#include <linux/init.h>
#include <linux/kbd_kern.h>
#include <linux/kernel.h>
-#include <linux/kobject.h>
+#include <linux/kref.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
+#include <linux/freezer.h>
#include <asm/uaccess.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.
/* 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
struct tty_struct *tty;
unsigned int count;
int do_wakeup;
- char outbuf[N_OUTBUF] __ALIGNED__;
+ char *outbuf;
+ int outbuf_size;
int n_outbuf;
uint32_t vtermno;
struct hv_ops *ops;
int irq_requested;
int irq;
struct list_head next;
- struct kobject kobj; /* ref count & hvc_struct lifetime */
+ struct kref kref; /* ref count & hvc_struct lifetime */
};
/* dynamic list of hvc_struct instances */
-static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
+static LIST_HEAD(hvc_structs);
/*
* Protect the list of hvc_struct instances from inserts and removals during
/*
* 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 canidate registered with hvc_instantiate().
+ * a console candidate registered with hvc_instantiate().
*/
static int last_hvc = -1;
/*
- * 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
+ * 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.
*/
-struct hvc_struct *hvc_get_by_index(int index)
+static struct hvc_struct *hvc_get_by_index(int index)
{
struct hvc_struct *hp;
unsigned long flags;
list_for_each_entry(hp, &hvc_structs, next) {
spin_lock_irqsave(&hp->lock, flags);
if (hp->index == index) {
- kobject_get(&hp->kobj);
+ kref_get(&hp->kref);
spin_unlock_irqrestore(&hp->lock, flags);
spin_unlock(&hvc_structs_lock);
return hp;
* hvc_console_setup() finds adapters.
*/
-void hvc_console_print(struct console *co, const char *b, unsigned count)
+static void hvc_console_print(struct console *co, const char *b,
+ unsigned count)
{
char c[N_OUTBUF] __ALIGNED__;
unsigned i = 0, n = 0;
if (index >= MAX_NR_HVC_CONSOLES)
return;
- /* This console adapter was removed so it is not useable. */
+ /* This console adapter was removed so it is not usable. */
if (vtermnos[index] < 0)
return;
return 0;
}
-struct console hvc_con_driver = {
+static struct console hvc_con_driver = {
.name = "hvc",
.write = hvc_console_print,
.device = hvc_console_device,
};
/*
- * Early console initialization. Preceeds driver initialization.
+ * Early console initialization. Precedes driver initialization.
*
* (1) we are first, and the user specified another driver
* -- index will remain -1
}
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
if (vtermnos[index] != -1)
return -1;
- /* make sure no no tty has been registerd in this index */
+ /* make sure no no tty has been registered in this index */
hp = hvc_get_by_index(index);
if (hp) {
- kobject_put(&hp->kobj);
+ kref_put(&hp->kref, destroy_hvc_struct);
return -1;
}
vtermnos[index] = vtermno;
cons_ops[index] = ops;
- /* reserve all indices upto and including this index */
+ /* reserve all indices up to and including this index */
if (last_hvc < index)
last_hvc = index;
return 0;
}
-EXPORT_SYMBOL(hvc_instantiate);
/* Wake the sleeping khvcd */
static void hvc_kick(void)
* 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)
+static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
{
/* if hvc_poll request a repoll, then kick the hvcd thread */
if (hvc_poll(dev_instance))
{
struct hvc_struct *hp;
unsigned long flags;
- int irq = NO_IRQ;
+ int irq = 0;
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");
+ /* 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. */
hp->tty = tty;
/* Save for request_irq outside of spin_lock. */
irq = hp->irq;
- if (irq != NO_IRQ)
+ if (irq)
hp->irq_requested = 1;
- kobjp = &hp->kobj;
-
spin_unlock_irqrestore(&hp->lock, flags);
/* check error, fallback to non-irq */
- if (irq != NO_IRQ)
+ if (irq)
rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "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.
+ * tty fields and return the kref reference.
*/
if (rc) {
spin_lock_irqsave(&hp->lock, flags);
hp->irq_requested = 0;
spin_unlock_irqrestore(&hp->lock, flags);
tty->driver_data = NULL;
- kobject_put(kobjp);
+ 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 */
static void hvc_close(struct tty_struct *tty, struct file * filp)
{
struct hvc_struct *hp;
- struct kobject *kobjp;
- int irq = NO_IRQ;
+ int irq = 0;
unsigned long flags;
if (tty_hung_up_p(filp))
/*
* 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.
