Add linker scripts

targets/stm32l432/linker/stm32l4xx.ld

@@ -14,13 +14,23 @@ _MIN_STACK_SIZE = 0x400;
 
 /*
     Memory layout of device:
-        20 KB            198KB-8            38 KB
-    | bootloader |    application     |  secrets/data |
+        20+2 KB            198KB-2KB -8            38 KB
+    | bootloader |          application      |  secrets/data |
+
+    Last 8 bytes in application space are occupied by bootloader flags - app
+    authorization and bootloader activation flag.
  */
 
+/* Current firmware version number
+Should be equal to (APPLICATION_END_ADDR-8) from targets/stm32l432/src/memory_layout.h:40 */
+_version_start = 0x08000000 + (128-19)*2048-8-8;
+
+/* flash length is (APPLICATION_END_PAGE-20*1024), where 20K is bootloader */
+
 MEMORY
 {
-    flash (rx)      : ORIGIN = 0x08005000, LENGTH = 198K - 8
+    flash (rx)      : ORIGIN = 0x08005000 + 2K, LENGTH = 198K - 8 - 8 - 2K
+    flash_v (rx)    : ORIGIN = 0x08000000 + (128-19)*2048 - 8 - 8, LENGTH = 8
     ram (xrw)       : ORIGIN = 0x20000000, LENGTH = 48K
     sram2 (rw)      : ORIGIN = 0x10000000, LENGTH = 16K
 }
@@ -47,6 +57,13 @@ SECTIONS
 
     _sidata = LOADADDR(.data);
 
+
+    .flag _version_start :
+    {
+      KEEP(*(.flag)) ;
+    } > flash_v
+
+
     .data :
     {
         . = ALIGN(8);