blob: f7ac31856572a141b328a5b94ca43035978bcc36 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 kobject construct. This kobject is also used by
61 * the vio bus to provide a vio device sysfs entry that this driver attaches
62 * device specific attributes to, including partner information. The vio bus
63 * framework also provides a sysfs entry for each vio driver. The hvcs driver
64 * provides driver attributes in this entry.
65 *
66 * For direction on installation and usage of this driver please reference
67 * Documentation/powerpc/hvcs.txt.
68 */
69
70#include <linux/device.h>
71#include <linux/init.h>
72#include <linux/interrupt.h>
73#include <linux/kernel.h>
74#include <linux/kobject.h>
75#include <linux/kthread.h>
76#include <linux/list.h>
77#include <linux/major.h>
78#include <linux/module.h>
79#include <linux/moduleparam.h>
80#include <linux/sched.h>
81#include <linux/spinlock.h>
82#include <linux/stat.h>
83#include <linux/tty.h>
84#include <linux/tty_flip.h>
85#include <asm/hvconsole.h>
86#include <asm/hvcserver.h>
87#include <asm/uaccess.h>
88#include <asm/vio.h>
89
90/*
91 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
92 * Removed braces around single statements following conditionals. Removed '=
93 * 0' after static int declarations since these default to zero. Removed
94 * list_for_each_safe() and replaced with list_for_each_entry() in
95 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
96 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
97 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
98 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
99 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
100 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
101 * list traversals from a deletion. Removed '= NULL' from pointer declaration
102 * statements since they are initialized NULL by default. Removed wmb()
103 * instances from hvcs_try_write(). They probably aren't needed with locking in
104 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
105 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
106 * the coupling between /dev/hvcs* and a vty-server can be automatically
107 * determined. Moved kobject_put() in hvcs_open outside of the
108 * spin_unlock_irqrestore().
109 *
110 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
111 * align with how the tty layer always assigns the lowest index available. This
112 * change resulted in a list of ints that denotes which indexes are available.
113 * Device additions and removals use the new hvcs_get_index() and
114 * hvcs_return_index() helper functions. The list is created with
115 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
116 * Without these fixes hotplug vty-server adapter support goes crazy with this
117 * driver if the user removes a vty-server adapter. Moved free_irq() outside of
118 * the hvcs_final_close() function in order to get it out of the spinlock.
119 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
120 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
Jon Mason2ef94812006-01-23 10:58:20 -0600121 * include/asm-powerpc/hvcserver.h
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 *
123 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
124 * prevent possible lockup with realtime scheduling as similarily pointed out by
125 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
126 * to reorder cleanup operations and prevent discarding of pending data during
127 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
128 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
129 */
130
131#define HVCS_DRIVER_VERSION "1.3.3"
132
133MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
134MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
135MODULE_LICENSE("GPL");
136MODULE_VERSION(HVCS_DRIVER_VERSION);
137
138/*
139 * Wait this long per iteration while trying to push buffered data to the
140 * hypervisor before allowing the tty to complete a close operation.
141 */
142#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
143
144/*
145 * Since the Linux TTY code does not currently (2-04-2004) support dynamic
146 * addition of tty derived devices and we shouldn't allocate thousands of
147 * tty_device pointers when the number of vty-server & vty partner connections
148 * will most often be much lower than this, we'll arbitrarily allocate
149 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
150 * register the tty_driver. This can be overridden using an insmod parameter.
151 */
152#define HVCS_DEFAULT_SERVER_ADAPTERS 64
153
154/*
155 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
156 * nodes as a sanity check. Theoretically there can be over 1 Billion
157 * vty-server & vty partner connections.
158 */
159#define HVCS_MAX_SERVER_ADAPTERS 1024
160
161/*
162 * We let Linux assign us a major number and we start the minors at zero. There
163 * is no intuitive mapping between minor number and the target vty-server
164 * adapter except that each new vty-server adapter is always assigned to the
165 * smallest minor number available.
166 */
167#define HVCS_MINOR_START 0
168
169/*
170 * The hcall interface involves putting 8 chars into each of two registers.
Jon Mason2ef94812006-01-23 10:58:20 -0600171 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)
172 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a
173 * little (tiny) bit slower because an unaligned load is slower than aligned
174 * load.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 */
176#define __ALIGNED__ __attribute__((__aligned__(8)))
177
178/*
179 * How much data can firmware send with each hvc_put_chars()? Maybe this
180 * should be moved into an architecture specific area.
181 */
182#define HVCS_BUFF_LEN 16
183
184/*
185 * This is the maximum amount of data we'll let the user send us (hvcs_write) at
186 * once in a chunk as a sanity check.
187 */
188#define HVCS_MAX_FROM_USER 4096
189
190/*
191 * Be careful when adding flags to this line discipline. Don't add anything
192 * that will cause echoing or we'll go into recursive loop echoing chars back
193 * and forth with the console drivers.
194 */
195static struct termios hvcs_tty_termios = {
196 .c_iflag = IGNBRK | IGNPAR,
197 .c_oflag = OPOST,
198 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
199 .c_cc = INIT_C_CC
200};
201
202/*
203 * This value is used to take the place of a command line parameter when the
204 * module is inserted. It starts as -1 and stays as such if the user doesn't
205 * specify a module insmod parameter. If they DO specify one then it is set to
206 * the value of the integer passed in.
207 */
208static int hvcs_parm_num_devs = -1;
209module_param(hvcs_parm_num_devs, int, 0);
210
211char hvcs_driver_name[] = "hvcs";
212char hvcs_device_node[] = "hvcs";
213char hvcs_driver_string[]
214 = "IBM hvcs (Hypervisor Virtual Console Server) Driver";
215
216/* Status of partner info rescan triggered via sysfs. */
217static int hvcs_rescan_status;
218
219static struct tty_driver *hvcs_tty_driver;
220
221/*
222 * In order to be somewhat sane this driver always associates the hvcs_struct
223 * index element with the numerically equal tty->index. This means that a
224 * hotplugged vty-server adapter will always map to the lowest index valued
225 * device node. If vty-servers were hotplug removed from the system and then
226 * new ones added the new vty-server may have the largest slot number of all
227 * the vty-server adapters in the partition but it may have the lowest dev node
228 * index of all the adapters due to the hole left by the hotplug removed
229 * adapter. There are a set of functions provided to get the lowest index for
230 * a new device as well as return the index to the list. This list is allocated
231 * with a number of elements equal to the number of device nodes requested when
232 * the module was inserted.
