Linux Kernel  3.7.1
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hvc_beat.c
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1 /*
2  * Beat hypervisor console driver
3  *
4  * (C) Copyright 2006 TOSHIBA CORPORATION
5  *
6  * This code is based on drivers/char/hvc_rtas.c:
7  * (C) Copyright IBM Corporation 2001-2005
8  * (C) Copyright Red Hat, Inc. 2005
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License along
21  * with this program; if not, write to the Free Software Foundation, Inc.,
22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23  */
24 
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/err.h>
28 #include <linux/string.h>
29 #include <linux/console.h>
30 #include <asm/prom.h>
31 #include <asm/hvconsole.h>
32 #include <asm/firmware.h>
33 
34 #include "hvc_console.h"
35 
36 extern int64_t beat_get_term_char(uint64_t, uint64_t *, uint64_t *, uint64_t *);
38 
40 
41 /* bug: only one queue is available regardless of vtermno */
42 static int hvc_beat_get_chars(uint32_t vtermno, char *buf, int cnt)
43 {
44  static unsigned char q[sizeof(unsigned long) * 2]
45  __attribute__((aligned(sizeof(unsigned long))));
46  static int qlen = 0;
47  u64 got;
48 
49 again:
50  if (qlen) {
51  if (qlen > cnt) {
52  memcpy(buf, q, cnt);
53  qlen -= cnt;
54  memmove(q + cnt, q, qlen);
55  return cnt;
56  } else { /* qlen <= cnt */
57  int r;
58 
59  memcpy(buf, q, qlen);
60  r = qlen;
61  qlen = 0;
62  return r;
63  }
64  }
65  if (beat_get_term_char(vtermno, &got,
66  ((u64 *)q), ((u64 *)q) + 1) == 0) {
67  qlen = got;
68  goto again;
69  }
70  return 0;
71 }
72 
73 static int hvc_beat_put_chars(uint32_t vtermno, const char *buf, int cnt)
74 {
75  unsigned long kb[2];
76  int rest, nlen;
77 
78  for (rest = cnt; rest > 0; rest -= nlen) {
79  nlen = (rest > 16) ? 16 : rest;
80  memcpy(kb, buf, nlen);
81  beat_put_term_char(vtermno, nlen, kb[0], kb[1]);
82  buf += nlen;
83  }
84  return cnt;
85 }
86 
87 static const struct hv_ops hvc_beat_get_put_ops = {
88  .get_chars = hvc_beat_get_chars,
89  .put_chars = hvc_beat_put_chars,
90 };
91 
92 static int hvc_beat_useit = 1;
93 
94 static int hvc_beat_config(char *p)
95 {
96  hvc_beat_useit = simple_strtoul(p, NULL, 0);
97  return 0;
98 }
99 
100 static int __init hvc_beat_console_init(void)
101 {
102  if (hvc_beat_useit && of_machine_is_compatible("Beat")) {
103  hvc_instantiate(0, 0, &hvc_beat_get_put_ops);
104  }
105  return 0;
106 }
107 
108 /* temp */
109 static int __init hvc_beat_init(void)
110 {
111  struct hvc_struct *hp;
112 
113  if (!firmware_has_feature(FW_FEATURE_BEAT))
114  return -ENODEV;
115 
116  hp = hvc_alloc(0, 0, &hvc_beat_get_put_ops, 16);
117  if (IS_ERR(hp))
118  return PTR_ERR(hp);
119  hvc_beat_dev = hp;
120  return 0;
121 }
122 
123 static void __exit hvc_beat_exit(void)
124 {
125  if (hvc_beat_dev)
126  hvc_remove(hvc_beat_dev);
127 }
128 
129 module_init(hvc_beat_init);
130 module_exit(hvc_beat_exit);
131 
132 __setup("hvc_beat=", hvc_beat_config);
133 
134 console_initcall(hvc_beat_console_init);