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1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Logging support
4  *
5  * Copyright (c) 2017 Google, Inc
6  * Written by Simon Glass <sjg@chromium.org>
7  */
8 
9 #ifndef __LOG_H
10 #define __LOG_H
11 
12 #include <dm/uclass-id.h>
13 #include <linux/list.h>
14 
15 /** Log levels supported, ranging from most to least important */
16 enum log_level_t {
17 	LOGL_EMERG = 0,		/*U-Boot is unstable */
18 	LOGL_ALERT,		/* Action must be taken immediately */
19 	LOGL_CRIT,		/* Critical conditions */
20 	LOGL_ERR,		/* Error that prevents something from working */
21 	LOGL_WARNING,		/* Warning may prevent optimial operation */
22 	LOGL_NOTICE,		/* Normal but significant condition, printf() */
23 	LOGL_INFO,		/* General information message */
24 	LOGL_DEBUG,		/* Basic debug-level message */
25 	LOGL_DEBUG_CONTENT,	/* Debug message showing full message content */
26 	LOGL_DEBUG_IO,		/* Debug message showing hardware I/O access */
27 
28 	LOGL_COUNT,
29 	LOGL_NONE,
30 
31 	LOGL_FIRST = LOGL_EMERG,
32 	LOGL_MAX = LOGL_DEBUG_IO,
33 };
34 
35 /**
36  * Log categories supported. Most of these correspond to uclasses (i.e.
37  * enum uclass_id) but there are also some more generic categories
38  */
39 enum log_category_t {
40 	LOGC_FIRST = 0,	/* First part mirrors UCLASS_... */
41 
42 	LOGC_NONE = UCLASS_COUNT,
43 	LOGC_ARCH,
44 	LOGC_BOARD,
45 	LOGC_CORE,
46 	LOGC_DM,	/* Core driver-model */
47 	LOGC_DT,	/* Device-tree */
48 	LOGC_EFI,	/* EFI implementation */
49 
50 	LOGC_COUNT,
51 	LOGC_END,
52 };
53 
54 /* Helper to cast a uclass ID to a log category */
log_uc_cat(enum uclass_id id)55 static inline int log_uc_cat(enum uclass_id id)
56 {
57 	return (enum log_category_t)id;
58 }
59 
60 /**
61  * _log() - Internal function to emit a new log record
62  *
63  * @cat: Category of log record (indicating which subsystem generated it)
64  * @level: Level of log record (indicating its severity)
65  * @file: File name of file where log record was generated
66  * @line: Line number in file where log record was generated
67  * @func: Function where log record was generated
68  * @fmt: printf() format string for log record
69  * @...: Optional parameters, according to the format string @fmt
70  * @return 0 if log record was emitted, -ve on error
71  */
72 int _log(enum log_category_t cat, enum log_level_t level, const char *file,
73 	 int line, const char *func, const char *fmt, ...);
74 
75 /* Define this at the top of a file to add a prefix to debug messages */
76 #ifndef pr_fmt
77 #define pr_fmt(fmt) fmt
78 #endif
79 
80 /* Use a default category if this file does not supply one */
81 #ifndef LOG_CATEGORY
82 #define LOG_CATEGORY LOGC_NONE
83 #endif
84 
85 /*
86  * This header may be including when CONFIG_LOG is disabled, in which case
87  * CONFIG_LOG_MAX_LEVEL is not defined. Add a check for this.
88  */
89 #if CONFIG_IS_ENABLED(LOG)
90 #define _LOG_MAX_LEVEL CONFIG_VAL(LOG_MAX_LEVEL)
91 #else
92 #define _LOG_MAX_LEVEL LOGL_INFO
93 #endif
94 
95 /* Emit a log record if the level is less that the maximum */
96 #define log(_cat, _level, _fmt, _args...) ({ \
97 	int _l = _level; \
98 	if (_l <= _LOG_MAX_LEVEL) \
99 		_log((enum log_category_t)(_cat), _l, __FILE__, __LINE__, \
100 		      __func__, \
101 		      pr_fmt(_fmt), ##_args); \
102 	})
103 
104 #ifdef DEBUG
105 #define _DEBUG	1
106 #else
107 #define _DEBUG	0
108 #endif
109 
110 #ifdef CONFIG_SPL_BUILD
111 #define _SPL_BUILD	1
112 #else
113 #define _SPL_BUILD	0
114 #endif
115 
116 #if !_DEBUG && CONFIG_IS_ENABLED(LOG)
117 
118 #define debug_cond(cond, fmt, args...)			\
119 	do {						\
120 		if (1)					\
121 			log(LOG_CATEGORY, LOGL_DEBUG, fmt, ##args); \
122 	} while (0)
123 
124 #else /* _DEBUG */
125 
126 /*
127  * Output a debug text when condition "cond" is met. The "cond" should be
128  * computed by a preprocessor in the best case, allowing for the best
129  * optimization.
