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/arch/powerpc/hvcs.rst. |
51 | */ |
52 | |
53 | #include <linux/device.h> |
54 | #include <linux/init.h> |
55 | #include <linux/completion.h> |
56 | #include <linux/interrupt.h> |
57 | #include <linux/kernel.h> |
58 | #include <linux/kref.h> |
59 | #include <linux/kthread.h> |
60 | #include <linux/list.h> |
61 | #include <linux/major.h> |
62 | #include <linux/module.h> |
63 | #include <linux/moduleparam.h> |
64 | #include <linux/sched.h> |
65 | #include <linux/slab.h> |
66 | #include <linux/spinlock.h> |
67 | #include <linux/stat.h> |
68 | #include <linux/tty.h> |
69 | #include <linux/tty_flip.h> |
70 | #include <asm/hvconsole.h> |
71 | #include <asm/hvcserver.h> |
72 | #include <linux/uaccess.h> |
73 | #include <linux/termios_internal.h> |
74 | #include <asm/vio.h> |
75 | |
76 | /* |
77 | * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00). |
78 | * Removed braces around single statements following conditionals. Removed '= |
79 | * 0' after static int declarations since these default to zero. Removed |
80 | * list_for_each_safe() and replaced with list_for_each_entry() in |
81 | * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is |
82 | * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking |
83 | * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int |
84 | * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to |
85 | * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init(). |
86 | * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the |
87 | * list traversals from a deletion. Removed '= NULL' from pointer declaration |
88 | * statements since they are initialized NULL by default. Removed wmb() |
89 | * instances from hvcs_try_write(). They probably aren't needed with locking in |
90 | * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in |
91 | * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that |
92 | * the coupling between /dev/hvcs* and a vty-server can be automatically |
93 | * determined. Moved kobject_put() in hvcs_open outside of the |
94 | * spin_unlock_irqrestore(). |
95 | * |
96 | * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it |
97 | * align with how the tty layer always assigns the lowest index available. This |
98 | * change resulted in a list of ints that denotes which indexes are available. |
99 | * Device additions and removals use the new hvcs_get_index() and |
100 | * hvcs_return_index() helper functions. The list is created with |
101 | * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list(). |
102 | * Without these fixes hotplug vty-server adapter support goes crazy with this |
103 | * driver if the user removes a vty-server adapter. Moved free_irq() outside of |
104 | * the hvcs_final_close() function in order to get it out of the spinlock. |
105 | * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping |
106 | * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from |
107 | * arch/powerepc/include/asm/hvcserver.h |
108 | * |
109 | * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to |
110 | * prevent possible lockup with realtime scheduling as similarly pointed out by |
111 | * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close() |
112 | * to reorder cleanup operations and prevent discarding of pending data during |
113 | * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in |
114 | * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed. |
115 | */ |
116 | |
117 | #define HVCS_DRIVER_VERSION "1.3.3" |
118 | |
119 | MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>" ); |
120 | MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver" ); |
121 | MODULE_LICENSE("GPL" ); |
122 | MODULE_VERSION(HVCS_DRIVER_VERSION); |
123 | |
124 | /* |
125 | * Wait this long per iteration while trying to push buffered data to the |
126 | * hypervisor before allowing the tty to complete a close operation. |
127 | */ |
128 | #define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ |
129 | |
130 | /* |
131 | * Since the Linux TTY code does not currently (2-04-2004) support dynamic |
132 | * addition of tty derived devices and we shouldn't allocate thousands of |
133 | * tty_device pointers when the number of vty-server & vty partner connections |
134 | * will most often be much lower than this, we'll arbitrarily allocate |
135 | * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we |
136 | * register the tty_driver. This can be overridden using an insmod parameter. |
137 | */ |
138 | #define HVCS_DEFAULT_SERVER_ADAPTERS 64 |
139 | |
140 | /* |
141 | * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device |
142 | * nodes as a sanity check. Theoretically there can be over 1 Billion |
143 | * vty-server & vty partner connections. |
144 | */ |
145 | #define HVCS_MAX_SERVER_ADAPTERS 1024 |
146 | |
147 | /* |
148 | * We let Linux assign us a major number and we start the minors at zero. There |
149 | * is no intuitive mapping between minor number and the target vty-server |
150 | * adapter except that each new vty-server adapter is always assigned to the |
151 | * smallest minor number available. |
152 | */ |
153 | #define HVCS_MINOR_START 0 |
154 | |
155 | /* |
156 | * The hcall interface involves putting 8 chars into each of two registers. |
157 | * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c) |
158 | * by casting char[16] to long[2]. It would work without __ALIGNED__, but a |
159 | * little (tiny) bit slower because an unaligned load is slower than aligned |
160 | * load. |
161 | */ |
162 | #define __ALIGNED__ __attribute__((__aligned__(8))) |
163 | |
164 | /* |
165 | * How much data can firmware send with each hvc_put_chars()? Maybe this |
166 | * should be moved into an architecture specific area. |
167 | */ |
168 | #define HVCS_BUFF_LEN 16 |
169 | |
170 | /* |
171 | * This is the maximum amount of data we'll let the user send us (hvcs_write) at |
172 | * once in a chunk as a sanity check. |
173 | */ |
174 | #define HVCS_MAX_FROM_USER 4096 |
175 | |
176 | /* |
177 | * Be careful when adding flags to this line discipline. Don't add anything |
