debug: tracing: Add Segger RTT linker section options

drivers/console/rtt_console.c

@@ -41,9 +41,7 @@ static int rtt_console_out(int character)
 	int max_cnt = CONFIG_RTT_TX_RETRY_CNT;
 
 	do {
-		SEGGER_RTT_LOCK();
-		cnt = SEGGER_RTT_WriteNoLock(0, &c, 1);
-		SEGGER_RTT_UNLOCK();
+		cnt = SEGGER_RTT_Write(0, &c, 1);
 
 		/* There are two possible reasons for not writing any data to
 		 * RTT:

modules/segger/CMakeLists.txt

@@ -10,6 +10,8 @@ if(CONFIG_USE_SEGGER_RTT)
     SEGGER_RTT_zephyr.c
   )
   zephyr_library_sources_ifdef(CONFIG_SEGGER_SYSTEMVIEW ${SEGGER_DIR}/SEGGER/SEGGER_SYSVIEW.c)
+  # Using sort key AAA to ensure that we are placed at start of RAM
+  zephyr_linker_sources_ifdef(CONFIG_SEGGER_RTT_SECTION_CUSTOM RAM_SECTIONS SORT_KEY aaa segger_rtt.ld)
 endif()
 
 if(CONFIG_SEGGER_DEBUGMON)

modules/segger/Kconfig

@@ -72,6 +72,7 @@ config SEGGER_RTT_MEMCPY_USE_BYTELOOP
 
 choice SEGGER_RTT_SECTION
 	prompt "Choose RTT data linker section"
+	default SEGGER_RTT_SECTION_CUSTOM
 
 config SEGGER_RTT_SECTION_NONE
 	bool "Place RTT data in the default linker section"
@@ -82,6 +83,43 @@ config SEGGER_RTT_SECTION_DTCM
 config SEGGER_RTT_SECTION_CCM
 	bool "Place RTT data in the CCM linker section"
 
+if CPU_CORTEX_M
+
+config SEGGER_RTT_SECTION_CUSTOM
+	bool "Place RTT data in custom linker section at RAM start"
+
+config SEGGER_RTT_SECTION_CUSTOM_DTS_REGION
+	bool "Place RTT data in custom linker section defined by a memory region in DTS"
+
+endif
+
+endchoice
+
+if SEGGER_RTT_SECTION_CUSTOM || SEGGER_RTT_SECTION_CUSTOM_DTS_REGION
+
+config SEGGER_RTT_SECTION_CUSTOM_NAME
+	string "Name of RTT data custom linker section"
+	default ".rtt_buff_data"
+
+endif
+
+choice SEGGER_RTT_INIT_MODE
+	prompt "RTT Initialization mode"
+	help
+		RTT inizialization function can avoid re-init of Cntrol Block
+		if another program (e.g. bootloader) has already initialized it.
+	default SEGGER_RTT_INIT_MODE_STRONG_CHECK if SEGGER_RTT_SECTION_CUSTOM
+	default SEGGER_RTT_INIT_MODE_STRONG_CHECK
+
+config SEGGER_RTT_INIT_MODE_ALWAYS
+	bool "RTT Initialization done without conditions"
+
+config SEGGER_RTT_INIT_MODE_STRONG_CHECK
+	bool "RTT Initialization done if full check on Control Block ID fails"
+
+config SEGGER_RTT_INIT_MODE_WEAK_CHECK
+	bool "RTT Initialization done if partial check on Control Block ID fails"
+
 endchoice
 
 endif

modules/segger/segger_rtt.ld

@@ -0,0 +1,7 @@
+SECTION_DATA_PROLOGUE(_RTT_SECTION_NAME,(NOLOAD),)
+{
+__rtt_buff_data_start = .;
+*(CONFIG_SEGGER_RTT_SECTION_CUSTOM_NAME)
+__rtt_buff_data_end = ALIGN(4);
+} GROUP_DATA_LINK_IN(RAMABLE_REGION, RAMABLE_REGION)
+__rtt_buff_data_size = __rtt_buff_data_end - __rtt_buff_data_start;