+ * exit cleanly because the kref 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;
*/
tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
- if (irq != NO_IRQ)
+ if (irq)
free_irq(irq, hp);
} else {
spin_unlock_irqrestore(&hp->lock, flags);
}
- kobject_put(kobjp);
+ 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 irq = NO_IRQ;
+ int irq = 0;
int temp_open_count;
- struct kobject *kobjp;
if (!hp)
return;
return;
}
- kobjp = &hp->kobj;
temp_open_count = hp->count;
hp->count = 0;
hp->n_outbuf = 0;
irq = hp->irq;
hp->irq_requested = 0;
spin_unlock_irqrestore(&hp->lock, flags);
- if (irq != NO_IRQ)
+ if (irq)
free_irq(irq, hp);
while(temp_open_count) {
--temp_open_count;
- kobject_put(kobjp);
+ kref_put(&hp->kref, destroy_hvc_struct);
}
}
if (hp->n_outbuf > 0)
hvc_push(hp);
- while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
+ while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
if (rsize > count)
rsize = count;
memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
/*
* 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
+ * 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)
if (!hp)
return -1;
- return N_OUTBUF - hp->n_outbuf;
+ return hp->outbuf_size - hp->n_outbuf;
}
static int hvc_chars_in_buffer(struct tty_struct *tty)
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
/* If we aren't interrupt driven and aren't throttled, we always
* request a reschedule
*/
- if (hp->irq == NO_IRQ)
+ if (hp->irq == 0)
poll_mask |= HVC_POLL_READ;
/* Read data if any */
sysrq_pressed = 1;
continue;
} else if (sysrq_pressed) {
- handle_sysrq(buf[i], NULL, tty);
+ handle_sysrq(buf[i], tty);
sysrq_pressed = 0;
continue;
}
bail:
spin_unlock_irqrestore(&hp->lock, flags);
- if (read_total)
+ 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);
-
+ }
+
return poll_mask;
}
* calling hvc_poll() who determines whether a console adapter support
* interrupts.
*/
-int khvcd(void *unused)
+static int khvcd(void *unused)
{
int poll_mask;
struct hvc_struct *hp;
+ set_freezable();
__set_current_state(TASK_RUNNING);
do {
poll_mask = 0;
hvc_kicked = 0;
+ try_to_freeze();
wmb();
if (cpus_empty(cpus_in_xmon)) {
spin_lock(&hvc_structs_lock);
if (!hvc_kicked) {
if (poll_mask == 0)
schedule();
- else
- msleep_interruptible(TIMEOUT);
+ else {
+ if (timeout < MAX_TIMEOUT)
+ timeout += (timeout >> 6) + 1;
+
+ msleep_interruptible(timeout);
+ }
}
__set_current_state(TASK_RUNNING);
} while (!kthread_should_stop());
return 0;
}
-static struct tty_operations hvc_ops = {
+static const struct tty_operations hvc_ops = {
.open = hvc_open,
.close = hvc_close,
.write = hvc_write,
.chars_in_buffer = hvc_chars_in_buffer,
};
-/* 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,
-};
-
struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
- struct hv_ops *ops)
+ struct hv_ops *ops, int outbuf_size)
{
struct hvc_struct *hp;
int i;
- hp = kmalloc(sizeof(*hp), GFP_KERNEL);
+ /* We wait until a driver actually comes along */
+ if (!hvc_driver) {
+ int err = hvc_init();
+ if (err)
+ return ERR_PTR(err);
+ }
+
+ hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
+ GFP_KERNEL);
if (!hp)
return ERR_PTR(-ENOMEM);
hp->vtermno = vtermno;
hp->irq = irq;
hp->ops = ops;
+ hp->outbuf_size = outbuf_size;
+ hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
- kobject_init(&hp->kobj);
- hp->kobj.ktype = &hvc_kobj_type;
+ kref_init(&hp->kref);
spin_lock_init(&hp->lock);
spin_lock(&hvc_structs_lock);
return hp;
}
-EXPORT_SYMBOL(hvc_alloc);
int __devexit hvc_remove(struct hvc_struct *hp)
{
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;
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
+ * 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_hangup
* below.
*/
- kobject_put(kobjp);
+ kref_put(&hp->kref, destroy_hvc_struct);
/*
* This function call will auto chain call hvc_hangup. The tty should
tty_hangup(tty);
return 0;
}
-EXPORT_SYMBOL(hvc_remove);
-/* Driver initialization. Follow console initialization. This is where the TTY
- * interfaces start to become available. */
-int __init hvc_init(void)
+/* 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)
- return -ENOMEM;
+ if (!drv) {
+ err = -ENOMEM;
+ goto out;
+ }
drv->owner = THIS_MODULE;
drv->driver_name = "hvc";
* 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(drv);
- return -EIO;
+ printk(KERN_ERR "Couldn't create kthread for console.\n");
+ err = PTR_ERR(hvc_task);
+ goto put_tty;
}
- if (tty_register_driver(drv))
- panic("Couldn't register hvc console driver\n");
+ err = tty_register_driver(drv);
+ if (err) {
+ printk(KERN_ERR "Couldn't register hvc console driver\n");
+ goto stop_thread;
+ }
+ /* FIXME: This mb() seems completely random. Remove it. */
mb();
hvc_driver = drv;
return 0;
+
+put_tty:
+ put_tty_driver(hvc_driver);
+stop_thread:
+ kthread_stop(hvc_task);
+ hvc_task = NULL;
+out:
+ return err;
}
-module_init(hvc_init);
-/* This isn't particularily necessary due to this being a console driver
+/* 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)
{
- kthread_stop(hvc_task);
+ 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_con_driver);
+ tty_unregister_driver(hvc_driver);
+ /* return tty_struct instances allocated in hvc_init(). */
+ put_tty_driver(hvc_driver);
+ unregister_console(&hvc_con_driver);
+ }
}
module_exit(hvc_exit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff