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-rw-r--r--drivers/tty/hvc/hvc_console.c914
1 files changed, 914 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
new file mode 100644
index 000000000000..e9cba13ee800
--- /dev/null
+++ b/drivers/tty/hvc/hvc_console.c
@@ -0,0 +1,914 @@
+/*
+ * 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);
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