178 | * that will cause echoing or we'll go into recursive loop echoing chars back |
179 | * and forth with the console drivers. |
180 | */ |
181 | static const struct ktermios hvcs_tty_termios = { |
182 | .c_iflag = IGNBRK | IGNPAR, |
183 | .c_oflag = OPOST, |
184 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, |
185 | .c_cc = INIT_C_CC, |
186 | .c_ispeed = 38400, |
187 | .c_ospeed = 38400 |
188 | }; |
189 | |
190 | /* |
191 | * This value is used to take the place of a command line parameter when the |
192 | * module is inserted. It starts as -1 and stays as such if the user doesn't |
193 | * specify a module insmod parameter. If they DO specify one then it is set to |
194 | * the value of the integer passed in. |
195 | */ |
196 | static int hvcs_parm_num_devs = -1; |
197 | module_param(hvcs_parm_num_devs, int, 0); |
198 | |
199 | static const char hvcs_driver_name[] = "hvcs" ; |
200 | static const char hvcs_device_node[] = "hvcs" ; |
201 | |
202 | /* Status of partner info rescan triggered via sysfs. */ |
203 | static int hvcs_rescan_status; |
204 | |
205 | static 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 | */ |
220 | static 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 | */ |
226 | static 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 | */ |
232 | static 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 | */ |
238 | static 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 | */ |
244 | static unsigned long *hvcs_pi_buff; |
245 | |
246 | /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */ |
247 | static DEFINE_SPINLOCK(hvcs_pi_lock); |
248 | |
249 | /* One vty-server per hvcs_struct */ |
250 | struct 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 | struct completion *destroyed; |
290 | }; |
291 | |
292 | static LIST_HEAD(hvcs_structs); |
293 | static DEFINE_SPINLOCK(hvcs_structs_lock); |
294 | static DEFINE_MUTEX(hvcs_init_mutex); |
295 | |
296 | static int hvcs_get_pi(struct hvcs_struct *hvcsd); |
297 | static int hvcs_rescan_devices_list(void); |
298 | |
299 | static void hvcs_partner_free(struct hvcs_struct *hvcsd); |
300 | |
301 | static int hvcs_initialize(void); |
302 | |
303 | #define HVCS_SCHED_READ 0x00000001 |
304 | #define HVCS_QUICK_READ 0x00000002 |
305 | #define HVCS_TRY_WRITE 0x00000004 |
306 | #define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ) |
307 | |
308 | static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) |
309 | { |
310 | return dev_get_drvdata(dev: &viod->dev); |
311 | } |
312 | /* The sysfs interface for the driver and devices */ |
313 | |
314 | static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf) |
315 | { |
316 | struct vio_dev *viod = to_vio_dev(dev); |
317 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
318 | unsigned long flags; |
319 | int retval; |
320 | |
321 | spin_lock_irqsave(&hvcsd->lock, flags); |
322 | retval = sprintf(buf, fmt: "%X\n" , hvcsd->p_unit_address); |
323 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
324 | return retval; |
325 | } |
326 | static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); |
327 | |
328 | static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf) |
329 | { |
330 | struct vio_dev *viod = to_vio_dev(dev); |
331 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
332 | unsigned long flags; |
333 | int retval; |
334 | |
335 | spin_lock_irqsave(&hvcsd->lock, flags); |
336 | retval = sprintf(buf, fmt: "%s\n" , &hvcsd->p_location_code[0]); |
337 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
338 | return retval; |
339 | } |
340 | static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); |
341 | |
342 | static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf, |
343 | size_t count) |
344 | { |
345 | /* |
346 | * Don't need this feature at the present time because firmware doesn't |
347 | * yet support multiple partners. |
348 | */ |
349 | printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n" ); |
350 | return -EPERM; |
351 | } |
352 | |
353 | static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf) |
354 | { |
355 | struct vio_dev *viod = to_vio_dev(dev); |
356 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
357 | unsigned long flags; |
358 | int retval; |
359 | |
360 | spin_lock_irqsave(&hvcsd->lock, flags); |
361 | retval = sprintf(buf, fmt: "%s\n" , &hvcsd->p_location_code[0]); |
362 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
363 | return retval; |
364 | } |
365 | |
366 | static DEVICE_ATTR(current_vty, |
367 | S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); |
368 | |
369 | static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf, |
370 | size_t count) |
371 | { |
372 | struct vio_dev *viod = to_vio_dev(dev); |
373 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
374 | unsigned long flags; |
375 | |
376 | /* writing a '0' to this sysfs entry will result in the disconnect. */ |
377 | if (simple_strtol(buf, NULL, 0) != 0) |
378 | return -EINVAL; |
379 | |
380 | spin_lock_irqsave(&hvcsd->lock, flags); |
381 | |
382 | if (hvcsd->port.count > 0) { |
383 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
384 | printk(KERN_INFO "HVCS: vterm state unchanged. " |
385 | "The hvcs device node is still in use.\n" ); |
386 | return -EPERM; |
387 | } |
388 | |
389 | if (hvcsd->connected == 0) { |
390 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
391 | printk(KERN_INFO "HVCS: vterm state unchanged. The" |
392 | " vty-server is not connected to a vty.\n" ); |
393 | return -EPERM; |
394 | } |
395 | |
396 | hvcs_partner_free(hvcsd); |
397 | printk(KERN_INFO "HVCS: Closed vty-server@%X and" |
398 | " partner vty@%X:%d connection.\n" , |
399 | hvcsd->vdev->unit_address, |
400 | hvcsd->p_unit_address, |
401 | (uint32_t)hvcsd->p_partition_ID); |
402 | |
403 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
404 | return count; |
405 | } |
406 | |
407 | static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf) |
408 | { |
409 | struct vio_dev *viod = to_vio_dev(dev); |
410 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
411 | unsigned long flags; |
412 | int retval; |
413 | |
414 | spin_lock_irqsave(&hvcsd->lock, flags); |
