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Diffstat (limited to 'drivers/char/hvc_console.c')
-rw-r--r--drivers/char/hvc_console.c831
1 files changed, 831 insertions, 0 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
new file mode 100644
index 000000000000..88cd858f74d0
--- /dev/null
+++ b/drivers/char/hvc_console.c
@@ -0,0 +1,831 @@
+/*
+ * 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/kobject.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 <asm/uaccess.h>
+#include <asm/hvconsole.h>
+#include <asm/vio.h>
+
+#define HVC_MAJOR 229
+#define HVC_MINOR 0
+
+#define TIMEOUT (10)
+
+/*
+ * 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 */
+
+/*
+ * The Linux TTY code does not support dynamic addition of tty derived devices
+ * so we need to know how many tty devices we might need when space is allocated
+ * for the tty device. Since this driver supports hotplug of vty adapters we
+ * need to make sure we have enough allocated.
+ */
+#define HVC_ALLOC_TTY_ADAPTERS 8
+
+static struct tty_driver *hvc_driver;
+#ifdef CONFIG_MAGIC_SYSRQ
+static int sysrq_pressed;
+#endif
+
+#define N_OUTBUF 16
+#define N_INBUF 16
+
+#define __ALIGNED__ __attribute__((__aligned__(8)))
+
+struct hvc_struct {
+ spinlock_t lock;
+ int index;
+ struct tty_struct *tty;
+ unsigned int count;
+ int do_wakeup;
+ char outbuf[N_OUTBUF] __ALIGNED__;
+ int n_outbuf;
+ uint32_t vtermno;
+ int irq_requested;
+ int irq;
+ struct list_head next;
+ struct kobject kobj; /* ref count & hvc_struct lifetime */
+ struct vio_dev *vdev;
+};
+
+/* dynamic list of hvc_struct instances */
+static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
+
+/*
+ * Protect the list of hvc_struct instances from inserts and removals during
+ * list traversal.
+ */
+static DEFINE_SPINLOCK(hvc_structs_lock);
+
+/*
+ * 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 uint32_t vtermnos[MAX_NR_HVC_CONSOLES];
+
+/* Used for accounting purposes */
+static int num_vterms = 0;
+
+static struct task_struct *hvc_task;
+
+/*
+ * This value is used to associate a tty->index value to a hvc_struct based
+ * upon order of exposure via hvc_probe().
+ */
+static int hvc_count = -1;
+
+/* Picks up late kicks after list walk but before schedule() */
+static int hvc_kicked;
+
+/* Wake the sleeping khvcd */
+static void hvc_kick(void)
+{
+ hvc_kicked = 1;
+ wake_up_process(hvc_task);
+}
+
+/*
+ * NOTE: This API isn't used if the console adapter doesn't support interrupts.
+ * In this case the console is poll driven.
+ */
+static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
+{
+ hvc_kick();
+ return IRQ_HANDLED;
+}
+
+static void hvc_unthrottle(struct tty_struct *tty)
+{
+ hvc_kick();
+}
+
+/*
+ * Do not call this function with either the hvc_strucst_lock or the hvc_struct
+ * lock held. If successful, this function increments the kobject reference
+ * count against the target hvc_struct so it should be released when finished.
+ */
+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) {
+ kobject_get(&hp->kobj);
+ 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;
+}
+
+/*
+ * 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 irq = NO_IRQ;
+ int rc = 0;
+ struct kobject *kobjp;
+
+ /* Auto increments kobject reference if found. */
+ if (!(hp = hvc_get_by_index(tty->index))) {
+ printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
+ return -ENODEV;
+ }
+
+ spin_lock_irqsave(&hp->lock, flags);
+ /* Check and then increment for fast path open. */
+ if (hp->count++ > 0) {
+ spin_unlock_irqrestore(&hp->lock, flags);
+ hvc_kick();
+ return 0;
+ } /* else count == 0 */
+
+ tty->driver_data = hp;
+ hp->tty = tty;
+ /* Save for request_irq outside of spin_lock. */
+ irq = hp->irq;
+ if (irq != NO_IRQ)
+ hp->irq_requested = 1;
+
+ kobjp = &hp->kobj;
+
+ spin_unlock_irqrestore(&hp->lock, flags);
+ /* check error, fallback to non-irq */
+ if (irq != NO_IRQ)
+ rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
+
+ /*
+ * If the request_irq() fails and 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 kobject reference.