233 */
234static int *hvcs_index_list;
235
236/*
237 * How large is the list? This is kept for traversal since the list is
238 * dynamically created.
239 */
240static int hvcs_index_count;
241
242/*
243 * Used by the khvcsd to pick up I/O operations when the kernel_thread is
244 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.
245 */
246static int hvcs_kicked;
247
248/*
249 * Use by the kthread construct for task operations like waking the sleeping
250 * thread and stopping the kthread.
251 */
252static struct task_struct *hvcs_task;
253
254/*
255 * We allocate this for the use of all of the hvcs_structs when they fetch
256 * partner info.
257 */
258static unsigned long *hvcs_pi_buff;
259
260/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
261static DEFINE_SPINLOCK(hvcs_pi_lock);
262
263/* One vty-server per hvcs_struct */
264struct hvcs_struct {
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 struct tty_struct *tty;
274 unsigned int open_count;
275
276 /*
277 * Used to tell the driver kernel_thread what operations need to take
278 * place upon this hvcs_struct instance.
279 */
280 int todo_mask;
281
282 /*
283 * This buffer is required so that when hvcs_write_room() reports that
284 * it can send HVCS_BUFF_LEN characters that it will buffer the full
285 * HVCS_BUFF_LEN characters if need be. This is essential for opost
286 * writes since they do not do high level buffering and expect to be
287 * able to send what the driver commits to sending buffering
288 * [e.g. tab to space conversions in n_tty.c opost()].
289 */
290 char buffer[HVCS_BUFF_LEN];
291 int chars_in_buffer;
292
293 /*
294 * Any variable below the kobject is valid before a tty is connected and
295 * stays valid after the tty is disconnected. These shouldn't be
296 * whacked until the koject refcount reaches zero though some entries
297 * may be changed via sysfs initiatives.
298 */
299 struct kobject kobj; /* ref count & hvcs_struct lifetime */
300 int connected; /* is the vty-server currently connected to a vty? */
301 uint32_t p_unit_address; /* partner unit address */
302 uint32_t p_partition_ID; /* partner partition ID */
303 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
304 struct list_head next; /* list management */
305 struct vio_dev *vdev;
306};
307
308/* Required to back map a kobject to its containing object */
309#define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj)
310
311static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs);
312static DEFINE_SPINLOCK(hvcs_structs_lock);
313
314static void hvcs_unthrottle(struct tty_struct *tty);
315static void hvcs_throttle(struct tty_struct *tty);
316static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
317 struct pt_regs *regs);
318
319static int hvcs_write(struct tty_struct *tty,
320 const unsigned char *buf, int count);
321static int hvcs_write_room(struct tty_struct *tty);
322static int hvcs_chars_in_buffer(struct tty_struct *tty);
323
324static int hvcs_has_pi(struct hvcs_struct *hvcsd);
325static void hvcs_set_pi(struct hvcs_partner_info *pi,
326 struct hvcs_struct *hvcsd);
327static int hvcs_get_pi(struct hvcs_struct *hvcsd);
328static int hvcs_rescan_devices_list(void);
329
330static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
331static void hvcs_partner_free(struct hvcs_struct *hvcsd);
332
333static int hvcs_enable_device(struct hvcs_struct *hvcsd,
334 uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
335
336static void destroy_hvcs_struct(struct kobject *kobj);
337static int hvcs_open(struct tty_struct *tty, struct file *filp);
338static void hvcs_close(struct tty_struct *tty, struct file *filp);
339static void hvcs_hangup(struct tty_struct * tty);
340
341static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd);
342static void hvcs_remove_device_attrs(struct vio_dev *vdev);
343static void hvcs_create_driver_attrs(void);
344static void hvcs_remove_driver_attrs(void);
345
346static int __devinit hvcs_probe(struct vio_dev *dev,
347 const struct vio_device_id *id);
348static int __devexit hvcs_remove(struct vio_dev *dev);
349static int __init hvcs_module_init(void);
350static void __exit hvcs_module_exit(void);
351
352#define HVCS_SCHED_READ 0x00000001
353#define HVCS_QUICK_READ 0x00000002
354#define HVCS_TRY_WRITE 0x00000004
355#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
356
357static void hvcs_kick(void)
358{
359 hvcs_kicked = 1;
360 wmb();
361 wake_up_process(hvcs_task);
362}
363
364static void hvcs_unthrottle(struct tty_struct *tty)
365{
366 struct hvcs_struct *hvcsd = tty->driver_data;
367 unsigned long flags;
368
369 spin_lock_irqsave(&hvcsd->lock, flags);
370 hvcsd->todo_mask |= HVCS_SCHED_READ;
371 spin_unlock_irqrestore(&hvcsd->lock, flags);
372 hvcs_kick();
373}
374
375static void hvcs_throttle(struct tty_struct *tty)
376{
377 struct hvcs_struct *hvcsd = tty->driver_data;
378 unsigned long flags;
379
380 spin_lock_irqsave(&hvcsd->lock, flags);
381 vio_disable_interrupts(hvcsd->vdev);
382 spin_unlock_irqrestore(&hvcsd->lock, flags);
383}
384
385/*
386 * If the device is being removed we don't have to worry about this interrupt
387 * handler taking any further interrupts because they are disabled which means
388 * the hvcs_struct will always be valid in this handler.
389 */
390static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
391 struct pt_regs *regs)
392{
393 struct hvcs_struct *hvcsd = dev_instance;
394
395 spin_lock(&hvcsd->lock);
396 vio_disable_interrupts(hvcsd->vdev);
397 hvcsd->todo_mask |= HVCS_SCHED_READ;
398 spin_unlock(&hvcsd->lock);
399 hvcs_kick();
400
401 return IRQ_HANDLED;
402}
403
404/* This function must be called with the hvcsd->lock held */
405static void hvcs_try_write(struct hvcs_struct *hvcsd)
406{
407 uint32_t unit_address = hvcsd->vdev->unit_address;
408 struct tty_struct *tty = hvcsd->tty;
409 int sent;
410
411 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
412 /* won't send partial writes */
413 sent = hvc_put_chars(unit_address,
414 &hvcsd->buffer[0],
415 hvcsd->chars_in_buffer );
416 if (sent > 0) {
417 hvcsd->chars_in_buffer = 0;
418 /* wmb(); */
419 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
420 /* wmb(); */
421
422 /*
423 * We are still obligated to deliver the data to the
424 * hypervisor even if the tty has been closed because
425 * we commited to delivering it. But don't try to wake
426 * a non-existent tty.
