1 /* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved.
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 and
5 * only version 2 as published by the Free Software Foundation.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
13 #include <linux/init.h>
16 #include <asm/processor.h>
18 #include "hvc_console.h"
21 #define DCC_STATUS_RX (1 << 30)
22 #define DCC_STATUS_TX (1 << 29)
24 static int hvc_dcc_put_chars(uint32_t vt
, const char *buf
, int count
)
28 for (i
= 0; i
< count
; i
++) {
29 while (__dcc_getstatus() & DCC_STATUS_TX
)
32 __dcc_putchar(buf
[i
]);
38 static int hvc_dcc_get_chars(uint32_t vt
, char *buf
, int count
)
42 for (i
= 0; i
< count
; ++i
)
43 if (__dcc_getstatus() & DCC_STATUS_RX
)
44 buf
[i
] = __dcc_getchar();
51 static bool hvc_dcc_check(void)
53 unsigned long time
= jiffies
+ (HZ
/ 10);
55 /* Write a test character to check if it is handled */
58 while (time_is_after_jiffies(time
)) {
59 if (!(__dcc_getstatus() & DCC_STATUS_TX
))
66 static const struct hv_ops hvc_dcc_get_put_ops
= {
67 .get_chars
= hvc_dcc_get_chars
,
68 .put_chars
= hvc_dcc_put_chars
,
71 static int __init
hvc_dcc_console_init(void)
76 hvc_instantiate(0, 0, &hvc_dcc_get_put_ops
);
79 console_initcall(hvc_dcc_console_init
);
81 static int __init
hvc_dcc_init(void)
86 hvc_alloc(0, 0, &hvc_dcc_get_put_ops
, 128);
89 device_initcall(hvc_dcc_init
);