mirror of
https://github.com/torvalds/linux.git
synced 2024-10-30 08:42:47 +00:00
611e097d77
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>
101 lines
3.1 KiB
C
101 lines
3.1 KiB
C
/*
|
|
* hvc_console.h
|
|
* Copyright (C) 2005 IBM Corporation
|
|
*
|
|
* Author(s):
|
|
* Ryan S. Arnold <rsa@us.ibm.com>
|
|
*
|
|
* hvc_console header information:
|
|
* moved here from include/asm-powerpc/hvconsole.h
|
|
* and drivers/char/hvc_console.c
|
|
*
|
|
* 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
|
|
*/
|
|
|
|
#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
|
|
* console devices on first stage console init. Any number beyond this range
|
|
* can't be used as a console device but is still a valid tty device.
|
|
*/
|
|
#define MAX_NR_HVC_CONSOLES 16
|
|
|
|
/*
|
|
* 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
|
|
|
|
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);
|
|
|
|
/* 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 data,
|
|
struct hv_ops *ops, int outbuf_size);
|
|
/* 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>
|
|
#else
|
|
static inline int cpus_are_in_xmon(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#endif // HVC_CONSOLE_H
|