forked from ~ljy/RK356X_SDK_RELEASE
blame | history | patch | commit | commitdiff
hc
2024-02-19 1c055e55a242a33e574e48be530e06770a210dcd 
 kernel/drivers/tty/serial/kgdboc.c
....@@ -8,6 +8,9 @@
88  *
99  * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
1010  */
11
+
12
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
+
1114 #include <linux/kernel.h>
1215 #include <linux/ctype.h>
1316 #include <linux/kgdb.h>
....@@ -17,6 +20,8 @@
1720 #include <linux/vt_kern.h>
1821 #include <linux/input.h>
1922 #include <linux/module.h>
23
+#include <linux/platform_device.h>
24
+#include <linux/serial_core.h>
2025 
2126 #define MAX_CONFIG_LEN		40
2227 
....@@ -24,6 +29,7 @@
2429 
2530 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
2631 static int configured		= -1;
32
+static DEFINE_MUTEX(config_mutex);
2733 
2834 static char config[MAX_CONFIG_LEN];
2935 static struct kparam_string kps = {
....@@ -34,6 +40,13 @@
3440 static int kgdboc_use_kms;  /* 1 if we use kernel mode switching */
3541 static struct tty_driver	*kgdb_tty_driver;
3642 static int			kgdb_tty_line;
43
+
44
+static struct platform_device *kgdboc_pdev;
45
+
46
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
47
+static struct kgdb_io		kgdboc_earlycon_io_ops;
48
+static int                      (*earlycon_orig_exit)(struct console *con);
49
+#endif /* IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
3750 
3851 #ifdef CONFIG_KDB_KEYBOARD
3952 static int kgdboc_reset_connect(struct input_handler *handler,
....@@ -128,13 +141,27 @@
128141 #define kgdboc_restore_input()
129142 #endif /* ! CONFIG_KDB_KEYBOARD */
130143 
144
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
145
+static void cleanup_earlycon(void)
146
+{
147
+	if (kgdboc_earlycon_io_ops.cons)
148
+		kgdb_unregister_io_module(&kgdboc_earlycon_io_ops);
149
+}
150
+#else /* !IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
151
+static inline void cleanup_earlycon(void) { }
152
+#endif /* !IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
153
+
131154 static void cleanup_kgdboc(void)
132155 {
156
+	cleanup_earlycon();
157
+
158
+	if (configured != 1)
159
+		return;
160
+
133161 	if (kgdb_unregister_nmi_console())
134162 		return;
135163 	kgdboc_unregister_kbd();
136
-	if (configured == 1)
137
-		kgdb_unregister_io_module(&kgdboc_io_ops);
164
+	kgdb_unregister_io_module(&kgdboc_io_ops);
138165 }
139166 
140167 static int configure_kgdboc(void)
....@@ -150,7 +177,7 @@
150177 		goto noconfig;
151178 	}
152179 
153
-	kgdboc_io_ops.is_console = 0;
180
+	kgdboc_io_ops.cons = NULL;
154181 	kgdb_tty_driver = NULL;
155182 
156183 	kgdboc_use_kms = 0;
....@@ -166,15 +193,13 @@
166193 	if (!p)
167194 		goto noconfig;
168195 
169
-	cons = console_drivers;
170
-	while (cons) {
196
+	for_each_console(cons) {
171197 		int idx;
172198 		if (cons->device && cons->device(cons, &idx) == p &&
173199 		    idx == tty_line) {
174
-			kgdboc_io_ops.is_console = 1;
200
+			kgdboc_io_ops.cons = cons;
175201 			break;
176202 		}
177
-		cons = cons->next;
178203 	}
179204 
180205 	kgdb_tty_driver = p;
....@@ -197,20 +222,79 @@
197222 	kgdb_unregister_io_module(&kgdboc_io_ops);
198223 noconfig:
199224 	kgdboc_unregister_kbd();
200
-	config[0] = 0;
201225 	configured = 0;
202
-	cleanup_kgdboc();
203226 
204227 	return err;
205228 }
206229 
230
+static int kgdboc_probe(struct platform_device *pdev)
231
+{
232
+	int ret = 0;
233
+
234
+	mutex_lock(&config_mutex);
235
+	if (configured != 1) {
236
+		ret = configure_kgdboc();
237
+
238
+		/* Convert "no device" to "defer" so we'll keep trying */
239
+		if (ret == -ENODEV)
240
+			ret = -EPROBE_DEFER;
241
+	}
242
+	mutex_unlock(&config_mutex);
243
+
244
+	return ret;
245
+}
246
+
247
+static struct platform_driver kgdboc_platform_driver = {
248
+	.probe = kgdboc_probe,
249
+	.driver = {
250
+		.name = "kgdboc",
251
+		.suppress_bind_attrs = true,
252
+	},
253
+};
254
+
207255 static int __init init_kgdboc(void)
208256 {
209
-	/* Already configured? */
210
-	if (configured == 1)
257
+	int ret;
258
+
259
+	/*
260
+	 * kgdboc is a little bit of an odd "platform_driver".  It can be
261
+	 * up and running long before the platform_driver object is
262
+	 * created and thus doesn't actually store anything in it.  There's
263
+	 * only one instance of kgdb so anything is stored as global state.
