ia64/linux-2.6.18-xen.hg

view drivers/char/hvcs.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /*
2 * IBM eServer Hypervisor Virtual Console Server Device Driver
3 * Copyright (C) 2003, 2004 IBM Corp.
4 * Ryan S. Arnold (rsa@us.ibm.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
21 *
22 * This is the device driver for the IBM Hypervisor Virtual Console Server,
23 * "hvcs". The IBM hvcs provides a tty driver interface to allow Linux
24 * user space applications access to the system consoles of logically
25 * partitioned operating systems, e.g. Linux, running on the same partitioned
26 * Power5 ppc64 system. Physical hardware consoles per partition are not
27 * practical on this hardware so system consoles are accessed by this driver
28 * using inter-partition firmware interfaces to virtual terminal devices.
29 *
30 * A vty is known to the HMC as a "virtual serial server adapter". It is a
31 * virtual terminal device that is created by firmware upon partition creation
32 * to act as a partitioned OS's console device.
33 *
34 * Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64
35 * Linux system upon their creation by the HMC or their exposure during boot.
36 * The non-user interactive backend of this driver is implemented as a vio
37 * device driver so that it can receive notification of vty-server lifetimes
38 * after it registers with the vio bus to handle vty-server probe and remove
39 * callbacks.
40 *
41 * Many vty-servers can be configured to connect to one vty, but a vty can
42 * only be actively connected to by a single vty-server, in any manner, at one
43 * time. If the HMC is currently hosting the console for a target Linux
44 * partition; attempts to open the tty device to the partition's console using
45 * the hvcs on any partition will return -EBUSY with every open attempt until
46 * the HMC frees the connection between its vty-server and the desired
47 * partition's vty device. Conversely, a vty-server may only be connected to
48 * a single vty at one time even though it may have several configured vty
49 * partner possibilities.
50 *
51 * Firmware does not provide notification of vty partner changes to this
52 * driver. This means that an HMC Super Admin may add or remove partner vtys
53 * from a vty-server's partner list but the changes will not be signaled to
54 * the vty-server. Firmware only notifies the driver when a vty-server is
55 * added or removed from the system. To compensate for this deficiency, this
56 * driver implements a sysfs update attribute which provides a method for
57 * rescanning partner information upon a user's request.
58 *
59 * Each vty-server, prior to being exposed to this driver is reference counted
60 * using the 2.6 Linux kernel 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 */
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>
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
121 * include/asm-powerpc/hvcserver.h
122 *
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 */
131 #define HVCS_DRIVER_VERSION "1.3.3"
133 MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
134 MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
135 MODULE_LICENSE("GPL");
136 MODULE_VERSION(HVCS_DRIVER_VERSION);
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 */
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
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
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
169 /*
170 * The hcall interface involves putting 8 chars into each of two registers.
171 * 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.
175 */
176 #define __ALIGNED__ __attribute__((__aligned__(8)))
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
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
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 */
195 static 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 };
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 */
208 static int hvcs_parm_num_devs = -1;
209 module_param(hvcs_parm_num_devs, int, 0);
211 char hvcs_driver_name[] = "hvcs";
212 char hvcs_device_node[] = "hvcs";
213 char hvcs_driver_string[]
214 = "IBM hvcs (Hypervisor Virtual Console Server) Driver";
216 /* Status of partner info rescan triggered via sysfs. */
217 static int hvcs_rescan_status;
219 static struct tty_driver *hvcs_tty_driver;
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 */
234 static int *hvcs_index_list;
236 /*
237 * How large is the list? This is kept for traversal since the list is
238 * dynamically created.
239 */
240 static int hvcs_index_count;
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 */
246 static int hvcs_kicked;
248 /*
249 * Use by the kthread construct for task operations like waking the sleeping
250 * thread and stopping the kthread.
251 */
252 static struct task_struct *hvcs_task;
254 /*
255 * We allocate this for the use of all of the hvcs_structs when they fetch
256 * partner info.
257 */
258 static unsigned long *hvcs_pi_buff;
260 /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
261 static DEFINE_SPINLOCK(hvcs_pi_lock);
263 /* One vty-server per hvcs_struct */
264 struct hvcs_struct {
265 spinlock_t lock;
267 /*
268 * This index identifies this hvcs device as the complement to a
269 * specific tty index.
