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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 48151 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | */ |
69 | |
70 | #include <linux/device.h> |
71 | #include <linux/init.h> |
72 | #include <linux/interrupt.h> |
73 | #include <linux/kernel.h> |
74 | #include <linux/kobject.h> |
75 | #include <linux/kthread.h> |
76 | #include <linux/list.h> |
77 | #include <linux/major.h> |
78 | #include <linux/module.h> |
79 | #include <linux/moduleparam.h> |
80 | #include <linux/sched.h> |
81 | #include <linux/spinlock.h> |
82 | #include <linux/stat.h> |
83 | #include <linux/tty.h> |
84 | #include <linux/tty_flip.h> |
85 | #include <asm/hvconsole.h> |
86 | #include <asm/hvcserver.h> |
87 | #include <asm/uaccess.h> |
88 | #include <asm/vio.h> |
89 | |
90 | /* |
91 | * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00). |
92 | * Removed braces around single statements following conditionals. Removed '= |
93 | * 0' after static int declarations since these default to zero. Removed |
94 | * list_for_each_safe() and replaced with list_for_each_entry() in |
95 | * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is |
96 | * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking |
97 | * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int |
98 | * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to |
99 | * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init(). |
100 | * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the |
101 | * list traversals from a deletion. Removed '= NULL' from pointer declaration |
102 | * statements since they are initialized NULL by default. Removed wmb() |
103 | * instances from hvcs_try_write(). They probably aren't needed with locking in |
104 | * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in |
105 | * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that |
106 | * the coupling between /dev/hvcs* and a vty-server can be automatically |
107 | * determined. Moved kobject_put() in hvcs_open outside of the |
108 | * spin_unlock_irqrestore(). |
109 | * |
110 | * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it |
111 | * align with how the tty layer always assigns the lowest index available. This |
112 | * change resulted in a list of ints that denotes which indexes are available. |
113 | * Device additions and removals use the new hvcs_get_index() and |
114 | * hvcs_return_index() helper functions. The list is created with |
115 | * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list(). |
116 | * Without these fixes hotplug vty-server adapter support goes crazy with this |
117 | * driver if the user removes a vty-server adapter. Moved free_irq() outside of |
118 | * the hvcs_final_close() function in order to get it out of the spinlock. |
119 | * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping |
120 | * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from |
121 | * arch/ppc64/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 | */ |
130 | |
131 | #define HVCS_DRIVER_VERSION "1.3.3" |
132 | |
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); |
137 | |
138 | /* |
139 | * Wait this long per iteration while trying to push buffered data to the |
140 | * hypervisor before allowing the tty to complete a close operation. |
141 | */ |
142 | #define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ |
143 | |
144 | /* |
145 | * Since the Linux TTY code does not currently (2-04-2004) support dynamic |
146 | * addition of tty derived devices and we shouldn't allocate thousands of |
147 | * tty_device pointers when the number of vty-server & vty partner connections |
148 | * will most often be much lower than this, we'll arbitrarily allocate |
149 | * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we |
150 | * register the tty_driver. This can be overridden using an insmod parameter. |
151 | */ |
152 | #define HVCS_DEFAULT_SERVER_ADAPTERS 64 |
153 | |
154 | /* |
155 | * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device |
156 | * nodes as a sanity check. Theoretically there can be over 1 Billion |
157 | * vty-server & vty partner connections. |
158 | */ |
159 | #define HVCS_MAX_SERVER_ADAPTERS 1024 |
160 | |
161 | /* |
162 | * We let Linux assign us a major number and we start the minors at zero. There |
163 | * is no intuitive mapping between minor number and the target vty-server |
164 | * adapter except that each new vty-server adapter is always assigned to the |
165 | * smallest minor number available. |
166 | */ |
167 | #define HVCS_MINOR_START 0 |
168 | |
169 | /* |
170 | * The hcall interface involves putting 8 chars into each of two registers. |
171 | * We load up those 2 registers (in arch/ppc64/hvconsole.c) by casting char[16] |
172 | * to long[2]. It would work without __ALIGNED__, but a little (tiny) bit |
173 | * slower because an unaligned load is slower than aligned load. |
174 | */ |
175 | #define __ALIGNED__ __attribute__((__aligned__(8))) |
176 | |
177 | /* |
178 | * How much data can firmware send with each hvc_put_chars()? Maybe this |
179 | * should be moved into an architecture specific area. |
180 | */ |
181 | #define HVCS_BUFF_LEN 16 |
182 | |
183 | /* |
184 | * This is the maximum amount of data we'll let the user send us (hvcs_write) at |
185 | * once in a chunk as a sanity check. |
186 | */ |
187 | #define HVCS_MAX_FROM_USER 4096 |
188 | |
189 | /* |
190 | * Be careful when adding flags to this line discipline. Don't add anything |
191 | * that will cause echoing or we'll go into recursive loop echoing chars back |
192 | * and forth with the console drivers. |
193 | */ |
194 | static struct termios hvcs_tty_termios = { |
195 | .c_iflag = IGNBRK | IGNPAR, |
196 | .c_oflag = OPOST, |
197 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, |
198 | .c_cc = INIT_C_CC |
199 | }; |
200 | |
201 | /* |
202 | * This value is used to take the place of a command line parameter when the |
203 | * module is inserted. It starts as -1 and stays as such if the user doesn't |
204 | * specify a module insmod parameter. If they DO specify one then it is set to |
205 | * the value of the integer passed in. |
206 | */ |
207 | static int hvcs_parm_num_devs = -1; |
208 | module_param(hvcs_parm_num_devs, int, 0); |
209 | |
210 | char hvcs_driver_name[] = "hvcs"; |
211 | char hvcs_device_node[] = "hvcs"; |
212 | char hvcs_driver_string[] |
213 | = "IBM hvcs (Hypervisor Virtual Console Server) Driver"; |
214 | |
215 | /* Status of partner info rescan triggered via sysfs. */ |
216 | static int hvcs_rescan_status; |
217 | |
218 | static struct tty_driver *hvcs_tty_driver; |
219 | |
220 | /* |
221 | * In order to be somewhat sane this driver always associates the hvcs_struct |
222 | * index element with the numerically equal tty->index. This means that a |
