1067 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM4 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM5 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.6 * Copyright (C) 2004 IBM Corporation7 *8 * Additional Author(s):9 * Ryan S. Arnold <rsa@us.ibm.com>10 */11 12#include <linux/console.h>13#include <linux/cpumask.h>14#include <linux/init.h>15#include <linux/kbd_kern.h>16#include <linux/kernel.h>17#include <linux/kthread.h>18#include <linux/list.h>19#include <linux/major.h>20#include <linux/atomic.h>21#include <linux/sysrq.h>22#include <linux/tty.h>23#include <linux/tty_flip.h>24#include <linux/sched.h>25#include <linux/spinlock.h>26#include <linux/delay.h>27#include <linux/freezer.h>28#include <linux/slab.h>29#include <linux/serial_core.h>30 31#include <linux/uaccess.h>32 33#include "hvc_console.h"34 35#define HVC_MAJOR 22936#define HVC_MINOR 037 38/*39 * Wait this long per iteration while trying to push buffered data to the40 * hypervisor before allowing the tty to complete a close operation.41 */42#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */43 44/*45 * These sizes are most efficient for vio, because they are the46 * native transfer size. We could make them selectable in the47 * future to better deal with backends that want other buffer sizes.48 */49#define N_OUTBUF 1650#define N_INBUF 1651 52#define __ALIGNED__ __attribute__((__aligned__(L1_CACHE_BYTES)))53 54static struct tty_driver *hvc_driver;55static struct task_struct *hvc_task;56 57/* Picks up late kicks after list walk but before schedule() */58static int hvc_kicked;59 60/* hvc_init is triggered from hvc_alloc, i.e. only when actually used */61static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1);62 63static HWJS_SUSPENDS int hvc_init(void);64 65#ifdef CONFIG_MAGIC_SYSRQ66static int sysrq_pressed;67#endif68 69/* dynamic list of hvc_struct instances */70static LIST_HEAD(hvc_structs);71 72/*73 * Protect the list of hvc_struct instances from inserts and removals during74 * list traversal.75 */76static DEFINE_MUTEX(hvc_structs_mutex);77 78/*79 * This value is used to assign a tty->index value to a hvc_struct based80 * upon order of exposure via hvc_probe(), when we can not match it to81 * a console candidate registered with hvc_instantiate().82 */83static int last_hvc = -1;84 85/*86 * Do not call this function with either the hvc_structs_mutex or the hvc_struct87 * lock held. If successful, this function increments the kref reference88 * count against the target hvc_struct so it should be released when finished.89 */90static HWJS_SUSPENDS struct hvc_struct *hvc_get_by_index(int index)91{92 struct hvc_struct *hp;93 unsigned long flags;94 95 mutex_lock(&hvc_structs_mutex);96 97 list_for_each_entry(hp, &hvc_structs, next) {98 spin_lock_irqsave(&hp->lock, flags);99 if (hp->index == index) {100 tty_port_get(&hp->port);101 spin_unlock_irqrestore(&hp->lock, flags);102 mutex_unlock(&hvc_structs_mutex);103 return hp;104 }105 spin_unlock_irqrestore(&hp->lock, flags);106 }107 hp = NULL;108 mutex_unlock(&hvc_structs_mutex);109 110 return hp;111}112 113static HWJS_SUSPENDS int __hvc_flush(const struct hv_ops *ops, uint32_t vtermno, bool wait)114{115 if (wait)116 might_sleep();117 118 if (ops->flush)119 return ops->flush(vtermno, wait);120 return 0;121}122 123static HWJS_SUSPENDS int hvc_console_flush(const struct hv_ops *ops, uint32_t vtermno)124{125 return __hvc_flush(ops, vtermno, false);126}127 