270 */
271 unsigned int index;
273 struct tty_struct *tty;
274 unsigned int open_count;
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;
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;
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 };
308 /* Required to back map a kobject to its containing object */
309 #define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj)
311 static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs);
312 static DEFINE_SPINLOCK(hvcs_structs_lock);
314 static void hvcs_unthrottle(struct tty_struct *tty);
315 static void hvcs_throttle(struct tty_struct *tty);
316 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
317 struct pt_regs *regs);
319 static int hvcs_write(struct tty_struct *tty,
320 const unsigned char *buf, int count);
321 static int hvcs_write_room(struct tty_struct *tty);
322 static int hvcs_chars_in_buffer(struct tty_struct *tty);
324 static int hvcs_has_pi(struct hvcs_struct *hvcsd);
325 static void hvcs_set_pi(struct hvcs_partner_info *pi,
326 struct hvcs_struct *hvcsd);
327 static int hvcs_get_pi(struct hvcs_struct *hvcsd);
328 static int hvcs_rescan_devices_list(void);
330 static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
331 static void hvcs_partner_free(struct hvcs_struct *hvcsd);
333 static int hvcs_enable_device(struct hvcs_struct *hvcsd,
334 uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
336 static void destroy_hvcs_struct(struct kobject *kobj);
337 static int hvcs_open(struct tty_struct *tty, struct file *filp);
338 static void hvcs_close(struct tty_struct *tty, struct file *filp);
339 static void hvcs_hangup(struct tty_struct * tty);
341 static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd);
342 static void hvcs_remove_device_attrs(struct vio_dev *vdev);
343 static void hvcs_create_driver_attrs(void);
344 static void hvcs_remove_driver_attrs(void);
346 static int __devinit hvcs_probe(struct vio_dev *dev,
347 const struct vio_device_id *id);
348 static int __devexit hvcs_remove(struct vio_dev *dev);
349 static int __init hvcs_module_init(void);
350 static void __exit hvcs_module_exit(void);
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)
357 static void hvcs_kick(void)
358 {
359 hvcs_kicked = 1;
360 wmb();
361 wake_up_process(hvcs_task);
362 }
364 static void hvcs_unthrottle(struct tty_struct *tty)
365 {
366 struct hvcs_struct *hvcsd = tty->driver_data;
367 unsigned long flags;
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 }
375 static void hvcs_throttle(struct tty_struct *tty)
376 {
377 struct hvcs_struct *hvcsd = tty->driver_data;
378 unsigned long flags;
380 spin_lock_irqsave(&hvcsd->lock, flags);
381 vio_disable_interrupts(hvcsd->vdev);
382 spin_unlock_irqrestore(&hvcsd->lock, flags);
383 }
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 */
390 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
391 struct pt_regs *regs)
392 {
393 struct hvcs_struct *hvcsd = dev_instance;
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();
401 return IRQ_HANDLED;
402 }
404 /* This function must be called with the hvcsd->lock held */
405 static 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;
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(); */
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 }
435 static 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;
443 spin_lock_irqsave(&hvcsd->lock, flags);
445 unit_address = hvcsd->vdev->unit_address;
446 tty = hvcsd->tty;
448 hvcs_try_write(hvcsd);
450 if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
451 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
452 goto bail;
453 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
454 goto bail;
456 /* remove the read masks */
457 hvcsd->todo_mask &= ~(HVCS_READ_MASK);
459 if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
460 got = hvc_get_chars(unit_address,
461 &buf[0],
462 HVCS_BUFF_LEN);
463 tty_insert_flip_string(tty, buf, got);
464 }
466 /* Give the TTY time to process the data we just sent. */
467 if (got)
468 hvcsd->todo_mask |= HVCS_QUICK_READ;
470 spin_unlock_irqrestore(&hvcsd->lock, flags);
471 /* This is synch because tty->low_latency == 1 */
472 if(got)
473 tty_flip_buffer_push(tty);
475 if (!got) {
476 /* Do this _after_ the flip_buffer_push */
477 spin_lock_irqsave(&hvcsd->lock, flags);
478 vio_enable_interrupts(hvcsd->vdev);
479 spin_unlock_irqrestore(&hvcsd->lock, flags);
480 }
482 return hvcsd->todo_mask;
484 bail:
485 spin_unlock_irqrestore(&hvcsd->lock, flags);
486 return hvcsd->todo_mask;
487 }
489 static int khvcsd(void *unused)
490 {
491 struct hvcs_struct *hvcsd;
492 int hvcs_todo_mask;
494 __set_current_state(TASK_RUNNING);
496 do {
497 hvcs_todo_mask = 0;
498 hvcs_kicked = 0;
499 wmb();
501 spin_lock(&hvcs_structs_lock);
502 list_for_each_entry(hvcsd, &hvcs_structs, next) {
503 hvcs_todo_mask |= hvcs_io(hvcsd);
504 }
505 spin_unlock(&hvcs_structs_lock);
507 /*
508 * If any of the hvcs adapters want to try a write or quick read
509 * don't schedule(), yield a smidgen then execute the hvcs_io
510 * thread again for those that want the write.
511 */
512 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
513 yield();
514 continue;
515 }
517 set_current_state(TASK_INTERRUPTIBLE);
518 if (!hvcs_kicked)
519 schedule();
520 __set_current_state(TASK_RUNNING);
521 } while (!kthread_should_stop());
523 return 0;
524 }
526 static struct vio_device_id hvcs_driver_table[] __devinitdata= {
527 {"serial-server", "hvterm2"},
528 { "", "" }
529 };
530 MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
532 static void hvcs_return_index(int index)
533 {
534 /* Paranoia check */
535 if (!hvcs_index_list)
536 return;
537 if (index < 0 || index >= hvcs_index_count)
538 return;
539 if (hvcs_index_list[index] == -1)
540 return;
541 else
542 hvcs_index_list[index] = -1;
543 }
545 /* callback when the kboject ref count reaches zero */
546 static void destroy_hvcs_struct(struct kobject *kobj)
547 {
548 struct hvcs_struct *hvcsd = from_kobj(kobj);
549 struct vio_dev *vdev;
550 unsigned long flags;
552 spin_lock(&hvcs_structs_lock);
553 spin_lock_irqsave(&hvcsd->lock, flags);
555 /* the list_del poisons the pointers */
556 list_del(&(hvcsd->next));
558 if (hvcsd->connected == 1) {
559 hvcs_partner_free(hvcsd);
560 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
561 " partner vty@%X:%d connection.\n",
562 hvcsd->vdev->unit_address,
563 hvcsd->p_unit_address,
564 (uint32_t)hvcsd->p_partition_ID);
565 }
566 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
567 hvcsd->vdev->unit_address);
569 vdev = hvcsd->vdev;
570 hvcsd->vdev = NULL;
572 hvcsd->p_unit_address = 0;
573 hvcsd->p_partition_ID = 0;
574 hvcs_return_index(hvcsd->index);
575 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
577 spin_unlock_irqrestore(&hvcsd->lock, flags);
578 spin_unlock(&hvcs_structs_lock);
580 hvcs_remove_device_attrs(vdev);
582 kfree(hvcsd);
583 }
585 static struct kobj_type hvcs_kobj_type = {
586 .release = destroy_hvcs_struct,
587 };
589 static int hvcs_get_index(void)
590 {
591 int i;
592 /* Paranoia check */
593 if (!hvcs_index_list) {
594 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
595 return -EFAULT;
596 }
597 /* Find the numerically lowest first free index. */
598 for(i = 0; i < hvcs_index_count; i++) {
599 if (hvcs_index_list[i] == -1) {
600 hvcs_index_list[i] = 0;
601 return i;
602 }
603 }
604 return -1;
605 }
607 static int __devinit hvcs_probe(
608 struct vio_dev *dev,
609 const struct vio_device_id *id)
610 {
611 struct hvcs_struct *hvcsd;
612 int index;
614 if (!dev || !id) {
615 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
616 return -EPERM;
617 }
619 /* early to avoid cleanup on failure */
620 index = hvcs_get_index();
621 if (index < 0) {
622 return -EFAULT;
623 }
625 hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL);
626 if (!hvcsd)
627 return -ENODEV;
629 /* hvcsd->tty is zeroed out with the memset */
630 memset(hvcsd, 0x00, sizeof(*hvcsd));
632 spin_lock_init(&hvcsd->lock);
633 /* Automatically incs the refcount the first time */
634 kobject_init(&hvcsd->kobj);
635 /* Set up the callback for terminating the hvcs_struct's life */
636 hvcsd->kobj.ktype = &hvcs_kobj_type;
638 hvcsd->vdev = dev;
639 dev->dev.driver_data = hvcsd;
641 hvcsd->index = index;
643 /* hvcsd->index = ++hvcs_struct_count; */
644 hvcsd->chars_in_buffer = 0;
645 hvcsd->todo_mask = 0;
646 hvcsd->connected = 0;
648 /*
649 * This will populate the hvcs_struct's partner info fields for the
650 * first time.
651 */
652 if (hvcs_get_pi(hvcsd)) {
653 printk(KERN_ERR "HVCS: Failed to fetch partner"
654 " info for vty-server@%X on device probe.\n",
655 hvcsd->vdev->unit_address);
656 }
658 /*
659 * If a user app opens a tty that corresponds to this vty-server before
660 * the hvcs_struct has been added to the devices list then the user app
661 * will get -ENODEV.
662 */
664 spin_lock(&hvcs_structs_lock);
666 list_add_tail(&(hvcsd->next), &hvcs_structs);
668 spin_unlock(&hvcs_structs_lock);
670 hvcs_create_device_attrs(hvcsd);
672 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
674 /*
675 * DON'T enable interrupts here because there is no user to receive the
676 * data.
677 */
678 return 0;
679 }
681 static int __devexit hvcs_remove(struct vio_dev *dev)
682 {
683 struct hvcs_struct *hvcsd = dev->dev.driver_data;
684 unsigned long flags;
685 struct kobject *kobjp;
686 struct tty_struct *tty;
688 if (!hvcsd)
689 return -ENODEV;
691 /* By this time the vty-server won't be getting any more interrups */
693 spin_lock_irqsave(&hvcsd->lock, flags);
695 tty = hvcsd->tty;
697 kobjp = &hvcsd->kobj;
699 spin_unlock_irqrestore(&hvcsd->lock, flags);
701 /*
702 * Let the last holder of this object cause it to be removed, which
703 * would probably be tty_hangup below.
704 */
705 kobject_put (kobjp);
707 /*
708 * The hangup is a scheduled function which will auto chain call
709 * hvcs_hangup. The tty should always be valid at this time unless a
710 * simultaneous tty close already cleaned up the hvcs_struct.
711 */
712 if (tty)
713 tty_hangup(tty);
715 printk(KERN_INFO "HVCS: vty-server@%X removed from the"
716 " vio bus.\n", dev->unit_address);
717 return 0;
718 };
720 static struct vio_driver hvcs_vio_driver = {
721 .id_table = hvcs_driver_table,
722 .probe = hvcs_probe,
723 .remove = hvcs_remove,
724 .driver = {
725 .name = hvcs_driver_name,
726 .owner = THIS_MODULE,
727 }
728 };
730 /* Only called from hvcs_get_pi please */
731 static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
732 {
733 int clclength;
735 hvcsd->p_unit_address = pi->unit_address;
736 hvcsd->p_partition_ID = pi->partition_ID;
737 clclength = strlen(&pi->location_code[0]);
738 if (clclength > HVCS_CLC_LENGTH)
739 clclength = HVCS_CLC_LENGTH;
741 /* copy the null-term char too */
742 strncpy(&hvcsd->p_location_code[0],
743 &pi->location_code[0], clclength + 1);
744 }
746 /*
747 * Traverse the list and add the partner info that is found to the hvcs_struct
748 * struct entry. NOTE: At this time I know that partner info will return a
749 * single entry but in the future there may be multiple partner info entries per
750 * vty-server and you'll want to zero out that list and reset it. If for some
751 * reason you have an old version of this driver but there IS more than one
752 * partner info then hvcsd->p_* will hold the last partner info data from the
753 * firmware query. A good way to update this code would be to replace the three
754 * partner info fields in hvcs_struct with a list of hvcs_partner_info
755 * instances.