264
+	 * The platform_driver is only created so that we can leverage the
265
+	 * kernel's mechanisms (like -EPROBE_DEFER) to call us when our
266
+	 * underlying tty is ready.  Here we init our platform driver and
267
+	 * then create the single kgdboc instance.
268
+	 */
269
+	ret = platform_driver_register(&kgdboc_platform_driver);
270
+	if (ret)
271
+		return ret;
272
+
273
+	kgdboc_pdev = platform_device_alloc("kgdboc", PLATFORM_DEVID_NONE);
274
+	if (!kgdboc_pdev) {
275
+		ret = -ENOMEM;
276
+		goto err_did_register;
277
+	}
278
+
279
+	ret = platform_device_add(kgdboc_pdev);
280
+	if (!ret)
211281 		return 0;
212282 
213
-	return configure_kgdboc();
283
+	platform_device_put(kgdboc_pdev);
284
+
285
+err_did_register:
286
+	platform_driver_unregister(&kgdboc_platform_driver);
287
+	return ret;
288
+}
289
+
290
+static void exit_kgdboc(void)
291
+{
292
+	mutex_lock(&config_mutex);
293
+	cleanup_kgdboc();
294
+	mutex_unlock(&config_mutex);
295
+
296
+	platform_device_unregister(kgdboc_pdev);
297
+	platform_driver_unregister(&kgdboc_platform_driver);
214298 }
215299 
216300 static int kgdboc_get_char(void)
....@@ -233,24 +317,19 @@
233317 				const struct kernel_param *kp)
234318 {
235319 	size_t len = strlen(kmessage);
320
+	int ret = 0;
236321 
237322 	if (len >= MAX_CONFIG_LEN) {
238
-		printk(KERN_ERR "kgdboc: config string too long\n");
323
+		pr_err("config string too long\n");
239324 		return -ENOSPC;
240325 	}
241326 
242
-	/* Only copy in the string if the init function has not run yet */
243
-	if (configured < 0) {
244
-		strcpy(config, kmessage);
245
-		return 0;
246
-	}
247
-
248327 	if (kgdb_connected) {
249
-		printk(KERN_ERR
250
-		       "kgdboc: Cannot reconfigure while KGDB is connected.\n");
251
-
328
+		pr_err("Cannot reconfigure while KGDB is connected.\n");
252329 		return -EBUSY;
253330 	}
331
+
332
+	mutex_lock(&config_mutex);
254333 
255334 	strcpy(config, kmessage);
256335 	/* Chop out \n char as a result of echo */
....@@ -260,8 +339,30 @@
260339 	if (configured == 1)
261340 		cleanup_kgdboc();
262341 
263
-	/* Go and configure with the new params. */
264
-	return configure_kgdboc();
342
+	/*
343
+	 * Configure with the new params as long as init already ran.
344
+	 * Note that we can get called before init if someone loads us
345
+	 * with "modprobe kgdboc kgdboc=..." or if they happen to use the
346
+	 * the odd syntax of "kgdboc.kgdboc=..." on the kernel command.
347
+	 */
348
+	if (configured >= 0)
349
+		ret = configure_kgdboc();
350
+
351
+	/*
352
+	 * If we couldn't configure then clear out the config.  Note that
353
+	 * specifying an invalid config on the kernel command line vs.
354
+	 * through sysfs have slightly different behaviors.  If we fail
355
+	 * to configure what was specified on the kernel command line
356
+	 * we'll leave it in the 'config' and return -EPROBE_DEFER from
357
+	 * our probe.  When specified through sysfs userspace is
358
+	 * responsible for loading the tty driver before setting up.
