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>
21 #define MAX_CONFIG_LEN 40
23 static struct kgdb_io kgdboc_io_ops;
25 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
26 static int configured = -1;
28 static char config[MAX_CONFIG_LEN];
29 static struct kparam_string kps = {
31 .maxlen = MAX_CONFIG_LEN,
34 static struct tty_driver *kgdb_tty_driver;
35 static int kgdb_tty_line;
37 #ifdef CONFIG_KDB_KEYBOARD
38 static int kgdboc_register_kbd(char **cptr)
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;
44 if (cptr[0][3] == ',')
53 static void kgdboc_unregister_kbd(void)
57 for (i = 0; i < kdb_poll_idx; i++) {
58 if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
60 kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
61 kdb_poll_funcs[kdb_poll_idx] = NULL;
66 #else /* ! CONFIG_KDB_KEYBOARD */
67 #define kgdboc_register_kbd(x) 0
68 #define kgdboc_unregister_kbd()
69 #endif /* ! CONFIG_KDB_KEYBOARD */
71 static int kgdboc_option_setup(char *opt)
73 if (strlen(opt) > MAX_CONFIG_LEN) {
74 printk(KERN_ERR "kgdboc: config string too long\n");
82 __setup("kgdboc=", kgdboc_option_setup);
84 static void cleanup_kgdboc(void)
86 kgdboc_unregister_kbd();
88 kgdb_unregister_io_module(&kgdboc_io_ops);
91 static int configure_kgdboc(void)
99 err = kgdboc_option_setup(config);
100 if (err || !strlen(config) || isspace(config[0]))
104 kgdboc_io_ops.is_console = 0;
105 kgdb_tty_driver = NULL;
107 if (kgdboc_register_kbd(&cptr))
110 p = tty_find_polling_driver(cptr, &tty_line);
114 cons = console_drivers;
117 if (cons->device && cons->device(cons, &idx) == p &&
119 kgdboc_io_ops.is_console = 1;
126 kgdb_tty_line = tty_line;
129 err = kgdb_register_io_module(&kgdboc_io_ops);
145 static int __init init_kgdboc(void)
147 /* Already configured? */
151 return configure_kgdboc();
154 static int kgdboc_get_char(void)
156 if (!kgdb_tty_driver)
158 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
162 static void kgdboc_put_char(u8 chr)
164 if (!kgdb_tty_driver)
166 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
170 static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
172 int len = strlen(kmessage);
174 if (len >= MAX_CONFIG_LEN) {
175 printk(KERN_ERR "kgdboc: config string too long\n");
179 /* Only copy in the string if the init function has not run yet */
180 if (configured < 0) {
181 strcpy(config, kmessage);
185 if (kgdb_connected) {
187 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
192 strcpy(config, kmessage);
193 /* Chop out \n char as a result of echo */
194 if (config[len - 1] == '\n')
195 config[len - 1] = '\0';
200 /* Go and configure with the new params. */
201 return configure_kgdboc();
204 static void kgdboc_pre_exp_handler(void)
206 /* Increment the module count when the debugger is active */
208 try_module_get(THIS_MODULE);
211 static void kgdboc_post_exp_handler(void)
213 /* decrement the module count when the debugger detaches */
215 module_put(THIS_MODULE);
218 static struct kgdb_io kgdboc_io_ops = {
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,
226 #ifdef CONFIG_KGDB_SERIAL_CONSOLE
227 /* This is only available if kgdboc is a built in for early debugging */
228 int __init kgdboc_early_init(char *opt)
230 /* save the first character of the config string because the
231 * init routine can destroy it.
235 kgdboc_option_setup(opt);
242 early_param("ekgdboc", kgdboc_early_init);
243 #endif /* CONFIG_KGDB_SERIAL_CONSOLE */
245 module_init(init_kgdboc);
246 module_exit(cleanup_kgdboc);
247 module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
248 MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
249 MODULE_DESCRIPTION("KGDB Console TTY Driver");
250 MODULE_LICENSE("GPL");