diff options
Diffstat (limited to 'kernel/drivers/tty/hvc/hvc_console.c')
| -rw-r--r-- | kernel/drivers/tty/hvc/hvc_console.c | 1022 |
1 files changed, 1022 insertions, 0 deletions
diff --git a/kernel/drivers/tty/hvc/hvc_console.c b/kernel/drivers/tty/hvc/hvc_console.c new file mode 100644 index 000000000..4fcec1d79 --- /dev/null +++ b/kernel/drivers/tty/hvc/hvc_console.c @@ -0,0 +1,1022 @@ +/* + * 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/atomic.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 <linux/serial_core.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; + +/* hvc_init is triggered from hvc_alloc, i.e. only when actually used */ +static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1); + +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) { + tty_port_get(&hp->port); + 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 characters on error + * but spin in case of -EAGAIN */ + if (r != -EAGAIN) + 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 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 hvc_port_destruct(struct tty_port *port) +{ + struct hvc_struct *hp = container_of(port, struct hvc_struct, port); + 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); +} + +static void hvc_check_console(int index) +{ + /* Already enabled, bail out */ + if (hvc_console.flags & CON_ENABLED) + return; + + /* 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); +} + +/* + * 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) { + tty_port_put(&hp->port); + 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; + + /* check if we need to re-register the kernel console */ + hvc_check_console(index); + + 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(); +} + +static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct hvc_struct *hp; + int rc; + + /* Auto increments kref reference if found. */ + if (!(hp = hvc_get_by_index(tty->index))) + return -ENODEV; + + tty->driver_data = hp; + + rc = tty_port_install(&hp->port, driver, tty); + if (rc) + tty_port_put(&hp->port); + return rc; +} + +/* + * 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 = tty->driver_data; + unsigned long flags; + int rc = 0; + + spin_lock_irqsave(&hp->port.lock, flags); + /* Check and then increment for fast path open. */ + if (hp->port.count++ > 0) { + spin_unlock_irqrestore(&hp->port.lock, flags); + hvc_kick(); + return 0; + } /* else count == 0 */ + spin_unlock_irqrestore(&hp->port.lock, flags); + + tty_port_tty_set(&hp->port, tty); + + 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) { + tty_port_tty_set(&hp->port, NULL); + tty->driver_data = NULL; + tty_port_put(&hp->port); + printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); + } else + /* We are ready... raise DTR/RTS */ + if (C_BAUD(tty)) + if (hp->ops->dtr_rts) + hp->ops->dtr_rts(hp, 1); + + /* 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->port.lock, flags); + + if (--hp->port.count == 0) { + spin_unlock_irqrestore(&hp->port.lock, flags); + /* We are done with the tty pointer now. */ + tty_port_tty_set(&hp->port, NULL); + + if (C_HUPCL(tty)) + if (hp->ops->dtr_rts) + hp->ops->dtr_rts(hp, 0); + + 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_from_close(tty, HVC_CLOSE_WAIT); + } else { + if (hp->port.count < 0) + printk(KERN_ERR "hvc_close %X: oops, count is %d\n", + hp->vtermno, hp->port.count); + spin_unlock_irqrestore(&hp->port.lock, flags); + } +} + +static void hvc_cleanup(struct tty_struct *tty) +{ + struct hvc_struct *hp = tty->driver_data; + + tty_port_put(&hp->port); +} + +static void hvc_hangup(struct tty_struct *tty) +{ + struct hvc_struct *hp = tty->driver_data; + unsigned long flags; + + if (!hp) + return; + + /* cancel pending tty resize work */ + cancel_work_sync(&hp->tty_resize); + + spin_lock_irqsave(&hp->port.