359
+	 */
360
+	if (ret)
361
+		config[0] = '\0';
362
+
363
+	mutex_unlock(&config_mutex);
364
+
365
+	return ret;
265366 }
266367 
267368 static int dbg_restore_graphics;
....@@ -297,21 +398,21 @@
297398 	.post_exception		= kgdboc_post_exp_handler,
298399 };
299400 
300
-#ifdef CONFIG_KGDB_SERIAL_CONSOLE
401
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
301402 static int kgdboc_option_setup(char *opt)
302403 {
303404 	if (!opt) {
304405 		pr_err("config string not provided\n");
305
-		return -EINVAL;
406
+		return 1;
306407 	}
307408 
308409 	if (strlen(opt) >= MAX_CONFIG_LEN) {
309410 		pr_err("config string too long\n");
310
-		return -ENOSPC;
411
+		return 1;
311412 	}
312413 	strcpy(config, opt);
313414 
314
-	return 0;
415
+	return 1;
315416 }
316417 
317418 __setup("kgdboc=", kgdboc_option_setup);
....@@ -320,23 +421,183 @@
320421 /* This is only available if kgdboc is a built in for early debugging */
321422 static int __init kgdboc_early_init(char *opt)
322423 {
323
-	/* save the first character of the config string because the
324
-	 * init routine can destroy it.
325
-	 */
326
-	char save_ch;
327
-
328424 	kgdboc_option_setup(opt);
329
-	save_ch = config[0];
330
-	init_kgdboc();
331
-	config[0] = save_ch;
425
+	configure_kgdboc();
332426 	return 0;
333427 }
334428 
335429 early_param("ekgdboc", kgdboc_early_init);
336
-#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
430
+
431
+static int kgdboc_earlycon_get_char(void)
432
+{
433
+	char c;
434
+
435
+	if (!kgdboc_earlycon_io_ops.cons->read(kgdboc_earlycon_io_ops.cons,
436
+					       &c, 1))
437
+		return NO_POLL_CHAR;
438
+
439
+	return c;
440
+}
441
+
442
+static void kgdboc_earlycon_put_char(u8 chr)
443
+{
444
+	kgdboc_earlycon_io_ops.cons->write(kgdboc_earlycon_io_ops.cons, &chr,
445
+					   1);
446
+}
447
+
448
+static void kgdboc_earlycon_pre_exp_handler(void)
449
+{
450
+	struct console *con;
451
+	static bool already_warned;
452
+
453
+	if (already_warned)
454
+		return;
455
+
456
+	/*
457
+	 * When the first normal console comes up the kernel will take all
458
+	 * the boot consoles out of the list.  Really, we should stop using
459
+	 * the boot console when it does that but until a TTY is registered
460
+	 * we have no other choice so we keep using it.  Since not all
461
+	 * serial drivers might be OK with this, print a warning once per
462
+	 * boot if we detect this case.
463
+	 */
464
+	for_each_console(con)
465
+		if (con == kgdboc_earlycon_io_ops.cons)
466
+			return;
467
+
468
+	already_warned = true;
469
+	pr_warn("kgdboc_earlycon is still using bootconsole\n");
470
+}
471
+
472
+static int kgdboc_earlycon_deferred_exit(struct console *con)
473
+{
474
+	/*
475
+	 * If we get here it means the boot console is going away but we
476
+	 * don't yet have a suitable replacement.  Don't pass through to
477
+	 * the original exit routine.  We'll call it later in our deinit()
478
+	 * function.  For now, restore the original exit() function pointer
479
+	 * as a sentinal that we've hit this point.
480
+	 */
481
+	con->exit = earlycon_orig_exit;
482
+
483
+	return 0;
484
+}
485
+
486
+static void kgdboc_earlycon_deinit(void)
487
+{
488
+	if (!kgdboc_earlycon_io_ops.cons)
489
+		return;
490
+
491
+	if (kgdboc_earlycon_io_ops.cons->exit == kgdboc_earlycon_deferred_exit)
492
+		/*
493
+		 * kgdboc_earlycon is exiting but original boot console exit
494
+		 * was never called (AKA kgdboc_earlycon_deferred_exit()
495
+		 * didn't ever run).  Undo our trap.
496
+		 */
497
+		kgdboc_earlycon_io_ops.cons->exit = earlycon_orig_exit;
498
+	else if (kgdboc_earlycon_io_ops.cons->exit)
499
+		/*
500
+		 * We skipped calling the exit() routine so we could try to
501
+		 * keep using the boot console even after it went away.  We're
502
+		 * finally done so call the function now.