756 *
757 * This function must be called with the hvcsd->lock held.
758 */
759 static int hvcs_get_pi(struct hvcs_struct *hvcsd)
760 {
761 struct hvcs_partner_info *pi;
762 uint32_t unit_address = hvcsd->vdev->unit_address;
763 struct list_head head;
764 int retval;
766 spin_lock(&hvcs_pi_lock);
767 if (!hvcs_pi_buff) {
768 spin_unlock(&hvcs_pi_lock);
769 return -EFAULT;
770 }
771 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
772 spin_unlock(&hvcs_pi_lock);
773 if (retval) {
774 printk(KERN_ERR "HVCS: Failed to fetch partner"
775 " info for vty-server@%x.\n", unit_address);
776 return retval;
777 }
779 /* nixes the values if the partner vty went away */
780 hvcsd->p_unit_address = 0;
781 hvcsd->p_partition_ID = 0;
783 list_for_each_entry(pi, &head, node)
784 hvcs_set_pi(pi, hvcsd);
786 hvcs_free_partner_info(&head);
787 return 0;
788 }
790 /*
791 * This function is executed by the driver "rescan" sysfs entry. It shouldn't
792 * be executed elsewhere, in order to prevent deadlock issues.
793 */
794 static int hvcs_rescan_devices_list(void)
795 {
796 struct hvcs_struct *hvcsd;
797 unsigned long flags;
799 spin_lock(&hvcs_structs_lock);
801 list_for_each_entry(hvcsd, &hvcs_structs, next) {
802 spin_lock_irqsave(&hvcsd->lock, flags);
803 hvcs_get_pi(hvcsd);
804 spin_unlock_irqrestore(&hvcsd->lock, flags);
805 }
807 spin_unlock(&hvcs_structs_lock);
809 return 0;
810 }
812 /*
813 * Farm this off into its own function because it could be more complex once
814 * multiple partners support is added. This function should be called with
815 * the hvcsd->lock held.
816 */
817 static int hvcs_has_pi(struct hvcs_struct *hvcsd)
818 {
819 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
820 return 0;
821 return 1;
822 }
824 /*
825 * NOTE: It is possible that the super admin removed a partner vty and then
826 * added a different vty as the new partner.
827 *
828 * This function must be called with the hvcsd->lock held.
829 */
830 static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
831 {
832 int retval;
833 unsigned int unit_address = hvcsd->vdev->unit_address;
835 /*
836 * If there wasn't any pi when the device was added it doesn't meant
837 * there isn't any now. This driver isn't notified when a new partner
838 * vty is added to a vty-server so we discover changes on our own.
839 * Please see comments in hvcs_register_connection() for justification
840 * of this bizarre code.
841 */
842 retval = hvcs_register_connection(unit_address,
843 hvcsd->p_partition_ID,
844 hvcsd->p_unit_address);
845 if (!retval) {
846 hvcsd->connected = 1;
847 return 0;
848 } else if (retval != -EINVAL)
849 return retval;
851 /*
852 * As per the spec re-get the pi and try again if -EINVAL after the
853 * first connection attempt.
854 */
855 if (hvcs_get_pi(hvcsd))
856 return -ENOMEM;
858 if (!hvcs_has_pi(hvcsd))
859 return -ENODEV;
861 retval = hvcs_register_connection(unit_address,
862 hvcsd->p_partition_ID,
863 hvcsd->p_unit_address);
864 if (retval != -EINVAL) {
865 hvcsd->connected = 1;
866 return retval;
867 }
869 /*
870 * EBUSY is the most likely scenario though the vty could have been
871 * removed or there really could be an hcall error due to the parameter
872 * data but thanks to ambiguous firmware return codes we can't really
873 * tell.
874 */
875 printk(KERN_INFO "HVCS: vty-server or partner"
876 " vty is busy. Try again later.\n");
877 return -EBUSY;
878 }
880 /* This function must be called with the hvcsd->lock held */
881 static void hvcs_partner_free(struct hvcs_struct *hvcsd)
882 {
883 int retval;
884 do {
885 retval = hvcs_free_connection(hvcsd->vdev->unit_address);
886 } while (retval == -EBUSY);
887 hvcsd->connected = 0;
888 }
890 /* This helper function must be called WITHOUT the hvcsd->lock held */
891 static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
892 unsigned int irq, struct vio_dev *vdev)
893 {
894 unsigned long flags;
895 int rc;
897 /*
898 * It is possible that the vty-server was removed between the time that
899 * the conn was registered and now.
900 */
901 if (!(rc = request_irq(irq, &hvcs_handle_interrupt,
902 IRQF_DISABLED, "ibmhvcs", hvcsd))) {
903 /*
904 * It is possible the vty-server was removed after the irq was
905 * requested but before we have time to enable interrupts.
906 */
907 if (vio_enable_interrupts(vdev) == H_SUCCESS)
908 return 0;
909 else {
910 printk(KERN_ERR "HVCS: int enable failed for"
911 " vty-server@%X.\n", unit_address);
912 free_irq(irq, hvcsd);
913 }
914 } else
915 printk(KERN_ERR "HVCS: irq req failed for"
916 " vty-server@%X.\n", unit_address);
918 spin_lock_irqsave(&hvcsd->lock, flags);
919 hvcs_partner_free(hvcsd);
920 spin_unlock_irqrestore(&hvcsd->lock, flags);
922 return rc;
924 }
926 /*
927 * This always increments the kobject ref count if the call is successful.