223 | * hotplugged vty-server adapter will always map to the lowest index valued |
224 | * device node. If vty-servers were hotplug removed from the system and then |
225 | * new ones added the new vty-server may have the largest slot number of all |
226 | * the vty-server adapters in the partition but it may have the lowest dev node |
227 | * index of all the adapters due to the hole left by the hotplug removed |
228 | * adapter. There are a set of functions provided to get the lowest index for |
229 | * a new device as well as return the index to the list. This list is allocated |
230 | * with a number of elements equal to the number of device nodes requested when |
231 | * the module was inserted. |
232 | */ |
233 | static int *hvcs_index_list; |
234 | |
235 | /* |
236 | * How large is the list? This is kept for traversal since the list is |
237 | * dynamically created. |
238 | */ |
239 | static int hvcs_index_count; |
240 | |
241 | /* |
242 | * Used by the khvcsd to pick up I/O operations when the kernel_thread is |
243 | * already awake but potentially shifted to TASK_INTERRUPTIBLE state. |
244 | */ |
245 | static int hvcs_kicked; |
246 | |
247 | /* |
248 | * Use by the kthread construct for task operations like waking the sleeping |
249 | * thread and stopping the kthread. |
250 | */ |
251 | static struct task_struct *hvcs_task; |
252 | |
253 | /* |
254 | * We allocate this for the use of all of the hvcs_structs when they fetch |
255 | * partner info. |
256 | */ |
257 | static unsigned long *hvcs_pi_buff; |
258 | |
259 | /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */ |
260 | static DEFINE_SPINLOCK(hvcs_pi_lock); |
261 | |
262 | /* One vty-server per hvcs_struct */ |
263 | struct hvcs_struct { |
264 | spinlock_t lock; |
265 | |
266 | /* |
267 | * This index identifies this hvcs device as the complement to a |
268 | * specific tty index. |
269 | */ |
270 | unsigned int index; |
271 | |
272 | struct tty_struct *tty; |
273 | unsigned int open_count; |
274 | |
275 | /* |
276 | * Used to tell the driver kernel_thread what operations need to take |
277 | * place upon this hvcs_struct instance. |
278 | */ |
279 | int todo_mask; |
280 | |
281 | /* |
282 | * This buffer is required so that when hvcs_write_room() reports that |
283 | * it can send HVCS_BUFF_LEN characters that it will buffer the full |
284 | * HVCS_BUFF_LEN characters if need be. This is essential for opost |
285 | * writes since they do not do high level buffering and expect to be |
286 | * able to send what the driver commits to sending buffering |
287 | * [e.g. tab to space conversions in n_tty.c opost()]. |
288 | */ |
289 | char buffer[HVCS_BUFF_LEN]; |
290 | int chars_in_buffer; |
291 | |
292 | /* |
293 | * Any variable below the kobject is valid before a tty is connected and |
294 | * stays valid after the tty is disconnected. These shouldn't be |
295 | * whacked until the koject refcount reaches zero though some entries |
296 | * may be changed via sysfs initiatives. |
297 | */ |
298 | struct kobject kobj; /* ref count & hvcs_struct lifetime */ |
299 | int connected; /* is the vty-server currently connected to a vty? */ |
300 | uint32_t p_unit_address; /* partner unit address */ |
301 | uint32_t p_partition_ID; /* partner partition ID */ |
302 | char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */ |
303 | struct list_head next; /* list management */ |
304 | struct vio_dev *vdev; |
305 | }; |
306 | |
307 | /* Required to back map a kobject to its containing object */ |
308 | #define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj) |
309 | |
310 | static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs); |
311 | static DEFINE_SPINLOCK(hvcs_structs_lock); |
312 | |
313 | static void hvcs_unthrottle(struct tty_struct *tty); |
314 | static void hvcs_throttle(struct tty_struct *tty); |
315 | static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance, |
316 | struct pt_regs *regs); |
317 | |
318 | static int hvcs_write(struct tty_struct *tty, |
319 | const unsigned char *buf, int count); |
320 | static int hvcs_write_room(struct tty_struct *tty); |
321 | static int hvcs_chars_in_buffer(struct tty_struct *tty); |
322 | |
323 | static int hvcs_has_pi(struct hvcs_struct *hvcsd); |
324 | static void hvcs_set_pi(struct hvcs_partner_info *pi, |
325 | struct hvcs_struct *hvcsd); |
326 | static int hvcs_get_pi(struct hvcs_struct *hvcsd); |
327 | static int hvcs_rescan_devices_list(void); |
328 | |
329 | static int hvcs_partner_connect(struct hvcs_struct *hvcsd); |
330 | static void hvcs_partner_free(struct hvcs_struct *hvcsd); |
331 | |
332 | static int hvcs_enable_device(struct hvcs_struct *hvcsd, |
333 | uint32_t unit_address, unsigned int irq, struct vio_dev *dev); |
334 | |
335 | static void destroy_hvcs_struct(struct kobject *kobj); |
336 | static int hvcs_open(struct tty_struct *tty, struct file *filp); |
337 | static void hvcs_close(struct tty_struct *tty, struct file *filp); |
338 | static void hvcs_hangup(struct tty_struct * tty); |
339 | |
340 | static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd); |
341 | static void hvcs_remove_device_attrs(struct vio_dev *vdev); |
342 | static void hvcs_create_driver_attrs(void); |
343 | static void hvcs_remove_driver_attrs(void); |
344 | |
345 | static int __devinit hvcs_probe(struct vio_dev *dev, |
346 | const struct vio_device_id *id); |
347 | static int __devexit hvcs_remove(struct vio_dev *dev); |
348 | static int __init hvcs_module_init(void); |
349 | static void __exit hvcs_module_exit(void); |
350 | |
351 | #define HVCS_SCHED_READ 0x00000001 |
352 | #define HVCS_QUICK_READ 0x00000002 |
353 | #define HVCS_TRY_WRITE 0x00000004 |
354 | #define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ) |
355 | |
356 | static void hvcs_kick(void) |
357 | { |
358 | hvcs_kicked = 1; |
359 | wmb(); |
360 | wake_up_process(hvcs_task); |
361 | } |
362 | |
363 | static void hvcs_unthrottle(struct tty_struct *tty) |
364 | { |
365 | struct hvcs_struct *hvcsd = tty->driver_data; |
366 | unsigned long flags; |
367 | |
368 | spin_lock_irqsave(&hvcsd->lock, flags); |
369 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
370 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
371 | hvcs_kick(); |
372 | } |
373 | |
374 | static void hvcs_throttle(struct tty_struct *tty) |
375 | { |
376 | struct hvcs_struct *hvcsd = tty->driver_data; |
377 | unsigned long flags; |
378 | |
379 | spin_lock_irqsave(&hvcsd->lock, flags); |
380 | vio_disable_interrupts(hvcsd->vdev); |
381 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
382 | } |
383 | |
384 | /* |
385 | * If the device is being removed we don't have to worry about this interrupt |
386 | * handler taking any further interrupts because they are disabled which means |
387 | * the hvcs_struct will always be valid in this handler. |
388 | */ |