503
+		 */
504
+		kgdboc_earlycon_io_ops.cons->exit(kgdboc_earlycon_io_ops.cons);
505
+
506
+	kgdboc_earlycon_io_ops.cons = NULL;
507
+}
508
+
509
+static struct kgdb_io kgdboc_earlycon_io_ops = {
510
+	.name			= "kgdboc_earlycon",
511
+	.read_char		= kgdboc_earlycon_get_char,
512
+	.write_char		= kgdboc_earlycon_put_char,
513
+	.pre_exception		= kgdboc_earlycon_pre_exp_handler,
514
+	.deinit			= kgdboc_earlycon_deinit,
515
+};
516
+
517
+#define MAX_CONSOLE_NAME_LEN (sizeof((struct console *) 0)->name)
518
+static char kgdboc_earlycon_param[MAX_CONSOLE_NAME_LEN] __initdata;
519
+static bool kgdboc_earlycon_late_enable __initdata;
520
+
521
+static int __init kgdboc_earlycon_init(char *opt)
522
+{
523
+	struct console *con;
524
+
525
+	kdb_init(KDB_INIT_EARLY);
526
+
527
+	/*
528
+	 * Look for a matching console, or if the name was left blank just
529
+	 * pick the first one we find.
530
+	 */
531
+	console_lock();
532
+	for_each_console(con) {
533
+		if (con->write && con->read &&
534
+		    (con->flags & (CON_BOOT | CON_ENABLED)) &&
535
+		    (!opt || !opt[0] || strcmp(con->name, opt) == 0))
536
+			break;
537
+	}
538
+
539
+	if (!con) {
540
+		/*
541
+		 * Both earlycon and kgdboc_earlycon are initialized during
542
+		 * early parameter parsing. We cannot guarantee earlycon gets
543
+		 * in first and, in any case, on ACPI systems earlycon may
544
+		 * defer its own initialization (usually to somewhere within
545
+		 * setup_arch() ). To cope with either of these situations
546
+		 * we can defer our own initialization to a little later in
547
+		 * the boot.
548
+		 */
549
+		if (!kgdboc_earlycon_late_enable) {
550
+			pr_info("No suitable earlycon yet, will try later\n");
551
+			if (opt)
552
+				strscpy(kgdboc_earlycon_param, opt,
553
+					sizeof(kgdboc_earlycon_param));
554
+			kgdboc_earlycon_late_enable = true;
555
+		} else {
556
+			pr_info("Couldn't find kgdb earlycon\n");
557
+		}
558
+		goto unlock;
559
+	}
560
+
561
+	kgdboc_earlycon_io_ops.cons = con;
562
+	pr_info("Going to register kgdb with earlycon '%s'\n", con->name);
563
+	if (kgdb_register_io_module(&kgdboc_earlycon_io_ops) != 0) {
564
+		kgdboc_earlycon_io_ops.cons = NULL;
565
+		pr_info("Failed to register kgdb with earlycon\n");
566
+	} else {
567
+		/* Trap exit so we can keep earlycon longer if needed. */
568
+		earlycon_orig_exit = con->exit;
569
+		con->exit = kgdboc_earlycon_deferred_exit;
570
+	}
571
+
572
+unlock:
573
+	console_unlock();
574
+
575
+	/* Non-zero means malformed option so we always return zero */
576
+	return 0;
577
+}
578
+
579
+early_param("kgdboc_earlycon", kgdboc_earlycon_init);
580
+
581
+/*
582
+ * This is only intended for the late adoption of an early console.
583
+ *
584
+ * It is not a reliable way to adopt regular consoles because we can not
585
+ * control what order console initcalls are made and, in any case, many
586
+ * regular consoles are registered much later in the boot process than
587
+ * the console initcalls!
588
+ */
589
+static int __init kgdboc_earlycon_late_init(void)
590
+{
591
+	if (kgdboc_earlycon_late_enable)
592
+		kgdboc_earlycon_init(kgdboc_earlycon_param);
593
+	return 0;
594
+}
595
+console_initcall(kgdboc_earlycon_late_init);
596
+
597
+#endif /* IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
337598 
338599 module_init(init_kgdboc);
339
-module_exit(cleanup_kgdboc);
600
+module_exit(exit_kgdboc);
340601 module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
341602 MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
342603 MODULE_DESCRIPTION("KGDB Console TTY Driver");