+++ /dev/null
-/*
- * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
- * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
- * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
- * Copyright (C) 2004 IBM Corporation
- *
- * Additional Author(s):
- * Ryan S. Arnold <rsa@us.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#include <linux/console.h>
-#include <linux/cpumask.h>
-#include <linux/init.h>
-#include <linux/kbd_kern.h>
-#include <linux/kernel.h>
-#include <linux/kthread.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/major.h>
-#include <linux/sysrq.h>
-#include <linux/tty.h>
-#include <linux/tty_flip.h>
-#include <linux/sched.h>
-#include <linux/spinlock.h>
-#include <linux/delay.h>
-#include <linux/freezer.h>
-#include <linux/slab.h>
-
-#include <asm/uaccess.h>
-
-#include "hvc_console.h"
-
-#define HVC_MAJOR 229
-#define HVC_MINOR 0
-
-/*
- * Wait this long per iteration while trying to push buffered data to the
- * hypervisor before allowing the tty to complete a close operation.
- */
-#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
-
-/*
- * These sizes are most efficient for vio, because they are the
- * native transfer size. We could make them selectable in the
- * future to better deal with backends that want other buffer sizes.
- */
-#define N_OUTBUF 16
-#define N_INBUF 16
-
-#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
-
-static struct tty_driver *hvc_driver;
-static struct task_struct *hvc_task;
-
-/* Picks up late kicks after list walk but before schedule() */
-static int hvc_kicked;
-
-static int hvc_init(void);
-
-#ifdef CONFIG_MAGIC_SYSRQ
-static int sysrq_pressed;
-#endif
-
-/* dynamic list of hvc_struct instances */
-static LIST_HEAD(hvc_structs);
-
-/*
- * Protect the list of hvc_struct instances from inserts and removals during
- * list traversal.
- */
-static DEFINE_SPINLOCK(hvc_structs_lock);
-
-/*
- * This value is used to assign a tty->index value to a hvc_struct based
- * upon order of exposure via hvc_probe(), when we can not match it to
- * a console candidate registered with hvc_instantiate().
- */
-static int last_hvc = -1;
-
-/*
- * Do not call this function with either the hvc_structs_lock or the hvc_struct
- * lock held. If successful, this function increments the kref reference
- * count against the target hvc_struct so it should be released when finished.
- */
-static struct hvc_struct *hvc_get_by_index(int index)
-{
- struct hvc_struct *hp;
- unsigned long flags;
-
- spin_lock(&hvc_structs_lock);
-
- list_for_each_entry(hp, &hvc_structs, next) {
- spin_lock_irqsave(&hp->lock, flags);
- if (hp->index == index) {
- kref_get(&hp->kref);
- spin_unlock_irqrestore(&hp->lock, flags);
- spin_unlock(&hvc_structs_lock);
- return hp;
- }
- spin_unlock_irqrestore(&hp->lock, flags);
- }
- hp = NULL;
-
- spin_unlock(&hvc_structs_lock);
- return hp;
-}
-
-
-/*
- * Initial console vtermnos for console API usage prior to full console
- * initialization. Any vty adapter outside this range will not have usable
- * console interfaces but can still be used as a tty device. This has to be
- * static because kmalloc will not work during early console init.
- */
-static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
-static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
- {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
-
-/*
- * Console APIs, NOT TTY. These APIs are available immediately when
- * hvc_console_setup() finds adapters.
