include/log.h

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