928 * Please remember to dec when you are done with the instance.
929 *
930 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
931 * calling this function or you will get deadlock.
932 */
933 struct hvcs_struct *hvcs_get_by_index(int index)
934 {
935 struct hvcs_struct *hvcsd = NULL;
936 unsigned long flags;
938 spin_lock(&hvcs_structs_lock);
939 /* We can immediately discard OOB requests */
940 if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
941 list_for_each_entry(hvcsd, &hvcs_structs, next) {
942 spin_lock_irqsave(&hvcsd->lock, flags);
943 if (hvcsd->index == index) {
944 kobject_get(&hvcsd->kobj);
945 spin_unlock_irqrestore(&hvcsd->lock, flags);
946 spin_unlock(&hvcs_structs_lock);
947 return hvcsd;
948 }
949 spin_unlock_irqrestore(&hvcsd->lock, flags);
950 }
951 hvcsd = NULL;
952 }
954 spin_unlock(&hvcs_structs_lock);
955 return hvcsd;
956 }
958 /*
959 * This is invoked via the tty_open interface when a user app connects to the
960 * /dev node.
961 */
962 static int hvcs_open(struct tty_struct *tty, struct file *filp)
963 {
964 struct hvcs_struct *hvcsd;
965 int rc, retval = 0;
966 unsigned long flags;
967 unsigned int irq;
968 struct vio_dev *vdev;
969 unsigned long unit_address;
970 struct kobject *kobjp;
972 if (tty->driver_data)
973 goto fast_open;
975 /*
976 * Is there a vty-server that shares the same index?
977 * This function increments the kobject index.
978 */
979 if (!(hvcsd = hvcs_get_by_index(tty->index))) {
980 printk(KERN_WARNING "HVCS: open failed, no device associated"
981 " with tty->index %d.\n", tty->index);
982 return -ENODEV;
983 }
985 spin_lock_irqsave(&hvcsd->lock, flags);
987 if (hvcsd->connected == 0)
988 if ((retval = hvcs_partner_connect(hvcsd)))
989 goto error_release;
991 hvcsd->open_count = 1;
992 hvcsd->tty = tty;
993 tty->driver_data = hvcsd;
995 /*
996 * Set this driver to low latency so that we actually have a chance at
997 * catching a throttled TTY after we flip_buffer_push. Otherwise the
998 * flush_to_async may not execute until after the kernel_thread has
999 * yielded and resumed the next flip_buffer_push resulting in data
1000 * loss.
1001 */
1002 tty->low_latency = 1;
1004 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1006 /*
1007 * Save these in the spinlock for the enable operations that need them
1008 * outside of the spinlock.
1009 */
1010 irq = hvcsd->vdev->irq;
1011 vdev = hvcsd->vdev;
1012 unit_address = hvcsd->vdev->unit_address;
1014 hvcsd->todo_mask |= HVCS_SCHED_READ;
1015 spin_unlock_irqrestore(&hvcsd->lock, flags);
1017 /*
1018 * This must be done outside of the spinlock because it requests irqs
1019 * and will grab the spinlock and free the connection if it fails.
1020 */
1021 if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) {
1022 kobject_put(&hvcsd->kobj);
1023 printk(KERN_WARNING "HVCS: enable device failed.\n");
1024 return rc;
1027 goto open_success;
1029 fast_open:
1030 hvcsd = tty->driver_data;
1032 spin_lock_irqsave(&hvcsd->lock, flags);
1033 if (!kobject_get(&hvcsd->kobj)) {
1034 spin_unlock_irqrestore(&hvcsd->lock, flags);
1035 printk(KERN_ERR "HVCS: Kobject of open"
1036 " hvcs doesn't exist.\n");
1037 return -EFAULT; /* Is this the right return value? */
1040 hvcsd->open_count++;
1042 hvcsd->todo_mask |= HVCS_SCHED_READ;
1043 spin_unlock_irqrestore(&hvcsd->lock, flags);
1044 open_success:
1045 hvcs_kick();
1047 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
1048 hvcsd->vdev->unit_address );
1050 return 0;
1052 error_release:
1053 kobjp = &hvcsd->kobj;
1054 spin_unlock_irqrestore(&hvcsd->lock, flags);
1055 kobject_put(&hvcsd->kobj);
1057 printk(KERN_WARNING "HVCS: partner connect failed.\n");
1058 return retval;
1061 static void hvcs_close(struct tty_struct *tty, struct file *filp)
1063 struct hvcs_struct *hvcsd;
1064 unsigned long flags;
1065 struct kobject *kobjp;
1066 int irq = NO_IRQ;
1068 /*
1069 * Is someone trying to close the file associated with this device after
1070 * we have hung up? If so tty->driver_data wouldn't be valid.
1071 */
1072 if (tty_hung_up_p(filp))
1073 return;
1075 /*
1076 * No driver_data means that this close was probably issued after a
1077 * failed hvcs_open by the tty layer's release_dev() api and we can just
1078 * exit cleanly.
1079 */
1080 if (!tty->driver_data)
1081 return;
1083 hvcsd = tty->driver_data;
1085 spin_lock_irqsave(&hvcsd->lock, flags);
1086 kobjp = &hvcsd->kobj;
1087 if (--hvcsd->open_count == 0) {
1089 vio_disable_interrupts(hvcsd->vdev);
1091 /*
1092 * NULL this early so that the kernel_thread doesn't try to
1093 * execute any operations on the TTY even though it is obligated
1094 * to deliver any pending I/O to the hypervisor.
