WSL2-Linux-Kernel/drivers/tty/hvc/hvc_rtas.c

111 строки
2.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* IBM RTAS driver interface to hvc_console.c
*
* (C) Copyright IBM Corporation 2001-2005
* (C) Copyright Red Hat, Inc. 2005
*
* Author(s): Maximino Augilar <IBM STI Design Center>
* : Ryan S. Arnold <rsa@us.ibm.com>
* : Utz Bacher <utz.bacher@de.ibm.com>
* : David Woodhouse <dwmw2@infradead.org>
*
* inspired by drivers/char/hvc_console.c
* written by Anton Blanchard and Paul Mackerras
*/
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <asm/irq.h>
#include <asm/rtas.h>
#include "hvc_console.h"
#define hvc_rtas_cookie 0x67781e15
struct hvc_struct *hvc_rtas_dev;
static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf,
int count)
{
int i;
for (i = 0; i < count; i++) {
if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
break;
}
return i;
}
static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count)
{
int i, c;
for (i = 0; i < count; i++) {
if (rtas_call(rtascons_get_char_token, 0, 2, &c))
break;
buf[i] = c;
}
return i;
}
static const struct hv_ops hvc_rtas_get_put_ops = {
.get_chars = hvc_rtas_read_console,
.put_chars = hvc_rtas_write_console,
};
static int __init hvc_rtas_init(void)
{
struct hvc_struct *hp;
if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
rtascons_put_char_token = rtas_token("put-term-char");
if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
return -EIO;
if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
rtascons_get_char_token = rtas_token("get-term-char");
if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
return -EIO;
BUG_ON(hvc_rtas_dev);
/* Allocate an hvc_struct for the console device we instantiated
* earlier. Save off hp so that we can return it on exit */
hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16);
if (IS_ERR(hp))
return PTR_ERR(hp);
hvc_rtas_dev = hp;
return 0;
}
device_initcall(hvc_rtas_init);
/* This will happen prior to module init. There is no tty at this time? */
static int __init hvc_rtas_console_init(void)
{
rtascons_put_char_token = rtas_token("put-term-char");
if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
return -EIO;
rtascons_get_char_token = rtas_token("get-term-char");
if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
return -EIO;
hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);
add_preferred_console("hvc", 0, NULL);
return 0;
}
console_initcall(hvc_rtas_console_init);