415 | retval = sprintf(buf, fmt: "%d\n" , hvcsd->connected); |
416 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
417 | return retval; |
418 | } |
419 | static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, |
420 | hvcs_vterm_state_show, hvcs_vterm_state_store); |
421 | |
422 | static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf) |
423 | { |
424 | struct vio_dev *viod = to_vio_dev(dev); |
425 | struct hvcs_struct *hvcsd = from_vio_dev(viod); |
426 | unsigned long flags; |
427 | int retval; |
428 | |
429 | spin_lock_irqsave(&hvcsd->lock, flags); |
430 | retval = sprintf(buf, fmt: "%d\n" , hvcsd->index); |
431 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
432 | return retval; |
433 | } |
434 | |
435 | static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL); |
436 | |
437 | static struct attribute *hvcs_dev_attrs[] = { |
438 | &dev_attr_partner_vtys.attr, |
439 | &dev_attr_partner_clcs.attr, |
440 | &dev_attr_current_vty.attr, |
441 | &dev_attr_vterm_state.attr, |
442 | &dev_attr_index.attr, |
443 | NULL, |
444 | }; |
445 | |
446 | ATTRIBUTE_GROUPS(hvcs_dev); |
447 | |
448 | static ssize_t rescan_show(struct device_driver *ddp, char *buf) |
449 | { |
450 | /* A 1 means it is updating, a 0 means it is done updating */ |
451 | return snprintf(buf, PAGE_SIZE, fmt: "%d\n" , hvcs_rescan_status); |
452 | } |
453 | |
454 | static ssize_t rescan_store(struct device_driver *ddp, const char * buf, |
455 | size_t count) |
456 | { |
457 | if ((simple_strtol(buf, NULL, 0) != 1) |
458 | && (hvcs_rescan_status != 0)) |
459 | return -EINVAL; |
460 | |
461 | hvcs_rescan_status = 1; |
462 | printk(KERN_INFO "HVCS: rescanning partner info for all" |
463 | " vty-servers.\n" ); |
464 | hvcs_rescan_devices_list(); |
465 | hvcs_rescan_status = 0; |
466 | return count; |
467 | } |
468 | |
469 | static DRIVER_ATTR_RW(rescan); |
470 | |
471 | static struct attribute *hvcs_attrs[] = { |
472 | &driver_attr_rescan.attr, |
473 | NULL, |
474 | }; |
475 | |
476 | ATTRIBUTE_GROUPS(hvcs); |
477 | |
478 | static void hvcs_kick(void) |
479 | { |
480 | hvcs_kicked = 1; |
481 | wmb(); |
482 | wake_up_process(tsk: hvcs_task); |
483 | } |
484 | |
485 | static void hvcs_unthrottle(struct tty_struct *tty) |
486 | { |
487 | struct hvcs_struct *hvcsd = tty->driver_data; |
488 | unsigned long flags; |
489 | |
490 | spin_lock_irqsave(&hvcsd->lock, flags); |
491 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
492 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
493 | hvcs_kick(); |
494 | } |
495 | |
496 | static void hvcs_throttle(struct tty_struct *tty) |
497 | { |
498 | struct hvcs_struct *hvcsd = tty->driver_data; |
499 | unsigned long flags; |
500 | |
501 | spin_lock_irqsave(&hvcsd->lock, flags); |
502 | vio_disable_interrupts(hvcsd->vdev); |
503 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
504 | } |
505 | |
506 | /* |
507 | * If the device is being removed we don't have to worry about this interrupt |
508 | * handler taking any further interrupts because they are disabled which means |
509 | * the hvcs_struct will always be valid in this handler. |
510 | */ |
511 | static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance) |
512 | { |
513 | struct hvcs_struct *hvcsd = dev_instance; |
514 | |
515 | spin_lock(lock: &hvcsd->lock); |
516 | vio_disable_interrupts(hvcsd->vdev); |
517 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
518 | spin_unlock(lock: &hvcsd->lock); |
519 | hvcs_kick(); |
520 | |
521 | return IRQ_HANDLED; |
522 | } |
523 | |
524 | /* This function must be called with the hvcsd->lock held */ |
525 | static void hvcs_try_write(struct hvcs_struct *hvcsd) |
526 | { |
527 | uint32_t unit_address = hvcsd->vdev->unit_address; |
528 | struct tty_struct *tty = hvcsd->port.tty; |
529 | int sent; |
530 | |
531 | if (hvcsd->todo_mask & HVCS_TRY_WRITE) { |
532 | /* won't send partial writes */ |
533 | sent = hvc_put_chars(unit_address, |
534 | &hvcsd->buffer[0], |
535 | hvcsd->chars_in_buffer ); |
536 | if (sent > 0) { |
537 | hvcsd->chars_in_buffer = 0; |
538 | /* wmb(); */ |
539 | hvcsd->todo_mask &= ~(HVCS_TRY_WRITE); |
540 | /* wmb(); */ |
541 | |
542 | /* |
543 | * We are still obligated to deliver the data to the |
544 | * hypervisor even if the tty has been closed because |
545 | * we committed to delivering it. But don't try to wake |
546 | * a non-existent tty. |
547 | */ |
548 | if (tty) { |
549 | tty_wakeup(tty); |
550 | } |
551 | } |
552 | } |
553 | } |
554 | |
555 | static int hvcs_io(struct hvcs_struct *hvcsd) |
556 | { |
557 | uint32_t unit_address; |
558 | struct tty_struct *tty; |
559 | char buf[HVCS_BUFF_LEN] __ALIGNED__; |
560 | unsigned long flags; |
561 | int got = 0; |
562 | |
563 | spin_lock_irqsave(&hvcsd->lock, flags); |
564 | |
565 | unit_address = hvcsd->vdev->unit_address; |
566 | tty = hvcsd->port.tty; |
567 | |
568 | hvcs_try_write(hvcsd); |
569 | |
570 | if (!tty || tty_throttled(tty)) { |
571 | hvcsd->todo_mask &= ~(HVCS_READ_MASK); |
572 | goto bail; |
573 | } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK))) |
574 | goto bail; |
575 | |
576 | /* remove the read masks */ |
577 | hvcsd->todo_mask &= ~(HVCS_READ_MASK); |
578 | |
579 | if (tty_buffer_request_room(port: &hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) { |
580 | got = hvc_get_chars(unit_address, |
581 | &buf[0], |
582 | HVCS_BUFF_LEN); |
583 | tty_insert_flip_string(port: &hvcsd->port, chars: buf, size: got); |
584 | } |
585 | |
586 | /* Give the TTY time to process the data we just sent. */ |
587 | if (got) |
588 | hvcsd->todo_mask |= HVCS_QUICK_READ; |
589 | |
590 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
591 | /* This is synch -- FIXME :js: it is not! */ |
592 | if (got) |
593 | tty_flip_buffer_push(port: &hvcsd->port); |
594 | else { |
595 | /* Do this _after_ the flip_buffer_push */ |
596 | spin_lock_irqsave(&hvcsd->lock, flags); |
597 | vio_enable_interrupts(hvcsd->vdev); |
598 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
599 | } |
600 | |
601 | return hvcsd->todo_mask; |
602 | |
603 | bail: |
604 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