- */
-
-static void hvc_console_print(struct console *co, const char *b,
- unsigned count)
-{
- char c[N_OUTBUF] __ALIGNED__;
- unsigned i = 0, n = 0;
- int r, donecr = 0, index = co->index;
-
- /* Console access attempt outside of acceptable console range. */
- if (index >= MAX_NR_HVC_CONSOLES)
- return;
-
- /* This console adapter was removed so it is not usable. */
- if (vtermnos[index] == -1)
- return;
-
- while (count > 0 || i > 0) {
- if (count > 0 && i < sizeof(c)) {
- if (b[n] == '\n' && !donecr) {
- c[i++] = '\r';
- donecr = 1;
- } else {
- c[i++] = b[n++];
- donecr = 0;
- --count;
- }
- } else {
- r = cons_ops[index]->put_chars(vtermnos[index], c, i);
- if (r <= 0) {
- /* throw away chars on error */
- i = 0;
- } else if (r > 0) {
- i -= r;
- if (i > 0)
- memmove(c, c+r, i);
- }
- }
- }
-}
-
-static struct tty_driver *hvc_console_device(struct console *c, int *index)
-{
- if (vtermnos[c->index] == -1)
- return NULL;
-
- *index = c->index;
- return hvc_driver;
-}
-
-static int __init hvc_console_setup(struct console *co, char *options)
-{
- if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
- return -ENODEV;
-
- if (vtermnos[co->index] == -1)
- return -ENODEV;
-
- return 0;
-}
-
-static struct console hvc_console = {
- .name = "hvc",
- .write = hvc_console_print,
- .device = hvc_console_device,
- .setup = hvc_console_setup,
- .flags = CON_PRINTBUFFER,
- .index = -1,
-};
-
-/*
- * Early console initialization. Precedes driver initialization.
- *
- * (1) we are first, and the user specified another driver
- * -- index will remain -1
- * (2) we are first and the user specified no driver
- * -- index will be set to 0, then we will fail setup.
- * (3) we are first and the user specified our driver
- * -- index will be set to user specified driver, and we will fail
- * (4) we are after driver, and this initcall will register us
- * -- if the user didn't specify a driver then the console will match
- *
- * Note that for cases 2 and 3, we will match later when the io driver
- * calls hvc_instantiate() and call register again.
- */
-static int __init hvc_console_init(void)
-{
- register_console(&hvc_console);
- return 0;
-}
-console_initcall(hvc_console_init);
-
-/* callback when the kboject ref count reaches zero. */
-static void destroy_hvc_struct(struct kref *kref)
-{
- struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
- unsigned long flags;
-
- spin_lock(&hvc_structs_lock);
-
- spin_lock_irqsave(&hp->lock, flags);
- list_del(&(hp->next));
- spin_unlock_irqrestore(&hp->lock, flags);
-
- spin_unlock(&hvc_structs_lock);
-
- kfree(hp);
-}
-
-/*
- * hvc_instantiate() is an early console discovery method which locates
- * consoles * prior to the vio subsystem discovering them. Hotplugged
- * vty adapters do NOT get an hvc_instantiate() callback since they
- * appear after early console init.
- */
-int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
-{
- struct hvc_struct *hp;
-
- if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
- return -1;
-
- if (vtermnos[index] != -1)
- return -1;
-
- /* make sure no no tty has been registered in this index */
- hp = hvc_get_by_index(index);
- if (hp) {
- kref_put(&hp->kref, destroy_hvc_struct);
- return -1;
- }
-
- vtermnos[index] = vtermno;
- cons_ops[index] = ops;
-
- /* reserve all indices up to and including this index */
- if (last_hvc < index)
- last_hvc = index;
-
- /* if this index is what the user requested, then register
- * now (setup won't fail at this point). It's ok to just
- * call register again if previously .setup failed.
- */
- if (index == hvc_console.index)
- register_console(&hvc_console);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(hvc_instantiate);
-
-/* Wake the sleeping khvcd */
-void hvc_kick(void)
-{
- hvc_kicked = 1;
- wake_up_process(hvc_task);
-}
-EXPORT_SYMBOL_GPL(hvc_kick);
-
-static void hvc_unthrottle(struct tty_struct *tty)
-{
- hvc_kick();
-}
-
-/*
- * The TTY interface won't be used until after the vio layer has exposed the vty
- * adapter to the kernel.
- */
-static int hvc_open(struct tty_struct *tty, struct file * filp)
-{
- struct hvc_struct *hp;
- unsigned long flags;
- int rc = 0;
-
- /* Auto increments kref reference if found. */
- if (!(hp = hvc_get_by_index(tty->index)))
- return -ENODEV;
-
- spin_lock_irqsave(&hp->lock, flags);
- /* Check and then increment for fast path open. */
- if (hp->count++ > 0) {
- tty_kref_get(tty);
- spin_unlock_irqrestore(&hp->lock, flags);
- hvc_kick();
- return 0;
- } /* else count == 0 */
-
- tty->driver_data = hp;
-
- hp->tty = tty_kref_get(tty);
-
- spin_unlock_irqrestore(&hp->lock, flags);
-
- if (hp->ops->notifier_add)
- rc = hp->ops->notifier_add(hp, hp->data);
-
- /*
- * If the notifier fails we return an error. The tty layer
- * will call hvc_close() after a failed open but we don't want to clean
- * up there so we'll clean up here and clear out the previously set
- * tty fields and return the kref reference.
- */
- if (rc) {
- spin_lock_irqsave(&hp->lock, flags);
- hp->tty = NULL;
- spin_unlock_irqrestore(&hp->lock, flags);
- tty_kref_put(tty);
- tty->driver_data = NULL;
- kref_put(&hp->kref, destroy_hvc_struct);
- printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
- }
- /* Force wakeup of the polling thread */
- hvc_kick();
-
- return rc;
-}
-
-static void hvc_close(struct tty_struct *tty, struct file * filp)
-{
- struct hvc_struct *hp;
- unsigned long flags;
-
- if (tty_hung_up_p(filp))
- return;
-
- /*
- * No driver_data means that this close was issued after a failed
- * hvc_open by the tty layer's release_dev() function and we can just
- * exit cleanly because the kref reference wasn't made.
- */
- if (!tty->driver_data)
- return;
-
- hp = tty->driver_data;
-
- spin_lock_irqsave(&hp->lock, flags);
-
- if (--hp->count == 0) {
- /* We are done with the tty pointer now. */
- hp->tty = NULL;
- spin_unlock_irqrestore(&hp->lock, flags);
-
- if (hp->ops->notifier_del)
- hp->ops->notifier_del(hp, hp->data);
-
- /* cancel pending tty resize work */
- cancel_work_sync(&hp->tty_resize);
-
- /*
- * Chain calls chars_in_buffer() and returns immediately if
- * there is no buffered data otherwise sleeps on a wait queue
- * waking periodically to check chars_in_buffer().
- */
- tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
- } else {
- if (hp->count < 0)
- printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
- hp->vtermno, hp->count);
- spin_unlock_irqrestore(&hp->lock, flags);
- }
-
- tty_kref_put(tty);
- kref_put(&hp->kref, destroy_hvc_struct);
-}
-
-static void hvc_hangup(struct tty_struct *tty)
-{
- struct hvc_struct *hp = tty->driver_data;
- unsigned long flags;
- int temp_open_count;
-
- if (!hp)
- return;
-
- /* cancel pending tty resize work */
- cancel_work_sync(&hp->tty_resize);
-
- spin_lock_irqsave(&hp->lock, flags);
-
- /*
- * The N_TTY line discipline has problems such that in a close vs
- * open->hangup case this can be called after the final close so prevent
- * that from happening for now.
- */
- if (hp->count <= 0) {
- spin_unlock_irqrestore(&hp->lock, flags);
- return;
- }
-
- temp_open_count = hp->count;
- hp->count = 0;
- hp->n_outbuf = 0;
- hp->tty = NULL;
-
- spin_unlock_irqrestore(&hp->lock, flags);
-
- if (hp->ops->notifier_hangup)
- hp->ops->notifier_hangup(hp, hp->data);
-
- while(temp_open_count) {
- --temp_open_count;
- tty_kref_put(tty);
- kref_put(&hp->kref, destroy_hvc_struct);
- }
-}
-
-/*
- * Push buffered characters whether they were just recently buffered or waiting
- * on a blocked hypervisor. Call this function with hp->lock held.
- */
-static int hvc_push(struct hvc_struct *hp)
-{
- int n;
-
- n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
- if (n <= 0) {
- if (n == 0) {
- hp->do_wakeup = 1;
- return 0;
- }
- /* throw away output on error; this happens when
- there is no session connected to the vterm. */
- hp->n_outbuf = 0;
- } else
- hp->n_outbuf -= n;
- if (hp->n_outbuf > 0)
- memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
- else
- hp->do_wakeup = 1;
-
- return n;
-}
-
-static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
-{
- struct hvc_struct *hp = tty->driver_data;
- unsigned long flags;
- int rsize, written = 0;
-
- /* This write was probably executed during a tty close. */
- if (!hp)
- return -EPIPE;
-
- if (hp->count <= 0)
- return -EIO;
-
- spin_lock_irqsave(&hp->lock, flags);
-
- /* Push pending writes */
- if (hp->n_outbuf > 0)
- hvc_push(hp);
-
- while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
- if (rsize > count)
- rsize = count;
- memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
- count -= rsize;
- buf += rsize;
- hp->n_outbuf += rsize;
- written += rsize;
- hvc_push(hp);
- }
- spin_unlock_irqrestore(&hp->lock, flags);
-
- /*
- * Racy, but harmless, kick thread if there is still pending data.