389 | static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance, |
390 | struct pt_regs *regs) |
391 | { |
392 | struct hvcs_struct *hvcsd = dev_instance; |
393 | |
394 | spin_lock(&hvcsd->lock); |
395 | vio_disable_interrupts(hvcsd->vdev); |
396 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
397 | spin_unlock(&hvcsd->lock); |
398 | hvcs_kick(); |
399 | |
400 | return IRQ_HANDLED; |
401 | } |
402 | |
403 | /* This function must be called with the hvcsd->lock held */ |
404 | static void hvcs_try_write(struct hvcs_struct *hvcsd) |
405 | { |
406 | uint32_t unit_address = hvcsd->vdev->unit_address; |
407 | struct tty_struct *tty = hvcsd->tty; |
408 | int sent; |
409 | |
410 | if (hvcsd->todo_mask & HVCS_TRY_WRITE) { |
411 | /* won't send partial writes */ |
412 | sent = hvc_put_chars(unit_address, |
413 | &hvcsd->buffer[0], |
414 | hvcsd->chars_in_buffer ); |
415 | if (sent > 0) { |
416 | hvcsd->chars_in_buffer = 0; |
417 | /* wmb(); */ |
418 | hvcsd->todo_mask &= ~(HVCS_TRY_WRITE); |
419 | /* wmb(); */ |
420 | |
421 | /* |
422 | * We are still obligated to deliver the data to the |
423 | * hypervisor even if the tty has been closed because |
424 | * we commited to delivering it. But don't try to wake |
425 | * a non-existent tty. |
426 | */ |
427 | if (tty) { |
428 | tty_wakeup(tty); |
429 | } |
430 | } |
431 | } |
432 | } |
433 | |
434 | static int hvcs_io(struct hvcs_struct *hvcsd) |
435 | { |
436 | uint32_t unit_address; |
437 | struct tty_struct *tty; |
438 | char buf[HVCS_BUFF_LEN] __ALIGNED__; |
439 | unsigned long flags; |
440 | int got = 0; |
441 | int i; |
442 | |
443 | spin_lock_irqsave(&hvcsd->lock, flags); |
444 | |
445 | unit_address = hvcsd->vdev->unit_address; |
446 | tty = hvcsd->tty; |
447 | |
448 | hvcs_try_write(hvcsd); |
449 | |
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; |
455 | |
456 | /* remove the read masks */ |
457 | hvcsd->todo_mask &= ~(HVCS_READ_MASK); |
458 | |
459 | if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) { |
460 | got = hvc_get_chars(unit_address, |
461 | &buf[0], |
462 | HVCS_BUFF_LEN); |
463 | for (i=0;got && i<got;i++) |
464 | tty_insert_flip_char(tty, buf[i], TTY_NORMAL); |
465 | } |
466 | |
467 | /* Give the TTY time to process the data we just sent. */ |
468 | if (got) |
469 | hvcsd->todo_mask |= HVCS_QUICK_READ; |
470 | |
471 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
472 | if (tty->flip.count) { |
473 | /* This is synch because tty->low_latency == 1 */ |
474 | tty_flip_buffer_push(tty); |
475 | } |
476 | |
477 | if (!got) { |
478 | /* Do this _after_ the flip_buffer_push */ |
479 | spin_lock_irqsave(&hvcsd->lock, flags); |
480 | vio_enable_interrupts(hvcsd->vdev); |
481 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
482 | } |
483 | |
484 | return hvcsd->todo_mask; |
485 | |
486 | bail: |
487 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
488 | return hvcsd->todo_mask; |
489 | } |
490 | |
491 | static int khvcsd(void *unused) |
492 | { |
493 | struct hvcs_struct *hvcsd; |
494 | int hvcs_todo_mask; |
495 | |
496 | __set_current_state(TASK_RUNNING); |
497 | |
498 | do { |
499 | hvcs_todo_mask = 0; |
500 | hvcs_kicked = 0; |
501 | wmb(); |
502 | |
503 | spin_lock(&hvcs_structs_lock); |
504 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
505 | hvcs_todo_mask |= hvcs_io(hvcsd); |
506 | } |
507 | spin_unlock(&hvcs_structs_lock); |
508 | |
509 | /* |
510 | * If any of the hvcs adapters want to try a write or quick read |
511 | * don't schedule(), yield a smidgen then execute the hvcs_io |
512 | * thread again for those that want the write. |
513 | */ |
514 | if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) { |
515 | yield(); |
516 | continue; |
517 | } |
518 | |
519 | set_current_state(TASK_INTERRUPTIBLE); |
520 | if (!hvcs_kicked) |
521 | schedule(); |
522 | __set_current_state(TASK_RUNNING); |
523 | } while (!kthread_should_stop()); |
524 | |
525 | return 0; |
526 | } |
527 | |
528 | static struct vio_device_id hvcs_driver_table[] __devinitdata= { |
529 | {"serial-server", "hvterm2"}, |
530 | { NULL, } |
531 | }; |
532 | MODULE_DEVICE_TABLE(vio, hvcs_driver_table); |
533 | |
534 | static void hvcs_return_index(int index) |
535 | { |
536 | /* Paranoia check */ |
537 | if (!hvcs_index_list) |
538 | return; |
539 | if (index < 0 || index >= hvcs_index_count) |
540 | return; |
541 | if (hvcs_index_list[index] == -1) |
542 | return; |
543 | else |
544 | hvcs_index_list[index] = -1; |
545 | } |
546 | |
547 | /* callback when the kboject ref count reaches zero */ |
548 | static void destroy_hvcs_struct(struct kobject *kobj) |
549 | { |
550 | struct hvcs_struct *hvcsd = from_kobj(kobj); |
551 | struct vio_dev *vdev; |
552 | unsigned long flags; |
553 | |
554 | spin_lock(&hvcs_structs_lock); |
555 | spin_lock_irqsave(&hvcsd->lock, flags); |
556 | |
557 | /* the list_del poisons the pointers */ |
558 | list_del(&(hvcsd->next)); |
559 | |
560 | if (hvcsd->connected == 1) { |
561 | hvcs_partner_free(hvcsd); |
562 | printk(KERN_INFO "HVCS: Closed vty-server@%X and" |
563 | " partner vty@%X:%d connection.\n", |
564 | hvcsd->vdev->unit_address, |
565 | hvcsd->p_unit_address, |
566 | (uint32_t)hvcsd->p_partition_ID); |
567 | } |
568 | printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n", |
569 | hvcsd->vdev->unit_address); |
570 | |
571 | vdev = hvcsd->vdev; |
572 | hvcsd->vdev = NULL; |
573 | |
574 | hvcsd->p_unit_address = 0; |
575 | hvcsd->p_partition_ID = 0; |
576 | hvcs_return_index(hvcsd->index); |
577 | memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1); |
578 | |
579 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
580 | spin_unlock(&hvcs_structs_lock); |
581 | |
582 | hvcs_remove_device_attrs(vdev); |
583 | |
584 | kfree(hvcsd); |
585 | } |
586 | |
587 | static struct kobj_type hvcs_kobj_type = { |
588 | .release = destroy_hvcs_struct, |
589 | }; |
590 | |
591 | static int hvcs_get_index(void) |
592 | { |
593 | int i; |
594 | /* Paranoia check */ |
595 | if (!hvcs_index_list) { |
596 | printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n"); |
597 | return -EFAULT; |
598 | } |
599 | /* Find the numerically lowest first free index. */ |
600 | for(i = 0; i < hvcs_index_count; i++) { |
601 | if (hvcs_index_list[i] == -1) { |
602 | hvcs_index_list[i] = 0; |
603 | return i; |
604 | } |
605 | } |
606 | return -1; |
607 | } |
608 | |
609 | static int __devinit hvcs_probe( |
610 | struct vio_dev *dev, |
611 | const struct vio_device_id *id) |
612 | { |
613 | struct hvcs_struct *hvcsd; |
614 | int index; |
615 | |
616 | if (!dev || !id) { |
617 | printk(KERN_ERR "HVCS: probed with invalid parameter.\n"); |
618 | return -EPERM; |
619 | } |
620 | |
621 | /* early to avoid cleanup on failure */ |
622 | index = hvcs_get_index(); |
623 | if (index < 0) { |
624 | return -EFAULT; |
625 | } |
626 | |
