logging: fix for 64 bit timestamp + new timestamp format option

Timestamps can be 32 or 64 bit long based on the platform and
build configurations. The proper way to handle these timestamps
is to use the ad-hoc log_timestamp_t variable.
This patch fixes some timestamp's reference which were still
using uint32_t changing them to log_timestamp_t.

Moreover also a new config is added in order to print the
timestamp as the Linux's kernel format. This might be useful
in AMP platforms in which Linux's and Zephyr's logs must be
interleaved in order to get a more comprehensive log solution.

Signed-off-by: Valerio Setti <[email protected]>

Author: valeriosetti

subsys/logging/Kconfig.formatting

@@ -88,4 +88,13 @@ config LOG_BACKEND_FORMAT_TIMESTAMP
 	help
 	  When enabled timestamp is formatted to hh:mm:ss:ms,us.
 
+config LOG_OUTPUT_FORMAT_LINUX_TIMESTAMP
+	bool "Format timestamp in Linux format"
+	default n
+	help
+	  This formatting is something in the middle between the pure raw format
+	  and the hh:mm:ss:ms,us one. It resembles the Linux's kernel format in
+	  which timestamps are printed as fixed point values with seconds on the
+	  left side of the point and microseconds on the right side.
+
 endmenu

subsys/logging/log_output.c

@@ -44,7 +44,18 @@ static const char *const colors[] = {
 };
 
 static uint32_t freq;
-static uint32_t timestamp_div;
+static log_timestamp_t timestamp_div;
+
+#define SECONDS_IN_DAY			86400U
+
+static uint32_t days_in_month[12] = {31, 28, 31, 30, 31, 30, 31,
+									31, 30, 31, 30, 31};
+
+struct YMD_date {
+	uint32_t year;
+	uint32_t month;
+	uint32_t day;
+};
 
 extern void log_output_msg_syst_process(const struct log_output *output,
 				struct log_msg *msg, uint32_t flag);
@@ -169,19 +180,68 @@ void log_output_flush(const struct log_output *output)
 	output->control_block->offset = 0;
 }
 
+static inline bool is_leap_year(uint32_t year)
+{
+	return (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0));
+}
+
+static void __attribute__((unused)) get_YMD_from_seconds(uint64_t seconds,
+			struct YMD_date *output_date)
+{
+	uint64_t tmp;
+	int i;
+
+	output_date->year = 1970;
+	output_date->month = 1;
+	output_date->day = 1;
+
+	/* compute the proper year */
+	while (1) {
+		tmp = (is_leap_year(output_date->year)) ?
+					366*SECONDS_IN_DAY : 365*SECONDS_IN_DAY;
+		if (tmp > seconds) {
+			break;
+		}
+		seconds -= tmp;
+		output_date->year++;
+	}
+	/* compute the proper month */
+	for (i = 0; i < sizeof(days_in_month); i++) {
+		tmp = ((i == 1) && is_leap_year(output_date->year)) ?
+					(days_in_month[i] + 1) * SECONDS_IN_DAY :
+					days_in_month[i] * SECONDS_IN_DAY;
+		if (tmp > seconds) {
+			output_date->month += i;
+			break;
+		}
+		seconds -= tmp;
+	}
+
+	output_date->day += seconds / SECONDS_IN_DAY;
+}
+
 static int timestamp_print(const struct log_output *output,
-			   uint32_t flags, uint32_t timestamp)
+			   uint32_t flags, log_timestamp_t timestamp)
 {
 	int length;
 	bool format =
 		(flags & LOG_OUTPUT_FLAG_FORMAT_TIMESTAMP) |
-		(flags & LOG_OUTPUT_FLAG_FORMAT_SYSLOG);
+		(flags & LOG_OUTPUT_FLAG_FORMAT_SYSLOG) |
+		IS_ENABLED(CONFIG_LOG_OUTPUT_FORMAT_LINUX_TIMESTAMP);
 
 
 	if (!format) {
+#ifndef CONFIG_LOG_TIMESTAMP_64BIT
 		length = print_formatted(output, "[%08lu] ", timestamp);
+#else
+		length = print_formatted(output, "[%016llu] ", timestamp);
+#endif
 	} else if (freq != 0U) {
+#ifndef CONFIG_LOG_TIMESTAMP_64BIT
 		uint32_t total_seconds;
+#else
+		uint64_t total_seconds;
+#endif
 		uint32_t remainder;
 		uint32_t seconds;
 		uint32_t hours;
@@ -216,14 +276,25 @@ static int timestamp_print(const struct log_output *output,
 			length = print_formatted(output, "%s.%06uZ ",
 						 time_str, ms * 1000U + us);
 #else
+			struct YMD_date date;
+
+			get_YMD_from_seconds(total_seconds, &date);
+			hours = hours % 24;
 			length = print_formatted(output,
-					"1970-01-01T%02u:%02u:%02u.%06uZ ",
+					"%04u-%02u-%02uT%02u:%02u:%02u.%06uZ ",
+					date.year, date.month, date.day,
 					hours, mins, seconds, ms * 1000U + us);
 #endif
 		} else {
-			length = print_formatted(output,
-						 "[%02u:%02u:%02u.%03u,%03u] ",
-						 hours, mins, seconds, ms, us);
+			if (IS_ENABLED(CONFIG_LOG_OUTPUT_FORMAT_LINUX_TIMESTAMP)) {
+				length = print_formatted(output,
+							"[%02u:%02u:%02u.%03u,%03u] ",
+							hours, mins, seconds, ms, us);
+			} else {
+				length = print_formatted(output,
+							"[%5ld.%06d] ",
+							total_seconds, ms * 1000U + us);
+			}
 		}
 	} else {
 		length = 0;
@@ -493,7 +564,7 @@ static void raw_string_print(struct log_msg *msg,
 }
 
 static uint32_t prefix_print(const struct log_output *output,
-			 uint32_t flags, bool func_on, uint32_t timestamp, uint8_t level,
+			 uint32_t flags, bool func_on, log_timestamp_t timestamp, uint8_t level,
 			 uint8_t domain_id, int16_t source_id)
 {
 	uint32_t length = 0U;