427 */
428 if (tty) {
429 tty_wakeup(tty);
430 }
431 }
432 }
433}
434
435static int hvcs_io(struct hvcs_struct *hvcsd)
436{
437 uint32_t unit_address;
438 struct tty_struct *tty;
439 char buf[HVCS_BUFF_LEN] __ALIGNED__;
440 unsigned long flags;
441 int got = 0;
442 int i;
443
444 spin_lock_irqsave(&hvcsd->lock, flags);
445
446 unit_address = hvcsd->vdev->unit_address;
447 tty = hvcsd->tty;
448
449 hvcs_try_write(hvcsd);
450
451 if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
452 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
453 goto bail;
454 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
455 goto bail;
456
457 /* remove the read masks */
458 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
459
Alan Cox33f0f882006-01-09 20:54:13 -0800460 if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 got = hvc_get_chars(unit_address,
462 &buf[0],
463 HVCS_BUFF_LEN);
Alan Cox33f0f882006-01-09 20:54:13 -0800464 tty_insert_flip_string(tty, buf, got);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 }
466
467 /* Give the TTY time to process the data we just sent. */
468 if (got)
469 hvcsd->todo_mask |= HVCS_QUICK_READ;
470
471 spin_unlock_irqrestore(&hvcsd->lock, flags);
Alan Cox33f0f882006-01-09 20:54:13 -0800472 /* This is synch because tty->low_latency == 1 */
473 if(got)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 tty_flip_buffer_push(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
476 if (!got) {
477 /* Do this _after_ the flip_buffer_push */
478 spin_lock_irqsave(&hvcsd->lock, flags);
479 vio_enable_interrupts(hvcsd->vdev);
480 spin_unlock_irqrestore(&hvcsd->lock, flags);
481 }
482
483 return hvcsd->todo_mask;
484
485 bail:
486 spin_unlock_irqrestore(&hvcsd->lock, flags);
487 return hvcsd->todo_mask;
488}
489
490static int khvcsd(void *unused)
491{
492 struct hvcs_struct *hvcsd;
493 int hvcs_todo_mask;
494
495 __set_current_state(TASK_RUNNING);
496
497 do {
498 hvcs_todo_mask = 0;
499 hvcs_kicked = 0;
500 wmb();
501
502 spin_lock(&hvcs_structs_lock);
503 list_for_each_entry(hvcsd, &hvcs_structs, next) {
504 hvcs_todo_mask |= hvcs_io(hvcsd);
505 }
506 spin_unlock(&hvcs_structs_lock);
507
508 /*
509 * If any of the hvcs adapters want to try a write or quick read
510 * don't schedule(), yield a smidgen then execute the hvcs_io
511 * thread again for those that want the write.
512 */
513 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
514 yield();
515 continue;
516 }
517
518 set_current_state(TASK_INTERRUPTIBLE);
519 if (!hvcs_kicked)
520 schedule();
521 __set_current_state(TASK_RUNNING);
522 } while (!kthread_should_stop());
523
524 return 0;
525}
526
527static struct vio_device_id hvcs_driver_table[] __devinitdata= {
528 {"serial-server", "hvterm2"},
Stephen Rothwellfb120da2005-08-17 16:42:59 +1000529 { "", "" }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530};
531MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
532
533static void hvcs_return_index(int index)
534{
535 /* Paranoia check */
536 if (!hvcs_index_list)
537 return;
538 if (index < 0 || index >= hvcs_index_count)
539 return;
540 if (hvcs_index_list[index] == -1)
541 return;
542 else
543 hvcs_index_list[index] = -1;
544}
545
546/* callback when the kboject ref count reaches zero */
547static void destroy_hvcs_struct(struct kobject *kobj)
548{
549 struct hvcs_struct *hvcsd = from_kobj(kobj);
550 struct vio_dev *vdev;
551 unsigned long flags;
552
553 spin_lock(&hvcs_structs_lock);
554 spin_lock_irqsave(&hvcsd->lock, flags);
555
556 /* the list_del poisons the pointers */
557 list_del(&(hvcsd->next));
558
559 if (hvcsd->connected == 1) {
560 hvcs_partner_free(hvcsd);
561 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
562 " partner vty@%X:%d connection.\n",
563 hvcsd->vdev->unit_address,
564 hvcsd->p_unit_address,
565 (uint32_t)hvcsd->p_partition_ID);
566 }
567 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
568 hvcsd->vdev->unit_address);
569
570 vdev = hvcsd->vdev;
571 hvcsd->vdev = NULL;
572
573 hvcsd->p_unit_address = 0;
574 hvcsd->p_partition_ID = 0;
575 hvcs_return_index(hvcsd->index);
576 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
577
578 spin_unlock_irqrestore(&hvcsd->lock, flags);
579 spin_unlock(&hvcs_structs_lock);
580
581 hvcs_remove_device_attrs(vdev);
582
583 kfree(hvcsd);
584}
585
586static struct kobj_type hvcs_kobj_type = {
587 .release = destroy_hvcs_struct,
588};
589
590static int hvcs_get_index(void)
591{
592 int i;
593 /* Paranoia check */
594 if (!hvcs_index_list) {
595 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
596 return -EFAULT;
597 }
598 /* Find the numerically lowest first free index. */
599 for(i = 0; i < hvcs_index_count; i++) {
600 if (hvcs_index_list[i] == -1) {
601 hvcs_index_list[i] = 0;
602 return i;
603 }
604 }
605 return -1;
606}
607
608static int __devinit hvcs_probe(
609 struct vio_dev *dev,
610 const struct vio_device_id *id)
611{
612 struct hvcs_struct *hvcsd;
613 int index;
614
615 if (!dev || !id) {
616 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
617 return -EPERM;
618 }
619
620 /* early to avoid cleanup on failure */
621 index = hvcs_get_index();
622 if (index < 0) {
623 return -EFAULT;
624 }
625
626 hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL);
627 if (!hvcsd)
628 return -ENODEV;
629
630 /* hvcsd->tty is zeroed out with the memset */
631 memset(hvcsd, 0x00, sizeof(*hvcsd));
632
633 spin_lock_init(&hvcsd->lock);
634 /* Automatically incs the refcount the first time */
635 kobject_init(&hvcsd->kobj);
636 /* Set up the callback for terminating the hvcs_struct's life */
637 hvcsd->kobj.ktype = &hvcs_kobj_type;
638
639 hvcsd->vdev = dev;
640 dev->dev.driver_data = hvcsd;
641
642 hvcsd->index = index;
643
644 /* hvcsd->index = ++hvcs_struct_count; */
645 hvcsd->chars_in_buffer = 0;
646 hvcsd->todo_mask = 0;
647 hvcsd->connected = 0;
648
649 /*
650 * This will populate the hvcs_struct's partner info fields for the
651 * first time.
