atsame51: add initial support for feather-m4-can

targets/atsame51j19a.json

@@ -0,0 +1,10 @@
+{
+	"inherits": ["cortex-m4"],
+	"build-tags": ["atsame51j19a", "atsame51j19", "atsame51", "atsame5x", "sam"],
+	"linkerscript": "targets/atsame5xx19.ld",
+	"extra-files": [
+		"src/device/sam/atsame51j19a.s"
+	],
+	"openocd-transport": "swd",
+	"openocd-target": "atsame5x"
+}

targets/atsame5xx19.ld

@@ -0,0 +1,10 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x00000000+0x4000, LENGTH = 0x00080000-0x4000  /* First 16KB used by bootloader */
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 0x00030000
+}
+
+_stack_size = 4K;
+
+INCLUDE "targets/arm.ld"

targets/feather-m4-can.json

@@ -0,0 +1,8 @@
+{
+    "inherits": ["atsame51j19a"],
+    "build-tags": ["feather_m4_can"],
+    "flash-1200-bps-reset": "true",
+    "flash-method": "msd",
+    "msd-volume-name": "FTHRCANBOOT",
+    "msd-firmware-name": "firmware.uf2"
+}