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.
6 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
8 * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
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.
14 #include <linux/kernel.h>
15 #include <linux/ctype.h>
16 #include <linux/kgdb.h>
17 #include <linux/kdb.h>
18 #include <linux/tty.h>
19 #include <linux/console.h>
20 #include <linux/vt_kern.h>
22 #define MAX_CONFIG_LEN 40
24 static struct kgdb_io kgdboc_io_ops
;
26 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
27 static int configured
= -1;
29 static char config
[MAX_CONFIG_LEN
];
30 static struct kparam_string kps
= {
32 .maxlen
= MAX_CONFIG_LEN
,
35 static int kgdboc_use_kms
; /* 1 if we use kernel mode switching */
36 static struct tty_driver
*kgdb_tty_driver
;
37 static int kgdb_tty_line
;
39 #ifdef CONFIG_KDB_KEYBOARD
40 static int kgdboc_register_kbd(char **cptr
)
42 if (strncmp(*cptr
, "kbd", 3) == 0) {
43 if (kdb_poll_idx
< KDB_POLL_FUNC_MAX
) {
44 kdb_poll_funcs
[kdb_poll_idx
] = kdb_get_kbd_char
;
46 if (cptr
[0][3] == ',')
55 static void kgdboc_unregister_kbd(void)
59 for (i
= 0; i
< kdb_poll_idx
; i
++) {
60 if (kdb_poll_funcs
[i
] == kdb_get_kbd_char
) {
62 kdb_poll_funcs
[i
] = kdb_poll_funcs
[kdb_poll_idx
];
63 kdb_poll_funcs
[kdb_poll_idx
] = NULL
;
68 #else /* ! CONFIG_KDB_KEYBOARD */
69 #define kgdboc_register_kbd(x) 0
70 #define kgdboc_unregister_kbd()
71 #endif /* ! CONFIG_KDB_KEYBOARD */
73 static int kgdboc_option_setup(char *opt
)
75 if (strlen(opt
) > MAX_CONFIG_LEN
) {
76 printk(KERN_ERR
"kgdboc: config string too long\n");
84 __setup("kgdboc=", kgdboc_option_setup
);
86 static void cleanup_kgdboc(void)
88 kgdboc_unregister_kbd();
90 kgdb_unregister_io_module(&kgdboc_io_ops
);
93 static int configure_kgdboc(void)
101 err
= kgdboc_option_setup(config
);
102 if (err
|| !strlen(config
) || isspace(config
[0]))
106 kgdboc_io_ops
.is_console
= 0;
107 kgdb_tty_driver
= NULL
;
110 if (strncmp(cptr
, "kms,", 4) == 0) {
115 if (kgdboc_register_kbd(&cptr
))
118 p
= tty_find_polling_driver(cptr
, &tty_line
);
122 cons
= console_drivers
;
125 if (cons
->device
&& cons
->device(cons
, &idx
) == p
&&
127 kgdboc_io_ops
.is_console
= 1;
134 kgdb_tty_line
= tty_line
;
137 err
= kgdb_register_io_module(&kgdboc_io_ops
);
153 static int __init
init_kgdboc(void)
155 /* Already configured? */
159 return configure_kgdboc();
162 static int kgdboc_get_char(void)
164 if (!kgdb_tty_driver
)
166 return kgdb_tty_driver
->ops
->poll_get_char(kgdb_tty_driver
,
170 static void kgdboc_put_char(u8 chr
)
172 if (!kgdb_tty_driver
)
174 kgdb_tty_driver
->ops
->poll_put_char(kgdb_tty_driver
,
178 static int param_set_kgdboc_var(const char *kmessage
, struct kernel_param
*kp
)
180 int len
= strlen(kmessage
);
182 if (len
>= MAX_CONFIG_LEN
) {
183 printk(KERN_ERR
"kgdboc: config string too long\n");
187 /* Only copy in the string if the init function has not run yet */
188 if (configured
< 0) {
189 strcpy(config
, kmessage
);
193 if (kgdb_connected
) {
195 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
200 strcpy(config
, kmessage
);
201 /* Chop out \n char as a result of echo */
202 if (config
[len
- 1] == '\n')
203 config
[len
- 1] = '\0';
208 /* Go and configure with the new params. */
209 return configure_kgdboc();
212 static int dbg_restore_graphics
;
214 static void kgdboc_pre_exp_handler(void)
216 if (!dbg_restore_graphics
&& kgdboc_use_kms
) {
217 dbg_restore_graphics
= 1;
218 con_debug_enter(vc_cons
[fg_console
].d
);
220 /* Increment the module count when the debugger is active */
222 try_module_get(THIS_MODULE
);
225 static void kgdboc_post_exp_handler(void)
227 /* decrement the module count when the debugger detaches */
229 module_put(THIS_MODULE
);
230 if (kgdboc_use_kms
&& dbg_restore_graphics
) {
231 dbg_restore_graphics
= 0;
236 static struct kgdb_io kgdboc_io_ops
= {
238 .read_char
= kgdboc_get_char
,
239 .write_char
= kgdboc_put_char
,
240 .pre_exception
= kgdboc_pre_exp_handler
,
241 .post_exception
= kgdboc_post_exp_handler
,
244 #ifdef CONFIG_KGDB_SERIAL_CONSOLE
245 /* This is only available if kgdboc is a built in for early debugging */
246 int __init
kgdboc_early_init(char *opt
)
248 /* save the first character of the config string because the
249 * init routine can destroy it.
253 kgdboc_option_setup(opt
);
260 early_param("ekgdboc", kgdboc_early_init
);
261 #endif /* CONFIG_KGDB_SERIAL_CONSOLE */
263 module_init(init_kgdboc
);
264 module_exit(cleanup_kgdboc
);
265 module_param_call(kgdboc
, param_set_kgdboc_var
, param_get_string
, &kps
, 0644);
266 MODULE_PARM_DESC(kgdboc
, "<serial_device>[,baud]");
267 MODULE_DESCRIPTION("KGDB Console TTY Driver");
268 MODULE_LICENSE("GPL");