130  */
131 #define debug_cond(cond, fmt, args...)			\
132 	do {						\
133 		if (cond)				\
134 			printf(pr_fmt(fmt), ##args);	\
135 	} while (0)
136 
137 #endif /* _DEBUG */
138 
139 /* Show a message if DEBUG is defined in a file */
140 #define debug(fmt, args...)			\
141 	debug_cond(_DEBUG, fmt, ##args)
142 
143 /* Show a message if not in SPL */
144 #define warn_non_spl(fmt, args...)			\
145 	debug_cond(!_SPL_BUILD, fmt, ##args)
146 
147 /*
148  * An assertion is run-time check done in debug mode only. If DEBUG is not
149  * defined then it is skipped. If DEBUG is defined and the assertion fails,
150  * then it calls panic*( which may or may not reset/halt U-Boot (see
151  * CONFIG_PANIC_HANG), It is hoped that all failing assertions are found
152  * before release, and after release it is hoped that they don't matter. But
153  * in any case these failing assertions cannot be fixed with a reset (which
154  * may just do the same assertion again).
155  */
156 void __assert_fail(const char *assertion, const char *file, unsigned int line,
157 		   const char *function);
158 #define assert(x) \
159 	({ if (!(x) && _DEBUG) \
160 		__assert_fail(#x, __FILE__, __LINE__, __func__); })
161 
162 #ifdef CONFIG_LOG_ERROR_RETURN
163 #define log_ret(_ret) ({ \
164 	int __ret = (_ret); \
165 	if (__ret < 0) \
166 		log(LOG_CATEGORY, LOGL_ERR, "returning err=%d\n", __ret); \
167 	__ret; \
168 	})
169 #else
170 #define log_ret(_ret) (_ret)
171 #endif
172 
173 /**
174  * struct log_rec - a single log record
175  *
176  * Holds information about a single record in the log
177  *
178  * Members marked as 'not allocated' are stored as pointers and the caller is
179  * responsible for making sure that the data pointed to is not overwritten.
180  * Memebers marked as 'allocated' are allocated (e.g. via strdup()) by the log
181  * system.
182  *
183  * @cat: Category, representing a uclass or part of U-Boot
184  * @level: Severity level, less severe is higher
185  * @file: Name of file where the log record was generated (not allocated)
186  * @line: Line number where the log record was generated
187  * @func: Function where the log record was generated (not allocated)
188  * @msg: Log message (allocated)
189  */
190 struct log_rec {
191 	enum log_category_t cat;
192 	enum log_level_t level;
193 	const char *file;
194 	int line;
195 	const char *func;
196 	const char *msg;
197 };
198 
199 struct log_device;
200 
201 /**
202  * struct log_driver - a driver which accepts and processes log records
203  *
204  * @name: Name of driver
205  */
206 struct log_driver {
207 	const char *name;
208 	/**
209 	 * emit() - emit a log record
210 	 *
211 	 * Called by the log system to pass a log record to a particular driver
212 	 * for processing. The filter is checked before calling this function.
213 	 */
214 	int (*emit)(struct log_device *ldev, struct log_rec *rec);
215 };
216 
217 /**
218  * struct log_device - an instance of a log driver
219  *
220  * Since drivers are set up at build-time we need to have a separate device for
221  * the run-time aspects of drivers (currently just a list of filters to apply
222  * to records send to this device).
223  *
224  * @next_filter_num: Seqence number of next filter filter added (0=no filters
225  *	yet). This increments with each new filter on the device, but never
226  *	decrements
227  * @drv: Pointer to driver for this device
228  * @filter_head: List of filters for this device
229  * @sibling_node: Next device in the list of all devices
230  */
231 struct log_device {
232 	int next_filter_num;
233 	struct log_driver *drv;
234 	struct list_head filter_head;
235 	struct list_head sibling_node;
236 };
237 
238 enum {
239 	LOGF_MAX_CATEGORIES = 5,	/* maximum categories per filter */
240 };
241 
242 enum log_filter_flags {
243 	LOGFF_HAS_CAT		= 1 << 0,	/* Filter has a category list */
244 };
245 
246 /**
247  * struct log_filter - criterial to filter out log messages
248  *
249  * @filter_num: Sequence number of this filter.  This is returned when adding a
250  *	new filter, and must be provided when removing a previously added
251  *	filter.