605 | return hvcsd->todo_mask; |
606 | } |
607 | |
608 | static int khvcsd(void *unused) |
609 | { |
610 | struct hvcs_struct *hvcsd; |
611 | int hvcs_todo_mask; |
612 | |
613 | __set_current_state(TASK_RUNNING); |
614 | |
615 | do { |
616 | hvcs_todo_mask = 0; |
617 | hvcs_kicked = 0; |
618 | wmb(); |
619 | |
620 | spin_lock(lock: &hvcs_structs_lock); |
621 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
622 | hvcs_todo_mask |= hvcs_io(hvcsd); |
623 | } |
624 | spin_unlock(lock: &hvcs_structs_lock); |
625 | |
626 | /* |
627 | * If any of the hvcs adapters want to try a write or quick read |
628 | * don't schedule(), yield a smidgen then execute the hvcs_io |
629 | * thread again for those that want the write. |
630 | */ |
631 | if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) { |
632 | yield(); |
633 | continue; |
634 | } |
635 | |
636 | set_current_state(TASK_INTERRUPTIBLE); |
637 | if (!hvcs_kicked) |
638 | schedule(); |
639 | __set_current_state(TASK_RUNNING); |
640 | } while (!kthread_should_stop()); |
641 | |
642 | return 0; |
643 | } |
644 | |
645 | static const struct vio_device_id hvcs_driver_table[] = { |
646 | {"serial-server" , "hvterm2" }, |
647 | { "" , "" } |
648 | }; |
649 | MODULE_DEVICE_TABLE(vio, hvcs_driver_table); |
650 | |
651 | static void hvcs_return_index(int index) |
652 | { |
653 | /* Paranoia check */ |
654 | if (!hvcs_index_list) |
655 | return; |
656 | if (index < 0 || index >= hvcs_index_count) |
657 | return; |
658 | if (hvcs_index_list[index] == -1) |
659 | return; |
660 | else |
661 | hvcs_index_list[index] = -1; |
662 | } |
663 | |
664 | static void hvcs_destruct_port(struct tty_port *p) |
665 | { |
666 | struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port); |
667 | struct completion *comp; |
668 | unsigned long flags; |
669 | |
670 | spin_lock(lock: &hvcs_structs_lock); |
671 | spin_lock_irqsave(&hvcsd->lock, flags); |
672 | |
673 | comp = hvcsd->destroyed; |
674 | /* the list_del poisons the pointers */ |
675 | list_del(entry: &(hvcsd->next)); |
676 | |
677 | if (hvcsd->connected == 1) { |
678 | hvcs_partner_free(hvcsd); |
679 | printk(KERN_INFO "HVCS: Closed vty-server@%X and" |
680 | " partner vty@%X:%d connection.\n" , |
681 | hvcsd->vdev->unit_address, |
682 | hvcsd->p_unit_address, |
683 | (uint32_t)hvcsd->p_partition_ID); |
684 | } |
685 | printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n" , |
686 | hvcsd->vdev->unit_address); |
687 | |
688 | hvcsd->vdev = NULL; |
689 | |
690 | hvcsd->p_unit_address = 0; |
691 | hvcsd->p_partition_ID = 0; |
692 | hvcsd->destroyed = NULL; |
693 | hvcs_return_index(index: hvcsd->index); |
694 | memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1); |
695 | |
696 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
697 | spin_unlock(lock: &hvcs_structs_lock); |
698 | |
699 | kfree(objp: hvcsd); |
700 | if (comp) |
701 | complete(comp); |
702 | } |
703 | |
704 | static const struct tty_port_operations hvcs_port_ops = { |
705 | .destruct = hvcs_destruct_port, |
706 | }; |
707 | |
708 | static int hvcs_get_index(void) |
709 | { |
710 | int i; |
711 | /* Paranoia check */ |
712 | if (!hvcs_index_list) { |
713 | printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n" ); |
714 | return -EFAULT; |
715 | } |
716 | /* Find the numerically lowest first free index. */ |
717 | for(i = 0; i < hvcs_index_count; i++) { |
718 | if (hvcs_index_list[i] == -1) { |
719 | hvcs_index_list[i] = 0; |
720 | return i; |
721 | } |
722 | } |
723 | return -1; |
724 | } |
725 | |
726 | static int hvcs_probe( |
727 | struct vio_dev *dev, |
728 | const struct vio_device_id *id) |
729 | { |
730 | struct hvcs_struct *hvcsd; |
731 | int index, rc; |
732 | |
733 | if (!dev || !id) { |
734 | printk(KERN_ERR "HVCS: probed with invalid parameter.\n" ); |
735 | return -EPERM; |
736 | } |
737 | |
738 | /* Make sure we are properly initialized */ |
739 | rc = hvcs_initialize(); |
740 | if (rc) { |
741 | pr_err("HVCS: Failed to initialize core driver.\n" ); |
742 | return rc; |
743 | } |
744 | |
745 | /* early to avoid cleanup on failure */ |
746 | index = hvcs_get_index(); |
747 | if (index < 0) { |
748 | return -EFAULT; |
749 | } |
750 | |
751 | hvcsd = kzalloc(size: sizeof(*hvcsd), GFP_KERNEL); |
752 | if (!hvcsd) |
753 | return -ENODEV; |
754 | |
755 | tty_port_init(port: &hvcsd->port); |
756 | hvcsd->port.ops = &hvcs_port_ops; |
757 | spin_lock_init(&hvcsd->lock); |
758 | |
759 | hvcsd->vdev = dev; |
760 | dev_set_drvdata(dev: &dev->dev, data: hvcsd); |
761 | |
762 | hvcsd->index = index; |
763 | |
764 | /* hvcsd->index = ++hvcs_struct_count; */ |
765 | hvcsd->chars_in_buffer = 0; |
766 | hvcsd->todo_mask = 0; |
767 | hvcsd->connected = 0; |
768 | |
769 | /* |
770 | * This will populate the hvcs_struct's partner info fields for the |
771 | * first time. |
772 | */ |
773 | if (hvcs_get_pi(hvcsd)) { |
774 | printk(KERN_ERR "HVCS: Failed to fetch partner" |
775 | " info for vty-server@%X on device probe.\n" , |
776 | hvcsd->vdev->unit_address); |
777 | } |
778 | |
779 | /* |
780 | * If a user app opens a tty that corresponds to this vty-server before |
781 | * the hvcs_struct has been added to the devices list then the user app |
782 | * will get -ENODEV. |
783 | */ |
784 | spin_lock(lock: &hvcs_structs_lock); |
785 | list_add_tail(new: &(hvcsd->next), head: &hvcs_structs); |
786 | spin_unlock(lock: &hvcs_structs_lock); |
787 | |
788 | printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n" , dev->unit_address); |
789 | |
790 | /* |
791 | * DON'T enable interrupts here because there is no user to receive the |
792 | * data. |
793 | */ |
794 | return 0; |
795 | } |
796 | |
797 | static void hvcs_remove(struct vio_dev *dev) |
798 | { |
799 | struct hvcs_struct *hvcsd = dev_get_drvdata(dev: &dev->dev); |
800 | DECLARE_COMPLETION_ONSTACK(comp); |
801 | unsigned long flags; |
802 | struct tty_struct *tty; |
803 | |
804 | /* By this time the vty-server won't be getting any more interrupts */ |
805 | |
806 | spin_lock_irqsave(&hvcsd->lock, flags); |
807 | |
808 | hvcsd->destroyed = ∁ |
809 | tty = tty_port_tty_get(port: &hvcsd->port); |
810 | |
