blob: a9a94ae7234951f3b30b25829c67d1ee13a3a8f2 [file] [log] [blame]
Jason Wesself2d937f2008-04-17 20:05:37 +02001/*
2 * Based on the same principle as kgdboe using the NETPOLL api, this
3 * driver uses a console polling api to implement a gdb serial inteface
4 * which is multiplexed on a console port.
5 *
6 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
7 *
8 * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14#include <linux/kernel.h>
15#include <linux/ctype.h>
16#include <linux/kgdb.h>
Jason Wesselada64e42010-05-20 21:04:24 -050017#include <linux/kdb.h>
Jason Wesself2d937f2008-04-17 20:05:37 +020018#include <linux/tty.h>
Jason Wesselefe2f292010-05-20 21:04:26 -050019#include <linux/console.h>
Jason Wesself2d937f2008-04-17 20:05:37 +020020
21#define MAX_CONFIG_LEN 40
22
23static struct kgdb_io kgdboc_io_ops;
24
25/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
26static int configured = -1;
27
28static char config[MAX_CONFIG_LEN];
29static struct kparam_string kps = {
30 .string = config,
31 .maxlen = MAX_CONFIG_LEN,
32};
33
34static struct tty_driver *kgdb_tty_driver;
35static int kgdb_tty_line;
36
Jason Wesselada64e42010-05-20 21:04:24 -050037#ifdef CONFIG_KDB_KEYBOARD
38static int kgdboc_register_kbd(char **cptr)
39{
40 if (strncmp(*cptr, "kbd", 3) == 0) {
41 if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
42 kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
43 kdb_poll_idx++;
44 if (cptr[0][3] == ',')
45 *cptr += 4;
46 else
47 return 1;
48 }
49 }
50 return 0;
51}
52
53static void kgdboc_unregister_kbd(void)
54{
55 int i;
56
57 for (i = 0; i < kdb_poll_idx; i++) {
58 if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
59 kdb_poll_idx--;
60 kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
61 kdb_poll_funcs[kdb_poll_idx] = NULL;
62 i--;
63 }
64 }
65}
66#else /* ! CONFIG_KDB_KEYBOARD */
67#define kgdboc_register_kbd(x) 0
68#define kgdboc_unregister_kbd()
69#endif /* ! CONFIG_KDB_KEYBOARD */
70
Jason Wesself2d937f2008-04-17 20:05:37 +020071static int kgdboc_option_setup(char *opt)
72{
73 if (strlen(opt) > MAX_CONFIG_LEN) {
74 printk(KERN_ERR "kgdboc: config string too long\n");
75 return -ENOSPC;
76 }
77 strcpy(config, opt);
78
79 return 0;
80}
81
82__setup("kgdboc=", kgdboc_option_setup);
83
Jason Wesselada64e42010-05-20 21:04:24 -050084static void cleanup_kgdboc(void)
85{
86 kgdboc_unregister_kbd();
87 if (configured == 1)
88 kgdb_unregister_io_module(&kgdboc_io_ops);
89}
90
Jason Wesself2d937f2008-04-17 20:05:37 +020091static int configure_kgdboc(void)
92{
93 struct tty_driver *p;
94 int tty_line = 0;
95 int err;
Jason Wesselada64e42010-05-20 21:04:24 -050096 char *cptr = config;
Jason Wesselefe2f292010-05-20 21:04:26 -050097 struct console *cons;
Jason Wesself2d937f2008-04-17 20:05:37 +020098
99 err = kgdboc_option_setup(config);
100 if (err || !strlen(config) || isspace(config[0]))
101 goto noconfig;
102
103 err = -ENODEV;
Jason Wesselefe2f292010-05-20 21:04:26 -0500104 kgdboc_io_ops.is_console = 0;
Jason Wesselada64e42010-05-20 21:04:24 -0500105 kgdb_tty_driver = NULL;
Jason Wesself2d937f2008-04-17 20:05:37 +0200106
Jason Wesselada64e42010-05-20 21:04:24 -0500107 if (kgdboc_register_kbd(&cptr))
108 goto do_register;
109
110 p = tty_find_polling_driver(cptr, &tty_line);
Jason Wesself2d937f2008-04-17 20:05:37 +0200111 if (!p)
112 goto noconfig;
113
Jason Wesselefe2f292010-05-20 21:04:26 -0500114 cons = console_drivers;
115 while (cons) {
116 int idx;
117 if (cons->device && cons->device(cons, &idx) == p &&
118 idx == tty_line) {
119 kgdboc_io_ops.is_console = 1;
120 break;
121 }
122 cons = cons->next;
123 }
124
Jason Wesself2d937f2008-04-17 20:05:37 +0200125 kgdb_tty_driver = p;