128/*129 * Wait for the console to flush before writing more to it. This sleeps.130 */131static HWJS_SUSPENDS int hvc_flush(struct hvc_struct *hp)132{133 return __hvc_flush(hp->ops, hp->vtermno, true);134}135 136/*137 * Initial console vtermnos for console API usage prior to full console138 * initialization. Any vty adapter outside this range will not have usable139 * console interfaces but can still be used as a tty device. This has to be140 * static because kmalloc will not work during early console init.141 */142static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];143static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =144 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};145 146/*147 * Console APIs, NOT TTY. These APIs are available immediately when148 * hvc_console_setup() finds adapters.149 */150 151static HWJS_SUSPENDS void hvc_console_print(struct console *co, const char *b,152 unsigned count)153{154 char c[N_OUTBUF] __ALIGNED__;155 unsigned i = 0, n = 0;156 int r, donecr = 0, index = co->index;157 158 /* Console access attempt outside of acceptable console range. */159 if (index >= MAX_NR_HVC_CONSOLES)160 return;161 162 /* This console adapter was removed so it is not usable. */163 if (vtermnos[index] == -1)164 return;165 166 while (count > 0 || i > 0) {167 if (count > 0 && i < sizeof(c)) {168 if (b[n] == '\n' && !donecr) {169 c[i++] = '\r';170 donecr = 1;171 } else {172 c[i++] = b[n++];173 donecr = 0;174 --count;175 }176 } else {177 r = cons_ops[index]->put_chars(vtermnos[index], c, i);178 if (r <= 0) {179 /* throw away characters on error180 * but spin in case of -EAGAIN */181 if (r != -EAGAIN) {182 i = 0;183 } else {184 hvc_console_flush(cons_ops[index],185 vtermnos[index]);186 }187 } else if (r > 0) {188 i -= r;189 if (i > 0)190 memmove(c, c+r, i);191 }192 }193 }194 hvc_console_flush(cons_ops[index], vtermnos[index]);195}196 197static struct tty_driver *hvc_console_device(struct console *c, int *index)198{199 if (vtermnos[c->index] == -1)200 return NULL;201 202 *index = c->index;203 return hvc_driver;204}205 206static int hvc_console_setup(struct console *co, char *options)207{ 208 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)209 return -ENODEV;210 211 if (vtermnos[co->index] == -1)212 return -ENODEV;213 214 return 0;215}216 217static struct console hvc_console = {218 .name = "hvc",219 .write = hvc_console_print,220 .device = hvc_console_device,221 .setup = hvc_console_setup,222 .flags = CON_PRINTBUFFER,223 .index = -1,224};225 226/*227 * Early console initialization. Precedes driver initialization.228 *229 * (1) we are first, and the user specified another driver230 * -- index will remain -1231 * (2) we are first and the user specified no driver232 * -- index will be set to 0, then we will fail setup.233 * (3) we are first and the user specified our driver234 * -- index will be set to user specified driver, and we will fail235 * (4) we are after driver, and this initcall will register us236 * -- if the user didn't specify a driver then the console will match237 *238 * Note that for cases 2 and 3, we will match later when the io driver239 * calls hvc_instantiate() and call register again.240 */241static HWJS_SUSPENDS int __init hvc_console_init(void)242{243 register_console(&hvc_console);244 return 0;245}246console_initcall(hvc_console_init);247 248/* callback when the kboject ref count reaches