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authorChristian Borntraeger <borntraeger@de.ibm.com>2008-06-20 17:24:08 +0400
committerRusty Russell <rusty@rustcorp.com.au>2008-07-25 06:06:06 +0400
commit611e097d7707741a336a0677d9d69bec40f29f3d (patch)
tree0b0059544914bf027ada51a1ba90f694c54df835 /drivers/char/hvc_console.h
parent066f4d82a67f621ddd547bfa4b9c94631d8457b0 (diff)
downloadlinux-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.h')
-rw-r--r--drivers/char/hvc_console.h35
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/char/hvc_console.h b/drivers/char/hvc_console.h
index 42ffb17e15df..d9ce10915625 100644
--- a/drivers/char/hvc_console.h
+++ b/drivers/char/hvc_console.h
@@ -26,6 +26,7 @@
#ifndef HVC_CONSOLE_H
#define HVC_CONSOLE_H
+#include <linux/kref.h>
/*
* This is the max number of console adapters that can/will be found as
@@ -42,24 +43,50 @@
*/
#define HVC_ALLOC_TTY_ADAPTERS 8
+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 data;
+ struct list_head next;
+ struct kref kref; /* ref count & hvc_struct lifetime */
+};
/* implemented by a low level driver */
struct hv_ops {
int (*get_chars)(uint32_t vtermno, char *buf, int count);
int (*put_chars)(uint32_t vtermno, const char *buf, int count);
-};
-struct hvc_struct;
+ /* Callbacks for notification. Called in open and close */
+ int (*notifier_add)(struct hvc_struct *hp, int irq);
+ void (*notifier_del)(struct hvc_struct *hp, int irq);
+};
/* Register a vterm and a slot index for use as a console (console_init) */
extern int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops);
/* register a vterm for hvc tty operation (module_init or hotplug add) */
-extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int irq,
+extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int data,
struct hv_ops *ops, int outbuf_size);
-/* remove a vterm from hvc tty operation (modele_exit or hotplug remove) */
+/* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
extern int __devexit hvc_remove(struct hvc_struct *hp);
+/* data available */
+int hvc_poll(struct hvc_struct *hp);
+void hvc_kick(void);
+
+/* default notifier for irq based notification */
+extern int notifier_add_irq(struct hvc_struct *hp, int data);
+extern void notifier_del_irq(struct hvc_struct *hp, int data);
+
#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
#include <asm/xmon.h>