1095 */
1096 hvcsd->tty = NULL;
1098 irq = hvcsd->vdev->irq;
1099 spin_unlock_irqrestore(&hvcsd->lock, flags);
1101 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
1103 /*
1104 * This line is important because it tells hvcs_open that this
1105 * device needs to be re-configured the next time hvcs_open is
1106 * called.
1107 */
1108 tty->driver_data = NULL;
1110 free_irq(irq, hvcsd);
1111 kobject_put(kobjp);
1112 return;
1113 } else if (hvcsd->open_count < 0) {
1114 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
1115 " is missmanaged.\n",
1116 hvcsd->vdev->unit_address, hvcsd->open_count);
1119 spin_unlock_irqrestore(&hvcsd->lock, flags);
1120 kobject_put(kobjp);
1123 static void hvcs_hangup(struct tty_struct * tty)
1125 struct hvcs_struct *hvcsd = tty->driver_data;
1126 unsigned long flags;
1127 int temp_open_count;
1128 struct kobject *kobjp;
1129 int irq = NO_IRQ;
1131 spin_lock_irqsave(&hvcsd->lock, flags);
1132 /* Preserve this so that we know how many kobject refs to put */
1133 temp_open_count = hvcsd->open_count;
1135 /*
1136 * Don't kobject put inside the spinlock because the destruction
1137 * callback may use the spinlock and it may get called before the
1138 * spinlock has been released. Get a pointer to the kobject and
1139 * kobject_put on that after releasing the spinlock.
1140 */
1141 kobjp = &hvcsd->kobj;
1143 vio_disable_interrupts(hvcsd->vdev);
1145 hvcsd->todo_mask = 0;
1147 /* I don't think the tty needs the hvcs_struct pointer after a hangup */
1148 hvcsd->tty->driver_data = NULL;
1149 hvcsd->tty = NULL;
1151 hvcsd->open_count = 0;
1153 /* This will drop any buffered data on the floor which is OK in a hangup
1154 * scenario. */
1155 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
1156 hvcsd->chars_in_buffer = 0;
1158 irq = hvcsd->vdev->irq;
1160 spin_unlock_irqrestore(&hvcsd->lock, flags);
1162 free_irq(irq, hvcsd);
1164 /*
1165 * We need to kobject_put() for every open_count we have since the
1166 * tty_hangup() function doesn't invoke a close per open connection on a
1167 * non-console device.
1168 */
1169 while(temp_open_count) {
1170 --temp_open_count;
1171 /*
1172 * The final put will trigger destruction of the hvcs_struct.
1173 * NOTE: If this hangup was signaled from user space then the
1174 * final put will never happen.
1175 */
1176 kobject_put(kobjp);
1180 /*
1181 * NOTE: This is almost always from_user since user level apps interact with the
1182 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by
1183 * hvcs_remove (which removes the target device and executes tty_hangup()) that
1184 * tty_hangup will allow hvcs_write time to complete execution before it
1185 * terminates our device.
1186 */
1187 static int hvcs_write(struct tty_struct *tty,
1188 const unsigned char *buf, int count)
1190 struct hvcs_struct *hvcsd = tty->driver_data;
1191 unsigned int unit_address;
1192 const unsigned char *charbuf;
1193 unsigned long flags;
1194 int total_sent = 0;
1195 int tosend = 0;
1196 int result = 0;
1198 /*
1199 * If they don't check the return code off of their open they may
1200 * attempt this even if there is no connected device.
1201 */
1202 if (!hvcsd)
1203 return -ENODEV;
1205 /* Reasonable size to prevent user level flooding */
1206 if (count > HVCS_MAX_FROM_USER) {
1207 printk(KERN_WARNING "HVCS write: count being truncated to"
1208 " HVCS_MAX_FROM_USER.\n");
1209 count = HVCS_MAX_FROM_USER;
1212 charbuf = buf;
1214 spin_lock_irqsave(&hvcsd->lock, flags);
1216 /*
1217 * Somehow an open succedded but the device was removed or the
1218 * connection terminated between the vty-server and partner vty during
1219 * the middle of a write operation? This is a crummy place to do this
1220 * but we want to keep it all in the spinlock.
1221 */
1222 if (hvcsd->open_count <= 0) {
1223 spin_unlock_irqrestore(&hvcsd->lock, flags);
1224 return -ENODEV;
1227 unit_address = hvcsd->vdev->unit_address;
1229 while (count > 0) {
1230 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));
1231 /*
1232 * No more space, this probably means that the last call to
1233 * hvcs_write() didn't succeed and the buffer was filled up.
1234 */
1235 if (!tosend)
1236 break;
1238 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],
1239 &charbuf[total_sent],
1240 tosend);
1242 hvcsd->chars_in_buffer += tosend;
1244 result = 0;
1246 /*
1247 * If this is true then we don't want to try writing to the
1248 * hypervisor because that is the kernel_threads job now. We'll
1249 * just add to the buffer.
1250 */
1251 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))
1252 /* won't send partial writes */
1253 result = hvc_put_chars(unit_address,
1254 &hvcsd->buffer[0],
1255 hvcsd->chars_in_buffer);
1257 /*
1258 * Since we know we have enough room in hvcsd->buffer for
1259 * tosend we record that it was sent regardless of whether the
1260 * hypervisor actually took it because we have it buffered.
