trace.c: add mtrace_printf() low-level shortcut

Direct access to mbox shared memory logging when DMA tracing is
either not initialized yet or disabled or found broken for any
reason.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

src/include/sof/trace/trace.h

@@ -413,4 +413,31 @@ struct tr_ctx {
 				     _TRACE_INV_ID, _TRACE_INV_ID, \
 				     fmt, ##__VA_ARGS__)
 
+/** Direct, low-level access to mbox / shared memory logging when DMA
+ * tracing is either not initialized yet or disabled or found broken for
+ * any reason.
+ * To keep it simpler than and with minimal dependencies on
+ * the huge number of lines above, this does not check arguments at compile
+ * time.
+ * There is neither log level filtering, throttling or any other
+ * advanced feature.
+ */
+#define mtrace_printf(log_level, format_str, ...)			\
+	do {								\
+		STATIC_ASSERT(META_COUNT_VARAGS_BEFORE_COMPILE(__VA_ARGS__)  \
+			      <= _TRACE_EVENT_MAX_ARGUMENT_COUNT,	\
+			      too_many_mtrace_printf_arguments);	\
+		_DECLARE_LOG_ENTRY(log_level, format_str, _TRACE_INV_CLASS, \
+				   META_COUNT_VARAGS_BEFORE_COMPILE(__VA_ARGS__)); \
+		mtrace_dict_entry((uint32_t)&log_entry,			\
+				  META_COUNT_VARAGS_BEFORE_COMPILE(__VA_ARGS__), \
+				  ##__VA_ARGS__);			\
+	} while (0)
+
+/** Adds log_header prefix and appends  arguments before sending */
+void mtrace_dict_entry(uint32_t log_entry_pointer, int n_args, ...);
+
+/** Posts a fully prepared log header + log entry */
+void mtrace_event(const char *complete_packet, uint32_t length);
+
 #endif /* __SOF_TRACE_TRACE_H__ */

src/trace/trace.c

@@ -70,7 +70,7 @@ struct trace {
 
 #define TRACE_ID_MASK ((1 << TRACE_ID_LENGTH) - 1)
 
-static void put_header(uint32_t *dst, const struct sof_uuid_entry *uid,
+static void put_header(void *dst, const struct sof_uuid_entry *uid,
 		       uint32_t id_1, uint32_t id_2,
 		       uint32_t entry, uint64_t timestamp)
 {
@@ -93,7 +93,7 @@ static void put_header(uint32_t *dst, const struct sof_uuid_entry *uid,
 }
 
 /** Ring buffer for the mailbox trace */
-static inline void mtrace_event(const char *data, uint32_t length)
+void mtrace_event(const char *data, uint32_t length)
 {
 	struct trace *trace = trace_get();
 	char *t = (char *)MAILBOX_TRACE_BASE;
@@ -531,3 +531,22 @@ void trace_init(struct sof *sof)
 
 	dma_trace_init_early(sof);
 }
+
+void mtrace_dict_entry(uint32_t dict_entry_address, int n_args, ...)
+{
+	va_list ap;
+	int i;
+	char packet[MESSAGE_SIZE(_TRACE_EVENT_MAX_ARGUMENT_COUNT)];
+	uint32_t *args = (uint32_t *)&packet[MESSAGE_SIZE(0)];
+	const uint64_t tstamp = platform_safe_get_time(timer_get());
+
+	put_header(packet, dt_tr.uuid_p, _TRACE_INV_ID, _TRACE_INV_ID,
+		   dict_entry_address, tstamp);
+
+	va_start(ap, n_args);
+	for (i = 0; i < n_args; i++)
+		args[i] = va_arg(ap, uint32_t);
+	va_end(ap);
+
+	mtrace_event(packet, MESSAGE_SIZE(n_args));
+}

zephyr/include/sof/trace/trace.h

@@ -25,18 +25,26 @@ struct timer;
 uint64_t platform_timer_get(struct timer *timer);
 
 /*
- * Use SOF macros, but let Zephyr take care of the physical log IO.
+ * Override SOF dictionary macros for now and let Zephyr take care of
+ * the physical log IO.
  */
 #undef _log_message
+#undef mtrace_printf
 
 #if USE_PRINTK
+#define mtrace_printf(level, format, ...)				\
+	do {								        \
+		if ((level) <= SOF_ZEPHYR_TRACE_LEVEL)                          \
+			printk("%llu: " format "\n", platform_timer_get(NULL),	\
+				##__VA_ARGS__);					\
+	} while (0)
 #define _log_message(log_func, atomic, level, comp_class, ctx, id1, id2, format, ...)	\
 	do {								        \
 		if ((level) <= SOF_ZEPHYR_TRACE_LEVEL)                          \
 			printk("%llu: " format "\n", platform_timer_get(NULL),	\
 				##__VA_ARGS__);					\
 	} while (0)
-#else
+#else /* not tested */
 #define _log_message(log_func, atomic, level, comp_class, ctx, id1, id2, format, ...)	\
 	do {								        \
 		Z_LOG(level, "%u: " format, (uint32_t)platform_timer_get(NULL),	\