627 | hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL); |
628 | if (!hvcsd) |
629 | return -ENODEV; |
630 | |
631 | /* hvcsd->tty is zeroed out with the memset */ |
632 | memset(hvcsd, 0x00, sizeof(*hvcsd)); |
633 | |
634 | spin_lock_init(&hvcsd->lock); |
635 | /* Automatically incs the refcount the first time */ |
636 | kobject_init(&hvcsd->kobj); |
637 | /* Set up the callback for terminating the hvcs_struct's life */ |
638 | hvcsd->kobj.ktype = &hvcs_kobj_type; |
639 | |
640 | hvcsd->vdev = dev; |
641 | dev->dev.driver_data = hvcsd; |
642 | |
643 | hvcsd->index = index; |
644 | |
645 | /* hvcsd->index = ++hvcs_struct_count; */ |
646 | hvcsd->chars_in_buffer = 0; |
647 | hvcsd->todo_mask = 0; |
648 | hvcsd->connected = 0; |
649 | |
650 | /* |
651 | * This will populate the hvcs_struct's partner info fields for the |
652 | * first time. |
653 | */ |
654 | if (hvcs_get_pi(hvcsd)) { |
655 | printk(KERN_ERR "HVCS: Failed to fetch partner" |
656 | " info for vty-server@%X on device probe.\n", |
657 | hvcsd->vdev->unit_address); |
658 | } |
659 | |
660 | /* |
661 | * If a user app opens a tty that corresponds to this vty-server before |
662 | * the hvcs_struct has been added to the devices list then the user app |
663 | * will get -ENODEV. |
664 | */ |
665 | |
666 | spin_lock(&hvcs_structs_lock); |
667 | |
668 | list_add_tail(&(hvcsd->next), &hvcs_structs); |
669 | |
670 | spin_unlock(&hvcs_structs_lock); |
671 | |
672 | hvcs_create_device_attrs(hvcsd); |
673 | |
674 | printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address); |
675 | |
676 | /* |
677 | * DON'T enable interrupts here because there is no user to receive the |
678 | * data. |
679 | */ |
680 | return 0; |
681 | } |
682 | |
683 | static int __devexit hvcs_remove(struct vio_dev *dev) |
684 | { |
685 | struct hvcs_struct *hvcsd = dev->dev.driver_data; |
686 | unsigned long flags; |
687 | struct kobject *kobjp; |
688 | struct tty_struct *tty; |
689 | |
690 | if (!hvcsd) |
691 | return -ENODEV; |
692 | |
693 | /* By this time the vty-server won't be getting any more interrups */ |
694 | |
695 | spin_lock_irqsave(&hvcsd->lock, flags); |
696 | |
697 | tty = hvcsd->tty; |
698 | |
699 | kobjp = &hvcsd->kobj; |
700 | |
701 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
702 | |
703 | /* |
704 | * Let the last holder of this object cause it to be removed, which |
705 | * would probably be tty_hangup below. |
706 | */ |
707 | kobject_put (kobjp); |
708 | |
709 | /* |
710 | * The hangup is a scheduled function which will auto chain call |
711 | * hvcs_hangup. The tty should always be valid at this time unless a |
712 | * simultaneous tty close already cleaned up the hvcs_struct. |
713 | */ |
714 | if (tty) |
715 | tty_hangup(tty); |
716 | |
717 | printk(KERN_INFO "HVCS: vty-server@%X removed from the" |
718 | " vio bus.\n", dev->unit_address); |
719 | return 0; |
720 | }; |
721 | |
722 | static struct vio_driver hvcs_vio_driver = { |
723 | .name = hvcs_driver_name, |
724 | .id_table = hvcs_driver_table, |
725 | .probe = hvcs_probe, |
726 | .remove = hvcs_remove, |
727 | }; |
728 | |
729 | /* Only called from hvcs_get_pi please */ |
730 | static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) |
731 | { |
732 | int clclength; |
733 | |
734 | hvcsd->p_unit_address = pi->unit_address; |
735 | hvcsd->p_partition_ID = pi->partition_ID; |
736 | clclength = strlen(&pi->location_code[0]); |
737 | if (clclength > HVCS_CLC_LENGTH) |
738 | clclength = HVCS_CLC_LENGTH; |
739 | |
740 | /* copy the null-term char too */ |
741 | strncpy(&hvcsd->p_location_code[0], |
742 | &pi->location_code[0], clclength + 1); |
743 | } |
744 | |
745 | /* |
746 | * Traverse the list and add the partner info that is found to the hvcs_struct |
747 | * struct entry. NOTE: At this time I know that partner info will return a |
748 | * single entry but in the future there may be multiple partner info entries per |
749 | * vty-server and you'll want to zero out that list and reset it. If for some |
750 | * reason you have an old version of this driver but there IS more than one |
751 | * partner info then hvcsd->p_* will hold the last partner info data from the |
752 | * firmware query. A good way to update this code would be to replace the three |
753 | * partner info fields in hvcs_struct with a list of hvcs_partner_info |
754 | * instances. |
755 | * |
756 | * This function must be called with the hvcsd->lock held. |
757 | */ |
758 | static int hvcs_get_pi(struct hvcs_struct *hvcsd) |
759 | { |
760 | struct hvcs_partner_info *pi; |
761 | uint32_t unit_address = hvcsd->vdev->unit_address; |
762 | struct list_head head; |
763 | int retval; |
764 | |
765 | spin_lock(&hvcs_pi_lock); |
766 | if (!hvcs_pi_buff) { |
767 | spin_unlock(&hvcs_pi_lock); |
768 | return -EFAULT; |
769 | } |
770 | retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff); |
771 | spin_unlock(&hvcs_pi_lock); |
772 | if (retval) { |
773 | printk(KERN_ERR "HVCS: Failed to fetch partner" |
774 | " info for vty-server@%x.\n", unit_address); |
775 | return retval; |
776 | } |
777 | |
778 | /* nixes the values if the partner vty went away */ |
779 | hvcsd->p_unit_address = 0; |
780 | hvcsd->p_partition_ID = 0; |
781 | |
782 | list_for_each_entry(pi, &head, node) |
783 | hvcs_set_pi(pi, hvcsd); |
784 | |
785 | hvcs_free_partner_info(&head); |
786 | return 0; |
787 | } |
788 | |
789 | /* |
790 | * This function is executed by the driver "rescan" sysfs entry. It shouldn't |
791 | * be executed elsewhere, in order to prevent deadlock issues. |
792 | */ |
793 | static int hvcs_rescan_devices_list(void) |
794 | { |
795 | struct hvcs_struct *hvcsd; |
796 | unsigned long flags; |
797 | |
798 | spin_lock(&hvcs_structs_lock); |
799 | |
800 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
801 | spin_lock_irqsave(&hvcsd->lock, flags); |
802 | hvcs_get_pi(hvcsd); |
803 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
804 | } |
805 | |
806 | spin_unlock(&hvcs_structs_lock); |
807 | |
808 | return 0; |
809 | } |
810 | |
811 | /* |
812 | * Farm this off into its own function because it could be more complex once |
813 | * multiple partners support is added. This function should be called with |
814 | * the hvcsd->lock held. |
815 | */ |
816 | static int hvcs_has_pi(struct hvcs_struct *hvcsd) |
817 | { |
818 | if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID)) |
819 | return 0; |
820 | return 1; |
821 | } |
822 | |
823 | /* |
824 | * NOTE: It is possible that the super admin removed a partner vty and then |
825 | * added a different vty as the new partner. |
826 | * |
827 | * This function must be called with the hvcsd->lock held. |
828 | */ |
829 | static int hvcs_partner_connect(struct hvcs_struct *hvcsd) |
830 | { |
831 | int retval; |
832 | unsigned int unit_address = hvcsd->vdev->unit_address; |
833 | |
834 | /* |
