blob: 69d8866de783f36a70ff38d63d4b47d9f0688385 [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 */
Alan Cox606d0992006-12-08 02:38:45 -0800195static struct ktermios hvcs_tty_termios = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 .c_iflag = IGNBRK | IGNPAR,
197 .c_oflag = OPOST,
198 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
Alan Cox606d0992006-12-08 02:38:45 -0800199 .c_cc = INIT_C_CC,
200 .c_ispeed = 38400,
201 .c_ospeed = 38400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202};
203
204/*
205 * This value is used to take the place of a command line parameter when the
206 * module is inserted. It starts as -1 and stays as such if the user doesn't
207 * specify a module insmod parameter. If they DO specify one then it is set to
208 * the value of the integer passed in.
209 */
210static int hvcs_parm_num_devs = -1;
211module_param(hvcs_parm_num_devs, int, 0);
212
Stephen Rothwellb1c30112007-07-22 00:25:00 +1000213static const char hvcs_driver_name[] = "hvcs";
214static const char hvcs_device_node[] = "hvcs";
215static const char hvcs_driver_string[]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 = "IBM hvcs (Hypervisor Virtual Console Server) Driver";
217
218/* Status of partner info rescan triggered via sysfs. */
219static int hvcs_rescan_status;
220
221static struct tty_driver *hvcs_tty_driver;
222
223/*
224 * In order to be somewhat sane this driver always associates the hvcs_struct
225 * index element with the numerically equal tty->index. This means that a
226 * hotplugged vty-server adapter will always map to the lowest index valued
227 * device node. If vty-servers were hotplug removed from the system and then
228 * new ones added the new vty-server may have the largest slot number of all
229 * the vty-server adapters in the partition but it may have the lowest dev node
230 * index of all the adapters due to the hole left by the hotplug removed
231 * adapter. There are a set of functions provided to get the lowest index for
232 * a new device as well as return the index to the list. This list is allocated
233 * with a number of elements equal to the number of device nodes requested when
234 * the module was inserted.
235 */
236static int *hvcs_index_list;
237
238/*
239 * How large is the list? This is kept for traversal since the list is
240 * dynamically created.
241 */
242static int hvcs_index_count;
243
244/*
245 * Used by the khvcsd to pick up I/O operations when the kernel_thread is
246 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.
247 */
248static int hvcs_kicked;
249
250/*
251 * Use by the kthread construct for task operations like waking the sleeping
252 * thread and stopping the kthread.
253 */
254static struct task_struct *hvcs_task;
255
256/*
257 * We allocate this for the use of all of the hvcs_structs when they fetch
258 * partner info.
259 */
260static unsigned long *hvcs_pi_buff;
261
262/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
263static DEFINE_SPINLOCK(hvcs_pi_lock);
264
265/* One vty-server per hvcs_struct */
266struct hvcs_struct {
267 spinlock_t lock;
268
269 /*
270 * This index identifies this hvcs device as the complement to a
271 * specific tty index.
272 */
273 unsigned int index;
274
275 struct tty_struct *tty;
276 unsigned int open_count;
277
278 /*
279 * Used to tell the driver kernel_thread what operations need to take
280 * place upon this hvcs_struct instance.
281 */
282 int todo_mask;
283
284 /*
285 * This buffer is required so that when hvcs_write_room() reports that
286 * it can send HVCS_BUFF_LEN characters that it will buffer the full
287 * HVCS_BUFF_LEN characters if need be. This is essential for opost
288 * writes since they do not do high level buffering and expect to be
289 * able to send what the driver commits to sending buffering
290 * [e.g. tab to space conversions in n_tty.c opost()].
291 */
292 char buffer[HVCS_BUFF_LEN];
293 int chars_in_buffer;
294
295 /*
296 * Any variable below the kobject is valid before a tty is connected and
297 * stays valid after the tty is disconnected. These shouldn't be
298 * whacked until the koject refcount reaches zero though some entries
299 * may be changed via sysfs initiatives.
300 */
301 struct kobject kobj; /* ref count & hvcs_struct lifetime */
302 int connected; /* is the vty-server currently connected to a vty? */
303 uint32_t p_unit_address; /* partner unit address */
304 uint32_t p_partition_ID; /* partner partition ID */
305 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
306 struct list_head next; /* list management */
307 struct vio_dev *vdev;
308};
309
310/* Required to back map a kobject to its containing object */
311#define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj)
312
313static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs);
314static DEFINE_SPINLOCK(hvcs_structs_lock);
315
316static void hvcs_unthrottle(struct tty_struct *tty);
317static void hvcs_throttle(struct tty_struct *tty);
David Howells7d12e782006-10-05 14:55:46 +0100318static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
320static int hvcs_write(struct tty_struct *tty,
321 const unsigned char *buf, int count);
322static int hvcs_write_room(struct tty_struct *tty);
323static int hvcs_chars_in_buffer(struct tty_struct *tty);
324
325static int hvcs_has_pi(struct hvcs_struct *hvcsd);
326static void hvcs_set_pi(struct hvcs_partner_info *pi,
327 struct hvcs_struct *hvcsd);
328static int hvcs_get_pi(struct hvcs_struct *hvcsd);
329static int hvcs_rescan_devices_list(void);
330
331static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
332static void hvcs_partner_free(struct hvcs_struct *hvcsd);
333
334static int hvcs_enable_device(struct hvcs_struct *hvcsd,
335 uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
336
337static void destroy_hvcs_struct(struct kobject *kobj);
338static int hvcs_open(struct tty_struct *tty, struct file *filp);
339static void hvcs_close(struct tty_struct *tty, struct file *filp);
340static void hvcs_hangup(struct tty_struct * tty);
341
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342static int __devinit hvcs_probe(struct vio_dev *dev,
343 const struct vio_device_id *id);
344static int __devexit hvcs_remove(struct vio_dev *dev);
345static int __init hvcs_module_init(void);
346static void __exit hvcs_module_exit(void);
347
348#define HVCS_SCHED_READ 0x00000001
349#define HVCS_QUICK_READ 0x00000002
350#define HVCS_TRY_WRITE 0x00000004
351#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
352
Linas Vepstasc15bb292006-12-06 20:38:07 -0800353static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
354{
355 return viod->dev.driver_data;
356}
357/* The sysfs interface for the driver and devices */
358
359static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
360{
361 struct vio_dev *viod = to_vio_dev(dev);
362 struct hvcs_struct *hvcsd = from_vio_dev(viod);
363 unsigned long flags;
364 int retval;
365
366 spin_lock_irqsave(&hvcsd->lock, flags);
367 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
368 spin_unlock_irqrestore(&hvcsd->lock, flags);
369 return retval;
370}
371static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
372
373static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
374{
375 struct vio_dev *viod = to_vio_dev(dev);
376 struct hvcs_struct *hvcsd = from_vio_dev(viod);
377 unsigned long flags;
378 int retval;
379
380 spin_lock_irqsave(&hvcsd->lock, flags);
381 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
382 spin_unlock_irqrestore(&hvcsd->lock, flags);
383 return retval;
384}
385static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
386
387static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
388 size_t count)
389{
390 /*
391 * Don't need this feature at the present time because firmware doesn't
392 * yet support multiple partners.
