debug_stream: text_msg: add optional assert_print() forwarding

Add optional support to route assert output through debug stream text
messages.

Introduce Kconfig option SOF_DEBUG_STREAM_TEXT_MSG_ASSERT_PRINT
(depends on EXCEPTION_DUMP_HOOK and ASSERT/ASSERT_VERBOSE).

Implement assert_print(const char *fmt, ...) to emit via ds_vamsg(),
and mirror to vprintk() when CONFIG_EXCEPTION_DUMP_HOOK_ONLY is not
set.

Avoid duplicate post-fault prints by skipping assert output after an
exception report has already been sent on the current CPU.

Export assert_print for use by assert paths.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

Author: Jyri Sarha

src/debug/debug_stream/Kconfig

@@ -65,4 +65,13 @@ config SOF_DEBUG_STREAM_TEXT_MSG
 	  ds_msg(). See include/user/debug_stream_text_msg.h for
 	  prototype.
 
+config SOF_DEBUG_STREAM_TEXT_MSG_ASSERT_PRINT
+	bool "Enable assert print sending through Debug-Stream"
+	depends on EXCEPTION_DUMP_HOOK && (ASSERT || ASSERT_VERBOSE)
+	help
+	  Enable assert print sending over debug stream as text
+	  message. This feature is also sensitive to Zephyr option
+	  CONFIG_EXCEPTION_DUMP_HOOK_ONLY. If that is set then the
+	  asserts are not printed through printk interface.
+
 endif

src/debug/debug_stream/debug_stream_text_msg.c

@@ -142,4 +142,25 @@ static int init_exception_dump_hook(void)
 }
 
 SYS_INIT(init_exception_dump_hook, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
+
+#if defined(CONFIG_SOF_DEBUG_STREAM_TEXT_MSG_ASSERT_PRINT)
+
+void assert_print(const char *fmt, ...)
+{
+	va_list ap;
+
+	/* Do not print assert after exception has been dumped */
+	if (reports_sent_cpu[arch_proc_id()] > 0)
+		return;
+
+	va_start(ap, fmt);
+
+	ds_vamsg(fmt, ap);
+#if !defined(CONFIG_EXCEPTION_DUMP_HOOK_ONLY)
+	vprintk(fmt, ap);
+#endif
+	va_end(ap);
+}
+EXPORT_SYMBOL(assert_print);
+#endif
 #endif