835 | * If there wasn't any pi when the device was added it doesn't meant |
836 | * there isn't any now. This driver isn't notified when a new partner |
837 | * vty is added to a vty-server so we discover changes on our own. |
838 | * Please see comments in hvcs_register_connection() for justification |
839 | * of this bizarre code. |
840 | */ |
841 | retval = hvcs_register_connection(unit_address, |
842 | hvcsd->p_partition_ID, |
843 | hvcsd->p_unit_address); |
844 | if (!retval) { |
845 | hvcsd->connected = 1; |
846 | return 0; |
847 | } else if (retval != -EINVAL) |
848 | return retval; |
849 | |
850 | /* |
851 | * As per the spec re-get the pi and try again if -EINVAL after the |
852 | * first connection attempt. |
853 | */ |
854 | if (hvcs_get_pi(hvcsd)) |
855 | return -ENOMEM; |
856 | |
857 | if (!hvcs_has_pi(hvcsd)) |
858 | return -ENODEV; |
859 | |
860 | retval = hvcs_register_connection(unit_address, |
861 | hvcsd->p_partition_ID, |
862 | hvcsd->p_unit_address); |
863 | if (retval != -EINVAL) { |
864 | hvcsd->connected = 1; |
865 | return retval; |
866 | } |
867 | |
868 | /* |
869 | * EBUSY is the most likely scenario though the vty could have been |
870 | * removed or there really could be an hcall error due to the parameter |
871 | * data but thanks to ambiguous firmware return codes we can't really |
872 | * tell. |
873 | */ |
874 | printk(KERN_INFO "HVCS: vty-server or partner" |
875 | " vty is busy. Try again later.\n"); |
876 | return -EBUSY; |
877 | } |
878 | |
879 | /* This function must be called with the hvcsd->lock held */ |
880 | static void hvcs_partner_free(struct hvcs_struct *hvcsd) |
881 | { |
882 | int retval; |
883 | do { |
884 | retval = hvcs_free_connection(hvcsd->vdev->unit_address); |
885 | } while (retval == -EBUSY); |
886 | hvcsd->connected = 0; |
887 | } |
888 | |
889 | /* This helper function must be called WITHOUT the hvcsd->lock held */ |
890 | static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address, |
891 | unsigned int irq, struct vio_dev *vdev) |
892 | { |
893 | unsigned long flags; |
894 | int rc; |
895 | |
896 | /* |
897 | * It is possible that the vty-server was removed between the time that |
898 | * the conn was registered and now. |
899 | */ |
900 | if (!(rc = request_irq(irq, &hvcs_handle_interrupt, |
901 | SA_INTERRUPT, "ibmhvcs", hvcsd))) { |
902 | /* |
903 | * It is possible the vty-server was removed after the irq was |
904 | * requested but before we have time to enable interrupts. |
905 | */ |
906 | if (vio_enable_interrupts(vdev) == H_Success) |
907 | return 0; |
908 | else { |
909 | printk(KERN_ERR "HVCS: int enable failed for" |
910 | " vty-server@%X.\n", unit_address); |
911 | free_irq(irq, hvcsd); |
912 | } |
913 | } else |
914 | printk(KERN_ERR "HVCS: irq req failed for" |
915 | " vty-server@%X.\n", unit_address); |
916 | |
917 | spin_lock_irqsave(&hvcsd->lock, flags); |
918 | hvcs_partner_free(hvcsd); |
919 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
920 | |
921 | return rc; |
922 | |
923 | } |
924 | |
925 | /* |
926 | * This always increments the kobject ref count if the call is successful. |
927 | * Please remember to dec when you are done with the instance. |
928 | * |
929 | * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when |
930 | * calling this function or you will get deadlock. |
931 | */ |
932 | struct hvcs_struct *hvcs_get_by_index(int index) |
933 | { |
934 | struct hvcs_struct *hvcsd = NULL; |
935 | unsigned long flags; |
936 | |
937 | spin_lock(&hvcs_structs_lock); |
938 | /* We can immediately discard OOB requests */ |
939 | if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) { |
940 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
941 | spin_lock_irqsave(&hvcsd->lock, flags); |
942 | if (hvcsd->index == index) { |
943 | kobject_get(&hvcsd->kobj); |
944 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
945 | spin_unlock(&hvcs_structs_lock); |
946 | return hvcsd; |
947 | } |
948 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
949 | } |
950 | hvcsd = NULL; |
951 | } |
952 | |
953 | spin_unlock(&hvcs_structs_lock); |
954 | return hvcsd; |
955 | } |
956 | |
957 | /* |
958 | * This is invoked via the tty_open interface when a user app connects to the |
959 | * /dev node. |
960 | */ |
961 | static int hvcs_open(struct tty_struct *tty, struct file *filp) |
962 | { |
963 | struct hvcs_struct *hvcsd; |
964 | int rc, retval = 0; |
965 | unsigned long flags; |
966 | unsigned int irq; |
967 | struct vio_dev *vdev; |
968 | unsigned long unit_address; |
969 | struct kobject *kobjp; |
970 | |
971 | if (tty->driver_data) |
972 | goto fast_open; |
973 | |
974 | /* |
975 | * Is there a vty-server that shares the same index? |
976 | * This function increments the kobject index. |
977 | */ |
978 | if (!(hvcsd = hvcs_get_by_index(tty->index))) { |
979 | printk(KERN_WARNING "HVCS: open failed, no device associated" |
980 | " with tty->index %d.\n", tty->index); |
981 | return -ENODEV; |
982 | } |
983 | |
984 | spin_lock_irqsave(&hvcsd->lock, flags); |
985 | |
986 | if (hvcsd->connected == 0) |
987 | if ((retval = hvcs_partner_connect(hvcsd))) |
988 | goto error_release; |
989 | |
990 | hvcsd->open_count = 1; |
991 | hvcsd->tty = tty; |
992 | tty->driver_data = hvcsd; |
993 | |
994 | /* |
995 | * Set this driver to low latency so that we actually have a chance at |
996 | * catching a throttled TTY after we flip_buffer_push. Otherwise the |
997 | * flush_to_async may not execute until after the kernel_thread has |
998 | * yielded and resumed the next flip_buffer_push resulting in data |
999 | * loss. |
1000 | */ |
1001 | tty->low_latency = 1; |
1002 | |
1003 | memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); |
1004 | |
1005 | /* |
1006 | * Save these in the spinlock for the enable operations that need them |
1007 | * outside of the spinlock. |
1008 | */ |
1009 | irq = hvcsd->vdev->irq; |
1010 | vdev = hvcsd->vdev; |
1011 | unit_address = hvcsd->vdev->unit_address; |
1012 | |
1013 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
1014 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1015 | |
1016 | /* |
1017 | * This must be done outside of the spinlock because it requests irqs |
1018 | * and will grab the spinlock and free the connection if it fails. |
1019 | */ |
1020 | if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) { |
1021 | kobject_put(&hvcsd->kobj); |
1022 | printk(KERN_WARNING "HVCS: enable device failed.\n"); |
1023 | return rc; |
1024 | } |
1025 | |
1026 | goto open_success; |
1027 | |
1028 | fast_open: |
1029 | hvcsd = tty->driver_data; |
1030 | |
1031 | spin_lock_irqsave(&hvcsd->lock, flags); |
1032 | if (!kobject_get(&hvcsd->kobj)) { |
1033 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1034 | printk(KERN_ERR "HVCS: Kobject of open" |
1035 | " hvcs doesn't exist.\n"); |