+ */
+ if (rc) {
+ spin_lock_irqsave(&hp->lock, flags);
+ hp->tty = NULL;
+ hp->irq_requested = 0;
+ spin_unlock_irqrestore(&hp->lock, flags);
+ tty->driver_data = NULL;
+ kobject_put(kobjp);
+ 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;
+ struct kobject *kobjp;
+ int irq = NO_IRQ;
+ 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 kobject reference wasn't made.
+ */
+ if (!tty->driver_data)
+ return;
+
+ hp = tty->driver_data;
+ spin_lock_irqsave(&hp->lock, flags);
+
+ kobjp = &hp->kobj;
+ if (--hp->count == 0) {
+ if (hp->irq_requested)
+ irq = hp->irq;
+ hp->irq_requested = 0;
+
+ /* We are done with the tty pointer now. */
+ hp->tty = NULL;
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ /*
+ * 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);
+
+ if (irq != NO_IRQ)
+ free_irq(irq, hp);
+
+ } 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);
+ }
+
+ kobject_put(kobjp);
+}
+
+static void hvc_hangup(struct tty_struct *tty)
+{
+ struct hvc_struct *hp = tty->driver_data;
+ unsigned long flags;
+ int irq = NO_IRQ;
+ int temp_open_count;
+ struct kobject *kobjp;
+
+ if (!hp)
+ return;
+
+ 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;
+ }
+
+ kobjp = &hp->kobj;
+ temp_open_count = hp->count;
+ hp->count = 0;
+ hp->n_outbuf = 0;
+ hp->tty = NULL;
+ if (hp->irq_requested)
+ /* Saved for use outside of spin_lock. */
+ irq = hp->irq;
+ hp->irq_requested = 0;
+ spin_unlock_irqrestore(&hp->lock, flags);
+ if (irq != NO_IRQ)
+ free_irq(irq, hp);
+ while(temp_open_count) {
+ --temp_open_count;
+ kobject_put(kobjp);
+ }
+}
+
+/*
+ * Push buffered characters whether they were just recently buffered or waiting
+ * on a blocked hypervisor. Call this function with hp->lock held.
+ */
+static void hvc_push(struct hvc_struct *hp)
+{
+ int n;
+
+ n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
+ if (n <= 0) {
+ if (n == 0)
+ return;
+ /* 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;
+}
+
+static inline int __hvc_write_kernel(struct hvc_struct *hp,
+ const unsigned char *buf, int count)
+{
+ unsigned long flags;
+ int rsize, written = 0;
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ /* Push pending writes */
+ if (hp->n_outbuf > 0)
+ hvc_push(hp);
+
+ while (count > 0 && (rsize = N_OUTBUF - 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);
+
+ return written;
+}
+static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
+{
+ struct hvc_struct *hp = tty->driver_data;
+ int written;
+
+ /* This write was probably executed during a tty close. */
+ if (!hp)
+ return -EPIPE;
+
+ if (hp->count <= 0)
+ return -EIO;
+
+ written = __hvc_write_kernel(hp, buf, count);
+
+ /*
+ * Racy, but harmless, kick thread if there is still pending data.
+ * There really is nothing wrong with kicking the thread, even if there
+ * is no buffered data.
+ */
+ if (hp->n_outbuf)
+ hvc_kick();
+
+ return written;
+}
+
+/*
+ * This is actually a contract between the driver and the tty layer outlining
+ * how much write room the driver can guarentee 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 N_OUTBUF - hp->n_outbuf;
+}
+
+static int hvc_chars_in_buffer(struct tty_struct *tty)
+{
+ struct hvc_struct *hp = tty->driver_data;
+
+ if (!hp)
+ return -1;
+ return hp->n_outbuf;
+}
+
+#define HVC_POLL_READ 0x00000001
+#define HVC_POLL_WRITE 0x00000002
+#define HVC_POLL_QUICK 0x00000004
+
+static 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;
+
+ spin_lock_irqsave(&hp->lock, flags);
+
+ /* Push pending writes */
+ if (hp->n_outbuf > 0)
+ hvc_push(hp);
+ /* Reschedule us if still some write pending */
+ if (hp->n_outbuf > 0)
+ poll_mask |= HVC_POLL_WRITE;
+
+ /* No tty attached, just skip */
+ tty = 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 interrupt driven and aren't throttled, we always
+ * request a reschedule
+ */
+ if (hp->irq == NO_IRQ)
+ poll_mask |= HVC_POLL_READ;
+
+ /* Read data if any */
+ for (;;) {
+ int count = N_INBUF;
+ if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
+ count = TTY_FLIPBUF_SIZE - tty->flip.count;
+
+ /* If flip is full, just reschedule a later read */
+ if (count == 0) {
+ poll_mask |= HVC_POLL_READ;
+ break;
+ }
+
+ n = hvc_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);
+ }
+ break;
+ }
+ for (i = 0; i < n; ++i) {
+#ifdef CONFIG_MAGIC_SYSRQ
+ /* Handle the SysRq Hack */
+ if (buf[i] == '\x0f') { /* ^O -- should support a sequence */
+ sysrq_pressed = 1;
+ continue;
+ } else if (sysrq_pressed) {
+ handle_sysrq(buf[i], NULL, tty);
+ sysrq_pressed = 0;
+ continue;
+ }
+#endif /* CONFIG_MAGIC_SYSRQ */
+ tty_insert_flip_char(tty, buf[i], 0);
+ }
+
+ if (tty->flip.count)
+ tty_schedule_flip(tty);
+
+ /*
+ * Account for the total amount read in one loop, and if above
+ * 64 bytes, we do a quick schedule loop to let the tty grok the
+ * data and eventually throttle us.
