android_kernel_xiaomi_sm8350/drivers/char/hvc_vio.c
Christian Borntraeger 611e097d77 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>
2008-07-25 12:06:06 +10:00

171 lines
4.1 KiB
C

/*
* vio driver interface to hvc_console.c
*
* This code was moved here to allow the remaing code to be reused as a
* generic polling mode with semi-reliable transport driver core to the
* console and tty subsystems.
*
*
* 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/types.h>
#include <linux/init.h>
#include <asm/hvconsole.h>
#include <asm/vio.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include "hvc_console.h"
char hvc_driver_name[] = "hvc_console";
static struct vio_device_id hvc_driver_table[] __devinitdata = {
{"serial", "hvterm1"},
{ "", "" }
};
MODULE_DEVICE_TABLE(vio, hvc_driver_table);
static int filtered_get_chars(uint32_t vtermno, char *buf, int count)
{
unsigned long got;
int i;
/*
* Vio firmware will read up to SIZE_VIO_GET_CHARS at its own discretion
* so we play safe and avoid the situation where got > count which could
* overload the flip buffer.
*/
if (count < SIZE_VIO_GET_CHARS)
return -EAGAIN;
got = hvc_get_chars(vtermno, buf, count);
/*
* Work around a HV bug where it gives us a null
* after every \r. -- paulus
*/
for (i = 1; i < got; ++i) {
if (buf[i] == 0 && buf[i-1] == '\r') {
--got;
if (i < got)
memmove(&buf[i], &buf[i+1],
got - i);
}
}
return got;
}
static struct hv_ops hvc_get_put_ops = {
.get_chars = filtered_get_chars,
.put_chars = hvc_put_chars,
.notifier_add = notifier_add_irq,
.notifier_del = notifier_del_irq,
};
static int __devinit hvc_vio_probe(struct vio_dev *vdev,
const struct vio_device_id *id)
{
struct hvc_struct *hp;
/* probed with invalid parameters. */
if (!vdev || !id)
return -EPERM;
hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops,
MAX_VIO_PUT_CHARS);
if (IS_ERR(hp))
return PTR_ERR(hp);
dev_set_drvdata(&vdev->dev, hp);
return 0;
}
static int __devexit hvc_vio_remove(struct vio_dev *vdev)
{
struct hvc_struct *hp = dev_get_drvdata(&vdev->dev);
return hvc_remove(hp);
}
static struct vio_driver hvc_vio_driver = {
.id_table = hvc_driver_table,
.probe = hvc_vio_probe,
.remove = hvc_vio_remove,
.driver = {
.name = hvc_driver_name,
.owner = THIS_MODULE,
}
};
static int hvc_vio_init(void)
{
int rc;
if (firmware_has_feature(FW_FEATURE_ISERIES))
return -EIO;
/* Register as a vio device to receive callbacks */
rc = vio_register_driver(&hvc_vio_driver);
return rc;
}
module_init(hvc_vio_init); /* after drivers/char/hvc_console.c */
static void hvc_vio_exit(void)
{
vio_unregister_driver(&hvc_vio_driver);
}
module_exit(hvc_vio_exit);
/* the device tree order defines our numbering */
static int hvc_find_vtys(void)
{
struct device_node *vty;
int num_found = 0;
for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL;
vty = of_find_node_by_name(vty, "vty")) {
const uint32_t *vtermno;
/* We have statically defined space for only a certain number
* of console adapters.
*/
if (num_found >= MAX_NR_HVC_CONSOLES)
break;
vtermno = of_get_property(vty, "reg", NULL);
if (!vtermno)
continue;
if (of_device_is_compatible(vty, "hvterm1")) {
hvc_instantiate(*vtermno, num_found, &hvc_get_put_ops);
++num_found;
}
}
return num_found;
}
console_initcall(hvc_find_vtys);