
973 *
974 * This function must be called with the hvcsd->lock held.
975 */
976static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
977{
978 int retval;
979 unsigned int unit_address = hvcsd->vdev->unit_address;
980
981 /*
982 * If there wasn't any pi when the device was added it doesn't meant
983 * there isn't any now. This driver isn't notified when a new partner
984 * vty is added to a vty-server so we discover changes on our own.
985 * Please see comments in hvcs_register_connection() for justification
986 * of this bizarre code.
987 */
988 retval = hvcs_register_connection(unit_address,
989 hvcsd->p_partition_ID,
990 hvcsd->p_unit_address);
991 if (!retval) {
992 hvcsd->connected = 1;
993 return 0;
994 } else if (retval != -EINVAL)
995 return retval;
996
997 /*
998 * As per the spec re-get the pi and try again if -EINVAL after the
999 * first connection attempt.
1000 */
1001 if (hvcs_get_pi(hvcsd))
1002 return -ENOMEM;
1003
1004 if (!hvcs_has_pi(hvcsd))
1005 return -ENODEV;
1006
1007 retval = hvcs_register_connection(unit_address,
1008 hvcsd->p_partition_ID,
1009 hvcsd->p_unit_address);
1010 if (retval != -EINVAL) {
1011 hvcsd->connected = 1;
1012 return retval;
1013 }
1014
1015 /*
1016 * EBUSY is the most likely scenario though the vty could have been
1017 * removed or there really could be an hcall error due to the parameter
1018 * data but thanks to ambiguous firmware return codes we can't really
1019 * tell.
1020 */
1021 printk(KERN_INFO "HVCS: vty-server or partner"
1022 " vty is busy. Try again later.\n");
1023 return -EBUSY;
1024}
1025
1026/* This function must be called with the hvcsd->lock held */
1027static void hvcs_partner_free(struct hvcs_struct *hvcsd)
1028{
1029 int retval;
1030 do {
1031 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
1032 } while (retval == -EBUSY);
1033 hvcsd->connected = 0;
1034}
1035
1036/* This helper function must be called WITHOUT the hvcsd->lock held */
1037static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
1038 unsigned int irq, struct vio_dev *vdev)
1039{
1040 unsigned long flags;
1041 int rc;
1042
1043 /*
1044 * It is possible that the vty-server was removed between the time that
1045 * the conn was registered and now.
1046 */
1047 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd);
1048 if (!rc) {
1049 /*
1050 * It is possible the vty-server was removed after the irq was
1051 * requested but before we have time to enable interrupts.
1052 */
1053 if (vio_enable_interrupts(vdev) == H_SUCCESS)
1054 return 0;
1055 else {
1056 printk(KERN_ERR "HVCS: int enable failed for"
1057 " vty-server@%X.\n", unit_address);
1058 free_irq(irq, hvcsd);
1059 }
1060 } else
1061 printk(KERN_ERR "HVCS: irq req failed for"
1062 " vty-server@%X.\n", unit_address);
1063
1064 spin_lock_irqsave(&hvcsd->lock, flags);
1065 hvcs_partner_free(hvcsd);
1066 spin_unlock_irqrestore(&hvcsd->lock, flags);
1067
1068 return rc;
1069
1070}
1071
1072/*
1073 * This always increments the kref ref count if the call is successful.
1074 * Please remember to dec when you are done with the instance.
1075 *
1076 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
1077 * calling this function or you will get deadlock.
1078 */
1079static struct hvcs_struct *hvcs_get_by_index(int index)
1080{
1081 struct hvcs_struct *hvcsd;
1082 unsigned long flags;
1083
1084 spin_lock(&hvcs_structs_lock);
1085 list_for_each_entry(hvcsd, &hvcs_structs, next) {
1086 spin_lock_irqsave(&hvcsd->lock, flags);
1087 if (hvcsd->index == index) {
1088 tty_port_get(&hvcsd->port);
1089 spin_unlock_irqrestore(&hvcsd->lock, flags);
1090 spin_unlock(&hvcs_structs_lock);
1091 return hvcsd;
1092 }
1093 spin_unlock_irqrestore(&hvcsd->lock, flags);
1094 }
1095 spin_unlock(&hvcs_structs_lock);
1096
1097 return NULL;
1098}
1099
1100static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty)
1101{
1102 struct hvcs_struct *hvcsd;
1103 struct vio_dev *vdev;
1104 unsigned long unit_address, flags;
1105 unsigned int irq;
1106 int retval;
1107
1108 /*
1109 * Is there a vty-server that shares the same index?