811 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
812 | |
813 | /* |
814 | * The tty should always be valid at this time unless a |
815 | * simultaneous tty close already cleaned up the hvcs_struct. |
816 | */ |
817 | if (tty) { |
818 | tty_vhangup(tty); |
819 | tty_kref_put(tty); |
820 | } |
821 | |
822 | tty_port_put(port: &hvcsd->port); |
823 | wait_for_completion(&comp); |
824 | printk(KERN_INFO "HVCS: vty-server@%X removed from the" |
825 | " vio bus.\n" , dev->unit_address); |
826 | }; |
827 | |
828 | static struct vio_driver hvcs_vio_driver = { |
829 | .id_table = hvcs_driver_table, |
830 | .probe = hvcs_probe, |
831 | .remove = hvcs_remove, |
832 | .name = hvcs_driver_name, |
833 | .driver = { |
834 | .groups = hvcs_groups, |
835 | .dev_groups = hvcs_dev_groups, |
836 | }, |
837 | }; |
838 | |
839 | /* Only called from hvcs_get_pi please */ |
840 | static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) |
841 | { |
842 | hvcsd->p_unit_address = pi->unit_address; |
843 | hvcsd->p_partition_ID = pi->partition_ID; |
844 | |
845 | /* copy the null-term char too */ |
846 | strscpy(hvcsd->p_location_code, pi->location_code, |
847 | sizeof(hvcsd->p_location_code)); |
848 | } |
849 | |
850 | /* |
851 | * Traverse the list and add the partner info that is found to the hvcs_struct |
852 | * struct entry. NOTE: At this time I know that partner info will return a |
853 | * single entry but in the future there may be multiple partner info entries per |
854 | * vty-server and you'll want to zero out that list and reset it. If for some |
855 | * reason you have an old version of this driver but there IS more than one |
856 | * partner info then hvcsd->p_* will hold the last partner info data from the |
857 | * firmware query. A good way to update this code would be to replace the three |
858 | * partner info fields in hvcs_struct with a list of hvcs_partner_info |
859 | * instances. |
860 | * |
861 | * This function must be called with the hvcsd->lock held. |
862 | */ |
863 | static int hvcs_get_pi(struct hvcs_struct *hvcsd) |
864 | { |
865 | struct hvcs_partner_info *pi; |
866 | uint32_t unit_address = hvcsd->vdev->unit_address; |
867 | struct list_head head; |
868 | int retval; |
869 | |
870 | spin_lock(lock: &hvcs_pi_lock); |
871 | if (!hvcs_pi_buff) { |
872 | spin_unlock(lock: &hvcs_pi_lock); |
873 | return -EFAULT; |
874 | } |
875 | retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff); |
876 | spin_unlock(lock: &hvcs_pi_lock); |
877 | if (retval) { |
878 | printk(KERN_ERR "HVCS: Failed to fetch partner" |
879 | " info for vty-server@%x.\n" , unit_address); |
880 | return retval; |
881 | } |
882 | |
883 | /* nixes the values if the partner vty went away */ |
884 | hvcsd->p_unit_address = 0; |
885 | hvcsd->p_partition_ID = 0; |
886 | |
887 | list_for_each_entry(pi, &head, node) |
888 | hvcs_set_pi(pi, hvcsd); |
889 | |
890 | hvcs_free_partner_info(&head); |
891 | return 0; |
892 | } |
893 | |
894 | /* |
895 | * This function is executed by the driver "rescan" sysfs entry. It shouldn't |
896 | * be executed elsewhere, in order to prevent deadlock issues. |
897 | */ |
898 | static int hvcs_rescan_devices_list(void) |
899 | { |
900 | struct hvcs_struct *hvcsd; |
901 | unsigned long flags; |
902 | |
903 | spin_lock(lock: &hvcs_structs_lock); |
904 | |
905 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
906 | spin_lock_irqsave(&hvcsd->lock, flags); |
907 | hvcs_get_pi(hvcsd); |
908 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
909 | } |
910 | |
911 | spin_unlock(lock: &hvcs_structs_lock); |
912 | |
913 | return 0; |
914 | } |
915 | |
916 | /* |
917 | * Farm this off into its own function because it could be more complex once |
918 | * multiple partners support is added. This function should be called with |
919 | * the hvcsd->lock held. |
920 | */ |
921 | static int hvcs_has_pi(struct hvcs_struct *hvcsd) |
922 | { |
923 | if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID)) |
924 | return 0; |
925 | return 1; |
926 | } |
927 | |
928 | /* |
929 | * NOTE: It is possible that the super admin removed a partner vty and then |
930 | * added a different vty as the new partner. |
931 | * |
932 | * This function must be called with the hvcsd->lock held. |
933 | */ |
934 | static int hvcs_partner_connect(struct hvcs_struct *hvcsd) |
935 | { |
936 | int retval; |
937 | unsigned int unit_address = hvcsd->vdev->unit_address; |
938 | |
939 | /* |
940 | * If there wasn't any pi when the device was added it doesn't meant |
941 | * there isn't any now. This driver isn't notified when a new partner |
942 | * vty is added to a vty-server so we discover changes on our own. |
943 | * Please see comments in hvcs_register_connection() for justification |
944 | * of this bizarre code. |
945 | */ |
946 | retval = hvcs_register_connection(unit_address, |
947 | hvcsd->p_partition_ID, |
948 | hvcsd->p_unit_address); |
949 | if (!retval) { |
950 | hvcsd->connected = 1; |
951 | return 0; |
952 | } else if (retval != -EINVAL) |
953 | return retval; |
954 | |
955 | /* |
956 | * As per the spec re-get the pi and try again if -EINVAL after the |
957 | * first connection attempt. |
958 | */ |
959 | if (hvcs_get_pi(hvcsd)) |
960 | return -ENOMEM; |
961 | |
962 | if (!hvcs_has_pi(hvcsd)) |
963 | return -ENODEV; |
964 | |
965 | retval = hvcs_register_connection(unit_address, |
966 | hvcsd->p_partition_ID, |
967 | hvcsd->p_unit_address); |
968 | if (retval != -EINVAL) { |
969 | hvcsd->connected = 1; |
970 | return retval; |
971 | } |
972 | |
973 | /* |
974 | * EBUSY is the most likely scenario though the vty could have been |
975 | * removed or there really could be an hcall error due to the parameter |
976 | * data but thanks to ambiguous firmware return codes we can't really |
977 | * tell. |
978 | */ |
979 | printk(KERN_INFO "HVCS: vty-server or partner" |
980 | " vty is busy. Try again later.\n" ); |
981 | return -EBUSY; |
982 | } |
983 | |
984 | /* This function must be called with the hvcsd->lock held */ |
985 | static void hvcs_partner_free(struct hvcs_struct *hvcsd) |
986 | { |
987 | int retval; |
988 | do { |