652 */
653 if (hvcs_get_pi(hvcsd)) {
654 printk(KERN_ERR "HVCS: Failed to fetch partner"
655 " info for vty-server@%X on device probe.\n",
656 hvcsd->vdev->unit_address);
657 }
658
659 /*
660 * If a user app opens a tty that corresponds to this vty-server before
661 * the hvcs_struct has been added to the devices list then the user app
662 * will get -ENODEV.
663 */
664
665 spin_lock(&hvcs_structs_lock);
666
667 list_add_tail(&(hvcsd->next), &hvcs_structs);
668
669 spin_unlock(&hvcs_structs_lock);
670
671 hvcs_create_device_attrs(hvcsd);
672
673 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
674
675 /*
676 * DON'T enable interrupts here because there is no user to receive the
677 * data.
678 */
679 return 0;
680}
681
682static int __devexit hvcs_remove(struct vio_dev *dev)
683{
684 struct hvcs_struct *hvcsd = dev->dev.driver_data;
685 unsigned long flags;
686 struct kobject *kobjp;
687 struct tty_struct *tty;
688
689 if (!hvcsd)
690 return -ENODEV;
691
692 /* By this time the vty-server won't be getting any more interrups */
693
694 spin_lock_irqsave(&hvcsd->lock, flags);
695
696 tty = hvcsd->tty;
697
698 kobjp = &hvcsd->kobj;
699
700 spin_unlock_irqrestore(&hvcsd->lock, flags);
701
702 /*
703 * Let the last holder of this object cause it to be removed, which
704 * would probably be tty_hangup below.
705 */
706 kobject_put (kobjp);
707
708 /*
709 * The hangup is a scheduled function which will auto chain call
710 * hvcs_hangup. The tty should always be valid at this time unless a
711 * simultaneous tty close already cleaned up the hvcs_struct.
712 */
713 if (tty)
714 tty_hangup(tty);
715
716 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
717 " vio bus.\n", dev->unit_address);
718 return 0;
719};
720
721static struct vio_driver hvcs_vio_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 .id_table = hvcs_driver_table,
723 .probe = hvcs_probe,
724 .remove = hvcs_remove,
Stephen Rothwell6fdf5392005-10-24 14:53:21 +1000725 .driver = {
726 .name = hvcs_driver_name,
Stephen Rothwell915124d2005-10-24 15:12:22 +1000727 .owner = THIS_MODULE,
Stephen Rothwell6fdf5392005-10-24 14:53:21 +1000728 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729};
730
731/* Only called from hvcs_get_pi please */
732static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
733{
734 int clclength;
735
736 hvcsd->p_unit_address = pi->unit_address;
737 hvcsd->p_partition_ID = pi->partition_ID;
738 clclength = strlen(&pi->location_code[0]);
739 if (clclength > HVCS_CLC_LENGTH)
740 clclength = HVCS_CLC_LENGTH;
741
742 /* copy the null-term char too */
743 strncpy(&hvcsd->p_location_code[0],
744 &pi->location_code[0], clclength + 1);
745}
746
747/*
748 * Traverse the list and add the partner info that is found to the hvcs_struct
749 * struct entry. NOTE: At this time I know that partner info will return a
750 * single entry but in the future there may be multiple partner info entries per
751 * vty-server and you'll want to zero out that list and reset it. If for some
752 * reason you have an old version of this driver but there IS more than one
753 * partner info then hvcsd->p_* will hold the last partner info data from the
754 * firmware query. A good way to update this code would be to replace the three
755 * partner info fields in hvcs_struct with a list of hvcs_partner_info
756 * instances.
757 *
758 * This function must be called with the hvcsd->lock held.
759 */
760static int hvcs_get_pi(struct hvcs_struct *hvcsd)
761{
762 struct hvcs_partner_info *pi;
763 uint32_t unit_address = hvcsd->vdev->unit_address;
764 struct list_head head;
765 int retval;
766
767 spin_lock(&hvcs_pi_lock);
768 if (!hvcs_pi_buff) {
769 spin_unlock(&hvcs_pi_lock);
770 return -EFAULT;
771 }
772 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
773 spin_unlock(&hvcs_pi_lock);
774 if (retval) {
775 printk(KERN_ERR "HVCS: Failed to fetch partner"
776 " info for vty-server@%x.\n", unit_address);
777 return retval;
778 }
779
780 /* nixes the values if the partner vty went away */
781 hvcsd->p_unit_address = 0;
782 hvcsd->p_partition_ID = 0;
783
784 list_for_each_entry(pi, &head, node)
785 hvcs_set_pi(pi, hvcsd);
786
787 hvcs_free_partner_info(&head);
788 return 0;
789}
790
791/*
792 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
793 * be executed elsewhere, in order to prevent deadlock issues.
794 */
795static int hvcs_rescan_devices_list(void)
796{
797 struct hvcs_struct *hvcsd;
798 unsigned long flags;
799
800 spin_lock(&hvcs_structs_lock);
801
802 list_for_each_entry(hvcsd, &hvcs_structs, next) {
803 spin_lock_irqsave(&hvcsd->lock, flags);
804 hvcs_get_pi(hvcsd);
805 spin_unlock_irqrestore(&hvcsd->lock, flags);
806 }
807
808 spin_unlock(&hvcs_structs_lock);
809
810 return 0;
811}
812
813/*
814 * Farm this off into its own function because it could be more complex once
815 * multiple partners support is added. This function should be called with
816 * the hvcsd->lock held.
817 */
818static int hvcs_has_pi(struct hvcs_struct *hvcsd)
819{
820 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
821 return 0;
822 return 1;
823}
824
825/*
826 * NOTE: It is possible that the super admin removed a partner vty and then
827 * added a different vty as the new partner.
828 *
829 * This function must be called with the hvcsd->lock held.
830 */
831static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
832{
833 int retval;
834 unsigned int unit_address = hvcsd->vdev->unit_address;
835
836 /*
837 * If there wasn't any pi when the device was added it doesn't meant
838 * there isn't any now. This driver isn't notified when a new partner
839 * vty is added to a vty-server so we discover changes on our own.
840 * Please see comments in hvcs_register_connection() for justification
841 * of this bizarre code.