393 */
394 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
395 return -EPERM;
396}
397
398static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
399{
400 struct vio_dev *viod = to_vio_dev(dev);
401 struct hvcs_struct *hvcsd = from_vio_dev(viod);
402 unsigned long flags;
403 int retval;
404
405 spin_lock_irqsave(&hvcsd->lock, flags);
406 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
407 spin_unlock_irqrestore(&hvcsd->lock, flags);
408 return retval;
409}
410
411static DEVICE_ATTR(current_vty,
412 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
413
414static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
415 size_t count)
416{
417 struct vio_dev *viod = to_vio_dev(dev);
418 struct hvcs_struct *hvcsd = from_vio_dev(viod);
419 unsigned long flags;
420
421 /* writing a '0' to this sysfs entry will result in the disconnect. */
422 if (simple_strtol(buf, NULL, 0) != 0)
423 return -EINVAL;
424
425 spin_lock_irqsave(&hvcsd->lock, flags);
426
427 if (hvcsd->open_count > 0) {
428 spin_unlock_irqrestore(&hvcsd->lock, flags);
429 printk(KERN_INFO "HVCS: vterm state unchanged. "
430 "The hvcs device node is still in use.\n");
431 return -EPERM;
432 }
433
434 if (hvcsd->connected == 0) {
435 spin_unlock_irqrestore(&hvcsd->lock, flags);
436 printk(KERN_INFO "HVCS: vterm state unchanged. The"
437 " vty-server is not connected to a vty.\n");
438 return -EPERM;
439 }
440
441 hvcs_partner_free(hvcsd);
442 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
443 " partner vty@%X:%d connection.\n",
444 hvcsd->vdev->unit_address,
445 hvcsd->p_unit_address,
446 (uint32_t)hvcsd->p_partition_ID);
447
448 spin_unlock_irqrestore(&hvcsd->lock, flags);
449 return count;
450}
451
452static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
453{
454 struct vio_dev *viod = to_vio_dev(dev);
455 struct hvcs_struct *hvcsd = from_vio_dev(viod);
456 unsigned long flags;
457 int retval;
458
459 spin_lock_irqsave(&hvcsd->lock, flags);
460 retval = sprintf(buf, "%d\n", hvcsd->connected);
461 spin_unlock_irqrestore(&hvcsd->lock, flags);
462 return retval;
463}
464static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
465 hvcs_vterm_state_show, hvcs_vterm_state_store);
466
467static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
468{
469 struct vio_dev *viod = to_vio_dev(dev);
470 struct hvcs_struct *hvcsd = from_vio_dev(viod);
471 unsigned long flags;
472 int retval;
473
474 spin_lock_irqsave(&hvcsd->lock, flags);
475 retval = sprintf(buf, "%d\n", hvcsd->index);
476 spin_unlock_irqrestore(&hvcsd->lock, flags);
477 return retval;
478}
479
480static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
481
482static struct attribute *hvcs_attrs[] = {
483 &dev_attr_partner_vtys.attr,
484 &dev_attr_partner_clcs.attr,
485 &dev_attr_current_vty.attr,
486 &dev_attr_vterm_state.attr,
487 &dev_attr_index.attr,
488 NULL,
489};
490
491static struct attribute_group hvcs_attr_group = {
492 .attrs = hvcs_attrs,
493};
494
495static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
496{
497 /* A 1 means it is updating, a 0 means it is done updating */
498 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
499}
500
501static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
502 size_t count)
503{
504 if ((simple_strtol(buf, NULL, 0) != 1)
505 && (hvcs_rescan_status != 0))
506 return -EINVAL;
507
508 hvcs_rescan_status = 1;
509 printk(KERN_INFO "HVCS: rescanning partner info for all"
510 " vty-servers.\n");
511 hvcs_rescan_devices_list();
512 hvcs_rescan_status = 0;
513 return count;
514}
515
516static DRIVER_ATTR(rescan,
517 S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
518
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519static void hvcs_kick(void)
520{
521 hvcs_kicked = 1;
522 wmb();
523 wake_up_process(hvcs_task);
524}
525
526static void hvcs_unthrottle(struct tty_struct *tty)
527{
528 struct hvcs_struct *hvcsd = tty->driver_data;
529 unsigned long flags;
530
531 spin_lock_irqsave(&hvcsd->lock, flags);
532 hvcsd->todo_mask |= HVCS_SCHED_READ;
533 spin_unlock_irqrestore(&hvcsd->lock, flags);
534 hvcs_kick();
535}
536
537static void hvcs_throttle(struct tty_struct *tty)
538{
539 struct hvcs_struct *hvcsd = tty->driver_data;
540 unsigned long flags;
541
542 spin_lock_irqsave(&hvcsd->lock, flags);
543 vio_disable_interrupts(hvcsd->vdev);
544 spin_unlock_irqrestore(&hvcsd->lock, flags);
545}
546
547/*
548 * If the device is being removed we don't have to worry about this interrupt
549 * handler taking any further interrupts because they are disabled which means
550 * the hvcs_struct will always be valid in this handler.
