diff options
author | Christian Borntraeger <borntraeger@de.ibm.com> | 2008-06-20 13:24:08 (GMT) |
---|---|---|
committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-07-25 02:06:06 (GMT) |
commit | 611e097d7707741a336a0677d9d69bec40f29f3d (patch) | |
tree | 0b0059544914bf027ada51a1ba90f694c54df835 /drivers/char/hvc_console.c | |
parent | 066f4d82a67f621ddd547bfa4b9c94631d8457b0 (diff) | |
download | linux-fsl-qoriq-611e097d7707741a336a0677d9d69bec40f29f3d.tar.xz |
hvc_console: rework setup to replace irq functions with callbacks
This patch tries to change hvc_console to not use request_irq/free_irq if
the backend does not use irqs. This allows virtio_console to use hvc_console
without having a linker reference to request_irq/free_irq.
In addition, together with patch 2/3 it improves the performance for virtio
console input. (an earlier version of this patch was tested by Yajin on lguest)
The irq specific code is moved to hvc_irq.c and selected by the drivers that
use irqs (System p, System i, XEN).
I replaced "int irq" with the opaque "int data". The request_irq and
free_irq calls are replaced with notifier_add and notifier_del. I have also
changed the code a bit to call the notifier_add and notifier_del inside the
spinlock area as the callbacks are found via hp->ops.
Changes since last version:
o remove ifdef
o reintroduce "irq_requested" as "notified"
o cleanups, sparse..
I did not move the timer based polling into a separate polling scheme. I
played with several variants, but it seems we need to sleep/schedule in
a thread even for irq based consoles, as there are throttleing and buffer
size constraints.
I also kept hvc_struct defined in hvc_console.h so that hvc_irq.c can access
the irq_requested element.
Feedback is appreciated. virtio_console is currently the only available console
for kvm on s390. I plan to push this change as soon as all affected parties
agree on it. I would love to get test results from System p, Xen etc.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/char/hvc_console.c')
-rw-r--r-- | drivers/char/hvc_console.c | 81 |
1 files changed, 18 insertions, 63 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index 2f9759d..2f5b7fb 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -27,7 +27,6 @@ #include <linux/init.h> #include <linux/kbd_kern.h> #include <linux/kernel.h> -#include <linux/kref.h> #include <linux/kthread.h> #include <linux/list.h> #include <linux/module.h> @@ -75,23 +74,6 @@ static int hvc_init(void); static int sysrq_pressed; #endif -struct hvc_struct { - spinlock_t lock; - int index; - struct tty_struct *tty; - unsigned int count; - int do_wakeup; - 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 kref kref; /* ref count & hvc_struct lifetime */ -}; - /* dynamic list of hvc_struct instances */ static LIST_HEAD(hvc_structs); @@ -300,26 +282,12 @@ int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops) } /* Wake the sleeping khvcd */ -static void hvc_kick(void) +void hvc_kick(void) { hvc_kicked = 1; wake_up_process(hvc_task); } -static int hvc_poll(struct hvc_struct *hp); - -/* - * 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) -{ - /* if hvc_poll request a repoll, then kick the hvcd thread */ - if (hvc_poll(dev_instance)) - hvc_kick(); - return IRQ_HANDLED; -} - static void hvc_unthrottle(struct tty_struct *tty) { hvc_kick(); @@ -333,7 +301,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) { struct hvc_struct *hp; unsigned long flags; - int irq = 0; int rc = 0; /* Auto increments kref reference if found. */ @@ -352,18 +319,15 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ hp->tty = tty; - /* Save for request_irq outside of spin_lock. */ - irq = hp->irq; - if (irq) - hp->irq_requested = 1; + + if (hp->ops->notifier_add) + rc = hp->ops->notifier_add(hp, hp->data); spin_unlock_irqrestore(&hp->lock, flags); - /* check error, fallback to non-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 + * 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. @@ -371,7 +335,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) 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; kref_put(&hp->kref, destroy_hvc_struct); @@ -386,7 +349,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) static void hvc_close(struct tty_struct *tty, struct file * filp) { struct hvc_struct *hp; - int irq = 0; unsigned long flags; if (tty_hung_up_p(filp)) @@ -404,9 +366,8 @@ static void hvc_close(struct tty_struct *tty, struct file * filp) spin_lock_irqsave(&hp->lock, flags); if (--hp->count == 0) { - if (hp->irq_requested) - irq = hp->irq; - hp->irq_requested = 0; + if (hp->ops->notifier_del) + hp->ops->notifier_del(hp, hp->data); /* We are done with the tty pointer now. */ hp->tty = NULL; @@ -418,10 +379,6 @@ static void hvc_close(struct tty_struct *tty, struct file * filp) * waking periodically to check chars_in_buffer(). */ tty_wait_until_sent(tty, HVC_CLOSE_WAIT); - - if (irq) - free_irq(irq, hp); - } else { if (hp->count < 0) printk(KERN_ERR "hvc_close %X: oops, count is %d\n", @@ -436,7 +393,6 @@ static void hvc_hangup(struct tty_struct *tty) { struct hvc_struct *hp = tty->driver_data; unsigned long flags; - int irq = 0; int temp_open_count; if (!hp) @@ -458,13 +414,12 @@ static void hvc_hangup(struct tty_struct *tty) 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; + + if (hp->ops->notifier_del) + hp->ops->notifier_del(hp, hp->data); + spin_unlock_irqrestore(&hp->lock, flags); - if (irq) - free_irq(irq, hp); + while(temp_open_count) { --temp_open_count; kref_put(&hp->kref, destroy_hvc_struct); @@ -575,7 +530,7 @@ static u32 timeout = MIN_TIMEOUT; #define HVC_POLL_READ 0x00000001 #define HVC_POLL_WRITE 0x00000002 -static int hvc_poll(struct hvc_struct *hp) +int hvc_poll(struct hvc_struct *hp) { struct tty_struct *tty; int i, n, poll_mask = 0; @@ -602,10 +557,10 @@ static int hvc_poll(struct hvc_struct *hp) if (test_bit(TTY_THROTTLED, &tty->flags)) goto throttled; - /* If we aren't interrupt driven and aren't throttled, we always + /* If we aren't notifier driven and aren't throttled, we always * request a reschedule */ - if (hp->irq == 0) + if (!hp->irq_requested) poll_mask |= HVC_POLL_READ; /* Read data if any */ @@ -733,7 +688,7 @@ static const struct tty_operations hvc_ops = { .chars_in_buffer = hvc_chars_in_buffer, }; -struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, +struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data, struct hv_ops *ops, int outbuf_size) { struct hvc_struct *hp; @@ -754,7 +709,7 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, memset(hp, 0x00, sizeof(*hp)); hp->vtermno = vtermno; - hp->irq = irq; + hp->data = data; hp->ops = ops; hp->outbuf_size = outbuf_size; hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; |