842 */
843 retval = hvcs_register_connection(unit_address,
844 hvcsd->p_partition_ID,
845 hvcsd->p_unit_address);
846 if (!retval) {
847 hvcsd->connected = 1;
848 return 0;
849 } else if (retval != -EINVAL)
850 return retval;
851
852 /*
853 * As per the spec re-get the pi and try again if -EINVAL after the
854 * first connection attempt.
855 */
856 if (hvcs_get_pi(hvcsd))
857 return -ENOMEM;
858
859 if (!hvcs_has_pi(hvcsd))
860 return -ENODEV;
861
862 retval = hvcs_register_connection(unit_address,
863 hvcsd->p_partition_ID,
864 hvcsd->p_unit_address);
865 if (retval != -EINVAL) {
866 hvcsd->connected = 1;
867 return retval;
868 }
869
870 /*
871 * EBUSY is the most likely scenario though the vty could have been
872 * removed or there really could be an hcall error due to the parameter
873 * data but thanks to ambiguous firmware return codes we can't really
874 * tell.
875 */
876 printk(KERN_INFO "HVCS: vty-server or partner"
877 " vty is busy. Try again later.\n");
878 return -EBUSY;
879}
880
881/* This function must be called with the hvcsd->lock held */
882static void hvcs_partner_free(struct hvcs_struct *hvcsd)
883{
884 int retval;
885 do {
886 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
887 } while (retval == -EBUSY);
888 hvcsd->connected = 0;
889}
890
891/* This helper function must be called WITHOUT the hvcsd->lock held */
892static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
893 unsigned int irq, struct vio_dev *vdev)
894{
895 unsigned long flags;
896 int rc;
897
898 /*
899 * It is possible that the vty-server was removed between the time that
900 * the conn was registered and now.
901 */
902 if (!(rc = request_irq(irq, &hvcs_handle_interrupt,
903 SA_INTERRUPT, "ibmhvcs", hvcsd))) {
904 /*
905 * It is possible the vty-server was removed after the irq was
906 * requested but before we have time to enable interrupts.
907 */
908 if (vio_enable_interrupts(vdev) == H_Success)
909 return 0;
910 else {
911 printk(KERN_ERR "HVCS: int enable failed for"
912 " vty-server@%X.\n", unit_address);
913 free_irq(irq, hvcsd);
914 }
915 } else
916 printk(KERN_ERR "HVCS: irq req failed for"
917 " vty-server@%X.\n", unit_address);
918
919 spin_lock_irqsave(&hvcsd->lock, flags);
920 hvcs_partner_free(hvcsd);
921 spin_unlock_irqrestore(&hvcsd->lock, flags);
922
923 return rc;
924
925}
926
927/*
928 * This always increments the kobject ref count if the call is successful.
929 * Please remember to dec when you are done with the instance.
930 *
931 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
932 * calling this function or you will get deadlock.
933 */
934struct hvcs_struct *hvcs_get_by_index(int index)
935{
936 struct hvcs_struct *hvcsd = NULL;
937 unsigned long flags;
938
939 spin_lock(&hvcs_structs_lock);
940 /* We can immediately discard OOB requests */
941 if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
942 list_for_each_entry(hvcsd, &hvcs_structs, next) {
943 spin_lock_irqsave(&hvcsd->lock, flags);
944 if (hvcsd->index == index) {
945 kobject_get(&hvcsd->kobj);
946 spin_unlock_irqrestore(&hvcsd->lock, flags);
947 spin_unlock(&hvcs_structs_lock);
948 return hvcsd;
949 }
950 spin_unlock_irqrestore(&hvcsd->lock, flags);
951 }
952 hvcsd = NULL;
953 }
954
955 spin_unlock(&hvcs_structs_lock);
956 return hvcsd;
957}
958
959/*
960 * This is invoked via the tty_open interface when a user app connects to the
961 * /dev node.
962 */
963static int hvcs_open(struct tty_struct *tty, struct file *filp)
964{
965 struct hvcs_struct *hvcsd;
966 int rc, retval = 0;
967 unsigned long flags;
968 unsigned int irq;
969 struct vio_dev *vdev;
970 unsigned long unit_address;
971 struct kobject *kobjp;
972
973 if (tty->driver_data)
974 goto fast_open;
975
976 /*
977 * Is there a vty-server that shares the same index?
978 * This function increments the kobject index.
979 */
980 if (!(hvcsd = hvcs_get_by_index(tty->index))) {
981 printk(KERN_WARNING "HVCS: open failed, no device associated"
982 " with tty->index %d.\n", tty->index);
983 return -ENODEV;
984 }
985
986 spin_lock_irqsave(&hvcsd->lock, flags);
987
988 if (hvcsd->connected == 0)
989 if ((retval = hvcs_partner_connect(hvcsd)))
990 goto error_release;
991
992 hvcsd->open_count = 1;
993 hvcsd->tty = tty;
994 tty->driver_data = hvcsd;
995
996 /*
997 * Set this driver to low latency so that we actually have a chance at
998 * catching a throttled TTY after we flip_buffer_push. Otherwise the
999 * flush_to_async may not execute until after the kernel_thread has
1000 * yielded and resumed the next flip_buffer_push resulting in data
1001 * loss.
1002 */
1003 tty->low_latency = 1;
1004
1005 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1006
1007 /*
1008 * Save these in the spinlock for the enable operations that need them
1009 * outside of the spinlock.
1010 */
1011 irq = hvcsd->vdev->irq;
1012 vdev = hvcsd->vdev;
1013 unit_address = hvcsd->vdev->unit_address;
1014
1015 hvcsd->todo_mask |= HVCS_SCHED_READ;
1016 spin_unlock_irqrestore(&hvcsd->lock, flags);
1017
1018 /*
1019 * This must be done outside of the spinlock because it requests irqs
1020 * and will grab the spinlock and free the connection if it fails.