- */
- if (hp->n_outbuf)
- hvc_kick();
-
- return written;
-}
-
-/**
- * hvc_set_winsz() - Resize the hvc tty terminal window.
- * @work: work structure.
- *
- * The routine shall not be called within an atomic context because it
- * might sleep.
- *
- * Locking: hp->lock
- */
-static void hvc_set_winsz(struct work_struct *work)
-{
- struct hvc_struct *hp;
- unsigned long hvc_flags;
- struct tty_struct *tty;
- struct winsize ws;
-
- hp = container_of(work, struct hvc_struct, tty_resize);
-
- spin_lock_irqsave(&hp->lock, hvc_flags);
- if (!hp->tty) {
- spin_unlock_irqrestore(&hp->lock, hvc_flags);
- return;
- }
- ws = hp->ws;
- tty = tty_kref_get(hp->tty);
- spin_unlock_irqrestore(&hp->lock, hvc_flags);
-
- tty_do_resize(tty, &ws);
- tty_kref_put(tty);
-}
-
-/*
- * This is actually a contract between the driver and the tty layer outlining
- * how much write room the driver can guarantee will be sent OR BUFFERED. This
- * driver MUST honor the return value.
- */
-static int hvc_write_room(struct tty_struct *tty)
-{
- struct hvc_struct *hp = tty->driver_data;
-
- if (!hp)
- return -1;
-
- return hp->outbuf_size - hp->n_outbuf;
-}
-
-static int hvc_chars_in_buffer(struct tty_struct *tty)
-{
- struct hvc_struct *hp = tty->driver_data;
-
- if (!hp)
- return 0;
- return hp->n_outbuf;
-}
-
-/*
- * timeout will vary between the MIN and MAX values defined here. By default
- * and during console activity we will use a default MIN_TIMEOUT of 10. When
- * the console is idle, we increase the timeout value on each pass through
- * msleep until we reach the max. This may be noticeable as a brief (average
- * one second) delay on the console before the console responds to input when
- * there has been no input for some time.
- */
-#define MIN_TIMEOUT (10)
-#define MAX_TIMEOUT (2000)
-static u32 timeout = MIN_TIMEOUT;
-
-#define HVC_POLL_READ 0x00000001
-#define HVC_POLL_WRITE 0x00000002
-
-int hvc_poll(struct hvc_struct *hp)
-{
- struct tty_struct *tty;
- int i, n, poll_mask = 0;
- char buf[N_INBUF] __ALIGNED__;
- unsigned long flags;
- int read_total = 0;
- int written_total = 0;
-
- spin_lock_irqsave(&hp->lock, flags);
-
- /* Push pending writes */
- if (hp->n_outbuf > 0)
- written_total = hvc_push(hp);
-
- /* Reschedule us if still some write pending */
- if (hp->n_outbuf > 0) {
- poll_mask |= HVC_POLL_WRITE;
- /* If hvc_push() was not able to write, sleep a few msecs */
- timeout = (written_total) ? 0 : MIN_TIMEOUT;
- }
-
- /* No tty attached, just skip */
- tty = tty_kref_get(hp->tty);
- if (tty == NULL)
- goto bail;
-
- /* Now check if we can get data (are we throttled ?) */
- if (test_bit(TTY_THROTTLED, &tty->flags))
- goto throttled;
-
- /* If we aren't notifier driven and aren't throttled, we always
- * request a reschedule
- */
- if (!hp->irq_requested)
- poll_mask |= HVC_POLL_READ;
-
- /* Read data if any */
- for (;;) {
- int count = tty_buffer_request_room(tty, N_INBUF);
-
- /* If flip is full, just reschedule a later read */
- if (count == 0) {
- poll_mask |= HVC_POLL_READ;
- break;
- }
-
- n = hp->ops->get_chars(hp->vtermno, buf, count);
- if (n <= 0) {
- /* Hangup the tty when disconnected from host */
- if (n == -EPIPE) {
- spin_unlock_irqrestore(&hp->lock, flags);
- tty_hangup(tty);
- spin_lock_irqsave(&hp->lock, flags);
- } else if ( n == -EAGAIN ) {
- /*
- * Some back-ends can only ensure a certain min
- * num of bytes read, which may be > 'count'.