551 */
David Howells7d12e782006-10-05 14:55:46 +0100552static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553{
554 struct hvcs_struct *hvcsd = dev_instance;
555
556 spin_lock(&hvcsd->lock);
557 vio_disable_interrupts(hvcsd->vdev);
558 hvcsd->todo_mask |= HVCS_SCHED_READ;
559 spin_unlock(&hvcsd->lock);
560 hvcs_kick();
561
562 return IRQ_HANDLED;
563}
564
565/* This function must be called with the hvcsd->lock held */
566static void hvcs_try_write(struct hvcs_struct *hvcsd)
567{
568 uint32_t unit_address = hvcsd->vdev->unit_address;
569 struct tty_struct *tty = hvcsd->tty;
570 int sent;
571
572 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
573 /* won't send partial writes */
574 sent = hvc_put_chars(unit_address,
575 &hvcsd->buffer[0],
576 hvcsd->chars_in_buffer );
577 if (sent > 0) {
578 hvcsd->chars_in_buffer = 0;
579 /* wmb(); */
580 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
581 /* wmb(); */
582
583 /*
584 * We are still obligated to deliver the data to the
585 * hypervisor even if the tty has been closed because
586 * we commited to delivering it. But don't try to wake
587 * a non-existent tty.
588 */
589 if (tty) {
590 tty_wakeup(tty);
591 }
592 }
593 }
594}
595
596static int hvcs_io(struct hvcs_struct *hvcsd)
597{
598 uint32_t unit_address;
599 struct tty_struct *tty;
600 char buf[HVCS_BUFF_LEN] __ALIGNED__;
601 unsigned long flags;
602 int got = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
604 spin_lock_irqsave(&hvcsd->lock, flags);
605
606 unit_address = hvcsd->vdev->unit_address;
607 tty = hvcsd->tty;
608
609 hvcs_try_write(hvcsd);
610
611 if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
612 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
613 goto bail;
614 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
615 goto bail;
616
617 /* remove the read masks */
618 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
619
Alan Cox33f0f882006-01-09 20:54:13 -0800620 if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 got = hvc_get_chars(unit_address,
622 &buf[0],
623 HVCS_BUFF_LEN);
Alan Cox33f0f882006-01-09 20:54:13 -0800624 tty_insert_flip_string(tty, buf, got);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 }
626
627 /* Give the TTY time to process the data we just sent. */
628 if (got)
629 hvcsd->todo_mask |= HVCS_QUICK_READ;
630
631 spin_unlock_irqrestore(&hvcsd->lock, flags);
Alan Cox33f0f882006-01-09 20:54:13 -0800632 /* This is synch because tty->low_latency == 1 */
633 if(got)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 tty_flip_buffer_push(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635
636 if (!got) {
637 /* Do this _after_ the flip_buffer_push */
638 spin_lock_irqsave(&hvcsd->lock, flags);
639 vio_enable_interrupts(hvcsd->vdev);
640 spin_unlock_irqrestore(&hvcsd->lock, flags);
641 }
642
643 return hvcsd->todo_mask;
644
645 bail:
646 spin_unlock_irqrestore(&hvcsd->lock, flags);
647 return hvcsd->todo_mask;
648}
649
650static int khvcsd(void *unused)
651{
652 struct hvcs_struct *hvcsd;
653 int hvcs_todo_mask;
654
655 __set_current_state(TASK_RUNNING);
656
657 do {
658 hvcs_todo_mask = 0;
659 hvcs_kicked = 0;
660 wmb();
661
662 spin_lock(&hvcs_structs_lock);
663 list_for_each_entry(hvcsd, &hvcs_structs, next) {
664 hvcs_todo_mask |= hvcs_io(hvcsd);
665 }
666 spin_unlock(&hvcs_structs_lock);
667
668 /*
669 * If any of the hvcs adapters want to try a write or quick read
670 * don't schedule(), yield a smidgen then execute the hvcs_io
671 * thread again for those that want the write.
672 */
673 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
674 yield();
675 continue;
676 }
677
678 set_current_state(TASK_INTERRUPTIBLE);
679 if (!hvcs_kicked)
680 schedule();
681 __set_current_state(TASK_RUNNING);
682 } while (!kthread_should_stop());
683
684 return 0;
685}
686
687static struct vio_device_id hvcs_driver_table[] __devinitdata= {
688 {"serial-server", "hvterm2"},
Stephen Rothwellfb120da2005-08-17 16:42:59 +1000689 { "", "" }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690};
691MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
692
693static void hvcs_return_index(int index)
694{
695 /* Paranoia check */
696 if (!hvcs_index_list)
697 return;
698 if (index < 0 || index >= hvcs_index_count)
699 return;
700 if (hvcs_index_list[index] == -1)
701 return;
702 else
703 hvcs_index_list[index] = -1;
704}
705
706/* callback when the kboject ref count reaches zero */
707static void destroy_hvcs_struct(struct kobject *kobj)
708{
709 struct hvcs_struct *hvcsd = from_kobj(kobj);
710 struct vio_dev *vdev;
711 unsigned long flags;
712
713 spin_lock(&hvcs_structs_lock);
714 spin_lock_irqsave(&hvcsd->lock, flags);
715
716 /* the list_del poisons the pointers */
717 list_del(&(hvcsd->next));
718
719 if (hvcsd->connected == 1) {
720 hvcs_partner_free(hvcsd);
721 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
722 " partner vty@%X:%d connection.\n",
723 hvcsd->vdev->unit_address,
724 hvcsd->p_unit_address,
725 (uint32_t)hvcsd->p_partition_ID);
726 }
727 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
728 hvcsd->vdev->unit_address);
729
730 vdev = hvcsd->vdev;
731 hvcsd->vdev = NULL;
732
733 hvcsd->p_unit_address = 0;
734 hvcsd->p_partition_ID = 0;
735 hvcs_return_index(hvcsd->index);
736 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
737
738 spin_unlock_irqrestore(&hvcsd->lock, flags);
739 spin_unlock(&hvcs_structs_lock);
740
Linas Vepstasc15bb292006-12-06 20:38:07 -0800741 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
743 kfree(hvcsd);