1036 | return -EFAULT; /* Is this the right return value? */ |
1037 | } |
1038 | |
1039 | hvcsd->open_count++; |
1040 | |
1041 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
1042 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1043 | open_success: |
1044 | hvcs_kick(); |
1045 | |
1046 | printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n", |
1047 | hvcsd->vdev->unit_address ); |
1048 | |
1049 | return 0; |
1050 | |
1051 | error_release: |
1052 | kobjp = &hvcsd->kobj; |
1053 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1054 | kobject_put(&hvcsd->kobj); |
1055 | |
1056 | printk(KERN_WARNING "HVCS: partner connect failed.\n"); |
1057 | return retval; |
1058 | } |
1059 | |
1060 | static void hvcs_close(struct tty_struct *tty, struct file *filp) |
1061 | { |
1062 | struct hvcs_struct *hvcsd; |
1063 | unsigned long flags; |
1064 | struct kobject *kobjp; |
1065 | int irq = NO_IRQ; |
1066 | |
1067 | /* |
1068 | * Is someone trying to close the file associated with this device after |
1069 | * we have hung up? If so tty->driver_data wouldn't be valid. |
1070 | */ |
1071 | if (tty_hung_up_p(filp)) |
1072 | return; |
1073 | |
1074 | /* |
1075 | * No driver_data means that this close was probably issued after a |
1076 | * failed hvcs_open by the tty layer's release_dev() api and we can just |
1077 | * exit cleanly. |
1078 | */ |
1079 | if (!tty->driver_data) |
1080 | return; |
1081 | |
1082 | hvcsd = tty->driver_data; |
1083 | |
1084 | spin_lock_irqsave(&hvcsd->lock, flags); |
1085 | kobjp = &hvcsd->kobj; |
1086 | if (--hvcsd->open_count == 0) { |
1087 | |
1088 | vio_disable_interrupts(hvcsd->vdev); |
1089 | |
1090 | /* |
1091 | * NULL this early so that the kernel_thread doesn't try to |
1092 | * execute any operations on the TTY even though it is obligated |
1093 | * to deliver any pending I/O to the hypervisor. |
1094 | */ |
1095 | hvcsd->tty = NULL; |
1096 | |
1097 | irq = hvcsd->vdev->irq; |
1098 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1099 | |
1100 | tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); |
1101 | |
1102 | /* |
1103 | * This line is important because it tells hvcs_open that this |
1104 | * device needs to be re-configured the next time hvcs_open is |
1105 | * called. |
1106 | */ |
1107 | tty->driver_data = NULL; |
1108 | |
1109 | free_irq(irq, hvcsd); |
1110 | kobject_put(kobjp); |
1111 | return; |
1112 | } else if (hvcsd->open_count < 0) { |
1113 | printk(KERN_ERR "HVCS: vty-server@%X open_count: %d" |
1114 | " is missmanaged.\n", |
1115 | hvcsd->vdev->unit_address, hvcsd->open_count); |
1116 | } |
1117 | |
1118 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1119 | kobject_put(kobjp); |
1120 | } |
1121 | |
1122 | static void hvcs_hangup(struct tty_struct * tty) |
1123 | { |
1124 | struct hvcs_struct *hvcsd = tty->driver_data; |
1125 | unsigned long flags; |
1126 | int temp_open_count; |
1127 | struct kobject *kobjp; |
1128 | int irq = NO_IRQ; |
1129 | |
1130 | spin_lock_irqsave(&hvcsd->lock, flags); |
1131 | /* Preserve this so that we know how many kobject refs to put */ |
1132 | temp_open_count = hvcsd->open_count; |
1133 | |
1134 | /* |
1135 | * Don't kobject put inside the spinlock because the destruction |
1136 | * callback may use the spinlock and it may get called before the |
1137 | * spinlock has been released. Get a pointer to the kobject and |
1138 | * kobject_put on that after releasing the spinlock. |
1139 | */ |
1140 | kobjp = &hvcsd->kobj; |
1141 | |
1142 | vio_disable_interrupts(hvcsd->vdev); |
1143 | |
1144 | hvcsd->todo_mask = 0; |
1145 | |
1146 | /* I don't think the tty needs the hvcs_struct pointer after a hangup */ |
1147 | hvcsd->tty->driver_data = NULL; |
1148 | hvcsd->tty = NULL; |
1149 | |
1150 | hvcsd->open_count = 0; |
1151 | |
1152 | /* This will drop any buffered data on the floor which is OK in a hangup |
1153 | * scenario. */ |
1154 | memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); |
1155 | hvcsd->chars_in_buffer = 0; |
1156 | |
1157 | irq = hvcsd->vdev->irq; |
1158 | |
1159 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1160 | |
1161 | free_irq(irq, hvcsd); |
1162 | |
1163 | /* |
1164 | * We need to kobject_put() for every open_count we have since the |
1165 | * tty_hangup() function doesn't invoke a close per open connection on a |
1166 | * non-console device. |
1167 | */ |
1168 | while(temp_open_count) { |
1169 | --temp_open_count; |
1170 | /* |
1171 | * The final put will trigger destruction of the hvcs_struct. |
1172 | * NOTE: If this hangup was signaled from user space then the |
1173 | * final put will never happen. |
1174 | */ |
1175 | kobject_put(kobjp); |
1176 | } |
1177 | } |
1178 | |
1179 | /* |
1180 | * NOTE: This is almost always from_user since user level apps interact with the |
1181 | * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by |
1182 | * hvcs_remove (which removes the target device and executes tty_hangup()) that |
1183 | * tty_hangup will allow hvcs_write time to complete execution before it |
1184 | * terminates our device. |
1185 | */ |
1186 | static int hvcs_write(struct tty_struct *tty, |
1187 | const unsigned char *buf, int count) |
1188 | { |
1189 | struct hvcs_struct *hvcsd = tty->driver_data; |
1190 | unsigned int unit_address; |
1191 | const unsigned char *charbuf; |
1192 | unsigned long flags; |
1193 | int total_sent = 0; |
1194 | int tosend = 0; |
1195 | int result = 0; |
1196 | |
1197 | /* |
1198 | * If they don't check the return code off of their open they may |
1199 | * attempt this even if there is no connected device. |
1200 | */ |
1201 | if (!hvcsd) |
1202 | return -ENODEV; |
1203 | |
1204 | /* Reasonable size to prevent user level flooding */ |
1205 | if (count > HVCS_MAX_FROM_USER) { |
1206 | printk(KERN_WARNING "HVCS write: count being truncated to" |
1207 | " HVCS_MAX_FROM_USER.\n"); |
1208 | count = HVCS_MAX_FROM_USER; |
1209 | } |
1210 | |
1211 | charbuf = buf; |
1212 | |
1213 | spin_lock_irqsave(&hvcsd->lock, flags); |
1214 | |
1215 | /* |
1216 | * Somehow an open succedded but the device was removed or the |
1217 | * connection terminated between the vty-server and partner vty during |
1218 | * the middle of a write operation? This is a crummy place to do this |
1219 | * but we want to keep it all in the spinlock. |
1220 | */ |
1221 | if (hvcsd->open_count <= 0) { |
1222 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1223 | return -ENODEV; |
1224 | } |
1225 | |
1226 | unit_address = hvcsd->vdev->unit_address; |
1227 | |
1228 | while (count > 0) { |
1229 | tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); |
1230 | /* |
1231 | * No more space, this probably means that the last call to |
1232 | * hvcs_write() didn't succeed and the buffer was filled up. |
1233 | */ |
1234 | if (!tosend) |
1235 | break; |
1236 | |
1237 | memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], |
1238 | &charbuf[total_sent], |
1239 | tosend); |
1240 | |
1241 | hvcsd->chars_in_buffer += tosend; |
1242 | |
1243 | result = 0; |
1244 | |
1245 | /* |
1246 | * If this is true then we don't want to try writing to the |
1247 | * hypervisor because that is the kernel_threads job now. We'll |
1248 | * just add to the buffer. |
1249 | */ |
1250 | if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) |
1251 | /* won't send partial writes */ |
1252 | result = hvc_put_chars(unit_address, |
1253 | &hvcsd->buffer[0], |
1254 | hvcsd->chars_in_buffer); |
1255 | |
1256 | /* |
1257 | * Since we know we have enough room in hvcsd->buffer for |
1258 | * tosend we record that it was sent regardless of whether the |
1259 | * hypervisor actually took it because we have it buffered. |
1260 | */ |
1261 | total_sent+=tosend; |
1262 | count-=tosend; |
1263 | if (result == 0) { |
1264 | hvcsd->todo_mask |= HVCS_TRY_WRITE; |
1265 | hvcs_kick(); |
1266 | break; |
1267 | } |
1268 | |
1269 | hvcsd->chars_in_buffer = 0; |
1270 | /* |
1271 | * Test after the chars_in_buffer reset otherwise this could |
1272 | * deadlock our writes if hvc_put_chars fails. |
1273 | */ |
1274 | if (result < 0) |
1275 | break; |
1276 | } |
1277 | |
1278 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1279 | |
1280 | if (result == -1) |
1281 | return -EIO; |
1282 | else |
1283 | return total_sent; |
1284 | } |
1285 | |
1286 | /* |
1287 | * This is really asking how much can we guarentee that we can send or that we |
1288 | * absolutely WILL BUFFER if we can't send it. This driver MUST honor the |
1289 | * return value, hence the reason for hvcs_struct buffering. |
1290 | */ |
1291 | static int hvcs_write_room(struct tty_struct *tty) |
1292 | { |
1293 | struct hvcs_struct *hvcsd = tty->driver_data; |
1294 | |
1295 | if (!hvcsd || hvcsd->open_count <= 0) |
1296 | return 0; |
1297 | |
1298 | return HVCS_BUFF_LEN - hvcsd->chars_in_buffer; |
1299 | } |
1300 | |
1301 | static int hvcs_chars_in_buffer(struct tty_struct *tty) |
1302 | { |
1303 | struct hvcs_struct *hvcsd = tty->driver_data; |
1304 | |
1305 | return hvcsd->chars_in_buffer; |
1306 | } |
1307 | |
1308 | static struct tty_operations hvcs_ops = { |
1309 | .open = hvcs_open, |
1310 | .close = hvcs_close, |
1311 | .hangup = hvcs_hangup, |
1312 | .write = hvcs_write, |
1313 | .write_room = hvcs_write_room, |
1314 | .chars_in_buffer = hvcs_chars_in_buffer, |
1315 | .unthrottle = hvcs_unthrottle, |
1316 | .throttle = hvcs_throttle, |
1317 | }; |
1318 | |
1319 | static int hvcs_alloc_index_list(int n) |
1320 | { |
1321 | int i; |
1322 | hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL); |
1323 | if (!hvcs_index_list) |
1324 | return -ENOMEM; |
1325 | hvcs_index_count = n; |
1326 | for(i = 0; i < hvcs_index_count; i++) |
1327 | hvcs_index_list[i] = -1; |
1328 | return 0; |
1329 | } |
1330 | |
1331 | static void hvcs_free_index_list(void) |
1332 | { |
1333 | /* Paranoia check to be thorough. */ |
1334 | if (hvcs_index_list) { |
1335 | kfree(hvcs_index_list); |
1336 | hvcs_index_list = NULL; |
1337 | hvcs_index_count = 0; |
1338 | } |
1339 | } |
1340 | |
1341 | static int __init hvcs_module_init(void) |
1342 | { |
1343 | int rc; |
1344 | int num_ttys_to_alloc; |
1345 | |
1346 | printk(KERN_INFO "Initializing %s\n", hvcs_driver_string); |
1347 | |
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; |
1354 | |
1355 | hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc); |
1356 | if (!hvcs_tty_driver) |
1357 | return -ENOMEM; |
1358 | |
1359 | if (hvcs_alloc_index_list(num_ttys_to_alloc)) |
1360 | return -ENOMEM; |
1361 | |
1362 | hvcs_tty_driver->owner = THIS_MODULE; |
1363 | |
1364 | hvcs_tty_driver->driver_name = hvcs_driver_name; |
1365 | hvcs_tty_driver->name = hvcs_device_node; |
1366 | hvcs_tty_driver->devfs_name = hvcs_device_node; |
1367 | |
1368 | /* |
1369 | * We'll let the system assign us a major number, indicated by leaving |
1370 | * it blank. |
1371 | */ |
1372 | |
1373 | hvcs_tty_driver->minor_start = HVCS_MINOR_START; |
1374 | hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; |
1375 | |
1376 | /* |
1377 | * We role our own so that we DONT ECHO. We can't echo because the |
1378 | * device we are connecting to already echoes by default and this would |
1379 | * throw us into a horrible recursive echo-echo-echo loop. |
1380 | */ |
1381 | hvcs_tty_driver->init_termios = hvcs_tty_termios; |
1382 | hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW; |
1383 | |
1384 | tty_set_operations(hvcs_tty_driver, &hvcs_ops); |
1385 | |
1386 | /* |
1387 | * The following call will result in sysfs entries that denote the |
1388 | * dynamically assigned major and minor numbers for our devices. |
1389 | */ |
1390 | if (tty_register_driver(hvcs_tty_driver)) { |
1391 | printk(KERN_ERR "HVCS: registration " |
1392 | " as a tty driver failed.\n"); |
1393 | hvcs_free_index_list(); |
1394 | put_tty_driver(hvcs_tty_driver); |
1395 | return -EIO; |
1396 | } |
1397 | |
1398 | hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL); |
1399 | if (!hvcs_pi_buff) { |
1400 | tty_unregister_driver(hvcs_tty_driver); |
1401 | hvcs_free_index_list(); |
1402 | put_tty_driver(hvcs_tty_driver); |
1403 | return -ENOMEM; |
1404 | } |
1405 | |
1406 | hvcs_task = kthread_run(khvcsd, NULL, "khvcsd"); |
1407 | if (IS_ERR(hvcs_task)) { |
1408 | printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n"); |
1409 | kfree(hvcs_pi_buff); |
1410 | tty_unregister_driver(hvcs_tty_driver); |
1411 | hvcs_free_index_list(); |
1412 | put_tty_driver(hvcs_tty_driver); |
1413 | return -EIO; |
1414 | } |
1415 | |
1416 | rc = vio_register_driver(&hvcs_vio_driver); |
1417 | |
1418 | /* |
1419 | * This needs to be done AFTER the vio_register_driver() call or else |
1420 | * the kobjects won't be initialized properly. |
1421 | */ |
1422 | hvcs_create_driver_attrs(); |
1423 | |
1424 | printk(KERN_INFO "HVCS: driver module inserted.\n"); |
1425 | |
1426 | return rc; |
1427 | } |
1428 | |
1429 | static void __exit hvcs_module_exit(void) |
1430 | { |
1431 | /* |
1432 | * This driver receives hvcs_remove callbacks for each device upon |
1433 | * module removal. |
1434 | */ |
1435 | |
1436 | /* |
1437 | * This synchronous operation will wake the khvcsd kthread if it is |
1438 | * asleep and will return when khvcsd has terminated. |
1439 | */ |
1440 | kthread_stop(hvcs_task); |
1441 | |
1442 | spin_lock(&hvcs_pi_lock); |
1443 | kfree(hvcs_pi_buff); |
1444 | hvcs_pi_buff = NULL; |
1445 | spin_unlock(&hvcs_pi_lock); |
1446 | |
1447 | hvcs_remove_driver_attrs(); |
1448 | |
1449 | vio_unregister_driver(&hvcs_vio_driver); |
1450 | |
1451 | tty_unregister_driver(hvcs_tty_driver); |
1452 | |
1453 | hvcs_free_index_list(); |
1454 | |
1455 | put_tty_driver(hvcs_tty_driver); |
1456 | |
1457 | printk(KERN_INFO "HVCS: driver module removed.\n"); |