1110 * This function increments the kref index.
1111 */
1112 hvcsd = hvcs_get_by_index(tty->index);
1113 if (!hvcsd) {
1114 printk(KERN_WARNING "HVCS: open failed, no device associated"
1115 " with tty->index %d.\n", tty->index);
1116 return -ENODEV;
1117 }
1118
1119 spin_lock_irqsave(&hvcsd->lock, flags);
1120
1121 if (hvcsd->connected == 0) {
1122 retval = hvcs_partner_connect(hvcsd);
1123 if (retval) {
1124 spin_unlock_irqrestore(&hvcsd->lock, flags);
1125 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1126 goto err_put;
1127 }
1128 }
1129
1130 hvcsd->port.count = 0;
1131 hvcsd->port.tty = tty;
1132 tty->driver_data = hvcsd;
1133
1134 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1135
1136 /*
1137 * Save these in the spinlock for the enable operations that need them
1138 * outside of the spinlock.
1139 */
1140 irq = hvcsd->vdev->irq;
1141 vdev = hvcsd->vdev;
1142 unit_address = hvcsd->vdev->unit_address;
1143
1144 hvcsd->todo_mask |= HVCS_SCHED_READ;
1145 spin_unlock_irqrestore(&hvcsd->lock, flags);
1146
1147 /*
1148 * This must be done outside of the spinlock because it requests irqs
1149 * and will grab the spinlock and free the connection if it fails.
1150 */
1151 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev);
1152 if (retval) {
1153 printk(KERN_WARNING "HVCS: enable device failed.\n");
1154 goto err_put;
1155 }
1156
1157 retval = tty_port_install(&hvcsd->port, driver, tty);
1158 if (retval)
1159 goto err_irq;
1160
1161 return 0;
1162err_irq:
1163 spin_lock_irqsave(&hvcsd->lock, flags);
1164 vio_disable_interrupts(hvcsd->vdev);
1165 spin_unlock_irqrestore(&hvcsd->lock, flags);
1166 free_irq(irq, hvcsd);
1167err_put:
1168 tty_port_put(&hvcsd->port);
1169
1170 return retval;
1171}
1172
1173/*
1174 * This is invoked via the tty_open interface when a user app connects to the
1175 * /dev node.
1176 */
1177static int hvcs_open(struct tty_struct *tty, struct file *filp)
1178{
1179 struct hvcs_struct *hvcsd = tty->driver_data;
1180 unsigned long flags;
1181
1182 spin_lock_irqsave(&hvcsd->lock, flags);
1183 hvcsd->port.count++;
1184 hvcsd->todo_mask |= HVCS_SCHED_READ;
1185 spin_unlock_irqrestore(&hvcsd->lock, flags);
1186
1187 hvcs_kick();
1188
1189 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1190 hvcsd->vdev->unit_address );
1191
1192 return 0;
1193}
1194
1195static void hvcs_close(struct tty_struct *tty, struct file *filp)
1196{
1197 struct hvcs_struct *hvcsd;
1198 unsigned long flags;
1199 int irq;
1200
1201 /*
1202 * Is someone trying to close the file associated with this device after
1203 * we have hung up? If so tty->driver_data wouldn't be valid.
1204 */
1205 if (tty_hung_up_p(filp))
1206 return;
1207
1208 /*
1209 * No driver_data means that this close was probably issued after a
1210 * failed hvcs_open by the tty layer's release_dev() api and we can just
1211 * exit cleanly.
1212 */
1213 if (!tty->driver_data)
1214 return;
1215
1216 hvcsd = tty->driver_data;
1217
1218 spin_lock_irqsave(&hvcsd->lock, flags);
1219 if (--hvcsd->port.count == 0) {
1220
1221 vio_disable_interrupts(hvcsd->vdev);
1222
1223 /*
1224 * NULL this early so that the kernel_thread doesn't try to
1225 * execute any operations on the TTY even though it is obligated
1226 * to deliver any pending I/O to the hypervisor.
