common/tf_log.c

   1 /*
   2  * Copyright (c) 2017-2019, Arm Limited and Contributors. All rights reserved.
   3  *
   4  * SPDX-License-Identifier: BSD-3-Clause
   5  */
   6
   7 #include <stdarg.h>
   8 #include <assert.h>
   9 #include <stdio.h>
  10
  11 #include <common/debug.h>
  12 #include <plat/common/platform.h>
  13
  14 /* Set the default maximum log level to the `LOG_LEVEL` build flag */
  15 static unsigned int max_log_level = LOG_LEVEL;
  16
  17 /*
  18  * The common log function which is invoked by TF-A code.
  19  * This function should not be directly invoked and is meant to be
  20  * only used by the log macros defined in debug.h. The function
  21  * expects the first character in the format string to be one of the
  22  * LOG_MARKER_* macros defined in debug.h.
  23  */
  24 void tf_log(const char *fmt, ...)
  25 {
  26         unsigned int log_level;
  27         va_list args;
  28         const char *prefix_str;
  29
  30         /* We expect the LOG_MARKER_* macro as the first character */
  31         log_level = fmt[0];
  32
  33         /* Verify that log_level is one of LOG_MARKER_* macro defined in debug.h */
  34         assert((log_level > 0U) && (log_level <= LOG_LEVEL_VERBOSE));
  35         assert((log_level % 10U) == 0U);
  36
  37         if (log_level > max_log_level)
  38                 return;
  39
  40         prefix_str = plat_log_get_prefix(log_level);
  41
  42         while (*prefix_str != '\0') {
  43                 (void)putchar(*prefix_str);
  44                 prefix_str++;
  45         }
  46
  47         va_start(args, fmt);
  48         (void)vprintf(fmt + 1, args);
  49         va_end(args);
  50 }
  51
  52 /*
  53  * The helper function to set the log level dynamically by platform. The
  54  * maximum log level is determined by `LOG_LEVEL` build flag at compile time
  55  * and this helper can set a lower (or equal) log level than the one at compile.
  56  */
  57 void tf_log_set_max_level(unsigned int log_level)
  58 {
  59         assert(log_level <= LOG_LEVEL_VERBOSE);
  60         assert((log_level % 10U) == 0U);
  61
  62         /* Cap log_level to the compile time maximum. */
  63         if (log_level <= (unsigned int)LOG_LEVEL)
  64                 max_log_level = log_level;
  65 }