1261 */
1262 total_sent+=tosend;
1263 count-=tosend;
1264 if (result == 0) {
1265 hvcsd->todo_mask |= HVCS_TRY_WRITE;
1266 hvcs_kick();
1267 break;
1270 hvcsd->chars_in_buffer = 0;
1271 /*
1272 * Test after the chars_in_buffer reset otherwise this could
1273 * deadlock our writes if hvc_put_chars fails.
1274 */
1275 if (result < 0)
1276 break;
1279 spin_unlock_irqrestore(&hvcsd->lock, flags);
1281 if (result == -1)
1282 return -EIO;
1283 else
1284 return total_sent;
1287 /*
1288 * This is really asking how much can we guarentee that we can send or that we
1289 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the
1290 * return value, hence the reason for hvcs_struct buffering.
1291 */
1292 static int hvcs_write_room(struct tty_struct *tty)
1294 struct hvcs_struct *hvcsd = tty->driver_data;
1296 if (!hvcsd || hvcsd->open_count <= 0)
1297 return 0;
1299 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;
1302 static int hvcs_chars_in_buffer(struct tty_struct *tty)
1304 struct hvcs_struct *hvcsd = tty->driver_data;
1306 return hvcsd->chars_in_buffer;
1309 static struct tty_operations hvcs_ops = {
1310 .open = hvcs_open,
1311 .close = hvcs_close,
1312 .hangup = hvcs_hangup,
1313 .write = hvcs_write,
1314 .write_room = hvcs_write_room,
1315 .chars_in_buffer = hvcs_chars_in_buffer,
1316 .unthrottle = hvcs_unthrottle,
1317 .throttle = hvcs_throttle,
1318 };
1320 static int hvcs_alloc_index_list(int n)
1322 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;
1333 static void hvcs_free_index_list(void)
1335 /* Paranoia check to be thorough. */
1336 kfree(hvcs_index_list);
1337 hvcs_index_list = NULL;
1338 hvcs_index_count = 0;
1341 static int __init hvcs_module_init(void)
1343 int rc;
1344 int num_ttys_to_alloc;
1346 printk(KERN_INFO "Initializing %s\n", hvcs_driver_string);
1348 /* Has the user specified an overload with an insmod param? */
1349 if (hvcs_parm_num_devs <= 0 ||
1350 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {
1351 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;
1352 } else
1353 num_ttys_to_alloc = hvcs_parm_num_devs;
1355 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc);
1356 if (!hvcs_tty_driver)
1357 return -ENOMEM;
1359 if (hvcs_alloc_index_list(num_ttys_to_alloc))
1360 return -ENOMEM;
1362 hvcs_tty_driver->owner = THIS_MODULE;
1364 hvcs_tty_driver->driver_name = hvcs_driver_name;
1365 hvcs_tty_driver->name = hvcs_device_node;
1367 /*
1368 * We'll let the system assign us a major number, indicated by leaving
1369 * it blank.
1370 */
1372 hvcs_tty_driver->minor_start = HVCS_MINOR_START;
1373 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1375 /*
1376 * We role our own so that we DONT ECHO. We can't echo because the
1377 * device we are connecting to already echoes by default and this would
1378 * throw us into a horrible recursive echo-echo-echo loop.
1379 */
1380 hvcs_tty_driver->init_termios = hvcs_tty_termios;
1381 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW;
1383 tty_set_operations(hvcs_tty_driver, &hvcs_ops);
1385 /*
1386 * The following call will result in sysfs entries that denote the
1387 * dynamically assigned major and minor numbers for our devices.
1388 */
1389 if (tty_register_driver(hvcs_tty_driver)) {
1390 printk(KERN_ERR "HVCS: registration "
1391 " as a tty driver failed.\n");
1392 hvcs_free_index_list();
1393 put_tty_driver(hvcs_tty_driver);
1394 return -EIO;
1397 hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
1398 if (!hvcs_pi_buff) {
1399 tty_unregister_driver(hvcs_tty_driver);
1400 hvcs_free_index_list();
1401 put_tty_driver(hvcs_tty_driver);
1402 return -ENOMEM;
1405 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
1406 if (IS_ERR(hvcs_task)) {
1407 printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n");
1408 kfree(hvcs_pi_buff);
1409 tty_unregister_driver(hvcs_tty_driver);
1410 hvcs_free_index_list();
1411 put_tty_driver(hvcs_tty_driver);
1412 return -EIO;
1415 rc = vio_register_driver(&hvcs_vio_driver);
1417 /*
1418 * This needs to be done AFTER the vio_register_driver() call or else
1419 * the kobjects won't be initialized properly.
1420 */
1421 hvcs_create_driver_attrs();
1423 printk(KERN_INFO "HVCS: driver module inserted.\n");
1425 return rc;
1428 static void __exit hvcs_module_exit(void)
1430 /*
1431 * This driver receives hvcs_remove callbacks for each device upon
1432 * module removal.
1433 */
1435 /*
1436 * This synchronous operation will wake the khvcsd kthread if it is
1437 * asleep and will return when khvcsd has terminated.