989 | retval = hvcs_free_connection(hvcsd->vdev->unit_address); |
990 | } while (retval == -EBUSY); |
991 | hvcsd->connected = 0; |
992 | } |
993 | |
994 | /* This helper function must be called WITHOUT the hvcsd->lock held */ |
995 | static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address, |
996 | unsigned int irq, struct vio_dev *vdev) |
997 | { |
998 | unsigned long flags; |
999 | int rc; |
1000 | |
1001 | /* |
1002 | * It is possible that the vty-server was removed between the time that |
1003 | * the conn was registered and now. |
1004 | */ |
1005 | rc = request_irq(irq, handler: &hvcs_handle_interrupt, flags: 0, name: "ibmhvcs" , dev: hvcsd); |
1006 | if (!rc) { |
1007 | /* |
1008 | * It is possible the vty-server was removed after the irq was |
1009 | * requested but before we have time to enable interrupts. |
1010 | */ |
1011 | if (vio_enable_interrupts(vdev) == H_SUCCESS) |
1012 | return 0; |
1013 | else { |
1014 | printk(KERN_ERR "HVCS: int enable failed for" |
1015 | " vty-server@%X.\n" , unit_address); |
1016 | free_irq(irq, hvcsd); |
1017 | } |
1018 | } else |
1019 | printk(KERN_ERR "HVCS: irq req failed for" |
1020 | " vty-server@%X.\n" , unit_address); |
1021 | |
1022 | spin_lock_irqsave(&hvcsd->lock, flags); |
1023 | hvcs_partner_free(hvcsd); |
1024 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1025 | |
1026 | return rc; |
1027 | |
1028 | } |
1029 | |
1030 | /* |
1031 | * This always increments the kref ref count if the call is successful. |
1032 | * Please remember to dec when you are done with the instance. |
1033 | * |
1034 | * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when |
1035 | * calling this function or you will get deadlock. |
1036 | */ |
1037 | static struct hvcs_struct *hvcs_get_by_index(int index) |
1038 | { |
1039 | struct hvcs_struct *hvcsd; |
1040 | unsigned long flags; |
1041 | |
1042 | spin_lock(lock: &hvcs_structs_lock); |
1043 | list_for_each_entry(hvcsd, &hvcs_structs, next) { |
1044 | spin_lock_irqsave(&hvcsd->lock, flags); |
1045 | if (hvcsd->index == index) { |
1046 | tty_port_get(port: &hvcsd->port); |
1047 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1048 | spin_unlock(lock: &hvcs_structs_lock); |
1049 | return hvcsd; |
1050 | } |
1051 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1052 | } |
1053 | spin_unlock(lock: &hvcs_structs_lock); |
1054 | |
1055 | return NULL; |
1056 | } |
1057 | |
1058 | static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty) |
1059 | { |
1060 | struct hvcs_struct *hvcsd; |
1061 | struct vio_dev *vdev; |
1062 | unsigned long unit_address, flags; |
1063 | unsigned int irq; |
1064 | int retval; |
1065 | |
1066 | /* |
1067 | * Is there a vty-server that shares the same index? |
1068 | * This function increments the kref index. |
1069 | */ |
1070 | hvcsd = hvcs_get_by_index(index: tty->index); |
1071 | if (!hvcsd) { |
1072 | printk(KERN_WARNING "HVCS: open failed, no device associated" |
1073 | " with tty->index %d.\n" , tty->index); |
1074 | return -ENODEV; |
1075 | } |
1076 | |
1077 | spin_lock_irqsave(&hvcsd->lock, flags); |
1078 | |
1079 | if (hvcsd->connected == 0) { |
1080 | retval = hvcs_partner_connect(hvcsd); |
1081 | if (retval) { |
1082 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1083 | printk(KERN_WARNING "HVCS: partner connect failed.\n" ); |
1084 | goto err_put; |
1085 | } |
1086 | } |
1087 | |
1088 | hvcsd->port.count = 0; |
1089 | hvcsd->port.tty = tty; |
1090 | tty->driver_data = hvcsd; |
1091 | |
1092 | memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); |
1093 | |
1094 | /* |
1095 | * Save these in the spinlock for the enable operations that need them |
1096 | * outside of the spinlock. |
1097 | */ |
1098 | irq = hvcsd->vdev->irq; |
1099 | vdev = hvcsd->vdev; |
1100 | unit_address = hvcsd->vdev->unit_address; |
1101 | |
1102 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
1103 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1104 | |
1105 | /* |
1106 | * This must be done outside of the spinlock because it requests irqs |
1107 | * and will grab the spinlock and free the connection if it fails. |
1108 | */ |
1109 | retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev); |
1110 | if (retval) { |
1111 | printk(KERN_WARNING "HVCS: enable device failed.\n" ); |
1112 | goto err_put; |
1113 | } |
1114 | |
1115 | retval = tty_port_install(port: &hvcsd->port, driver, tty); |
1116 | if (retval) |
1117 | goto err_irq; |
1118 | |
1119 | return 0; |
1120 | err_irq: |
1121 | spin_lock_irqsave(&hvcsd->lock, flags); |
1122 | vio_disable_interrupts(hvcsd->vdev); |
1123 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1124 | free_irq(irq, hvcsd); |
1125 | err_put: |
1126 | tty_port_put(port: &hvcsd->port); |
1127 | |
1128 | return retval; |
1129 | } |
1130 | |
1131 | /* |
1132 | * This is invoked via the tty_open interface when a user app connects to the |
1133 | * /dev node. |
1134 | */ |
1135 | static int hvcs_open(struct tty_struct *tty, struct file *filp) |
1136 | { |
1137 | struct hvcs_struct *hvcsd = tty->driver_data; |
1138 | unsigned long flags; |
1139 | |
1140 | spin_lock_irqsave(&hvcsd->lock, flags); |
1141 | hvcsd->port.count++; |
1142 | hvcsd->todo_mask |= HVCS_SCHED_READ; |
1143 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1144 | |
1145 | hvcs_kick(); |
1146 | |
1147 | printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n" , |
1148 | hvcsd->vdev->unit_address ); |
1149 | |
1150 | return 0; |
1151 | } |
1152 | |
1153 | static void hvcs_close(struct tty_struct *tty, struct file *filp) |
1154 | { |
1155 | struct hvcs_struct *hvcsd; |
1156 | unsigned long flags; |
1157 | int irq; |
1158 | |
1159 | /* |
1160 | * Is someone trying to close the file associated with this device after |
1161 | * we have hung up? If so tty->driver_data wouldn't be valid. |
1162 | */ |
1163 | if (tty_hung_up_p(filp)) |
1164 | return; |
1165 | |
1166 | /* |
1167 | * No driver_data means that this close was probably issued after a |
1168 | * failed hvcs_open by the tty layer's release_dev() api and we can just |
1169 | * exit cleanly. |
1170 | */ |
1171 | if (!tty->driver_data) |
1172 | return; |
