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

Warning: That file was not part of the compilation database. It may have many parsing errors.