- * Let the tty clear the flip buff to make room.
- */
- poll_mask |= HVC_POLL_READ;
- }
- break;
- }
- for (i = 0; i < n; ++i) {
-#ifdef CONFIG_MAGIC_SYSRQ
- if (hp->index == hvc_console.index) {
- /* Handle the SysRq Hack */
- /* XXX should support a sequence */
- if (buf[i] == '\x0f') { /* ^O */
- /* if ^O is pressed again, reset
- * sysrq_pressed and flip ^O char */
- sysrq_pressed = !sysrq_pressed;
- if (sysrq_pressed)
- continue;
- } else if (sysrq_pressed) {
- handle_sysrq(buf[i]);
- sysrq_pressed = 0;
- continue;
- }
- }
-#endif /* CONFIG_MAGIC_SYSRQ */
- tty_insert_flip_char(tty, buf[i], 0);
- }
-
- read_total += n;
- }
- throttled:
- /* Wakeup write queue if necessary */
- if (hp->do_wakeup) {
- hp->do_wakeup = 0;
- tty_wakeup(tty);
- }
- bail:
- spin_unlock_irqrestore(&hp->lock, flags);
-
- if (read_total) {
- /* Activity is occurring, so reset the polling backoff value to
- a minimum for performance. */
- timeout = MIN_TIMEOUT;
-
- tty_flip_buffer_push(tty);
- }
- if (tty)
- tty_kref_put(tty);
-
- return poll_mask;
-}
-EXPORT_SYMBOL_GPL(hvc_poll);
-
-/**
- * __hvc_resize() - Update terminal window size information.
- * @hp: HVC console pointer
- * @ws: Terminal window size structure
- *
- * Stores the specified window size information in the hvc structure of @hp.
- * The function schedule the tty resize update.
- *
- * Locking: Locking free; the function MUST be called holding hp->lock
- */
-void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
-{
- hp->ws = ws;
- schedule_work(&hp->tty_resize);
-}
-EXPORT_SYMBOL_GPL(__hvc_resize);
-
-/*
- * This kthread is either polling or interrupt driven. This is determined by
- * calling hvc_poll() who determines whether a console adapter support
- * interrupts.
- */
-static int khvcd(void *unused)
-{
- int poll_mask;
- struct hvc_struct *hp;
-
- set_freezable();
- do {
- poll_mask = 0;
- hvc_kicked = 0;
- try_to_freeze();
- wmb();
- if (!cpus_are_in_xmon()) {
- spin_lock(&hvc_structs_lock);
- list_for_each_entry(hp, &hvc_structs, next) {
- poll_mask |= hvc_poll(hp);
- }
- spin_unlock(&hvc_structs_lock);
- } else
- poll_mask |= HVC_POLL_READ;
- if (hvc_kicked)
- continue;
- set_current_state(TASK_INTERRUPTIBLE);
- if (!hvc_kicked) {
- if (poll_mask == 0)
- schedule();
- else {
- if (timeout < MAX_TIMEOUT)
- timeout += (timeout >> 6) + 1;
-
- msleep_interruptible(timeout);
- }
- }
- __set_current_state(TASK_RUNNING);
- } while (!kthread_should_stop());
-
- return 0;
-}
-
-static const struct tty_operations hvc_ops = {
- .open = hvc_open,
- .close = hvc_close,
- .write = hvc_write,
- .hangup = hvc_hangup,
- .unthrottle = hvc_unthrottle,
- .write_room = hvc_write_room,
- .chars_in_buffer = hvc_chars_in_buffer,
-};
-
-struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
- const struct hv_ops *ops,
- int outbuf_size)
-{
- struct hvc_struct *hp;
- int i;
-
- /* We wait until a driver actually comes along */
- if (!hvc_driver) {
- int err = hvc_init();
- if (err)
- return ERR_PTR(err);
- }
-
- hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
- GFP_KERNEL);
- if (!hp)
- return ERR_PTR(-ENOMEM);
-
- hp->vtermno = vtermno;
- hp->data = data;
- hp->ops = ops;
- hp->outbuf_size = outbuf_size;
- hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
-
- kref_init(&hp->kref);
-
- INIT_WORK(&hp->tty_resize, hvc_set_winsz);
- spin_lock_init(&hp->lock);
- spin_lock(&hvc_structs_lock);
-
- /*
- * find index to use:
- * see if this vterm id matches one registered for console.
