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(&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");