1227 */
1228 hvcsd->port.tty = NULL;
1229
1230 irq = hvcsd->vdev->irq;
1231 spin_unlock_irqrestore(&hvcsd->lock, flags);
1232
1233 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1234
1235 /*
1236 * This line is important because it tells hvcs_open that this
1237 * device needs to be re-configured the next time hvcs_open is
1238 * called.
1239 */
1240 tty->driver_data = NULL;
1241
1242 free_irq(irq, hvcsd);
1243 return;
1244 } else if (hvcsd->port.count < 0) {
1245 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
1246 " is missmanaged.\n",
1247 hvcsd->vdev->unit_address, hvcsd->port.count);
1248 }
1249
1250 spin_unlock_irqrestore(&hvcsd->lock, flags);
1251}
1252
1253static void hvcs_cleanup(struct tty_struct * tty)
1254{
1255 struct hvcs_struct *hvcsd = tty->driver_data;
1256
1257 tty_port_put(&hvcsd->port);
1258}
1259
1260static void hvcs_hangup(struct tty_struct * tty)
1261{
1262 struct hvcs_struct *hvcsd = tty->driver_data;
1263 unsigned long flags;
1264 int temp_open_count;
1265 int irq;
1266
1267 spin_lock_irqsave(&hvcsd->lock, flags);
1268 /* Preserve this so that we know how many kref refs to put */
1269 temp_open_count = hvcsd->port.count;
1270
1271 /*
1272 * Don't kref put inside the spinlock because the destruction
1273 * callback may use the spinlock and it may get called before the
1274 * spinlock has been released.
1275 */
1276 vio_disable_interrupts(hvcsd->vdev);
1277
1278 hvcsd->todo_mask = 0;
1279
1280 /* I don't think the tty needs the hvcs_struct pointer after a hangup */
1281 tty->driver_data = NULL;
1282 hvcsd->port.tty = NULL;
1283
1284 hvcsd->port.count = 0;
1285
1286 /* This will drop any buffered data on the floor which is OK in a hangup
1287 * scenario. */
1288 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1289 hvcsd->chars_in_buffer = 0;
1290
1291 irq = hvcsd->vdev->irq;
1292
1293 spin_unlock_irqrestore(&hvcsd->lock, flags);
1294
1295 free_irq(irq, hvcsd);
1296
1297 /*
1298 * We need to kref_put() for every open_count we have since the
1299 * tty_hangup() function doesn't invoke a close per open connection on a
1300 * non-console device.
1301 */
1302 while(temp_open_count) {
1303 --temp_open_count;
1304 /*
1305 * The final put will trigger destruction of the hvcs_struct.
1306 * NOTE: If this hangup was signaled from user space then the
1307 * final put will never happen.
1308 */
1309 tty_port_put(&hvcsd->port);
1310 }
1311}
1312
1313/*
1314 * NOTE: This is almost always from_user since user level apps interact with the
1315 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1316 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1317 * tty_hangup will allow hvcs_write time to complete execution before it
1318 * terminates our device.
1319 */
1320static int hvcs_write(struct tty_struct *tty,
1321 const unsigned char *buf, int count)
1322{
1323 struct hvcs_struct *hvcsd = tty->driver_data;
1324 unsigned int unit_address;
1325 const unsigned char *charbuf;
1326 unsigned long flags;
1327 int total_sent = 0;
1328 int tosend = 0;
1329 int result = 0;
1330
1331 /*
1332 * If they don't check the return code off of their open they may
1333 * attempt this even if there is no connected device.
1334 */
1335 if (!hvcsd)
1336 return -ENODEV;
1337
1338 /* Reasonable size to prevent user level flooding */
1339 if (count > HVCS_MAX_FROM_USER) {
1340 printk(KERN_WARNING "HVCS write: count being truncated to"
1341 " HVCS_MAX_FROM_USER.\n");
1342 count = HVCS_MAX_FROM_USER;
1343 }
1344
1345 charbuf = buf;
1346
1347 spin_lock_irqsave(&hvcsd->lock, flags);
1348
1349 /*
1350 * Somehow an open succeeded but the device was removed or the
1351 * connection terminated between the vty-server and partner vty during
1352 * the middle of a write operation? This is a crummy place to do this
1353 * but we want to keep it all in the spinlock.
