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>
21 #include <linux/input.h>
22 #include <linux/module.h>
24 #define MAX_CONFIG_LEN 40
26 static struct kgdb_io kgdboc_io_ops
;
28 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
29 static int configured
= -1;
31 static char config
[MAX_CONFIG_LEN
];
32 static struct kparam_string kps
= {
34 .maxlen
= MAX_CONFIG_LEN
,
37 static int kgdboc_use_kms
; /* 1 if we use kernel mode switching */
38 static struct tty_driver
*kgdb_tty_driver
;
39 static int kgdb_tty_line
;
41 #ifdef CONFIG_KDB_KEYBOARD
42 static int kgdboc_reset_connect(struct input_handler
*handler
,
43 struct input_dev
*dev
,
44 const struct input_device_id
*id
)
46 input_reset_device(dev
);
48 /* Retrun an error - we do not want to bind, just to reset */
52 static void kgdboc_reset_disconnect(struct input_handle
*handle
)
54 /* We do not expect anyone to actually bind to us */
58 static const struct input_device_id kgdboc_reset_ids
[] = {
60 .flags
= INPUT_DEVICE_ID_MATCH_EVBIT
,
61 .evbit
= { BIT_MASK(EV_KEY
) },
66 static struct input_handler kgdboc_reset_handler
= {
67 .connect
= kgdboc_reset_connect
,
68 .disconnect
= kgdboc_reset_disconnect
,
69 .name
= "kgdboc_reset",
70 .id_table
= kgdboc_reset_ids
,
73 static DEFINE_MUTEX(kgdboc_reset_mutex
);
75 static void kgdboc_restore_input_helper(struct work_struct
*dummy
)
78 * We need to take a mutex to prevent several instances of
79 * this work running on different CPUs so they don't try
80 * to register again already registered handler.
82 mutex_lock(&kgdboc_reset_mutex
);
84 if (input_register_handler(&kgdboc_reset_handler
) == 0)
85 input_unregister_handler(&kgdboc_reset_handler
);
87 mutex_unlock(&kgdboc_reset_mutex
);
90 static DECLARE_WORK(kgdboc_restore_input_work
, kgdboc_restore_input_helper
);
92 static void kgdboc_restore_input(void)
94 if (likely(system_state
== SYSTEM_RUNNING
))
95 schedule_work(&kgdboc_restore_input_work
);
98 static int kgdboc_register_kbd(char **cptr
)
100 if (strncmp(*cptr
, "kbd", 3) == 0) {
101 if (kdb_poll_idx
< KDB_POLL_FUNC_MAX
) {
102 kdb_poll_funcs
[kdb_poll_idx
] = kdb_get_kbd_char
;
104 if (cptr
[0][3] == ',')
113 static void kgdboc_unregister_kbd(void)
117 for (i
= 0; i
< kdb_poll_idx
; i
++) {
118 if (kdb_poll_funcs
[i
] == kdb_get_kbd_char
) {
120 kdb_poll_funcs
[i
] = kdb_poll_funcs
[kdb_poll_idx
];
121 kdb_poll_funcs
[kdb_poll_idx
] = NULL
;
125 flush_work_sync(&kgdboc_restore_input_work
);
127 #else /* ! CONFIG_KDB_KEYBOARD */
128 #define kgdboc_register_kbd(x) 0
129 #define kgdboc_unregister_kbd()
130 #define kgdboc_restore_input()
131 #endif /* ! CONFIG_KDB_KEYBOARD */
133 static int kgdboc_option_setup(char *opt
)
135 if (strlen(opt
) >= MAX_CONFIG_LEN
) {
136 printk(KERN_ERR
"kgdboc: config string too long\n");
144 __setup("kgdboc=", kgdboc_option_setup
);
146 static void cleanup_kgdboc(void)
148 if (kgdb_unregister_nmi_console())
150 kgdboc_unregister_kbd();
152 kgdb_unregister_io_module(&kgdboc_io_ops
);
155 static int configure_kgdboc(void)
157 struct tty_driver
*p
;
161 struct console