744}
745
746static struct kobj_type hvcs_kobj_type = {
747 .release = destroy_hvcs_struct,
748};
749
750static int hvcs_get_index(void)
751{
752 int i;
753 /* Paranoia check */
754 if (!hvcs_index_list) {
755 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
756 return -EFAULT;
757 }
758 /* Find the numerically lowest first free index. */
759 for(i = 0; i < hvcs_index_count; i++) {
760 if (hvcs_index_list[i] == -1) {
761 hvcs_index_list[i] = 0;
762 return i;
763 }
764 }
765 return -1;
766}
767
768static int __devinit hvcs_probe(
769 struct vio_dev *dev,
770 const struct vio_device_id *id)
771{
772 struct hvcs_struct *hvcsd;
773 int index;
Linas Vepstasc15bb292006-12-06 20:38:07 -0800774 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
776 if (!dev || !id) {
777 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
778 return -EPERM;
779 }
780
781 /* early to avoid cleanup on failure */
782 index = hvcs_get_index();
783 if (index < 0) {
784 return -EFAULT;
785 }
786
Yoann Padioleaudd00cc42007-07-19 01:49:03 -0700787 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 if (!hvcsd)
789 return -ENODEV;
790
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
792 spin_lock_init(&hvcsd->lock);
793 /* Automatically incs the refcount the first time */
794 kobject_init(&hvcsd->kobj);
795 /* Set up the callback for terminating the hvcs_struct's life */
796 hvcsd->kobj.ktype = &hvcs_kobj_type;
797
798 hvcsd->vdev = dev;
799 dev->dev.driver_data = hvcsd;
800
801 hvcsd->index = index;
802
803 /* hvcsd->index = ++hvcs_struct_count; */
804 hvcsd->chars_in_buffer = 0;
805 hvcsd->todo_mask = 0;
806 hvcsd->connected = 0;
807
808 /*
809 * This will populate the hvcs_struct's partner info fields for the
810 * first time.
811 */
812 if (hvcs_get_pi(hvcsd)) {
813 printk(KERN_ERR "HVCS: Failed to fetch partner"
814 " info for vty-server@%X on device probe.\n",
815 hvcsd->vdev->unit_address);
816 }
817
818 /*
819 * If a user app opens a tty that corresponds to this vty-server before
820 * the hvcs_struct has been added to the devices list then the user app
821 * will get -ENODEV.
822 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 spin_lock(&hvcs_structs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 list_add_tail(&(hvcsd->next), &hvcs_structs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 spin_unlock(&hvcs_structs_lock);
826
Linas Vepstasc15bb292006-12-06 20:38:07 -0800827 retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group);
828 if (retval) {
829 printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n",
830 hvcsd->vdev->unit_address);
831 return retval;
832 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
834 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
835
836 /*
837 * DON'T enable interrupts here because there is no user to receive the
838 * data.
839 */
840 return 0;
841}
842
843static int __devexit hvcs_remove(struct vio_dev *dev)
844{
845 struct hvcs_struct *hvcsd = dev->dev.driver_data;
846 unsigned long flags;
847 struct kobject *kobjp;
848 struct tty_struct *tty;
849
850 if (!hvcsd)
851 return -ENODEV;
852
853 /* By this time the vty-server won't be getting any more interrups */
854
855 spin_lock_irqsave(&hvcsd->lock, flags);
856
857 tty = hvcsd->tty;
858
859 kobjp = &hvcsd->kobj;
860
861 spin_unlock_irqrestore(&hvcsd->lock, flags);
862
863 /*
864 * Let the last holder of this object cause it to be removed, which
865 * would probably be tty_hangup below.
866 */
867 kobject_put (kobjp);
868
869 /*
870 * The hangup is a scheduled function which will auto chain call
871 * hvcs_hangup. The tty should always be valid at this time unless a
872 * simultaneous tty close already cleaned up the hvcs_struct.
873 */
874 if (tty)
875 tty_hangup(tty);
876
877 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
878 " vio bus.\n", dev->unit_address);
879 return 0;
880};
881
882static struct vio_driver hvcs_vio_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 .id_table = hvcs_driver_table,
884 .probe = hvcs_probe,
885 .remove = hvcs_remove,
Stephen Rothwell6fdf5392005-10-24 14:53:21 +1000886 .driver = {
887 .name = hvcs_driver_name,
Stephen Rothwell915124d2005-10-24 15:12:22 +1000888 .owner = THIS_MODULE,
Stephen Rothwell6fdf5392005-10-24 14:53:21 +1000889 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890};
891
892/* Only called from hvcs_get_pi please */
893static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
894{
895 int clclength;
896
897 hvcsd->p_unit_address = pi->unit_address;
898 hvcsd->p_partition_ID = pi->partition_ID;
899 clclength = strlen(&pi->location_code[0]);
900 if (clclength > HVCS_CLC_LENGTH)
901 clclength = HVCS_CLC_LENGTH;
902
903 /* copy the null-term char too */
904 strncpy(&hvcsd->p_location_code[0],
905 &pi->location_code[0], clclength + 1);
906}
907
908/*
909 * Traverse the list and add the partner info that is found to the hvcs_struct
910 * struct entry. NOTE: At this time I know that partner info will return a
911 * single entry but in the future there may be multiple partner info entries per
912 * vty-server and you'll want to zero out that list and reset it. If for some
913 * reason you have an old version of this driver but there IS more than one
914 * partner info then hvcsd->p_* will hold the last partner info data from the
915 * firmware query. A good way to update this code would be to replace the three
916 * partner info fields in hvcs_struct with a list of hvcs_partner_info
917 * instances.
918 *
919 * This function must be called with the hvcsd->lock held.