126 kgdb_tty_line = tty_line;
127
Jason Wesselada64e42010-05-20 21:04:24 -0500128do_register:
Jason Wesself2d937f2008-04-17 20:05:37 +0200129 err = kgdb_register_io_module(&kgdboc_io_ops);
130 if (err)
131 goto noconfig;
132
133 configured = 1;
134
135 return 0;
136
137noconfig:
138 config[0] = 0;
139 configured = 0;
Jason Wesselada64e42010-05-20 21:04:24 -0500140 cleanup_kgdboc();
Jason Wesself2d937f2008-04-17 20:05:37 +0200141
142 return err;
143}
144
145static int __init init_kgdboc(void)
146{
147 /* Already configured? */
148 if (configured == 1)
149 return 0;
150
151 return configure_kgdboc();
152}
153
Jason Wesself2d937f2008-04-17 20:05:37 +0200154static int kgdboc_get_char(void)
155{
Jason Wesselada64e42010-05-20 21:04:24 -0500156 if (!kgdb_tty_driver)
157 return -1;
Alan Coxf34d7a52008-04-30 00:54:13 -0700158 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
159 kgdb_tty_line);
Jason Wesself2d937f2008-04-17 20:05:37 +0200160}
161
162static void kgdboc_put_char(u8 chr)
163{
Jason Wesselada64e42010-05-20 21:04:24 -0500164 if (!kgdb_tty_driver)
165 return;
Alan Coxf34d7a52008-04-30 00:54:13 -0700166 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
167 kgdb_tty_line, chr);
Jason Wesself2d937f2008-04-17 20:05:37 +0200168}
169
170static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
171{
Jason Wesselc191e5a2008-02-15 14:55:52 -0600172 int len = strlen(kmessage);
173
174 if (len >= MAX_CONFIG_LEN) {
Jason Wesself2d937f2008-04-17 20:05:37 +0200175 printk(KERN_ERR "kgdboc: config string too long\n");
176 return -ENOSPC;
177 }
178
179 /* Only copy in the string if the init function has not run yet */
180 if (configured < 0) {
181 strcpy(config, kmessage);
182 return 0;
183 }
184
185 if (kgdb_connected) {
186 printk(KERN_ERR
187 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
188
189 return -EBUSY;
190 }
191
192 strcpy(config, kmessage);
Jason Wesselc191e5a2008-02-15 14:55:52 -0600193 /* Chop out \n char as a result of echo */
194 if (config[len - 1] == '\n')
195 config[len - 1] = '\0';
Jason Wesself2d937f2008-04-17 20:05:37 +0200196
197 if (configured == 1)
198 cleanup_kgdboc();
199
200 /* Go and configure with the new params. */
201 return configure_kgdboc();
202}
203
204static void kgdboc_pre_exp_handler(void)
205{
206 /* Increment the module count when the debugger is active */
207 if (!kgdb_connected)
208 try_module_get(THIS_MODULE);
209}
210
211static void kgdboc_post_exp_handler(void)
212{
213 /* decrement the module count when the debugger detaches */
214 if (!kgdb_connected)
215 module_put(THIS_MODULE);
216}
217
218static struct kgdb_io kgdboc_io_ops = {
219 .name = "kgdboc",
220 .read_char = kgdboc_get_char,
221 .write_char = kgdboc_put_char,
222 .pre_exception = kgdboc_pre_exp_handler,
223 .post_exception = kgdboc_post_exp_handler,
224};
225
Jason Wessel97311912010-05-20 21:04:30 -0500226#ifdef CONFIG_KGDB_SERIAL_CONSOLE
227/* This is only available if kgdboc is a built in for early debugging */
228int __init kgdboc_early_init(char *opt)
229{
230 /* save the first character of the config string because the
231 * init routine can destroy it.
232 */
233 char save_ch;
234
235 kgdboc_option_setup(opt);
236 save_ch = config[0];
237 init_kgdboc();
238 config[0] = save_ch;
239 return 0;
240}
241
242early_param("ekgdboc", kgdboc_early_init);
243#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
244
Jason Wesself2d937f2008-04-17 20:05:37 +0200245module_init(init_kgdboc);
246module_exit(cleanup_kgdboc);
247module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
248MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
249MODULE_DESCRIPTION("KGDB Console TTY Driver");
250MODULE_LICENSE("GPL");