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>
23 #define MAX_CONFIG_LEN 40
25 static struct kgdb_io kgdboc_io_ops;
27 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
28 static int configured = -1;
30 static char config[MAX_CONFIG_LEN];
31 static struct kparam_string kps = {
33 .maxlen = MAX_CONFIG_LEN,
36 static int kgdboc_use_kms; /* 1 if we use kernel mode switching */
37 static struct tty_driver *kgdb_tty_driver;
38 static int kgdb_tty_line;
40 #ifdef CONFIG_KDB_KEYBOARD
41 static int kgdboc_reset_connect(struct input_handler *handler,
42 struct input_dev *dev,
43 const struct input_device_id *id)
45 input_reset_device(dev);
47 /* Retrun an error - we do not want to bind, just to reset */
51 static void kgdboc_reset_disconnect(struct input_handle *handle)
53 /* We do not expect anyone to actually bind to us */
57 static const struct input_device_id kgdboc_reset_ids[] = {
59 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
60 .evbit = { BIT_MASK(EV_KEY) },
65 static struct input_handler kgdboc_reset_handler = {
66 .connect = kgdboc_reset_connect,
67 .disconnect = kgdboc_reset_disconnect,
68 .name = "kgdboc_reset",
69 .id_table = kgdboc_reset_ids,
72 static DEFINE_MUTEX(kgdboc_reset_mutex);
74 static void kgdboc_restore_input_helper(struct work_struct *dummy)
77 * We need to take a mutex to prevent several instances of
78 * this work running on different CPUs so they don't try
79 * to register again already registered handler.
81 mutex_lock(&kgdboc_reset_mutex);
83 if (input_register_handler(&kgdboc_reset_handler) == 0)
84 input_unregister_handler(&kgdboc_reset_handler);
86 mutex_unlock(&kgdboc_reset_mutex);
89 static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper);
91 static void kgdboc_restore_input(void)
93 if (likely(system_state == SYSTEM_RUNNING))
94 schedule_work(&kgdboc_restore_input_work);
97 static int kgdboc_register_kbd(char **cptr)
99 if (strncmp(*cptr, "kbd", 3) == 0) {
100 if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
101 kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
103 if (cptr[0][3] == ',')
112 static void kgdboc_unregister_kbd(void)
116 for (i = 0; i < kdb_poll_idx; i++) {
117 if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
119 kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
120 kdb_poll_funcs[kdb_poll_idx] = NULL;
124 flush_work_sync(&kgdboc_restore_input_work);
126 #else /* ! CONFIG_KDB_KEYBOARD */
127 #define kgdboc_register_kbd(x) 0
128 #define kgdboc_unregister_kbd()
129 #define kgdboc_restore_input()
130 #endif /* ! CONFIG_KDB_KEYBOARD */
132 static int kgdboc_option_setup(char *opt)
134 if (strlen(opt) > MAX_CONFIG_LEN) {
135 printk(KERN_ERR "kgdboc: config string too long\n");
143 __setup("kgdboc=", kgdboc_option_setup);
145 static void cleanup_kgdboc(void)
147 kgdboc_unregister_kbd();
149 kgdb_unregister_io_module(&kgdboc_io_ops);
152 static int configure_kgdboc(void)
154 struct tty_driver *p;
158 struct console *cons;
160 err = kgdboc_option_setup(config);
161 if (err || !strlen(config) || isspace(config[0]))
165 kgdboc_io_ops.is_console = 0;
166 kgdb_tty_driver = NULL;
169 if (strncmp(cptr, "kms,", 4) == 0) {
174 if (kgdboc_register_kbd(&cptr))
177 p = tty_find_polling_driver(cptr, &tty_line);
181 cons = console_drivers;
184 if (cons->device && cons->device(cons, &idx) == p &&
186 kgdboc_io_ops.is_console = 1;
193 kgdb_tty_line = tty_line;
196 err = kgdb_register_io_module(&kgdboc_io_ops);
212 static int __init init_kgdboc(void)
214 /* Already configured? */
218 return configure_kgdboc();
221 static int kgdboc_get_char(void)
223 if (!kgdb_tty_driver)
225 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
229 static void kgdboc_put_char(u8 chr)
231 if (!kgdb_tty_driver)
233 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
237 static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
239 int len = strlen(kmessage);
241 if (len >= MAX_CONFIG_LEN) {
242 printk(KERN_ERR "kgdboc: config string too long\n");
246 /* Only copy in the string if the init function has not run yet */
247 if (configured < 0) {
248 strcpy(config, kmessage);
252 if (kgdb_connected) {
254 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
259 strcpy(config, kmessage);
260 /* Chop out \n char as a result of echo */
261 if (config[len - 1] == '\n')
262 config[len - 1] = '\0';
267 /* Go and configure with the new params. */
268 return configure_kgdboc();
271 static int dbg_restore_graphics;
273 static void kgdboc_pre_exp_handler(void)
275 if (!dbg_restore_graphics && kgdboc_use_kms) {
276 dbg_restore_graphics = 1;
277 con_debug_enter(vc_cons[fg_console].d);
279 /* Increment the module count when the debugger is active */
281 try_module_get(THIS_MODULE);
284 static void kgdboc_post_exp_handler(void)
286 /* decrement the module count when the debugger detaches */
288 module_put(THIS_MODULE);
289 if (kgdboc_use_kms && dbg_restore_graphics) {
290 dbg_restore_graphics = 0;
293 kgdboc_restore_input();
296 static struct kgdb_io kgdboc_io_ops = {
298 .read_char = kgdboc_get_char,
299 .write_char = kgdboc_put_char,
300 .pre_exception = kgdboc_pre_exp_handler,
301 .post_exception = kgdboc_post_exp_handler,
304 #ifdef CONFIG_KGDB_SERIAL_CONSOLE
305 /* This is only available if kgdboc is a built in for early debugging */
306 static int __init kgdboc_early_init(char *opt)
308 /* save the first character of the config string because the
309 * init routine can destroy it.
313 kgdboc_option_setup(opt);
320 early_param("ekgdboc", kgdboc_early_init);
321 #endif /* CONFIG_KGDB_SERIAL_CONSOLE */
323 module_init(init_kgdboc);
324 module_exit(cleanup_kgdboc);
325 module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
326 MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
327 MODULE_DESCRIPTION("KGDB Console TTY Driver");
328 MODULE_LICENSE("GPL");