920 */
921static int hvcs_get_pi(struct hvcs_struct *hvcsd)
922{
923 struct hvcs_partner_info *pi;
924 uint32_t unit_address = hvcsd->vdev->unit_address;
925 struct list_head head;
926 int retval;
927
928 spin_lock(&hvcs_pi_lock);
929 if (!hvcs_pi_buff) {
930 spin_unlock(&hvcs_pi_lock);
931 return -EFAULT;
932 }
933 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
934 spin_unlock(&hvcs_pi_lock);
935 if (retval) {
936 printk(KERN_ERR "HVCS: Failed to fetch partner"
937 " info for vty-server@%x.\n", unit_address);
938 return retval;
939 }
940
941 /* nixes the values if the partner vty went away */
942 hvcsd->p_unit_address = 0;
943 hvcsd->p_partition_ID = 0;
944
945 list_for_each_entry(pi, &head, node)
946 hvcs_set_pi(pi, hvcsd);
947
948 hvcs_free_partner_info(&head);
949 return 0;
950}
951
952/*
953 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
954 * be executed elsewhere, in order to prevent deadlock issues.
955 */
956static int hvcs_rescan_devices_list(void)
957{
958 struct hvcs_struct *hvcsd;
959 unsigned long flags;
960
961 spin_lock(&hvcs_structs_lock);
962
963 list_for_each_entry(hvcsd, &hvcs_structs, next) {
964 spin_lock_irqsave(&hvcsd->lock, flags);
965 hvcs_get_pi(hvcsd);
966 spin_unlock_irqrestore(&hvcsd->lock, flags);
967 }
968
969 spin_unlock(&hvcs_structs_lock);
970
971 return 0;
972}
973
974/*
975 * Farm this off into its own function because it could be more complex once
976 * multiple partners support is added. This function should be called with
977 * the hvcsd->lock held.
978 */
979static int hvcs_has_pi(struct hvcs_struct *hvcsd)
980{
981 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
982 return 0;
983 return 1;
984}
985
986/*
987 * NOTE: It is possible that the super admin removed a partner vty and then
988 * added a different vty as the new partner.
989 *
990 * This function must be called with the hvcsd->lock held.
991 */
992static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
993{
994 int retval;
995 unsigned int unit_address = hvcsd->vdev->unit_address;
996
997 /*
998 * If there wasn't any pi when the device was added it doesn't meant
999 * there isn't any now. This driver isn't notified when a new partner
1000 * vty is added to a vty-server so we discover changes on our own.
1001 * Please see comments in hvcs_register_connection() for justification
1002 * of this bizarre code.
1003 */
1004 retval = hvcs_register_connection(unit_address,
1005 hvcsd->p_partition_ID,
1006 hvcsd->p_unit_address);
1007 if (!retval) {
1008 hvcsd->connected = 1;
1009 return 0;
1010 } else if (retval != -EINVAL)
1011 return retval;
1012
1013 /*
1014 * As per the spec re-get the pi and try again if -EINVAL after the
1015 * first connection attempt.
1016 */
1017 if (hvcs_get_pi(hvcsd))
1018 return -ENOMEM;
1019
1020 if (!hvcs_has_pi(hvcsd))
1021 return -ENODEV;
1022
1023 retval = hvcs_register_connection(unit_address,
1024 hvcsd->p_partition_ID,
1025 hvcsd->p_unit_address);
1026 if (retval != -EINVAL) {
1027 hvcsd->connected = 1;
1028 return retval;
1029 }
1030
1031 /*
1032 * EBUSY is the most likely scenario though the vty could have been
1033 * removed or there really could be an hcall error due to the parameter
1034 * data but thanks to ambiguous firmware return codes we can't really
1035 * tell.
1036 */
1037 printk(KERN_INFO "HVCS: vty-server or partner"
1038 " vty is busy. Try again later.\n");
1039 return -EBUSY;
1040}
1041
1042/* This function must be called with the hvcsd->lock held */
1043static void hvcs_partner_free(struct hvcs_struct *hvcsd)
1044{
1045 int retval;
1046 do {
1047 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
1048 } while (retval == -EBUSY);
1049 hvcsd->connected = 0;
1050}
1051
1052/* This helper function must be called WITHOUT the hvcsd->lock held */
1053static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
1054 unsigned int irq, struct vio_dev *vdev)
1055{
1056 unsigned long flags;
1057 int rc;
1058
1059 /*
1060 * It is possible that the vty-server was removed between the time that
1061 * the conn was registered and now.
1062 */
1063 if (!(rc = request_irq(irq, &hvcs_handle_interrupt,
Thomas Gleixner0f2ed4c2006-07-01 19:29:33 -07001064 IRQF_DISABLED, "ibmhvcs", hvcsd))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 /*
1066 * It is possible the vty-server was removed after the irq was
1067 * requested but before we have time to enable interrupts.
1068 */
Segher Boessenkool706c8c92006-03-30 14:49:40 +02001069 if (vio_enable_interrupts(vdev) == H_SUCCESS)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 return 0;
1071 else {
1072 printk(KERN_ERR "HVCS: int enable failed for"
1073 " vty-server@%X.\n", unit_address);
1074 free_irq(irq, hvcsd);
1075 }
1076 } else
1077 printk(KERN_ERR "HVCS: irq req failed for"
1078 " vty-server@%X.\n", unit_address);
1079
1080 spin_lock_irqsave(&hvcsd->lock, flags);
1081 hvcs_partner_free(hvcsd);
1082 spin_unlock_irqrestore(&hvcsd->lock, flags);
1083
1084 return rc;
1085
1086}
1087
1088/*
1089 * This always increments the kobject ref count if the call is successful.
1090 * Please remember to dec when you are done with the instance.
1091 *
1092 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
1093 * calling this function or you will get deadlock.
