add uf2 target for uf2 bootloader board: metro m0/m4 feather nrf52840

hw/bsp/feather_nrf52840_express/board.mk

@@ -12,7 +12,7 @@ CFLAGS += \
 CFLAGS += -Wno-error=undef 
 
 # All source paths should be relative to the top level.
-LD_FILE = hw/mcu/nordic/nrfx/mdk/nrf52840_xxaa.ld
+LD_FILE = hw/bsp/feather_nrf52840_express/nrf52840_s140_v6.ld
 
 LDFLAGS += -L$(TOP)/hw/mcu/nordic/nrfx/mdk
 
@@ -47,5 +47,8 @@ FREERTOS_PORT = ARM_CM4F
 JLINK_DEVICE = nRF52840_xxAA
 JLINK_IF = swd
 
+# For uf2 conversion
+UF2_FAMILY = 0xADA52840
+
 # flash using jlink
 flash: flash-jlink

hw/bsp/feather_nrf52840_express/nrf52840_s140_v6.ld

@@ -0,0 +1,38 @@
+/* Linker script to configure memory regions. */
+
+SEARCH_DIR(.)
+GROUP(-lgcc -lc -lnosys)
+
+MEMORY
+{
+  FLASH (rx)     : ORIGIN = 0x26000, LENGTH = 0xED000 - 0x26000
+
+  /* SRAM required by S132 depend on
+   * - Attribute Table Size
+   * - Vendor UUID count
+   * - Max ATT MTU
+   * - Concurrent connection peripheral + central + secure links
+   * - Event Len, HVN queue, Write CMD queue
+   */ 
+  RAM (rwx) :  ORIGIN = 0x20003400, LENGTH = 0x20040000 - 0x20003400
+}
+
+SECTIONS
+{
+  . = ALIGN(4);
+  .svc_data :
+  {
+    PROVIDE(__start_svc_data = .);
+    KEEP(*(.svc_data))
+    PROVIDE(__stop_svc_data = .);
+  } > RAM
+  
+  .fs_data :
+  {
+    PROVIDE(__start_fs_data = .);
+    KEEP(*(.fs_data))
+    PROVIDE(__stop_fs_data = .);
+  } > RAM
+} INSERT AFTER .data;
+
+INCLUDE "nrf52_common.ld"