*cons
;
163 err
= kgdboc_option_setup(config
);
164 if (err
|| !strlen(config
) || isspace(config
[0]))
168 kgdboc_io_ops
.is_console
= 0;
169 kgdb_tty_driver
= NULL
;
172 if (strncmp(cptr
, "kms,", 4) == 0) {
177 if (kgdboc_register_kbd(&cptr
))
180 p
= tty_find_polling_driver(cptr
, &tty_line
);
184 cons
= console_drivers
;
187 if (cons
->device
&& cons
->device(cons
, &idx
) == p
&&
189 kgdboc_io_ops
.is_console
= 1;
196 kgdb_tty_line
= tty_line
;
199 err
= kgdb_register_io_module(&kgdboc_io_ops
);
203 err
= kgdb_register_nmi_console();
212 kgdb_unregister_io_module(&kgdboc_io_ops
);
214 kgdboc_unregister_kbd();
222 static int __init
init_kgdboc(void)
224 /* Already configured? */
228 return configure_kgdboc();
231 static int kgdboc_get_char(void)
233 if (!kgdb_tty_driver
)
235 return kgdb_tty_driver
->ops
->poll_get_char(kgdb_tty_driver
,
239 static void kgdboc_put_char(u8 chr
)
241 if (!kgdb_tty_driver
)
243 kgdb_tty_driver
->ops
->poll_put_char(kgdb_tty_driver
,
247 static int param_set_kgdboc_var(const char *kmessage
, struct kernel_param
*kp
)
249 int len
= strlen(kmessage
);
251 if (len
>= MAX_CONFIG_LEN
) {
252 printk(KERN_ERR
"kgdboc: config string too long\n");
256 /* Only copy in the string if the init function has not run yet */
257 if (configured
< 0) {
258 strcpy(config
, kmessage
);
262 if (kgdb_connected
) {
264 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
269 strcpy(config
, kmessage
);
270 /* Chop out \n char as a result of echo */
271 if (config
[len
- 1] == '\n')
272 config
[len
- 1] = '\0';
277 /* Go and configure with the new params. */
278 return configure_kgdboc();
281 static int dbg_restore_graphics
;
283 static void kgdboc_pre_exp_handler(void)
285 if (!dbg_restore_graphics
&& kgdboc_use_kms
) {
286 dbg_restore_graphics
= 1;
287 con_debug_enter(vc_cons
[fg_console
].d
);
289 /* Increment the module count when the debugger is active */
291 try_module_get(THIS_MODULE
);
294 static void kgdboc_post_exp_handler(void)
296 /* decrement the module count when the debugger detaches */
298 module_put(THIS_MODULE
);
299 if (kgdboc_use_kms
&& dbg_restore_graphics
) {
300 dbg_restore_graphics
= 0;
303 kgdboc_restore_input();
306 static struct kgdb_io kgdboc_io_ops
= {
308 .read_char
= kgdboc_get_char
,
309 .write_char
= kgdboc_put_char
,
310 .pre_exception
= kgdboc_pre_exp_handler
,
311 .post_exception
= kgdboc_post_exp_handler
,
314 #ifdef CONFIG_KGDB_SERIAL_CONSOLE
315 /* This is only available if kgdboc is a built in for early debugging */
316 static int __init
kgdboc_early_init(char *opt
)
318 /* save the first character of the config string because the
319 * init routine can destroy it.
323 kgdboc_option_setup(opt
);
330 early_param("ekgdboc", kgdboc_early_init
);
331 #endif /* CONFIG_KGDB_SERIAL_CONSOLE */
333 module_init(init_kgdboc
);
334 module_exit(cleanup_kgdboc
);
335 module_param_call(kgdboc
, param_set_kgdboc_var
, param_get_string
, &kps
, 0644);
336 MODULE_PARM_DESC(kgdboc
, "<serial_device>[,baud]");
337 MODULE_DESCRIPTION("KGDB Console TTY Driver");
338 MODULE_LICENSE("GPL");