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->port.count <= 0) { + spin_unlock_irqrestore(&hp->port.lock, flags); + return; + } + + hp->port.count = 0; + spin_unlock_irqrestore(&hp->port.lock, flags); + tty_port_tty_set(&hp->port, NULL); + + hp->n_outbuf = 0; + + if (hp->ops->notifier_hangup) + hp->ops->notifier_hangup(hp, hp->data); +} + +/* + * 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 || n == -EAGAIN) { + 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; + + /* FIXME what's this (unprotected) check for? */ + if (hp->port.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); + + tty = tty_port_tty_get(&hp->port); + if (!tty) + return; + + spin_lock_irqsave(&hp->lock, hvc_flags); + ws = hp->ws; + 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 0; + + 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_port_tty_get(&hp->port); + 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(&hp->port, 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(&hp->port, 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(&hp->port); + } + 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 { + unsigned long j_timeout; + + if (timeout < MAX_TIMEOUT) + timeout += (timeout >> 6) + 1; + + /* + * We don't use msleep_interruptible otherwise + * "kick" will fail to wake us up + */ + j_timeout = msecs_to_jiffies(timeout) + 1; + schedule_timeout_interruptible(j_timeout); + } + } + __set_current_state(TASK_RUNNING); + } while (!kthread_should_stop()); + + return 0; +} + +static int hvc_tiocmget(struct tty_struct *tty) +{ + struct hvc_struct *hp = tty->driver_data; + + if (!hp || !hp->ops->tiocmget) + return -EINVAL; + return hp->ops->tiocmget(hp); +} + +static int hvc_tiocmset(struct tty_struct *tty, + unsigned int set, unsigned int clear) +{ + struct hvc_struct *hp = tty->driver_data; + + if (!hp || !hp->ops->tiocmset) + return -EINVAL; + return hp->ops->tiocmset(hp, set, clear); +} + +#ifdef CONFIG_CONSOLE_POLL +static int hvc_poll_init(struct tty_driver *driver, int line, char *options) +{ + return 0; +} + +static int hvc_poll_get_char(struct tty_driver *driver, int line) +{ + struct tty_struct *tty = driver->ttys[0]; + struct hvc_struct *hp = tty->driver_data; + int n; + char ch; + + n = hp->ops->get_chars(hp->vtermno, &ch, 1); + + if (n == 0) + return NO_POLL_CHAR; + + return ch; +} + +static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) +{ + struct tty_struct *tty = driver->ttys[0]; + struct hvc_struct *hp = tty->driver_data; + int n; + + do { + n = hp->ops->put_chars(hp->vtermno, &ch, 1); + } while (n <= 0); +} +#endif + +static const struct tty_operations hvc_ops = { + .install = hvc_install, + .open = hvc_open, + .close = hvc_close, + .cleanup = hvc_cleanup, + .write = hvc_write, + .hangup = hvc_hangup, + .unthrottle = hvc_unthrottle, + .write_room = hvc_write_room, + .chars_in_buffer = hvc_chars_in_buffer, + .tiocmget = hvc_tiocmget, + .tiocmset = hvc_tiocmset, +#ifdef CONFIG_CONSOLE_POLL + .poll_init = hvc_poll_init, + .poll_get_char = hvc_poll_get_char, + .poll_put_char = hvc_poll_put_char, +#endif +}; + +static const struct tty_port_operations hvc_port_ops = { + .destruct = hvc_port_destruct, +}; + +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 (atomic_inc_not_zero(&hvc_needs_init)) { + 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))]; + + tty_port_init(&hp->port); + hp->port.ops = &hvc_port_ops; + + 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; + cons_ops[i] = ops; + vtermnos[i] = vtermno; + + list_add_tail(&(hp->next), &hvc_structs); + spin_unlock(&hvc_structs_lock); + + /* check if we need to re-register the kernel console */ + hvc_check_console(i); + + return hp; +} +EXPORT_SYMBOL_GPL(hvc_alloc); + +int hvc_remove(struct hvc_struct *hp) +{ + unsigned long flags; + struct tty_struct *tty; + + tty = tty_port_tty_get(&hp->port); + + spin_lock_irqsave(&hp->lock, flags); + if (hp->index < MAX_NR_HVC_CONSOLES) { + console_lock(); + vtermnos[hp->index] = -1; + cons_ops[hp->index] = NULL; + console_unlock(); + } + + /* 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. + */ + tty_port_put(&hp->port); + + /* + * 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->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); |