1354 */
1355 if (hvcsd->port.count <= 0) {
1356 spin_unlock_irqrestore(&hvcsd->lock, flags);
1357 return -ENODEV;
1358 }
1359
1360 unit_address = hvcsd->vdev->unit_address;
1361
1362 while (count > 0) {
1363 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1364 /*
1365 * No more space, this probably means that the last call to
1366 * hvcs_write() didn't succeed and the buffer was filled up.
1367 */
1368 if (!tosend)
1369 break;
1370
1371 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1372 &charbuf[total_sent],
1373 tosend);
1374
1375 hvcsd->chars_in_buffer += tosend;
1376
1377 result = 0;
1378
1379 /*
1380 * If this is true then we don't want to try writing to the
1381 * hypervisor because that is the kernel_threads job now. We'll
1382 * just add to the buffer.
1383 */
1384 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1385 /* won't send partial writes */
1386 result = hvc_put_chars(unit_address,
1387 &hvcsd->buffer[0],
1388 hvcsd->chars_in_buffer);
1389
1390 /*
1391 * Since we know we have enough room in hvcsd->buffer for
1392 * tosend we record that it was sent regardless of whether the
1393 * hypervisor actually took it because we have it buffered.
1394 */
1395 total_sent+=tosend;
1396 count-=tosend;
1397 if (result == 0) {
1398 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1399 hvcs_kick();
1400 break;
1401 }
1402
1403 hvcsd->chars_in_buffer = 0;
1404 /*
1405 * Test after the chars_in_buffer reset otherwise this could
1406 * deadlock our writes if hvc_put_chars fails.
1407 */
1408 if (result < 0)
1409 break;
1410 }
1411
1412 spin_unlock_irqrestore(&hvcsd->lock, flags);
1413
1414 if (result == -1)
1415 return -EIO;
1416 else
1417 return total_sent;
1418}
1419
1420/*
1421 * This is really asking how much can we guarantee that we can send or that we
1422 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1423 * return value, hence the reason for hvcs_struct buffering.
1424 */
1425static int hvcs_write_room(struct tty_struct *tty)
1426{
1427 struct hvcs_struct *hvcsd = tty->driver_data;
1428
1429 if (!hvcsd || hvcsd->port.count <= 0)
1430 return 0;
1431
1432 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1433}
1434
1435static int hvcs_chars_in_buffer(struct tty_struct *tty)
1436{
1437 struct hvcs_struct *hvcsd = tty->driver_data;
1438
1439 return hvcsd->chars_in_buffer;
1440}
1441
1442static const struct tty_operations hvcs_ops = {
1443 .install = hvcs_install,
1444 .open = hvcs_open,
1445 .close = hvcs_close,
1446 .cleanup = hvcs_cleanup,
1447 .hangup = hvcs_hangup,
1448 .write = hvcs_write,
1449 .write_room = hvcs_write_room,
1450 .chars_in_buffer = hvcs_chars_in_buffer,
1451 .unthrottle = hvcs_unthrottle,
1452 .throttle = hvcs_throttle,
1453};
1454
1455static int hvcs_alloc_index_list(int n)
1456{
1457 int i;
1458
1459 hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL);
1460 if (!hvcs_index_list)
1461 return -ENOMEM;
1462 hvcs_index_count = n;
1463 for (i = 0; i < hvcs_index_count; i++)
1464 hvcs_index_list[i] = -1;
1465 return 0;
1466}
1467
1468static void hvcs_free_index_list(void)
1469{
1470 /* Paranoia check to be thorough. */
1471 kfree(hvcs_index_list);
1472 hvcs_index_list = NULL;
1473 hvcs_index_count = 0;
1474}
1475
1476static int hvcs_initialize(void)
1477{
1478 int rc, num_ttys_to_alloc;
1479
1480 mutex_lock(&hvcs_init_mutex);
1481 if (hvcs_task) {
1482 mutex_unlock(&hvcs_init_mutex);
1483 return 0;
1484 }
1485
1486 /* Has the user specified an overload with an insmod param? */
1487 if (hvcs_parm_num_devs <= 0 ||
1488 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1489 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1490 } else
1491 num_ttys_to_alloc = hvcs_parm_num_devs;
1492
1493 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
1494 if (!hvcs_tty_driver) {
1495 mutex_unlock(&hvcs_init_mutex);
1496 return -ENOMEM;
1497 }
1498
1499 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
1500 rc = -ENOMEM;
1501 goto index_fail;
1502 }
1503
1504 hvcs_tty_driver->driver_name = hvcs_driver_name;
1505 hvcs_tty_driver->name = hvcs_device_node;
1506
1507 /*
1508 * We'll let the system assign us a major number, indicated by leaving
1509 * it blank.