1438 */
1439 kthread_stop(hvcs_task);
1441 spin_lock(&hvcs_pi_lock);
1442 kfree(hvcs_pi_buff);
1443 hvcs_pi_buff = NULL;
1444 spin_unlock(&hvcs_pi_lock);
1446 hvcs_remove_driver_attrs();
1448 vio_unregister_driver(&hvcs_vio_driver);
1450 tty_unregister_driver(hvcs_tty_driver);
1452 hvcs_free_index_list();
1454 put_tty_driver(hvcs_tty_driver);
1456 printk(KERN_INFO "HVCS: driver module removed.\n");
1459 module_init(hvcs_module_init);
1460 module_exit(hvcs_module_exit);
1462 static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
1464 return viod->dev.driver_data;
1466 /* The sysfs interface for the driver and devices */
1468 static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
1470 struct vio_dev *viod = to_vio_dev(dev);
1471 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1472 unsigned long flags;
1473 int retval;
1475 spin_lock_irqsave(&hvcsd->lock, flags);
1476 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
1477 spin_unlock_irqrestore(&hvcsd->lock, flags);
1478 return retval;
1480 static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
1482 static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
1484 struct vio_dev *viod = to_vio_dev(dev);
1485 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1486 unsigned long flags;
1487 int retval;
1489 spin_lock_irqsave(&hvcsd->lock, flags);
1490 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
1491 spin_unlock_irqrestore(&hvcsd->lock, flags);
1492 return retval;
1494 static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
1496 static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
1497 size_t count)
1499 /*
1500 * Don't need this feature at the present time because firmware doesn't
1501 * yet support multiple partners.
1502 */
1503 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
1504 return -EPERM;
1507 static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
1509 struct vio_dev *viod = to_vio_dev(dev);
1510 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1511 unsigned long flags;
1512 int retval;
1514 spin_lock_irqsave(&hvcsd->lock, flags);
1515 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
1516 spin_unlock_irqrestore(&hvcsd->lock, flags);
1517 return retval;
1520 static DEVICE_ATTR(current_vty,
1521 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
1523 static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
1524 size_t count)
1526 struct vio_dev *viod = to_vio_dev(dev);
1527 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1528 unsigned long flags;
1530 /* writing a '0' to this sysfs entry will result in the disconnect. */
1531 if (simple_strtol(buf, NULL, 0) != 0)
1532 return -EINVAL;
1534 spin_lock_irqsave(&hvcsd->lock, flags);
1536 if (hvcsd->open_count > 0) {
1537 spin_unlock_irqrestore(&hvcsd->lock, flags);
1538 printk(KERN_INFO "HVCS: vterm state unchanged. "
1539 "The hvcs device node is still in use.\n");
1540 return -EPERM;
1543 if (hvcsd->connected == 0) {
1544 spin_unlock_irqrestore(&hvcsd->lock, flags);
1545 printk(KERN_INFO "HVCS: vterm state unchanged. The"
1546 " vty-server is not connected to a vty.\n");
1547 return -EPERM;
1550 hvcs_partner_free(hvcsd);
1551 printk(KERN_INFO "HVCS: Closed vty-server@%X and"
1552 " partner vty@%X:%d connection.\n",
1553 hvcsd->vdev->unit_address,
1554 hvcsd->p_unit_address,
1555 (uint32_t)hvcsd->p_partition_ID);
1557 spin_unlock_irqrestore(&hvcsd->lock, flags);
1558 return count;
1561 static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
1563 struct vio_dev *viod = to_vio_dev(dev);
1564 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1565 unsigned long flags;
1566 int retval;
1568 spin_lock_irqsave(&hvcsd->lock, flags);
1569 retval = sprintf(buf, "%d\n", hvcsd->connected);
1570 spin_unlock_irqrestore(&hvcsd->lock, flags);
1571 return retval;
1573 static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
1574 hvcs_vterm_state_show, hvcs_vterm_state_store);
1576 static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
1578 struct vio_dev *viod = to_vio_dev(dev);
1579 struct hvcs_struct *hvcsd = from_vio_dev(viod);
1580 unsigned long flags;
1581 int retval;
1583 spin_lock_irqsave(&hvcsd->lock, flags);
1584 retval = sprintf(buf, "%d\n", hvcsd->index);
1585 spin_unlock_irqrestore(&hvcsd->lock, flags);
1586 return retval;
1589 static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
1591 static struct attribute *hvcs_attrs[] = {
1592 &dev_attr_partner_vtys.attr,
1593 &dev_attr_partner_clcs.attr,
1594 &dev_attr_current_vty.attr,
1595 &dev_attr_vterm_state.attr,
1596 &dev_attr_index.attr,
1597 NULL,
1598 };
1600 static struct attribute_group hvcs_attr_group = {
1601 .attrs = hvcs_attrs,
1602 };
1604 static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd)
1606 struct vio_dev *vdev = hvcsd->vdev;
1607 sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group);
1610 static void hvcs_remove_device_attrs(struct vio_dev *vdev)
1612 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
1615 static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
1617 /* A 1 means it is updating, a 0 means it is done updating */
1618 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
1621 static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
1622 size_t count)
1624 if ((simple_strtol(buf, NULL, 0) != 1)
1625 && (hvcs_rescan_status != 0))
1626 return -EINVAL;
1628 hvcs_rescan_status = 1;
1629 printk(KERN_INFO "HVCS: rescanning partner info for all"
1630 " vty-servers.\n");
1631 hvcs_rescan_devices_list();
1632 hvcs_rescan_status = 0;
1633 return count;
1635 static DRIVER_ATTR(rescan,
1636 S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
1638 static void hvcs_create_driver_attrs(void)
1640 struct device_driver *driverfs = &(hvcs_vio_driver.driver);
1641 driver_create_file(driverfs, &driver_attr_rescan);
1644 static void hvcs_remove_driver_attrs(void)
1646 struct device_driver *driverfs = &(hvcs_vio_driver.driver);
1647 driver_remove_file(driverfs, &driver_attr_rescan);