zero. */249static HWJS_SUSPENDS void hvc_port_destruct(struct tty_port *port)250{251 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);252 unsigned long flags;253 254 mutex_lock(&hvc_structs_mutex);255 256 spin_lock_irqsave(&hp->lock, flags);257 list_del(&(hp->next));258 spin_unlock_irqrestore(&hp->lock, flags);259 260 mutex_unlock(&hvc_structs_mutex);261 262 kfree(hp);263}264 265static HWJS_SUSPENDS void hvc_check_console(int index)266{267 /* Already registered, bail out */268 if (console_is_registered(&hvc_console))269 return;270 271 /* If this index is what the user requested, then register272 * now (setup won't fail at this point). It's ok to just273 * call register again if previously .setup failed.274 */275 if (index == hvc_console.index)276 register_console(&hvc_console);277}278 279/*280 * hvc_instantiate() is an early console discovery method which locates281 * consoles * prior to the vio subsystem discovering them. Hotplugged282 * vty adapters do NOT get an hvc_instantiate() callback since they283 * appear after early console init.284 */285int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)286{287 struct hvc_struct *hp;288 289 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)290 return -1;291 292 if (vtermnos[index] != -1)293 return -1;294 295 /* make sure no tty has been registered in this index */296 hp = hvc_get_by_index(index);297 if (hp) {298 tty_port_put(&hp->port);299 return -1;300 }301 302 vtermnos[index] = vtermno;303 cons_ops[index] = ops;304 305 /* check if we need to re-register the kernel console */306 hvc_check_console(index);307 308 return 0;309}310EXPORT_SYMBOL_GPL(hvc_instantiate);311 312/* Wake the sleeping khvcd */313void hvc_kick(void)314{315 hvc_kicked = 1;316 wake_up_process(hvc_task);317}318EXPORT_SYMBOL_GPL(hvc_kick);319 320static HWJS_SUSPENDS void hvc_unthrottle(struct tty_struct *tty)321{322 hvc_kick();323}324 325static HWJS_SUSPENDS int hvc_install(struct tty_driver *driver, struct tty_struct *tty)326{327 struct hvc_struct *hp;328 int rc;329 330 /* Auto increments kref reference if found. */331 hp = hvc_get_by_index(tty->index);332 if (!hp)333 return -ENODEV;334 335 tty->driver_data = hp;336 337 rc = tty_port_install(&hp->port, driver, tty);338 if (rc)339 tty_port_put(&hp->port);340 return rc;341}342 343/*344 * The TTY interface won't be used until after the vio layer has exposed the vty345 * adapter to the kernel.346 */347static HWJS_SUSPENDS int hvc_open(struct tty_struct *tty, struct file * filp)348{349 struct hvc_struct *hp = tty->driver_data;350 unsigned long flags;351 int rc = 0;352 353 spin_lock_irqsave(&hp->port.lock, flags);354 /* Check and then increment for fast path open. */355 if (hp->port.count++ > 0) {356 spin_unlock_irqrestore(&hp->port.lock, flags);357 hvc_kick();358 return 0;359 } /* else count == 0 */360 spin_unlock_irqrestore(&hp->port.lock, flags);361 362 tty_port_tty_set(&hp->port, tty);363 364 if (hp->ops->notifier_add)365 rc = hp->ops->notifier_add(hp, hp->data);366 367 /*368 * If the notifier fails we return an error. The tty layer369 * will call hvc_close() after a failed open but we don't want to clean370 * up there so we'll clean up here and clear out the previously set371 * tty fields and return the kref reference.372 */373 if (rc) {374 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);375 } else {376 /* We are ready... raise DTR/RTS */377 if (C_BAUD(tty))378 if (hp->ops->dtr_rts)379 