mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Timur Tabi](/assets/img/avatar_default.png)
hvc_instantiate() and hvc_alloc() return errors if they fail, so don't ignore them. Signed-off-by: Timur Tabi <timur@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
96 lines
2 KiB
C
96 lines
2 KiB
C
/* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 and
|
|
* only version 2 as published by the Free Software Foundation.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
|
|
#include <asm/dcc.h>
|
|
#include <asm/processor.h>
|
|
|
|
#include "hvc_console.h"
|
|
|
|
/* DCC Status Bits */
|
|
#define DCC_STATUS_RX (1 << 30)
|
|
#define DCC_STATUS_TX (1 << 29)
|
|
|
|
static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++) {
|
|
while (__dcc_getstatus() & DCC_STATUS_TX)
|
|
cpu_relax();
|
|
|
|
__dcc_putchar(buf[i]);
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; ++i)
|
|
if (__dcc_getstatus() & DCC_STATUS_RX)
|
|
buf[i] = __dcc_getchar();
|
|
else
|
|
break;
|
|
|
|
return i;
|
|
}
|
|
|
|
static bool hvc_dcc_check(void)
|
|
{
|
|
unsigned long time = jiffies + (HZ / 10);
|
|
|
|
/* Write a test character to check if it is handled */
|
|
__dcc_putchar('\n');
|
|
|
|
while (time_is_after_jiffies(time)) {
|
|
if (!(__dcc_getstatus() & DCC_STATUS_TX))
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static const struct hv_ops hvc_dcc_get_put_ops = {
|
|
.get_chars = hvc_dcc_get_chars,
|
|
.put_chars = hvc_dcc_put_chars,
|
|
};
|
|
|
|
static int __init hvc_dcc_console_init(void)
|
|
{
|
|
int ret;
|
|
|
|
if (!hvc_dcc_check())
|
|
return -ENODEV;
|
|
|
|
/* Returns -1 if error */
|
|
ret = hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
|
|
|
|
return ret < 0 ? -ENODEV : 0;
|
|
}
|
|
console_initcall(hvc_dcc_console_init);
|
|
|
|
static int __init hvc_dcc_init(void)
|
|
{
|
|
struct hvc_struct *p;
|
|
|
|
if (!hvc_dcc_check())
|
|
return -ENODEV;
|
|
|
|
p = hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
|
|
|
|
return PTR_ERR_OR_ZERO(p);
|
|
}
|
|
device_initcall(hvc_dcc_init);
|