1173 | |
1174 | hvcsd = tty->driver_data; |
1175 | |
1176 | spin_lock_irqsave(&hvcsd->lock, flags); |
1177 | if (hvcsd->port.count == 0) { |
1178 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1179 | return; |
1180 | } else if (--hvcsd->port.count == 0) { |
1181 | |
1182 | vio_disable_interrupts(hvcsd->vdev); |
1183 | |
1184 | /* |
1185 | * NULL this early so that the kernel_thread doesn't try to |
1186 | * execute any operations on the TTY even though it is obligated |
1187 | * to deliver any pending I/O to the hypervisor. |
1188 | */ |
1189 | hvcsd->port.tty = NULL; |
1190 | |
1191 | irq = hvcsd->vdev->irq; |
1192 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1193 | |
1194 | tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); |
1195 | |
1196 | free_irq(irq, hvcsd); |
1197 | return; |
1198 | } else if (hvcsd->port.count < 0) { |
1199 | printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n" , |
1200 | hvcsd->vdev->unit_address, hvcsd->port.count); |
1201 | } |
1202 | |
1203 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1204 | } |
1205 | |
1206 | static void hvcs_cleanup(struct tty_struct * tty) |
1207 | { |
1208 | struct hvcs_struct *hvcsd = tty->driver_data; |
1209 | |
1210 | /* |
1211 | * This line is important because it tells hvcs_open that this |
1212 | * device needs to be re-configured the next time hvcs_open is |
1213 | * called. |
1214 | */ |
1215 | tty->driver_data = NULL; |
1216 | |
1217 | tty_port_put(port: &hvcsd->port); |
1218 | } |
1219 | |
1220 | static void hvcs_hangup(struct tty_struct * tty) |
1221 | { |
1222 | struct hvcs_struct *hvcsd = tty->driver_data; |
1223 | unsigned long flags; |
1224 | int irq; |
1225 | |
1226 | spin_lock_irqsave(&hvcsd->lock, flags); |
1227 | |
1228 | /* |
1229 | * Don't kref put inside the spinlock because the destruction |
1230 | * callback may use the spinlock and it may get called before the |
1231 | * spinlock has been released. |
1232 | */ |
1233 | vio_disable_interrupts(hvcsd->vdev); |
1234 | |
1235 | hvcsd->todo_mask = 0; |
1236 | hvcsd->port.tty = NULL; |
1237 | hvcsd->port.count = 0; |
1238 | |
1239 | /* This will drop any buffered data on the floor which is OK in a hangup |
1240 | * scenario. */ |
1241 | memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); |
1242 | hvcsd->chars_in_buffer = 0; |
1243 | |
1244 | irq = hvcsd->vdev->irq; |
1245 | |
1246 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1247 | |
1248 | free_irq(irq, hvcsd); |
1249 | } |
1250 | |
1251 | /* |
1252 | * NOTE: This is almost always from_user since user level apps interact with the |
1253 | * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by |
1254 | * hvcs_remove (which removes the target device and executes tty_hangup()) that |
1255 | * tty_hangup will allow hvcs_write time to complete execution before it |
1256 | * terminates our device. |
1257 | */ |
1258 | static ssize_t hvcs_write(struct tty_struct *tty, const u8 *buf, size_t count) |
1259 | { |
1260 | struct hvcs_struct *hvcsd = tty->driver_data; |
1261 | unsigned int unit_address; |
1262 | const unsigned char *charbuf; |
1263 | unsigned long flags; |
1264 | size_t total_sent = 0; |
1265 | size_t tosend = 0; |
1266 | int result = 0; |
1267 | |
1268 | /* |
1269 | * If they don't check the return code off of their open they may |
1270 | * attempt this even if there is no connected device. |
1271 | */ |
1272 | if (!hvcsd) |
1273 | return -ENODEV; |
1274 | |
1275 | /* Reasonable size to prevent user level flooding */ |
1276 | if (count > HVCS_MAX_FROM_USER) { |
1277 | printk(KERN_WARNING "HVCS write: count being truncated to" |
1278 | " HVCS_MAX_FROM_USER.\n" ); |
1279 | count = HVCS_MAX_FROM_USER; |
1280 | } |
1281 | |
1282 | charbuf = buf; |
1283 | |
1284 | spin_lock_irqsave(&hvcsd->lock, flags); |
1285 | |
1286 | /* |
1287 | * Somehow an open succeeded but the device was removed or the |
1288 | * connection terminated between the vty-server and partner vty during |
1289 | * the middle of a write operation? This is a crummy place to do this |
1290 | * but we want to keep it all in the spinlock. |
1291 | */ |
1292 | if (hvcsd->port.count <= 0) { |
1293 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1294 | return -ENODEV; |
1295 | } |
1296 | |
1297 | unit_address = hvcsd->vdev->unit_address; |
1298 | |
1299 | while (count > 0) { |
1300 | tosend = min_t(size_t, count, |
1301 | (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); |
1302 | /* |
1303 | * No more space, this probably means that the last call to |
1304 | * hvcs_write() didn't succeed and the buffer was filled up. |
1305 | */ |
1306 | if (!tosend) |
1307 | break; |
1308 | |
1309 | memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], |
1310 | &charbuf[total_sent], |
1311 | tosend); |
1312 | |
1313 | hvcsd->chars_in_buffer += tosend; |
1314 | |
1315 | result = 0; |
1316 | |
1317 | /* |
1318 | * If this is true then we don't want to try writing to the |
1319 | * hypervisor because that is the kernel_threads job now. We'll |
1320 | * just add to the buffer. |
1321 | */ |
1322 | if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) |
1323 | /* won't send partial writes */ |
1324 | result = hvc_put_chars(unit_address, |
1325 | &hvcsd->buffer[0], |
1326 | hvcsd->chars_in_buffer); |
1327 | |
1328 | /* |
1329 | * Since we know we have enough room in hvcsd->buffer for |
1330 | * tosend we record that it was sent regardless of whether the |
1331 | * hypervisor actually took it because we have it buffered. |
1332 | */ |
1333 | total_sent+=tosend; |
1334 | count-=tosend; |
1335 | if (result == 0) { |
1336 | hvcsd->todo_mask |= HVCS_TRY_WRITE; |
1337 | hvcs_kick(); |
1338 | break; |
1339 | } |
1340 | |
1341 | hvcsd->chars_in_buffer = 0; |
1342 | /* |
1343 | * Test after the chars_in_buffer reset otherwise this could |
1344 | * deadlock our writes if hvc_put_chars fails. |
1345 | */ |
1346 | if (result < 0) |
1347 | break; |
1348 | } |
1349 | |
1350 | spin_unlock_irqrestore(lock: &hvcsd->lock, flags); |
1351 | |
1352 | if (result == -1) |
1353 | return -EIO; |
1354 | else |
1355 | return total_sent; |
1356 | } |
1357 | |
1358 | /* |