1094 */
Stephen Rothwellb1c30112007-07-22 00:25:00 +10001095static struct hvcs_struct *hvcs_get_by_index(int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096{
1097 struct hvcs_struct *hvcsd = NULL;
1098 unsigned long flags;
1099
1100 spin_lock(&hvcs_structs_lock);
1101 /* We can immediately discard OOB requests */
1102 if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
1103 list_for_each_entry(hvcsd, &hvcs_structs, next) {
1104 spin_lock_irqsave(&hvcsd->lock, flags);
1105 if (hvcsd->index == index) {
1106 kobject_get(&hvcsd->kobj);
1107 spin_unlock_irqrestore(&hvcsd->lock, flags);
1108 spin_unlock(&hvcs_structs_lock);
1109 return hvcsd;
1110 }
1111 spin_unlock_irqrestore(&hvcsd->lock, flags);
1112 }
1113 hvcsd = NULL;
1114 }
1115
1116 spin_unlock(&hvcs_structs_lock);
1117 return hvcsd;
1118}
1119
1120/*
1121 * This is invoked via the tty_open interface when a user app connects to the
1122 * /dev node.
1123 */
1124static int hvcs_open(struct tty_struct *tty, struct file *filp)
1125{
1126 struct hvcs_struct *hvcsd;
1127 int rc, retval = 0;
1128 unsigned long flags;
1129 unsigned int irq;
1130 struct vio_dev *vdev;
1131 unsigned long unit_address;
1132 struct kobject *kobjp;
1133
1134 if (tty->driver_data)
1135 goto fast_open;
1136
1137 /*
1138 * Is there a vty-server that shares the same index?
1139 * This function increments the kobject index.
1140 */
1141 if (!(hvcsd = hvcs_get_by_index(tty->index))) {
1142 printk(KERN_WARNING "HVCS: open failed, no device associated"
1143 " with tty->index %d.\n", tty->index);
1144 return -ENODEV;
1145 }
1146
1147 spin_lock_irqsave(&hvcsd->lock, flags);
1148
1149 if (hvcsd->connected == 0)
1150 if ((retval = hvcs_partner_connect(hvcsd)))
1151 goto error_release;
1152
1153 hvcsd->open_count = 1;
1154 hvcsd->tty = tty;
1155 tty->driver_data = hvcsd;
1156
1157 /*
1158 * Set this driver to low latency so that we actually have a chance at
1159 * catching a throttled TTY after we flip_buffer_push. Otherwise the
1160 * flush_to_async may not execute until after the kernel_thread has
1161 * yielded and resumed the next flip_buffer_push resulting in data
1162 * loss.
1163 */
1164 tty->low_latency = 1;
1165
1166 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1167
1168 /*
1169 * Save these in the spinlock for the enable operations that need them
1170 * outside of the spinlock.
1171 */
1172 irq = hvcsd->vdev->irq;
1173 vdev = hvcsd->vdev;
1174 unit_address = hvcsd->vdev->unit_address;
1175
1176 hvcsd->todo_mask |= HVCS_SCHED_READ;
1177 spin_unlock_irqrestore(&hvcsd->lock, flags);
1178
1179 /*
1180 * This must be done outside of the spinlock because it requests irqs
1181 * and will grab the spinlock and free the connection if it fails.
1182 */
1183 if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) {
1184 kobject_put(&hvcsd->kobj);
1185 printk(KERN_WARNING "HVCS: enable device failed.\n");
1186 return rc;
1187 }
1188
1189 goto open_success;
1190
1191fast_open:
1192 hvcsd = tty->driver_data;
1193
1194 spin_lock_irqsave(&hvcsd->lock, flags);
1195 if (!kobject_get(&hvcsd->kobj)) {
1196 spin_unlock_irqrestore(&hvcsd->lock, flags);
1197 printk(KERN_ERR "HVCS: Kobject of open"
1198 " hvcs doesn't exist.\n");
1199 return -EFAULT; /* Is this the right return value? */
1200 }
1201
1202 hvcsd->open_count++;
1203
1204 hvcsd->todo_mask |= HVCS_SCHED_READ;
1205 spin_unlock_irqrestore(&hvcsd->lock, flags);
1206open_success:
1207 hvcs_kick();
1208
1209 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1210 hvcsd->vdev->unit_address );
1211
1212 return 0;
1213
1214error_release:
1215 kobjp = &hvcsd->kobj;
1216 spin_unlock_irqrestore(&hvcsd->lock, flags);
1217 kobject_put(&hvcsd->kobj);
1218
1219 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1220 return retval;
1221}
1222
1223static void hvcs_close(struct tty_struct *tty, struct file *filp)
1224{
1225 struct hvcs_struct *hvcsd;
1226 unsigned long flags;
1227 struct kobject *kobjp;
1228 int irq = NO_IRQ;
1229
1230 /*
1231 * Is someone trying to close the file associated with this device after
1232 * we have hung up? If so tty->driver_data wouldn't be valid.
1233 */
1234 if (tty_hung_up_p(filp))
1235 return;
1236
1237 /*
1238 * No driver_data means that this close was probably issued after a
1239 * failed hvcs_open by the tty layer's release_dev() api and we can just
1240 * exit cleanly.
1241 */
1242 if (!tty->driver_data)
1243 return;
1244
1245 hvcsd = tty->driver_data;
1246
1247 spin_lock_irqsave(&hvcsd->lock, flags);
1248 kobjp = &hvcsd->kobj;
1249 if (--hvcsd->open_count == 0) {
1250
1251 vio_disable_interrupts(hvcsd->vdev);
1252
1253 /*
1254 * NULL this early so that the kernel_thread doesn't try to
1255 * execute any operations on the TTY even though it is obligated
1256 * to deliver any pending I/O to the hypervisor.
1257 */
1258 hvcsd->tty = NULL;
1259
1260 irq = hvcsd->vdev->irq;
1261 spin_unlock_irqrestore(&hvcsd->lock, flags);
1262
1263 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1264
1265 /*
1266 * This line is important because it tells hvcs_open that this
1267 * device needs to be re-configured the next time hvcs_open is
1268 * called.