252  * @flags: Flags for this filter (LOGFF_...)
253  * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
254  *	then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
255  *	can be provided
256  * @max_level: Maximum log level to allow
257  * @file_list: List of files to allow, separated by comma. If NULL then all
258  *	files are permitted
259  * @sibling_node: Next filter in the list of filters for this log device
260  */
261 struct log_filter {
262 	int filter_num;
263 	int flags;
264 	enum log_category_t cat_list[LOGF_MAX_CATEGORIES];
265 	enum log_level_t max_level;
266 	const char *file_list;
267 	struct list_head sibling_node;
268 };
269 
270 #define LOG_DRIVER(_name) \
271 	ll_entry_declare(struct log_driver, _name, log_driver)
272 
273 /**
274  * log_get_cat_name() - Get the name of a category
275  *
276  * @cat: Category to look up
277  * @return category name (which may be a uclass driver name) if found, or
278  *	 "<invalid>" if invalid, or "<missing>" if not found
279  */
280 const char *log_get_cat_name(enum log_category_t cat);
281 
282 /**
283  * log_get_cat_by_name() - Look up a category by name
284  *
285  * @name: Name to look up
286  * @return category ID, or LOGC_NONE if not found
287  */
288 enum log_category_t log_get_cat_by_name(const char *name);
289 
290 /**
291  * log_get_level_name() - Get the name of a log level
292  *
293  * @level: Log level to look up
294  * @return log level name (in ALL CAPS)
295  */
296 const char *log_get_level_name(enum log_level_t level);
297 
298 /**
299  * log_get_level_by_name() - Look up a log level by name
300  *
301  * @name: Name to look up
302  * @return log level ID, or LOGL_NONE if not found
303  */
304 enum log_level_t log_get_level_by_name(const char *name);
305 
306 /* Log format flags (bit numbers) for gd->log_fmt. See log_fmt_chars */
307 enum log_fmt {
308 	LOGF_CAT	= 0,
309 	LOGF_LEVEL,
310 	LOGF_FILE,
311 	LOGF_LINE,
312 	LOGF_FUNC,
313 	LOGF_MSG,
314 
315 	LOGF_COUNT,
316 	LOGF_DEFAULT = (1 << LOGF_FUNC) | (1 << LOGF_MSG),
317 	LOGF_ALL = 0x3f,
318 };
319 
320 /* Handle the 'log test' command */
321 int do_log_test(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[]);
322 
323 /**
324  * log_add_filter() - Add a new filter to a log device
325  *
326  * @drv_name: Driver name to add the filter to (since each driver only has a
327  *	single device)
328  * @cat_list: List of categories to allow (terminated by LOGC_none). If empty
329  *	then all categories are permitted. Up to LOGF_MAX_CATEGORIES entries
330  *	can be provided
331  * @max_level: Maximum log level to allow
332  * @file_list: List of files to allow, separated by comma. If NULL then all
333  *	files are permitted
334  * @return the sequence number of the new filter (>=0) if the filter was added,
335  *	or a -ve value on error
336  */
337 int log_add_filter(const char *drv_name, enum log_category_t cat_list[],
338 		   enum log_level_t max_level, const char *file_list);
339 
340 /**
341  * log_remove_filter() - Remove a filter from a log device
342  *
343  * @drv_name: Driver name to remove the filter from (since each driver only has
344  *	a single device)
345  * @filter_num: Filter number to remove (as returned by log_add_filter())
346  * @return 0 if the filter was removed, -ENOENT if either the driver or the
347  *	filter number was not found
348  */
349 int log_remove_filter(const char *drv_name, int filter_num);
350 
351 #if CONFIG_IS_ENABLED(LOG)
352 /**
353  * log_init() - Set up the log system ready for use
354  *
355  * @return 0 if OK, -ENOMEM if out of memory
356  */
357 int log_init(void);
358 #else
log_init(void)359 static inline int log_init(void)
360 {
361 	return 0;
362 }
363 #endif
364 
365 #endif
366