1510 */
1511
1512 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1513 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1514
1515 /*
1516 * We role our own so that we DONT ECHO. We can't echo because the
1517 * device we are connecting to already echoes by default and this would
1518 * throw us into a horrible recursive echo-echo-echo loop.
1519 */
1520 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1521 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;
1522
1523 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1524
1525 /*
1526 * The following call will result in sysfs entries that denote the
1527 * dynamically assigned major and minor numbers for our devices.
1528 */
1529 if (tty_register_driver(hvcs_tty_driver)) {
1530 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
1531 rc = -EIO;
1532 goto register_fail;
1533 }
1534
1535 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL);
1536 if (!hvcs_pi_buff) {
1537 rc = -ENOMEM;
1538 goto buff_alloc_fail;
1539 }
1540
1541 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1542 if (IS_ERR(hvcs_task)) {
1543 printk(KERN_ERR "HVCS: khvcsd creation failed.\n");
1544 rc = -EIO;
1545 goto kthread_fail;
1546 }
1547 mutex_unlock(&hvcs_init_mutex);
1548 return 0;
1549
1550kthread_fail:
1551 free_page((unsigned long)hvcs_pi_buff);
1552buff_alloc_fail:
1553 tty_unregister_driver(hvcs_tty_driver);
1554register_fail:
1555 hvcs_free_index_list();
1556index_fail:
1557 put_tty_driver(hvcs_tty_driver);
1558 hvcs_tty_driver = NULL;
1559 mutex_unlock(&hvcs_init_mutex);
1560 return rc;
1561}
1562
1563static int __init hvcs_module_init(void)
1564{
1565 int rc = vio_register_driver(&hvcs_vio_driver);
1566 if (rc) {
1567 printk(KERN_ERR "HVCS: can't register vio driver\n");
1568 return rc;
1569 }
1570
1571 pr_info("HVCS: Driver registered.\n");
1572
1573 /* This needs to be done AFTER the vio_register_driver() call or else
1574 * the kobjects won't be initialized properly.
1575 */
1576 rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan);
1577 if (rc)
1578 pr_warning("HVCS: Failed to create rescan file (err %d)\n", rc);
1579
1580 return 0;
1581}
1582
1583static void __exit hvcs_module_exit(void)
1584{
1585 /*
1586 * This driver receives hvcs_remove callbacks for each device upon
1587 * module removal.
1588 */
1589 vio_unregister_driver(&hvcs_vio_driver);
1590 if (!hvcs_task)
1591 return;
1592
1593 /*
1594 * This synchronous operation will wake the khvcsd kthread if it is
1595 * asleep and will return when khvcsd has terminated.
1596 */
1597 kthread_stop(hvcs_task);
1598
1599 spin_lock(&hvcs_pi_lock);
1600 free_page((unsigned long)hvcs_pi_buff);
1601 hvcs_pi_buff = NULL;
1602 spin_unlock(&hvcs_pi_lock);
1603
1604 driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
1605
1606 tty_unregister_driver(hvcs_tty_driver);
1607
1608 hvcs_free_index_list();
1609
1610 put_tty_driver(hvcs_tty_driver);
1611
1612 printk(KERN_INFO "HVCS: driver module removed.\n");
1613}
1614
1615module_init(hvcs_module_init);
1616module_exit(hvcs_module_exit);