1269 */
1270 tty->driver_data = NULL;
1271
1272 free_irq(irq, hvcsd);
1273 kobject_put(kobjp);
1274 return;
1275 } else if (hvcsd->open_count < 0) {
1276 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
1277 " is missmanaged.\n",
1278 hvcsd->vdev->unit_address, hvcsd->open_count);
1279 }
1280
1281 spin_unlock_irqrestore(&hvcsd->lock, flags);
1282 kobject_put(kobjp);
1283}
1284
1285static void hvcs_hangup(struct tty_struct * tty)
1286{
1287 struct hvcs_struct *hvcsd = tty->driver_data;
1288 unsigned long flags;
1289 int temp_open_count;
1290 struct kobject *kobjp;
1291 int irq = NO_IRQ;
1292
1293 spin_lock_irqsave(&hvcsd->lock, flags);
1294 /* Preserve this so that we know how many kobject refs to put */
1295 temp_open_count = hvcsd->open_count;
1296
1297 /*
1298 * Don't kobject put inside the spinlock because the destruction
1299 * callback may use the spinlock and it may get called before the
1300 * spinlock has been released. Get a pointer to the kobject and
1301 * kobject_put on that after releasing the spinlock.
1302 */
1303 kobjp = &hvcsd->kobj;
1304
1305 vio_disable_interrupts(hvcsd->vdev);
1306
1307 hvcsd->todo_mask = 0;
1308
1309 /* I don't think the tty needs the hvcs_struct pointer after a hangup */
1310 hvcsd->tty->driver_data = NULL;
1311 hvcsd->tty = NULL;
1312
1313 hvcsd->open_count = 0;
1314
1315 /* This will drop any buffered data on the floor which is OK in a hangup
1316 * scenario. */
1317 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1318 hvcsd->chars_in_buffer = 0;
1319
1320 irq = hvcsd->vdev->irq;
1321
1322 spin_unlock_irqrestore(&hvcsd->lock, flags);
1323
1324 free_irq(irq, hvcsd);
1325
1326 /*
1327 * We need to kobject_put() for every open_count we have since the
1328 * tty_hangup() function doesn't invoke a close per open connection on a
1329 * non-console device.
1330 */
1331 while(temp_open_count) {
1332 --temp_open_count;
1333 /*
1334 * The final put will trigger destruction of the hvcs_struct.
1335 * NOTE: If this hangup was signaled from user space then the
1336 * final put will never happen.
1337 */
1338 kobject_put(kobjp);
1339 }
1340}
1341
1342/*
1343 * NOTE: This is almost always from_user since user level apps interact with the
1344 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1345 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1346 * tty_hangup will allow hvcs_write time to complete execution before it
1347 * terminates our device.
1348 */
1349static int hvcs_write(struct tty_struct *tty,
1350 const unsigned char *buf, int count)
1351{
1352 struct hvcs_struct *hvcsd = tty->driver_data;
1353 unsigned int unit_address;
1354 const unsigned char *charbuf;
1355 unsigned long flags;
1356 int total_sent = 0;
1357 int tosend = 0;
1358 int result = 0;
1359
1360 /*
1361 * If they don't check the return code off of their open they may
1362 * attempt this even if there is no connected device.
1363 */
1364 if (!hvcsd)
1365 return -ENODEV;
1366
1367 /* Reasonable size to prevent user level flooding */
1368 if (count > HVCS_MAX_FROM_USER) {
1369 printk(KERN_WARNING "HVCS write: count being truncated to"
1370 " HVCS_MAX_FROM_USER.\n");
1371 count = HVCS_MAX_FROM_USER;
1372 }
1373
1374 charbuf = buf;
1375
1376 spin_lock_irqsave(&hvcsd->lock, flags);
1377
1378 /*
1379 * Somehow an open succedded but the device was removed or the
1380 * connection terminated between the vty-server and partner vty during
1381 * the middle of a write operation? This is a crummy place to do this
1382 * but we want to keep it all in the spinlock.
1383 */
1384 if (hvcsd->open_count <= 0) {
1385 spin_unlock_irqrestore(&hvcsd->lock, flags);
1386 return -ENODEV;
1387 }
1388
1389 unit_address = hvcsd->vdev->unit_address;
1390
1391 while (count > 0) {
1392 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1393 /*
1394 * No more space, this probably means that the last call to
1395 * hvcs_write() didn't succeed and the buffer was filled up.
1396 */
1397 if (!tosend)
1398 break;
1399
1400 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1401 &charbuf[total_sent],
1402 tosend);
1403
1404 hvcsd->chars_in_buffer += tosend;
1405
1406 result = 0;
1407
1408 /*
1409 * If this is true then we don't want to try writing to the
1410 * hypervisor because that is the kernel_threads job now. We'll
1411 * just add to the buffer.
1412 */
1413 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1414 /* won't send partial writes */
1415 result = hvc_put_chars(unit_address,
1416 &hvcsd->buffer[0],
1417 hvcsd->chars_in_buffer);
1418
1419 /*
1420 * Since we know we have enough room in hvcsd->buffer for
1421 * tosend we record that it was sent regardless of whether the
1422 * hypervisor actually took it because we have it buffered.
1423 */
1424 total_sent+=tosend;
1425 count-=tosend;
1426 if (result == 0) {
1427 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1428 hvcs_kick();
1429 break;
1430 }
1431
1432 hvcsd->chars_in_buffer = 0;
1433 /*
1434 * Test after the chars_in_buffer reset otherwise this could
1435 * deadlock our writes if hvc_put_chars fails.
1436 */
1437 if (result < 0)
1438 break;
1439 }
1440
1441 spin_unlock_irqrestore(&hvcsd->lock, flags);
1442
1443 if (result == -1)
1444 return -EIO;
1445 else
1446 return total_sent;
1447}
1448
1449/*
1450 * This is really asking how much can we guarentee that we can send or that we
1451 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1452 * return value, hence the reason for hvcs_struct buffering.