hp->ops->dtr_rts(hp, true);380 tty_port_set_initialized(&hp->port, true);381 }382 383 /* Force wakeup of the polling thread */384 hvc_kick();385 386 return rc;387}388 389static HWJS_SUSPENDS void hvc_close(struct tty_struct *tty, struct file * filp)390{391 struct hvc_struct *hp = tty->driver_data;392 unsigned long flags;393 394 if (tty_hung_up_p(filp))395 return;396 397 spin_lock_irqsave(&hp->port.lock, flags);398 399 if (--hp->port.count == 0) {400 spin_unlock_irqrestore(&hp->port.lock, flags);401 /* We are done with the tty pointer now. */402 tty_port_tty_set(&hp->port, NULL);403 404 if (!tty_port_initialized(&hp->port))405 return;406 407 if (C_HUPCL(tty))408 if (hp->ops->dtr_rts)409 hp->ops->dtr_rts(hp, false);410 411 if (hp->ops->notifier_del)412 hp->ops->notifier_del(hp, hp->data);413 414 /* cancel pending tty resize work */415 cancel_work_sync(&hp->tty_resize);416 417 /*418 * Chain calls chars_in_buffer() and returns immediately if419 * there is no buffered data otherwise sleeps on a wait queue420 * waking periodically to check chars_in_buffer().421 */422 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);423 tty_port_set_initialized(&hp->port, false);424 } else {425 if (hp->port.count < 0)426 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",427 hp->vtermno, hp->port.count);428 spin_unlock_irqrestore(&hp->port.lock, flags);429 }430}431 432static void hvc_cleanup(struct tty_struct *tty)433{434 struct hvc_struct *hp = tty->driver_data;435 436 tty_port_put(&hp->port);437}438 439static HWJS_SUSPENDS void hvc_hangup(struct tty_struct *tty)440{441 struct hvc_struct *hp = tty->driver_data;442 unsigned long flags;443 444 if (!hp)445 return;446 447 /* cancel pending tty resize work */448 cancel_work_sync(&hp->tty_resize);449 450 spin_lock_irqsave(&hp->port.lock, flags);451 452 /*453 * The N_TTY line discipline has problems such that in a close vs454 * open->hangup case this can be called after the final close so prevent455 * that from happening for now.456 */457 if (hp->port.count <= 0) {458 spin_unlock_irqrestore(&hp->port.lock, flags);459 return;460 }461 462 hp->port.count = 0;463 spin_unlock_irqrestore(&hp->port.lock, flags);464 tty_port_tty_set(&hp->port, NULL);465 466 hp->n_outbuf = 0;467 468 if (hp->ops->notifier_hangup)469 hp->ops->notifier_hangup(hp, hp->data);470}471 472/*473 * Push buffered characters whether they were just recently buffered or waiting474 * on a blocked hypervisor. Call this function with hp->lock held.475 */476static HWJS_SUSPENDS int hvc_push(struct hvc_struct *hp)477{478 int n;479 480 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);481 if (n <= 0) {482 if (n == 0 || n == -EAGAIN) {483 hp->do_wakeup = 1;484 return 0;485 }486 /* throw away output on error; this happens when487 there is no session connected to the vterm. */488 hp->n_outbuf = 0;489 } else490 hp->n_outbuf -= n;491 if (hp->n_outbuf > 0)492 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);493 else494 hp->do_wakeup = 1;495 496 return n;497}498 499static HWJS_SUSPENDS ssize_t hvc_write(struct tty_struct *tty, const u8 *buf, size_t count)500{501 struct hvc_struct *hp = tty->driver_data;502 unsigned long flags;503 size_t rsize, written = 0;504 505 /* This write was probably executed during a tty close. */506 if (!hp)507 return -EPIPE;508 509 /* FIXME what's this (unprotected) check for? */510 if (hp->port.count <= 0)511 return -EIO;512 513 while (count > 0) {514 int ret = 0;515 516 spin_lock_irqsave(&hp->lock, flags);517 518 rsize = hp->outbuf_size - hp->n_outbuf;519 520 if (rsize) {521 if (rsize > count)522 rsize = count;523 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);524 count -= rsize;525 buf += rsize;526 hp->n_outbuf += rsize;527 written += rsize;528 }529 530 if (hp->n_outbuf > 0)531 ret = hvc_push(hp);532 533 spin_unlock_irqrestore(&hp->lock, flags);534 535 if (!ret)536 break;537 538 if (count) {539 if (hp->n_outbuf > 0)540 hvc_flush(hp);541 cond_resched();542 }543 }544 545 /*546 * Racy, but harmless, kick thread if there is still pending data.547 */548 if (hp->n_outbuf)549 hvc_kick();550 551 return written;552}553 554/**555 * hvc_set_winsz() - Resize the hvc tty terminal window.556 * @work: work structure.557 *558 * The routine shall not be called within an atomic context because it559 * might sleep.560 *561 * Locking: hp->lock562 */563static void hvc_set_winsz(struct work_struct *work)564{565 struct hvc_struct *hp;566 unsigned long hvc_flags;567 struct tty_struct *tty;568 struct winsize ws;569 570 hp = container_of(work, struct hvc_struct, tty_resize);571 572 tty = tty_port_tty_get(&hp->port);573 if (!tty)574 return;575 576 spin_lock_irqsave(&hp->lock, hvc_flags);577 ws = hp->ws;578 spin_unlock_irqrestore(&hp->lock, hvc_flags);579 580 tty_do_resize(tty, &ws);581 tty_kref_put(tty);582}583 584/*585 * This is actually a contract between the driver and the tty layer outlining586 * how much write room the driver can guarantee will be sent OR BUFFERED. This587 * driver MUST honor the return value.588 */589static unsigned int hvc_write_room(struct tty_struct *tty)590{591 struct hvc_struct *hp = tty->driver_data;592 593 if (!hp)594 return 0;595 596 return hp->outbuf_size - hp->n_outbuf;597}598 599static unsigned int hvc_chars_in_buffer(struct tty_struct *tty)600{601 struct hvc_struct *hp = tty->driver_data;602 603 if (!hp)604 return 0;605 return hp->n_outbuf;606}607 608/*609 * timeout will vary between the MIN and MAX values defined here. By default610 * and during console activity we will use a default MIN_TIMEOUT of 10. When611 * the console is idle, we increase the timeout value on each pass through612 * msleep until we reach the max. This may be noticeable as a brief (average613 * one second) delay on the console before the console responds to input when614 * there has been no input for some time.615 */616#define MIN_TIMEOUT (10)617#define MAX_TIMEOUT (2000)618static u32 timeout = MIN_TIMEOUT;619 620/*621 * Maximum number of bytes to get from the console driver if hvc_poll is622 * called from driver (and can't sleep). Any more than this and we break623 * and start polling with khvcd. This value was derived from an OpenBMC624 * console with the OPAL driver that results in about 0.25ms interrupts off625 * latency.626 */627#define HVC_ATOMIC_READ_MAX 128628 629#define HVC_POLL_READ 0x00000001630#define HVC_POLL_WRITE 0x00000002631 632static int __hvc_poll(struct hvc_struct *hp, bool may_sleep)633{634 struct tty_struct *tty;635 int i, n, count, poll_mask = 0;636 char buf[N_INBUF] __ALIGNED__;637 unsigned long flags;638 int read_total = 0;639 int written_total = 0;640 641 spin_lock_irqsave(&hp->lock, flags);642 643 /* Push pending writes */644 if (hp->n_outbuf > 0)645 written_total = hvc_push(hp);646 647 /* Reschedule us if still some write pending */648 if (hp->n_outbuf > 0) {649 poll_mask |= HVC_POLL_WRITE;650 /* If hvc_push() was not able to write, sleep a few msecs */651 timeout = (written_total) ? 