1359 | * This is really asking how much can we guarantee that we can send or that we |
1360 | * absolutely WILL BUFFER if we can't send it. This driver MUST honor the |
1361 | * return value, hence the reason for hvcs_struct buffering. |
1362 | */ |
1363 | static unsigned int hvcs_write_room(struct tty_struct *tty) |
1364 | { |
1365 | struct hvcs_struct *hvcsd = tty->driver_data; |
1366 | |
1367 | if (!hvcsd || hvcsd->port.count <= 0) |
1368 | return 0; |
1369 | |
1370 | return HVCS_BUFF_LEN - hvcsd->chars_in_buffer; |
1371 | } |
1372 | |
1373 | static unsigned int hvcs_chars_in_buffer(struct tty_struct *tty) |
1374 | { |
1375 | struct hvcs_struct *hvcsd = tty->driver_data; |
1376 | |
1377 | return hvcsd->chars_in_buffer; |
1378 | } |
1379 | |
1380 | static const struct tty_operations hvcs_ops = { |
1381 | .install = hvcs_install, |
1382 | .open = hvcs_open, |
1383 | .close = hvcs_close, |
1384 | .cleanup = hvcs_cleanup, |
1385 | .hangup = hvcs_hangup, |
1386 | .write = hvcs_write, |
1387 | .write_room = hvcs_write_room, |
1388 | .chars_in_buffer = hvcs_chars_in_buffer, |
1389 | .unthrottle = hvcs_unthrottle, |
1390 | .throttle = hvcs_throttle, |
1391 | }; |
1392 | |
1393 | static int hvcs_alloc_index_list(int n) |
1394 | { |
1395 | int i; |
1396 | |
1397 | hvcs_index_list = kmalloc_array(n, size: sizeof(hvcs_index_count), |
1398 | GFP_KERNEL); |
1399 | if (!hvcs_index_list) |
1400 | return -ENOMEM; |
1401 | hvcs_index_count = n; |
1402 | for (i = 0; i < hvcs_index_count; i++) |
1403 | hvcs_index_list[i] = -1; |
1404 | return 0; |
1405 | } |
1406 | |
1407 | static void hvcs_free_index_list(void) |
1408 | { |
1409 | /* Paranoia check to be thorough. */ |
1410 | kfree(objp: hvcs_index_list); |
1411 | hvcs_index_list = NULL; |
1412 | hvcs_index_count = 0; |
1413 | } |
1414 | |
1415 | static int hvcs_initialize(void) |
1416 | { |
1417 | int rc, num_ttys_to_alloc; |
1418 | |
1419 | mutex_lock(&hvcs_init_mutex); |
1420 | if (hvcs_task) { |
1421 | mutex_unlock(lock: &hvcs_init_mutex); |
1422 | return 0; |
1423 | } |
1424 | |
1425 | /* Has the user specified an overload with an insmod param? */ |
1426 | if (hvcs_parm_num_devs <= 0 || |
1427 | (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) { |
1428 | num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS; |
1429 | } else |
1430 | num_ttys_to_alloc = hvcs_parm_num_devs; |
1431 | |
1432 | hvcs_tty_driver = tty_alloc_driver(num_ttys_to_alloc, |
1433 | TTY_DRIVER_REAL_RAW); |
1434 | if (IS_ERR(ptr: hvcs_tty_driver)) { |
1435 | mutex_unlock(lock: &hvcs_init_mutex); |
1436 | return PTR_ERR(ptr: hvcs_tty_driver); |
1437 | } |
1438 | |
1439 | if (hvcs_alloc_index_list(n: num_ttys_to_alloc)) { |
1440 | rc = -ENOMEM; |
1441 | goto index_fail; |
1442 | } |
1443 | |
1444 | hvcs_tty_driver->driver_name = hvcs_driver_name; |
1445 | hvcs_tty_driver->name = hvcs_device_node; |
1446 | |
1447 | /* |
1448 | * We'll let the system assign us a major number, indicated by leaving |
1449 | * it blank. |
1450 | */ |
1451 | |
1452 | hvcs_tty_driver->minor_start = HVCS_MINOR_START; |
1453 | hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; |
1454 | |
1455 | /* |
1456 | * We role our own so that we DONT ECHO. We can't echo because the |
1457 | * device we are connecting to already echoes by default and this would |
1458 | * throw us into a horrible recursive echo-echo-echo loop. |
1459 | */ |
1460 | hvcs_tty_driver->init_termios = hvcs_tty_termios; |
1461 | |
1462 | tty_set_operations(driver: hvcs_tty_driver, op: &hvcs_ops); |
1463 | |
1464 | /* |
1465 | * The following call will result in sysfs entries that denote the |
1466 | * dynamically assigned major and minor numbers for our devices. |
1467 | */ |
1468 | if (tty_register_driver(driver: hvcs_tty_driver)) { |
1469 | printk(KERN_ERR "HVCS: registration as a tty driver failed.\n" ); |
1470 | rc = -EIO; |
1471 | goto register_fail; |
1472 | } |
1473 | |
1474 | hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL); |
1475 | if (!hvcs_pi_buff) { |
1476 | rc = -ENOMEM; |
1477 | goto buff_alloc_fail; |
1478 | } |
1479 | |
1480 | hvcs_task = kthread_run(khvcsd, NULL, "khvcsd" ); |
1481 | if (IS_ERR(ptr: hvcs_task)) { |
1482 | printk(KERN_ERR "HVCS: khvcsd creation failed.\n" ); |
1483 | rc = -EIO; |
1484 | goto kthread_fail; |
1485 | } |
1486 | mutex_unlock(lock: &hvcs_init_mutex); |
1487 | return 0; |
1488 | |
1489 | kthread_fail: |
1490 | free_page((unsigned long)hvcs_pi_buff); |
1491 | buff_alloc_fail: |
1492 | tty_unregister_driver(driver: hvcs_tty_driver); |
1493 | register_fail: |
1494 | hvcs_free_index_list(); |
1495 | index_fail: |
1496 | tty_driver_kref_put(driver: hvcs_tty_driver); |
1497 | hvcs_tty_driver = NULL; |
1498 | mutex_unlock(lock: &hvcs_init_mutex); |
1499 | return rc; |
1500 | } |
1501 | |
1502 | static int __init hvcs_module_init(void) |
1503 | { |
1504 | int rc = vio_register_driver(&hvcs_vio_driver); |
1505 | if (rc) { |
1506 | printk(KERN_ERR "HVCS: can't register vio driver\n" ); |
1507 | return rc; |
1508 | } |
1509 | |
1510 | pr_info("HVCS: Driver registered.\n" ); |
1511 | |
1512 | return 0; |
1513 | } |
1514 | |
1515 | static void __exit hvcs_module_exit(void) |
1516 | { |
1517 | /* |
1518 | * This driver receives hvcs_remove callbacks for each device upon |
1519 | * module removal. |
1520 | */ |
1521 | vio_unregister_driver(&hvcs_vio_driver); |
1522 | if (!hvcs_task) |
1523 | return; |
1524 | |
1525 | /* |
1526 | * This synchronous operation will wake the khvcsd kthread if it is |
1527 | * asleep and will return when khvcsd has terminated. |
1528 | */ |
1529 | kthread_stop(k: hvcs_task); |
1530 | |
1531 | spin_lock(lock: &hvcs_pi_lock); |
1532 | free_page((unsigned long)hvcs_pi_buff); |
1533 | hvcs_pi_buff = NULL; |
1534 | spin_unlock(lock: &hvcs_pi_lock); |
1535 | |
1536 | tty_unregister_driver(driver: hvcs_tty_driver); |
1537 | |
1538 | hvcs_free_index_list(); |
1539 | |
1540 | tty_driver_kref_put(driver: hvcs_tty_driver); |
1541 | |
1542 | printk(KERN_INFO "HVCS: driver module removed.\n" ); |
1543 | } |
1544 | |
1545 | module_init(hvcs_module_init); |
1546 | module_exit(hvcs_module_exit); |
1547 | |