1453 */
1454static int hvcs_write_room(struct tty_struct *tty)
1455{
1456 struct hvcs_struct *hvcsd = tty->driver_data;
1457
1458 if (!hvcsd || hvcsd->open_count <= 0)
1459 return 0;
1460
1461 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1462}
1463
1464static int hvcs_chars_in_buffer(struct tty_struct *tty)
1465{
1466 struct hvcs_struct *hvcsd = tty->driver_data;
1467
1468 return hvcsd->chars_in_buffer;
1469}
1470
Jeff Dikeb68e31d2006-10-02 02:17:18 -07001471static const struct tty_operations hvcs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 .open = hvcs_open,
1473 .close = hvcs_close,
1474 .hangup = hvcs_hangup,
1475 .write = hvcs_write,
1476 .write_room = hvcs_write_room,
1477 .chars_in_buffer = hvcs_chars_in_buffer,
1478 .unthrottle = hvcs_unthrottle,
1479 .throttle = hvcs_throttle,
1480};
1481
1482static int hvcs_alloc_index_list(int n)
1483{
1484 int i;
Jesper Juhl8f760782006-06-27 02:55:06 -07001485
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL);
1487 if (!hvcs_index_list)
1488 return -ENOMEM;
1489 hvcs_index_count = n;
Jesper Juhl8f760782006-06-27 02:55:06 -07001490 for (i = 0; i < hvcs_index_count; i++)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 hvcs_index_list[i] = -1;
1492 return 0;
1493}
1494
1495static void hvcs_free_index_list(void)
1496{
1497 /* Paranoia check to be thorough. */
Jesper Juhl8f760782006-06-27 02:55:06 -07001498 kfree(hvcs_index_list);
1499 hvcs_index_list = NULL;
1500 hvcs_index_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501}
1502
1503static int __init hvcs_module_init(void)
1504{
1505 int rc;
1506 int num_ttys_to_alloc;
1507
1508 printk(KERN_INFO "Initializing %s\n", hvcs_driver_string);
1509
1510 /* Has the user specified an overload with an insmod param? */
1511 if (hvcs_parm_num_devs <= 0 ||
1512 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1513 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1514 } else
1515 num_ttys_to_alloc = hvcs_parm_num_devs;
1516
1517 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
1518 if (!hvcs_tty_driver)
1519 return -ENOMEM;
1520
Linas Vepstasc15bb292006-12-06 20:38:07 -08001521 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
1522 rc = -ENOMEM;
1523 goto index_fail;
1524 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525
1526 hvcs_tty_driver->owner = THIS_MODULE;
1527
1528 hvcs_tty_driver->driver_name = hvcs_driver_name;
1529 hvcs_tty_driver->name = hvcs_device_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530
1531 /*
1532 * We'll let the system assign us a major number, indicated by leaving
1533 * it blank.
1534 */
1535
1536 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1537 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1538
1539 /*
1540 * We role our own so that we DONT ECHO. We can't echo because the
1541 * device we are connecting to already echoes by default and this would
1542 * throw us into a horrible recursive echo-echo-echo loop.
1543 */
1544 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1545 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;
1546
1547 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1548
1549 /*
1550 * The following call will result in sysfs entries that denote the
1551 * dynamically assigned major and minor numbers for our devices.
1552 */
1553 if (tty_register_driver(hvcs_tty_driver)) {
Linas Vepstasc15bb292006-12-06 20:38:07 -08001554 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
1555 rc = -EIO;
1556 goto register_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 }
1558
1559 hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
1560 if (!hvcs_pi_buff) {
Linas Vepstasc15bb292006-12-06 20:38:07 -08001561 rc = -ENOMEM;
1562 goto buff_alloc_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563 }
1564
1565 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1566 if (IS_ERR(hvcs_task)) {
1567 printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n");
Linas Vepstasc15bb292006-12-06 20:38:07 -08001568 rc = -EIO;
1569 goto kthread_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 }
1571
1572 rc = vio_register_driver(&hvcs_vio_driver);
Linas Vepstasc15bb292006-12-06 20:38:07 -08001573 if (rc) {
1574 printk(KERN_ERR "HVCS: can't register vio driver\n");
1575 goto vio_fail;
1576 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577
1578 /*
1579 * This needs to be done AFTER the vio_register_driver() call or else
1580 * the kobjects won't be initialized properly.
1581 */
Linas Vepstasc15bb292006-12-06 20:38:07 -08001582 rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan);
1583 if (rc) {
1584 printk(KERN_ERR "HVCS: sysfs attr create failed\n");
1585 goto attr_fail;
1586 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587
1588 printk(KERN_INFO "HVCS: driver module inserted.\n");
1589
Linas Vepstasc15bb292006-12-06 20:38:07 -08001590 return 0;
1591
1592attr_fail:
1593 vio_unregister_driver(&hvcs_vio_driver);
1594vio_fail:
1595 kthread_stop(hvcs_task);
1596kthread_fail:
1597 kfree(hvcs_pi_buff);
1598buff_alloc_fail:
1599 tty_unregister_driver(hvcs_tty_driver);
1600register_fail:
1601 hvcs_free_index_list();
1602index_fail:
1603 put_tty_driver(hvcs_tty_driver);
1604 hvcs_tty_driver = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 return rc;
1606}
1607
1608static void __exit hvcs_module_exit(void)
1609{
1610 /*
1611 * This driver receives hvcs_remove callbacks for each device upon
1612 * module removal.
1613 */
1614
1615 /*
1616 * This synchronous operation will wake the khvcsd kthread if it is
1617 * asleep and will return when khvcsd has terminated.
1618 */
1619 kthread_stop(hvcs_task);
1620
1621 spin_lock(&hvcs_pi_lock);
1622 kfree(hvcs_pi_buff);
1623 hvcs_pi_buff = NULL;
1624 spin_unlock(&hvcs_pi_lock);
1625
Linas Vepstasc15bb292006-12-06 20:38:07 -08001626 driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627
1628 vio_unregister_driver(&hvcs_vio_driver);
1629
1630 tty_unregister_driver(hvcs_tty_driver);
1631
1632 hvcs_free_index_list();
1633
1634 put_tty_driver(hvcs_tty_driver);
1635
1636 printk(KERN_INFO "HVCS: driver module removed.\n");
1637}
1638
1639module_init(hvcs_module_init);
1640module_exit(hvcs_module_exit);