- */
- for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
- if (vtermnos[i] == hp->vtermno &&
- cons_ops[i] == hp->ops)
- break;
-
- /* no matching slot, just use a counter */
- if (i >= MAX_NR_HVC_CONSOLES)
- i = ++last_hvc;
-
- hp->index = i;
-
- list_add_tail(&(hp->next), &hvc_structs);
- spin_unlock(&hvc_structs_lock);
-
- return hp;
-}
-EXPORT_SYMBOL_GPL(hvc_alloc);
-
-int hvc_remove(struct hvc_struct *hp)
-{
- unsigned long flags;
- struct tty_struct *tty;
-
- spin_lock_irqsave(&hp->lock, flags);
- tty = tty_kref_get(hp->tty);
-
- if (hp->index < MAX_NR_HVC_CONSOLES)
- vtermnos[hp->index] = -1;
-
- /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
-
- spin_unlock_irqrestore(&hp->lock, flags);
-
- /*
- * We 'put' the instance that was grabbed when the kref instance
- * was initialized using kref_init(). Let the last holder of this
- * kref cause it to be removed, which will probably be the tty_vhangup
- * below.
- */
- kref_put(&hp->kref, destroy_hvc_struct);
-
- /*
- * This function call will auto chain call hvc_hangup.
- */
- if (tty) {
- tty_vhangup(tty);
- tty_kref_put(tty);
- }
- return 0;
-}
-EXPORT_SYMBOL_GPL(hvc_remove);
-
-/* Driver initialization: called as soon as someone uses hvc_alloc(). */
-static int hvc_init(void)
-{
- struct tty_driver *drv;
- int err;
-
- /* We need more than hvc_count adapters due to hotplug additions. */
- drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
- if (!drv) {
- err = -ENOMEM;
- goto out;
- }
-
- drv->owner = THIS_MODULE;
- drv->driver_name = "hvc";
- drv->name = "hvc";
- drv->major = HVC_MAJOR;
- drv->minor_start = HVC_MINOR;
- drv->type = TTY_DRIVER_TYPE_SYSTEM;
- drv->init_termios = tty_std_termios;
- drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
- tty_set_operations(drv, &hvc_ops);
-
- /* Always start the kthread because there can be hotplug vty adapters
- * added later. */
- hvc_task = kthread_run(khvcd, NULL, "khvcd");
- if (IS_ERR(hvc_task)) {
- printk(KERN_ERR "Couldn't create kthread for console.\n");
- err = PTR_ERR(hvc_task);
- goto put_tty;
- }
-
- err = tty_register_driver(drv);
- if (err) {
- printk(KERN_ERR "Couldn't register hvc console driver\n");
- goto stop_thread;
- }
-
- /*
- * Make sure tty is fully registered before allowing it to be
- * found by hvc_console_device.
- */
- smp_mb();
- hvc_driver = drv;
- return 0;
-
-stop_thread:
- kthread_stop(hvc_task);
- hvc_task = NULL;
-put_tty:
- put_tty_driver(drv);
-out:
- return err;
-}
-
-/* This isn't particularly necessary due to this being a console driver
- * but it is nice to be thorough.
- */
-static void __exit hvc_exit(void)
-{
- if (hvc_driver) {
- kthread_stop(hvc_task);
-
- tty_unregister_driver(hvc_driver);
- /* return tty_struct instances allocated in hvc_init(). */
- put_tty_driver(hvc_driver);
- unregister_console(&hvc_console);
- }
-}
-module_exit(hvc_exit);
projects / mv-sheeva.git / blobdiff