diff options
Diffstat (limited to 'drivers/char/hvc_console.c')
| -rw-r--r-- | drivers/char/hvc_console.c | 914 |
1 files changed, 0 insertions, 914 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c deleted file mode 100644 index e9cba13ee80..00000000000 --- a/drivers/char/hvc_console.c +++ /dev/null @@ -1,914 +0,0 @@ -/* - * 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); |