+ */
+ read_total += n;
+ if (read_total >= 64) {
+ poll_mask |= HVC_POLL_QUICK;
+ break;
+ }
+ }
+ throttled:
+ /* Wakeup write queue if necessary */
+ if (hp->do_wakeup) {
+ hp->do_wakeup = 0;
+ tty_wakeup(tty);
+ }
+ bail:
+ spin_unlock_irqrestore(&hp->lock, flags);
+
+ return poll_mask;
+}
+
+#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
+extern cpumask_t cpus_in_xmon;
+#else
+static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
+#endif
+
+/*
+ * This kthread is either polling or interrupt driven. This is determined by
+ * calling hvc_poll() who determines whether a console adapter support
+ * interrupts.
+ */
+int khvcd(void *unused)
+{
+ int poll_mask;
+ struct hvc_struct *hp;
+
+ __set_current_state(TASK_RUNNING);
+ do {
+ poll_mask = 0;
+ hvc_kicked = 0;
+ wmb();
+ if (cpus_empty(cpus_in_xmon)) {
+ spin_lock(&hvc_structs_lock);
+ list_for_each_entry(hp, &hvc_structs, next) {
+ /*hp = list_entry(node, struct hvc_struct, * next); */
+ poll_mask |= hvc_poll(hp);
+ }
+ spin_unlock(&hvc_structs_lock);
+ } else
+ poll_mask |= HVC_POLL_READ;
+ if (hvc_kicked)
+ continue;
+ if (poll_mask & HVC_POLL_QUICK) {
+ yield();
+ continue;
+ }
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!hvc_kicked) {
+ if (poll_mask == 0)
+ schedule();
+ else
+ msleep_interruptible(TIMEOUT);
+ }
+ __set_current_state(TASK_RUNNING);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+static 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,
+};
+
+char hvc_driver_name[] = "hvc_console";
+
+static struct vio_device_id hvc_driver_table[] __devinitdata= {
+ {"serial", "hvterm1"},
+ { NULL, }
+};
+MODULE_DEVICE_TABLE(vio, hvc_driver_table);
+
+/* callback when the kboject ref count reaches zero. */
+static void destroy_hvc_struct(struct kobject *kobj)
+{
+ struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
+ 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 struct kobj_type hvc_kobj_type = {
+ .release = destroy_hvc_struct,
+};
+
+static int __devinit hvc_probe(
+ struct vio_dev *dev,
+ const struct vio_device_id *id)
+{
+ struct hvc_struct *hp;
+
+ /* probed with invalid parameters. */
+ if (!dev || !id)
+ return -EPERM;
+
+ hp = kmalloc(sizeof(*hp), GFP_KERNEL);
+ if (!hp)
+ return -ENOMEM;
+
+ memset(hp, 0x00, sizeof(*hp));
+ hp->vtermno = dev->unit_address;
+ hp->vdev = dev;
+ hp->vdev->dev.driver_data = hp;
+ hp->irq = dev->irq;
+
+ kobject_init(&hp->kobj);
+ hp->kobj.ktype = &hvc_kobj_type;
+
+ spin_lock_init(&hp->lock);
+ spin_lock(&hvc_structs_lock);
+ hp->index = ++hvc_count;
+ list_add_tail(&(hp->next), &hvc_structs);
+ spin_unlock(&hvc_structs_lock);
+
+ return 0;
+}
+
+static int __devexit hvc_remove(struct vio_dev *dev)
+{
+ struct hvc_struct *hp = dev->dev.driver_data;
+ unsigned long flags;
+ struct kobject *kobjp;
+ struct tty_struct *tty;
+
+ spin_lock_irqsave(&hp->lock, flags);
+ tty = hp->tty;
+ kobjp = &hp->kobj;
+
+ 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 kobject instance
+ * was intialized using kobject_init(). Let the last holder of this
+ * kobject cause it to be removed, which will probably be the tty_hangup
+ * below.