1021 */
1022 if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) {
1023 kobject_put(&hvcsd->kobj);
1024 printk(KERN_WARNING "HVCS: enable device failed.\n");
1025 return rc;
1026 }
1027
1028 goto open_success;
1029
1030fast_open:
1031 hvcsd = tty->driver_data;
1032
1033 spin_lock_irqsave(&hvcsd->lock, flags);
1034 if (!kobject_get(&hvcsd->kobj)) {
1035 spin_unlock_irqrestore(&hvcsd->lock, flags);
1036 printk(KERN_ERR "HVCS: Kobject of open"
1037 " hvcs doesn't exist.\n");
1038 return -EFAULT; /* Is this the right return value? */
1039 }
1040
1041 hvcsd->open_count++;
1042
1043 hvcsd->todo_mask |= HVCS_SCHED_READ;
1044 spin_unlock_irqrestore(&hvcsd->lock, flags);
1045open_success:
1046 hvcs_kick();
1047
1048 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1049 hvcsd->vdev->unit_address );
1050
1051 return 0;
1052
1053error_release:
1054 kobjp = &hvcsd->kobj;
1055 spin_unlock_irqrestore(&hvcsd->lock, flags);
1056 kobject_put(&hvcsd->kobj);
1057
1058 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1059 return retval;
1060}
1061
1062static void hvcs_close(struct tty_struct *tty, struct file *filp)
1063{
1064 struct hvcs_struct *hvcsd;
1065 unsigned long flags;
1066 struct kobject *kobjp;
1067 int irq = NO_IRQ;
1068
1069 /*
1070 * Is someone trying to close the file associated with this device after
1071 * we have hung up? If so tty->driver_data wouldn't be valid.
1072 */
1073 if (tty_hung_up_p(filp))
1074 return;
1075
1076 /*
1077 * No driver_data means that this close was probably issued after a
1078 * failed hvcs_open by the tty layer's release_dev() api and we can just
1079 * exit cleanly.
1080 */
1081 if (!tty->driver_data)
1082 return;
1083
1084 hvcsd = tty->driver_data;
1085
1086 spin_lock_irqsave(&hvcsd->lock, flags);
1087 kobjp = &hvcsd->kobj;
1088 if (--hvcsd->open_count == 0) {
1089
1090 vio_disable_interrupts(hvcsd->vdev);
1091
1092 /*
1093 * NULL this early so that the kernel_thread doesn't try to
1094 * execute any operations on the TTY even though it is obligated
1095 * to deliver any pending I/O to the hypervisor.
1096 */
1097 hvcsd->tty = NULL;
1098
1099 irq = hvcsd->vdev->irq;
1100 spin_unlock_irqrestore(&hvcsd->lock, flags);
1101
1102 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1103
1104 /*
1105 * This line is important because it tells hvcs_open that this
1106 * device needs to be re-configured the next time hvcs_open is
1107 * called.
1108 */
1109 tty->driver_data = NULL;
1110
1111 free_irq(irq, hvcsd);
1112 kobject_put(kobjp);
1113 return;
1114 } else if (hvcsd->open_count < 0) {
1115 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
1116 " is missmanaged.\n",
1117 hvcsd->vdev->unit_address, hvcsd->open_count);
1118 }
1119
1120 spin_unlock_irqrestore(&hvcsd->lock, flags);
1121 kobject_put(kobjp);
1122}
1123
1124static void hvcs_hangup(struct tty_struct * tty)
1125{
1126 struct hvcs_struct *hvcsd = tty->driver_data;
1127 unsigned long flags;
1128 int temp_open_count;
1129 struct kobject *kobjp;
1130 int irq = NO_IRQ;
1131
1132 spin_lock_irqsave(&hvcsd->lock, flags);
1133 /* Preserve this so that we know how many kobject refs to put */
1134 temp_open_count = hvcsd->open_count;
1135
1136 /*
1137 * Don't kobject put inside the spinlock because the destruction
1138 * callback may use the spinlock and it may get called before the
1139 * spinlock has been released. Get a pointer to the kobject and
1140 * kobject_put on that after releasing the spinlock.
1141 */
1142 kobjp = &hvcsd->kobj;
1143
1144 vio_disable_interrupts(hvcsd->vdev);
1145
1146 hvcsd->todo_mask = 0;
1147
1148 /* I don't think the tty needs the hvcs_struct pointer after a hangup */
1149 hvcsd->tty->driver_data = NULL;
1150 hvcsd->tty = NULL;
1151
1152 hvcsd->open_count = 0;
1153
1154 /* This will drop any buffered data on the floor which is OK in a hangup
1155 * scenario. */
1156 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1157 hvcsd->chars_in_buffer = 0;
1158
1159 irq = hvcsd->vdev->irq;
1160
1161 spin_unlock_irqrestore(&hvcsd->lock, flags);
1162
1163 free_irq(irq, hvcsd);
1164
1165 /*
1166 * We need to kobject_put() for every open_count we have since the
1167 * tty_hangup() function doesn't invoke a close per open connection on a
1168 * non-console device.
1169 */
1170 while(temp_open_count) {
1171 --temp_open_count;
1172 /*
1173 * The final put will trigger destruction of the hvcs_struct.
1174 * NOTE: If this hangup was signaled from user space then the
1175 * final put will never happen.
1176 */
1177 kobject_put(kobjp);
1178 }
1179}
1180
1181/*
1182 * NOTE: This is almost always from_user since user level apps interact with the
1183 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1184 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1185 * tty_hangup will allow hvcs_write time to complete execution before it
1186 * terminates our device.
1187 */
1188static int hvcs_write(struct tty_struct *tty,
1189 const unsigned char *buf, int count)
1190{
1191 struct hvcs_struct *hvcsd = tty->driver_data;
1192 unsigned int unit_address;
1193 const unsigned char *charbuf;
1194 unsigned long flags;
1195 int total_sent = 0;
1196 int tosend = 0;
1197 int result = 0;
1198
1199 /*
1200 * If they don't check the return code off of their open they may
1201 * attempt this even if there is no connected device.
1202 */
1203 if (!hvcsd)
1204 return -ENODEV;
1205
1206 /* Reasonable size to prevent user level flooding */
1207 if (count > HVCS_MAX_FROM_USER) {
1208 printk(KERN_WARNING "HVCS write: count being truncated to"
1209 " HVCS_MAX_FROM_USER.\n");
1210 count = HVCS_MAX_FROM_USER;
1211 }
1212
1213 charbuf = buf;
1214
1215 spin_lock_irqsave(&hvcsd->lock, flags);
1216
1217 /*
1218 * Somehow an open succedded but the device was removed or the
1219 * connection terminated between the vty-server and partner vty during
1220 * the middle of a write operation? This is a crummy place to do this
1221 * but we want to keep it all in the spinlock.
1222 */
1223 if (hvcsd->open_count <= 0) {
1224 spin_unlock_irqrestore(&hvcsd->lock, flags);
1225 return -ENODEV;
1226 }
1227
1228 unit_address = hvcsd->vdev->unit_address;
1229
1230 while (count > 0) {
1231 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1232 /*
1233 * No more space, this probably means that the last call to
1234 * hvcs_write() didn't succeed and the buffer was filled up.