1458 | } |
1459 | |
1460 | module_init(hvcs_module_init); |
1461 | module_exit(hvcs_module_exit); |
1462 | |
1463 | static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) |
1464 | { |
1465 | return viod->dev.driver_data; |
1466 | } |
1467 | /* The sysfs interface for the driver and devices */ |
1468 | |
1469 | static ssize_t hvcs_partner_vtys_show(struct device *dev, char *buf) |
1470 | { |
1471 | struct vio_dev *viod = to_vio_dev(dev); |
1472 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1473 | unsigned long flags; |
1474 | int retval; |
1475 | |
1476 | spin_lock_irqsave(&hvcsd->lock, flags); |
1477 | retval = sprintf(buf, "%X\n", hvcsd->p_unit_address); |
1478 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1479 | return retval; |
1480 | } |
1481 | static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); |
1482 | |
1483 | static ssize_t hvcs_partner_clcs_show(struct device *dev, char *buf) |
1484 | { |
1485 | struct vio_dev *viod = to_vio_dev(dev); |
1486 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1487 | unsigned long flags; |
1488 | int retval; |
1489 | |
1490 | spin_lock_irqsave(&hvcsd->lock, flags); |
1491 | retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); |
1492 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1493 | return retval; |
1494 | } |
1495 | static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); |
1496 | |
1497 | static ssize_t hvcs_current_vty_store(struct device *dev, const char * buf, |
1498 | size_t count) |
1499 | { |
1500 | /* |
1501 | * Don't need this feature at the present time because firmware doesn't |
1502 | * yet support multiple partners. |
1503 | */ |
1504 | printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n"); |
1505 | return -EPERM; |
1506 | } |
1507 | |
1508 | static ssize_t hvcs_current_vty_show(struct device *dev, char *buf) |
1509 | { |
1510 | struct vio_dev *viod = to_vio_dev(dev); |
1511 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1512 | unsigned long flags; |
1513 | int retval; |
1514 | |
1515 | spin_lock_irqsave(&hvcsd->lock, flags); |
1516 | retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); |
1517 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1518 | return retval; |
1519 | } |
1520 | |
1521 | static DEVICE_ATTR(current_vty, |
1522 | S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); |
1523 | |
1524 | static ssize_t hvcs_vterm_state_store(struct device *dev, const char *buf, |
1525 | size_t count) |
1526 | { |
1527 | struct vio_dev *viod = to_vio_dev(dev); |
1528 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1529 | unsigned long flags; |
1530 | |
1531 | /* writing a '0' to this sysfs entry will result in the disconnect. */ |
1532 | if (simple_strtol(buf, NULL, 0) != 0) |
1533 | return -EINVAL; |
1534 | |
1535 | spin_lock_irqsave(&hvcsd->lock, flags); |
1536 | |
1537 | if (hvcsd->open_count > 0) { |
1538 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1539 | printk(KERN_INFO "HVCS: vterm state unchanged. " |
1540 | "The hvcs device node is still in use.\n"); |
1541 | return -EPERM; |
1542 | } |
1543 | |
1544 | if (hvcsd->connected == 0) { |
1545 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1546 | printk(KERN_INFO "HVCS: vterm state unchanged. The" |
1547 | " vty-server is not connected to a vty.\n"); |
1548 | return -EPERM; |
1549 | } |
1550 | |
1551 | hvcs_partner_free(hvcsd); |
1552 | printk(KERN_INFO "HVCS: Closed vty-server@%X and" |
1553 | " partner vty@%X:%d connection.\n", |
1554 | hvcsd->vdev->unit_address, |
1555 | hvcsd->p_unit_address, |
1556 | (uint32_t)hvcsd->p_partition_ID); |
1557 | |
1558 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1559 | return count; |
1560 | } |
1561 | |
1562 | static ssize_t hvcs_vterm_state_show(struct device *dev, char *buf) |
1563 | { |
1564 | struct vio_dev *viod = to_vio_dev(dev); |
1565 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1566 | unsigned long flags; |
1567 | int retval; |
1568 | |
1569 | spin_lock_irqsave(&hvcsd->lock, flags); |
1570 | retval = sprintf(buf, "%d\n", hvcsd->connected); |
1571 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1572 | return retval; |
1573 | } |
1574 | static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, |
1575 | hvcs_vterm_state_show, hvcs_vterm_state_store); |
1576 | |
1577 | static ssize_t hvcs_index_show(struct device *dev, char *buf) |
1578 | { |
1579 | struct vio_dev *viod = to_vio_dev(dev); |
1580 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
1581 | unsigned long flags; |
1582 | int retval; |
1583 | |
1584 | spin_lock_irqsave(&hvcsd->lock, flags); |
1585 | retval = sprintf(buf, "%d\n", hvcsd->index); |
1586 | spin_unlock_irqrestore(&hvcsd->lock, flags); |
1587 | return retval; |
1588 | } |
1589 | |
1590 | static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL); |
1591 | |
1592 | static struct attribute *hvcs_attrs[] = { |
1593 | &dev_attr_partner_vtys.attr, |
1594 | &dev_attr_partner_clcs.attr, |
1595 | &dev_attr_current_vty.attr, |
1596 | &dev_attr_vterm_state.attr, |
1597 | &dev_attr_index.attr, |
1598 | NULL, |
1599 | }; |
1600 | |
1601 | static struct attribute_group hvcs_attr_group = { |
1602 | .attrs = hvcs_attrs, |
1603 | }; |
1604 | |
1605 | static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd) |
1606 | { |
1607 | struct vio_dev *vdev = hvcsd->vdev; |
1608 | sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group); |
1609 | } |
1610 | |
1611 | static void hvcs_remove_device_attrs(struct vio_dev *vdev) |
1612 | { |
1613 | sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group); |
1614 | } |
1615 | |
1616 | static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf) |
1617 | { |
1618 | /* A 1 means it is updating, a 0 means it is done updating */ |
1619 | return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status); |
1620 | } |
1621 | |
1622 | static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf, |
1623 | size_t count) |
1624 | { |
1625 | if ((simple_strtol(buf, NULL, 0) != 1) |
1626 | && (hvcs_rescan_status != 0)) |
1627 | return -EINVAL; |
1628 | |
1629 | hvcs_rescan_status = 1; |
1630 | printk(KERN_INFO "HVCS: rescanning partner info for all" |
1631 | " vty-servers.\n"); |
1632 | hvcs_rescan_devices_list(); |
1633 | hvcs_rescan_status = 0; |
1634 | return count; |
1635 | } |
1636 | static DRIVER_ATTR(rescan, |
1637 | S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store); |
1638 | |
1639 | static void hvcs_create_driver_attrs(void) |
1640 | { |
1641 | struct device_driver *driverfs = &(hvcs_vio_driver.driver); |
1642 | driver_create_file(driverfs, &driver_attr_rescan); |
1643 | } |
1644 | |
1645 | static void hvcs_remove_driver_attrs(void) |
1646 | { |
1647 | struct device_driver *driverfs = &(hvcs_vio_driver.driver); |
1648 | driver_remove_file(driverfs, &driver_attr_rescan); |
1649 | } |