+ */
+ kobject_put(kobjp);
+
+ /*
+ * This function call will auto chain call hvc_hangup. The tty should
+ * always be valid at this time unless a simultaneous tty close already
+ * cleaned up the hvc_struct.
+ */
+ if (tty)
+ tty_hangup(tty);
+ return 0;
+}
+
+static struct vio_driver hvc_vio_driver = {
+ .name = hvc_driver_name,
+ .id_table = hvc_driver_table,
+ .probe = hvc_probe,
+ .remove = hvc_remove,
+};
+
+/* Driver initialization. Follow console initialization. This is where the TTY
+ * interfaces start to become available. */
+int __init hvc_init(void)
+{
+ int rc;
+
+ /* We need more than num_vterms adapters due to hotplug additions. */
+ hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
+ /* hvc_driver = alloc_tty_driver(num_vterms); */
+ if (!hvc_driver)
+ return -ENOMEM;
+
+ hvc_driver->owner = THIS_MODULE;
+ hvc_driver->devfs_name = "hvc/";
+ hvc_driver->driver_name = "hvc";
+ hvc_driver->name = "hvc";
+ hvc_driver->major = HVC_MAJOR;
+ hvc_driver->minor_start = HVC_MINOR;
+ hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
+ hvc_driver->init_termios = tty_std_termios;
+ hvc_driver->flags = TTY_DRIVER_REAL_RAW;
+ tty_set_operations(hvc_driver, &hvc_ops);
+
+ if (tty_register_driver(hvc_driver))
+ panic("Couldn't register hvc console driver\n");
+
+ /* 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)) {
+ panic("Couldn't create kthread for console.\n");
+ put_tty_driver(hvc_driver);
+ return -EIO;
+ }
+
+ /* Register as a vio device to receive callbacks */
+ rc = vio_register_driver(&hvc_vio_driver);
+
+ return rc;
+}
+
+/* This isn't particularily necessary due to this being a console driver but it
+ * is nice to be thorough */
+static void __exit hvc_exit(void)
+{
+ kthread_stop(hvc_task);
+
+ vio_unregister_driver(&hvc_vio_driver);
+ tty_unregister_driver(hvc_driver);
+ /* return tty_struct instances allocated in hvc_init(). */
+ put_tty_driver(hvc_driver);
+}
+
+/*
+ * Console APIs, NOT TTY. These APIs are available immediately when
+ * hvc_console_setup() finds adapters.
+ */
+
+/*
+ * 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 the appear after early console init.
+ */
+int hvc_instantiate(uint32_t vtermno, int index)
+{
+ if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
+ return -1;
+
+ if (vtermnos[index] != -1)
+ return -1;
+
+ vtermnos[index] = vtermno;
+ return 0;
+}
+
+void hvc_console_print(struct console *co, const char *b, unsigned count)
+{
+ char c[16] __ALIGNED__;
+ unsigned i = 0, n = 0;
+ int r, donecr = 0;
+
+ /* Console access attempt outside of acceptable console range. */
+ if (co->index >= MAX_NR_HVC_CONSOLES)
+ return;
+
+ /* This console adapter was removed so it is not useable. */
+ if (vtermnos[co->index] < 0)
+ 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 = hvc_put_chars(vtermnos[co->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)
+{
+ *index = c->index;
+ return hvc_driver;
+}
+
+static int __init hvc_console_setup(struct console *co, char *options)
+{
+ return 0;
+}
+
+struct console hvc_con_driver = {
+ .name = "hvc",
+ .write = hvc_console_print,
+ .device = hvc_console_device,
+ .setup = hvc_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
+/* Early console initialization. Preceeds driver initialization. */
+static int __init hvc_console_init(void)
+{
+ int i;
+
+ for (i=0; i<MAX_NR_HVC_CONSOLES; i++)
+ vtermnos[i] = -1;
+ num_vterms = hvc_find_vtys();
+ register_console(&hvc_con_driver);
+ return 0;
+}
+console_initcall(hvc_console_init);
+
+module_init(hvc_init);
+module_exit(hvc_exit);