1235 */
1236 if (!tosend)
1237 break;
1238
1239 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1240 &charbuf[total_sent],
1241 tosend);
1242
1243 hvcsd->chars_in_buffer += tosend;
1244
1245 result = 0;
1246
1247 /*
1248 * If this is true then we don't want to try writing to the
1249 * hypervisor because that is the kernel_threads job now. We'll
1250 * just add to the buffer.
1251 */
1252 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1253 /* won't send partial writes */
1254 result = hvc_put_chars(unit_address,
1255 &hvcsd->buffer[0],
1256 hvcsd->chars_in_buffer);
1257
1258 /*
1259 * Since we know we have enough room in hvcsd->buffer for
1260 * tosend we record that it was sent regardless of whether the
1261 * hypervisor actually took it because we have it buffered.
1262 */
1263 total_sent+=tosend;
1264 count-=tosend;
1265 if (result == 0) {
1266 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1267 hvcs_kick();
1268 break;
1269 }
1270
1271 hvcsd->chars_in_buffer = 0;
1272 /*
1273 * Test after the chars_in_buffer reset otherwise this could
1274 * deadlock our writes if hvc_put_chars fails.
1275 */
1276 if (result < 0)
1277 break;
1278 }
1279
1280 spin_unlock_irqrestore(&hvcsd->lock, flags);
1281
1282 if (result == -1)
1283 return -EIO;
1284 else
1285 return total_sent;
1286}
1287
1288/*
1289 * This is really asking how much can we guarentee that we can send or that we
1290 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1291 * return value, hence the reason for hvcs_struct buffering.
1292 */
1293static int hvcs_write_room(struct tty_struct *tty)
1294{
1295 struct hvcs_struct *hvcsd = tty->driver_data;
1296
1297 if (!hvcsd || hvcsd->open_count <= 0)
1298 return 0;
1299
1300 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1301}
1302
1303static int hvcs_chars_in_buffer(struct tty_struct *tty)
1304{
1305 struct hvcs_struct *hvcsd = tty->driver_data;
1306
1307 return hvcsd->chars_in_buffer;
1308}
1309
1310static struct tty_operations hvcs_ops = {
1311 .open = hvcs_open,
1312 .close = hvcs_close,
1313 .hangup = hvcs_hangup,
1314 .write = hvcs_write,
1315 .write_room = hvcs_write_room,
1316 .chars_in_buffer = hvcs_chars_in_buffer,
1317 .unthrottle = hvcs_unthrottle,
1318 .throttle = hvcs_throttle,
1319};
1320
1321static int hvcs_alloc_index_list(int n)
1322{
1323 int i;
1324 hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL);
1325 if (!hvcs_index_list)
1326 return -ENOMEM;
1327 hvcs_index_count = n;
1328 for(i = 0; i < hvcs_index_count; i++)
1329 hvcs_index_list[i] = -1;
1330 return 0;
1331}
1332
1333static void hvcs_free_index_list(void)
1334{
1335 /* Paranoia check to be thorough. */
1336 if (hvcs_index_list) {
1337 kfree(hvcs_index_list);
1338 hvcs_index_list = NULL;
1339 hvcs_index_count = 0;
1340 }
1341}
1342
1343static int __init hvcs_module_init(void)
1344{
1345 int rc;
1346 int num_ttys_to_alloc;
1347
1348 printk(KERN_INFO "Initializing %s\n", hvcs_driver_string);
1349
1350 /* Has the user specified an overload with an insmod param? */
1351 if (hvcs_parm_num_devs <= 0 ||
1352 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1353 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1354 } else
1355 num_ttys_to_alloc = hvcs_parm_num_devs;
1356
1357 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
1358 if (!hvcs_tty_driver)
1359 return -ENOMEM;
1360
1361 if (hvcs_alloc_index_list(num_ttys_to_alloc))
1362 return -ENOMEM;
1363
1364 hvcs_tty_driver->owner = THIS_MODULE;
1365
1366 hvcs_tty_driver->driver_name = hvcs_driver_name;
1367 hvcs_tty_driver->name = hvcs_device_node;
1368 hvcs_tty_driver->devfs_name = hvcs_device_node;
1369
1370 /*
1371 * We'll let the system assign us a major number, indicated by leaving
1372 * it blank.
1373 */
1374
1375 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1376 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1377
1378 /*
1379 * We role our own so that we DONT ECHO. We can't echo because the
1380 * device we are connecting to already echoes by default and this would
1381 * throw us into a horrible recursive echo-echo-echo loop.
1382 */
1383 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1384 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;
1385
1386 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1387
1388 /*
1389 * The following call will result in sysfs entries that denote the
1390 * dynamically assigned major and minor numbers for our devices.
1391 */
1392 if (tty_register_driver(hvcs_tty_driver)) {
1393 printk(KERN_ERR "HVCS: registration "
1394 " as a tty driver failed.\n");
1395 hvcs_free_index_list();
1396 put_tty_driver(hvcs_tty_driver);
1397 return -EIO;
1398 }
1399
1400 hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
1401 if (!hvcs_pi_buff) {
1402 tty_unregister_driver(hvcs_tty_driver);
1403 hvcs_free_index_list();
1404 put_tty_driver(hvcs_tty_driver);
1405 return -ENOMEM;
1406 }
1407
1408 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1409 if (IS_ERR(hvcs_task)) {
1410 printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n");
1411 kfree(hvcs_pi_buff);
1412 tty_unregister_driver(hvcs_tty_driver);
1413 hvcs_free_index_list();
1414 put_tty_driver(hvcs_tty_driver);
1415 return -EIO;
1416 }
1417
1418 rc = vio_register_driver(&hvcs_vio_driver);
1419
1420 /*
1421 * This needs to be done AFTER the vio_register_driver() call or else
1422 * the kobjects won't be initialized properly.
1423 */
1424 hvcs_create_driver_attrs();
1425
1426 printk(KERN_INFO "HVCS: driver module inserted.\n");
1427
1428 return rc;
1429}
1430
1431static void __exit hvcs_module_exit(void)
1432{
1433 /*
1434 * This driver receives hvcs_remove callbacks for each device upon
1435 * module removal.
1436 */
1437
1438 /*
1439 * This synchronous operation will wake the khvcsd kthread if it is
1440 * asleep and will return when khvcsd has terminated.