0 : MIN_TIMEOUT;652 }653 654 if (may_sleep) {655 spin_unlock_irqrestore(&hp->lock, flags);656 cond_resched();657 spin_lock_irqsave(&hp->lock, flags);658 }659 660 /* No tty attached, just skip */661 tty = tty_port_tty_get(&hp->port);662 if (tty == NULL)663 goto bail;664 665 /* Now check if we can get data (are we throttled ?) */666 if (tty_throttled(tty))667 goto out;668 669 /* If we aren't notifier driven and aren't throttled, we always670 * request a reschedule671 */672 if (!hp->irq_requested)673 poll_mask |= HVC_POLL_READ;674 675 read_again:676 /* Read data if any */677 count = tty_buffer_request_room(&hp->port, N_INBUF);678 679 /* If flip is full, just reschedule a later read */680 if (count == 0) {681 poll_mask |= HVC_POLL_READ;682 goto out;683 }684 685 n = hp->ops->get_chars(hp->vtermno, buf, count);686 if (n <= 0) {687 /* Hangup the tty when disconnected from host */688 if (n == -EPIPE) {689 spin_unlock_irqrestore(&hp->lock, flags);690 tty_hangup(tty);691 spin_lock_irqsave(&hp->lock, flags);692 } else if ( n == -EAGAIN ) {693 /*694 * Some back-ends can only ensure a certain min695 * num of bytes read, which may be > 'count'.696 * Let the tty clear the flip buff to make room.697 */698 poll_mask |= HVC_POLL_READ;699 }700 goto out;701 }702 703 for (i = 0; i < n; ++i) {704#ifdef CONFIG_MAGIC_SYSRQ705 if (hp->index == hvc_console.index) {706 /* Handle the SysRq Hack */707 /* XXX should support a sequence */708 if (buf[i] == '\x0f') { /* ^O */709 /* if ^O is pressed again, reset710 * sysrq_pressed and flip ^O char */711 sysrq_pressed = !sysrq_pressed;712 if (sysrq_pressed)713 continue;714 } else if (sysrq_pressed) {715 handle_sysrq(buf[i]);716 sysrq_pressed = 0;717 continue;718 }719 }720#endif /* CONFIG_MAGIC_SYSRQ */721 tty_insert_flip_char(&hp->port, buf[i], 0);722 }723 read_total += n;724 725 if (may_sleep) {726 /* Keep going until the flip is full */727 spin_unlock_irqrestore(&hp->lock, flags);728 cond_resched();729 spin_lock_irqsave(&hp->lock, flags);730 goto read_again;731 } else if (read_total < HVC_ATOMIC_READ_MAX) {732 /* Break and defer if it's a large read in atomic */733 goto read_again;734 }735 736 /*737 * Latency break, schedule another poll immediately.738 */739 poll_mask |= HVC_POLL_READ;740 741 out:742 /* Wakeup write queue if necessary */743 if (hp->do_wakeup) {744 hp->do_wakeup = 0;745 tty_wakeup(tty);746 }747 bail:748 spin_unlock_irqrestore(&hp->lock, flags);749 750 if (read_total) {751 /* Activity is occurring, so reset the polling backoff value to752 a minimum for performance. */753 timeout = MIN_TIMEOUT;754 755 tty_flip_buffer_push(&hp->port);756 }757 tty_kref_put(tty);758 759 return poll_mask;760}761 762int hvc_poll(struct hvc_struct *hp)763{764 return __hvc_poll(hp, false);765}766EXPORT_SYMBOL_GPL(hvc_poll);767 768/**769 * __hvc_resize() - Update terminal window size information.770 * @hp: HVC console pointer771 * @ws: Terminal window size structure772 *773 * Stores the specified window size information in the hvc structure of @hp.774 * The function schedule the tty resize update.775 *776 * Locking: Locking free; the function MUST be called holding hp->lock777 */778void __hvc_resize(struct hvc_struct *hp, struct winsize ws)779{780 hp->ws = ws;781 schedule_work(&hp->tty_resize);782}783EXPORT_SYMBOL_GPL(__hvc_resize);784 785/*786 * This kthread is either polling or interrupt driven. This is determined by787 * calling hvc_poll() who determines whether a console adapter support788 * interrupts.789 */790static HWJS_SUSPENDS int khvcd(void *unused)791{792 int poll_mask;793 struct hvc_struct *hp;794 795 set_freezable();796 do {797 poll_mask = 0;798 hvc_kicked = 0;799 try_to_freeze();800 wmb();801 if (!cpus_are_in_xmon()) {802 mutex_lock(&hvc_structs_mutex);803 list_for_each_entry(hp, &hvc_structs, next) {804 poll_mask |= __hvc_poll(hp, true);805 cond_resched();806 }807 mutex_unlock(&hvc_structs_mutex);808 } else809 poll_mask |= HVC_POLL_READ;810 if (hvc_kicked)811 continue;812 set_current_state(TASK_INTERRUPTIBLE);813 if (!hvc_kicked) {814 if (poll_mask == 0)815 schedule();816 else {817 unsigned long j_timeout;818 819 if (timeout < MAX_TIMEOUT)820 timeout += (timeout >> 6) + 1;821 822 /*823 * We don't use msleep_interruptible otherwise824 * "kick" will fail to wake us up825 */826 j_timeout = msecs_to_jiffies(timeout) + 1;827 schedule_timeout_interruptible(j_timeout);828 }829 }830 __set_current_state(TASK_RUNNING);831 } while (!kthread_should_stop());832 833 return 0;834}835 836static HWJS_SUSPENDS int hvc_tiocmget(struct tty_struct *tty)837{838 struct hvc_struct *hp = tty->driver_data;839 840 if (!hp || !hp->ops->tiocmget)841 return -EINVAL;842 return hp->ops->tiocmget(hp);843}844 845static HWJS_SUSPENDS int hvc_tiocmset(struct tty_struct *tty,846 unsigned int set, unsigned int clear)847{848 struct hvc_struct *hp = tty->driver_data;849 850 if (!hp || !hp->ops->tiocmset)851 return -EINVAL;852 return hp->ops->tiocmset(hp, set, clear);853}854 855#ifdef CONFIG_CONSOLE_POLL856static int hvc_poll_init(struct tty_driver *driver, int line, char *options)857{858 return 0;859}860 861static int hvc_poll_get_char(struct tty_driver *driver, int line)862{863 struct tty_struct *tty = driver->ttys[0];864 struct hvc_struct *hp = tty->driver_data;865 int n;866 char ch;867 868 n = hp->ops->get_chars(hp->vtermno, &ch, 1);869 870 if (n <= 0)871 return NO_POLL_CHAR;872 873 return ch;874}875 876static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)877{878 struct tty_struct *tty = driver->ttys[0];879 struct hvc_struct *hp = tty->driver_data;880 int n;881 882 do {883 n = hp->ops->put_chars(hp->vtermno, &ch, 1);884 } while (n <= 0);885}886#endif887 888static const struct tty_operations hvc_ops = {889 .install = hvc_install,890 .open = hvc_open,891 .close = hvc_close,892 .cleanup = hvc_cleanup,893 .write = hvc_write,894 .hangup = hvc_hangup,895 .unthrottle = hvc_unthrottle,896 .write_room = hvc_write_room,897 .chars_in_buffer = hvc_chars_in_buffer,898 .tiocmget = hvc_tiocmget,899 .tiocmset = hvc_tiocmset,900#ifdef CONFIG_CONSOLE_POLL901 .poll_init = hvc_poll_init,902 .poll_get_char = hvc_poll_get_char,903 .poll_put_char = hvc_poll_put_char,904#endif905};906 907static const struct tty_port_operations hvc_port_ops = {908 .destruct = hvc_port_destruct,909};910 911struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,912 const struct hv_ops *ops,913 int outbuf_size)914{915 struct hvc_struct *hp;916 int i;917 918 /* We wait until a driver actually comes along */919 if (atomic_inc_not_zero(&hvc_needs_init)) {920 int err = hvc_init();921 if (err)922 return ERR_PTR(err);923 }924 925 hp = kzalloc(struct_size(hp, outbuf, outbuf_size), GFP_KERNEL);926 if (!hp)927 return ERR_PTR(-ENOMEM);928 929 hp->vtermno = vtermno;930 hp->data = data;931 hp->ops = ops;932 hp->outbuf_size = outbuf_size;933 934 tty_port_init(&hp->port);935 hp->port.ops = &hvc_port_ops;936 937 INIT_WORK(&hp->tty_resize, hvc_set_winsz);938 spin_lock_init(&hp->lock);939 mutex_lock(&hvc_structs_mutex);940 941 /*942 * find index to use:943 * see if this vterm id matches one registered for console.944 */945 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)946 if (vtermnos[i] == hp->vtermno &&947 cons_ops[i] == hp->ops)948 break;949 950 if (i >= MAX_NR_HVC_CONSOLES) {951 952 /* find 'empty' slot for console */953 for (i = 0; i < MAX_NR_HVC_CONSOLES && vtermnos[i] != -1; i++) {954 }955 956 /* no matching slot, just use a counter */957 if (i == MAX_NR_HVC_CONSOLES)958 i = ++last_hvc + MAX_NR_HVC_CONSOLES;959 }960 961 hp->index = i;962 if (i < MAX_NR_HVC_CONSOLES) {963 cons_ops[i] = ops;964 vtermnos[i] = vtermno;965 }966 967 list_add_tail(&(hp->next), &hvc_structs);968 mutex_unlock(&hvc_structs_mutex);969 970 /* check if we need to re-register the kernel console */971 hvc_check_console(i);972 973 return hp;974}975EXPORT_SYMBOL_GPL(hvc_alloc);976 977void hvc_remove(struct hvc_struct *hp)978{979 unsigned long flags;980 struct tty_struct *tty;981 982 tty = tty_port_tty_get(&hp->port);983 984 console_lock();985 spin_lock_irqsave(&hp->lock, flags);986 if (hp->index < MAX_NR_HVC_CONSOLES) {987 vtermnos[hp->index] = -1;988 cons_ops[hp->index] = NULL;989 }990 991 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */992 993 spin_unlock_irqrestore(&hp->lock, flags);994 console_unlock();995 996 /*997 * We 'put' the instance that was grabbed when the kref instance998 * was initialized using kref_init(). Let the last holder of this999 * kref cause it to be removed, which will probably be the tty_vhangup1000 * below.1001 */1002 tty_port_put(&hp->port);1003 1004 /*1005 * This function call will auto chain call hvc_hangup.1006 */1007 if (tty) {1008 tty_vhangup(tty);1009 tty_kref_put(tty);1010 }1011}1012EXPORT_SYMBOL_GPL(hvc_remove);1013 1014/* Driver initialization: called as soon as someone uses hvc_alloc(). */1015static HWJS_SUSPENDS int hvc_init(void)1016{1017 struct tty_driver *drv;1018 int err;1019 1020 /* We need more than hvc_count adapters due to hotplug additions. */1021 drv = tty_alloc_driver(HVC_ALLOC_TTY_ADAPTERS, TTY_DRIVER_REAL_RAW |1022 TTY_DRIVER_RESET_TERMIOS);1023 if (IS_ERR(drv)) {1024 err = PTR_ERR(drv);1025 goto out;1026 }1027 1028 drv->driver_name = "hvc";1029 drv->name = "hvc";1030 drv->major = HVC_MAJOR;1031 drv->minor_start = HVC_MINOR;1032 drv->type = TTY_DRIVER_TYPE_SYSTEM;1033 drv->init_termios = tty_std_termios;1034 tty_set_operations(drv, &hvc_ops);1035 1036 /* Always start the kthread because there can be hotplug vty adapters1037 * added later. */1038 hvc_task = kthread_run(khvcd, NULL, "khvcd");1039 if (IS_ERR(hvc_task)) {1040 printk(KERN_ERR "Couldn't create kthread for console.\n");1041 err = PTR_ERR(hvc_task);1042 goto put_tty;1043 }1044 1045 err = tty_register_driver(drv);1046 if (err) {1047 printk(KERN_ERR "Couldn't register hvc console driver\n");1048 goto stop_thread;1049 }1050 1051 /*1052 * Make sure tty is fully registered before allowing it to be1053 * found by hvc_console_device.1054 */1055 smp_mb();1056 hvc_driver = drv;1057 return 0;1058 1059stop_thread:1060 kthread_stop(hvc_task);1061 hvc_task = NULL;1062put_tty:1063 tty_driver_kref_put(drv);1064out:1065 return err;1066}1067