1441 */
1442 kthread_stop(hvcs_task);
1443
1444 spin_lock(&hvcs_pi_lock);
1445 kfree(hvcs_pi_buff);
1446 hvcs_pi_buff = NULL;
1447 spin_unlock(&hvcs_pi_lock);
1448
1449 hvcs_remove_driver_attrs();
1450
1451 vio_unregister_driver(&hvcs_vio_driver);
1452
1453 tty_unregister_driver(hvcs_tty_driver);
1454
1455 hvcs_free_index_list();
1456
1457 put_tty_driver(hvcs_tty_driver);
1458
1459 printk(KERN_INFO "HVCS: driver module removed.\n");
1460}
1461
1462module_init(hvcs_module_init);
1463module_exit(hvcs_module_exit);
1464
1465static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
1466{
1467 return viod->dev.driver_data;
1468}
1469/* The sysfs interface for the driver and devices */
1470
Yani Ioannou74880c02005-05-17 06:41:12 -04001471static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472{
1473 struct vio_dev *viod = to_vio_dev(dev);
1474 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1475 unsigned long flags;
1476 int retval;
1477
1478 spin_lock_irqsave(&hvcsd->lock, flags);
1479 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
1480 spin_unlock_irqrestore(&hvcsd->lock, flags);
1481 return retval;
1482}
1483static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
1484
Yani Ioannou74880c02005-05-17 06:41:12 -04001485static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486{
1487 struct vio_dev *viod = to_vio_dev(dev);
1488 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1489 unsigned long flags;
1490 int retval;
1491
1492 spin_lock_irqsave(&hvcsd->lock, flags);
1493 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
1494 spin_unlock_irqrestore(&hvcsd->lock, flags);
1495 return retval;
1496}
1497static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
1498
Yani Ioannou74880c02005-05-17 06:41:12 -04001499static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 size_t count)
1501{
1502 /*
1503 * Don't need this feature at the present time because firmware doesn't
1504 * yet support multiple partners.
1505 */
1506 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
1507 return -EPERM;
1508}
1509
Yani Ioannou74880c02005-05-17 06:41:12 -04001510static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511{
1512 struct vio_dev *viod = to_vio_dev(dev);
1513 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1514 unsigned long flags;
1515 int retval;
1516
1517 spin_lock_irqsave(&hvcsd->lock, flags);
1518 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
1519 spin_unlock_irqrestore(&hvcsd->lock, flags);
1520 return retval;
1521}
1522
1523static DEVICE_ATTR(current_vty,
1524 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
1525
Yani Ioannou74880c02005-05-17 06:41:12 -04001526static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 size_t count)
1528{
1529 struct vio_dev *viod = to_vio_dev(dev);
1530 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1531 unsigned long flags;
1532
1533 /* writing a '0' to this sysfs entry will result in the disconnect. */
1534 if (simple_strtol(buf, NULL, 0) != 0)
1535 return -EINVAL;
1536
1537 spin_lock_irqsave(&hvcsd->lock, flags);
1538
1539 if (hvcsd->open_count > 0) {
1540 spin_unlock_irqrestore(&hvcsd->lock, flags);
1541 printk(KERN_INFO "HVCS: vterm state unchanged. "
1542 "The hvcs device node is still in use.\n");
1543 return -EPERM;
1544 }
1545
1546 if (hvcsd->connected == 0) {
1547 spin_unlock_irqrestore(&hvcsd->lock, flags);
1548 printk(KERN_INFO "HVCS: vterm state unchanged. The"
1549 " vty-server is not connected to a vty.\n");
1550 return -EPERM;
1551 }
1552
1553 hvcs_partner_free(hvcsd);
1554 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
1555 " partner vty@%X:%d connection.\n",
1556 hvcsd->vdev->unit_address,
1557 hvcsd->p_unit_address,
1558 (uint32_t)hvcsd->p_partition_ID);
1559
1560 spin_unlock_irqrestore(&hvcsd->lock, flags);
1561 return count;
1562}
1563
Yani Ioannou74880c02005-05-17 06:41:12 -04001564static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565{
1566 struct vio_dev *viod = to_vio_dev(dev);
1567 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1568 unsigned long flags;
1569 int retval;
1570
1571 spin_lock_irqsave(&hvcsd->lock, flags);
1572 retval = sprintf(buf, "%d\n", hvcsd->connected);
1573 spin_unlock_irqrestore(&hvcsd->lock, flags);
1574 return retval;
1575}
1576static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
1577 hvcs_vterm_state_show, hvcs_vterm_state_store);
1578
Yani Ioannou74880c02005-05-17 06:41:12 -04001579static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580{
1581 struct vio_dev *viod = to_vio_dev(dev);
1582 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1583 unsigned long flags;
1584 int retval;
1585
1586 spin_lock_irqsave(&hvcsd->lock, flags);
1587 retval = sprintf(buf, "%d\n", hvcsd->index);
1588 spin_unlock_irqrestore(&hvcsd->lock, flags);
1589 return retval;
1590}
1591
1592static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
1593
1594static struct attribute *hvcs_attrs[] = {
1595 &dev_attr_partner_vtys.attr,
1596 &dev_attr_partner_clcs.attr,
1597 &dev_attr_current_vty.attr,
1598 &dev_attr_vterm_state.attr,
1599 &dev_attr_index.attr,
1600 NULL,
1601};
1602
1603static struct attribute_group hvcs_attr_group = {
1604 .attrs = hvcs_attrs,
1605};
1606
1607static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd)
1608{
1609 struct vio_dev *vdev = hvcsd->vdev;
1610 sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group);
1611}
1612
1613static void hvcs_remove_device_attrs(struct vio_dev *vdev)
1614{
1615 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
1616}
1617
1618static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
1619{
1620 /* A 1 means it is updating, a 0 means it is done updating */
1621 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
1622}
1623
1624static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
1625 size_t count)
1626{
1627 if ((simple_strtol(buf, NULL, 0) != 1)
1628 && (hvcs_rescan_status != 0))
1629 return -EINVAL;
1630
1631 hvcs_rescan_status = 1;
1632 printk(KERN_INFO "HVCS: rescanning partner info for all"
1633 " vty-servers.\n");
1634 hvcs_rescan_devices_list();
1635 hvcs_rescan_status = 0;
1636 return count;
1637}
1638static DRIVER_ATTR(rescan,
1639 S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
1640
1641static void hvcs_create_driver_attrs(void)
1642{
1643 struct device_driver *driverfs = &(hvcs_vio_driver.driver);
1644 driver_create_file(driverfs, &driver_attr_rescan);
1645}
1646
1647static void hvcs_remove_driver_attrs(void)
1648{
1649 struct device_driver *driverfs = &(hvcs_vio_driver.driver);
1650 driver_remove_file(driverfs, &driver_attr_rescan);
1651}