scripts: west_commands: runners: esp32: add flash encryption option

Add an argument `--esp-encrypt` to flash an ESP32 series chip with
encrypted flash.

The content of the binary is encrypted on the fly by the chip. It is
not required to know the encryption key. However, the fuses that
disable encrypted flash download must be kept enabled for this to work.

Signed-off-by: Martin Jäger <[email protected]>

scripts/west_commands/runners/esp32.py

@@ -19,7 +19,7 @@ def __init__(self, cfg, device, boot_address, part_table_address,
                  app_address, erase=False, reset=False, baud=921600,
                  flash_size='detect', flash_freq='40m', flash_mode='dio',
                  espidf='espidf', bootloader_bin=None, partition_table_bin=None,
-                 no_stub=False):
+                 encrypt=False, no_stub=False):
         super().__init__(cfg)
         self.elf = cfg.elf_file
         self.app_bin = cfg.bin_file
@@ -36,6 +36,7 @@ def __init__(self, cfg, device, boot_address, part_table_address,
         self.espidf = espidf
         self.bootloader_bin = bootloader_bin
         self.partition_table_bin = partition_table_bin
+        self.encrypt = encrypt
         self.no_stub = no_stub
 
     @classmethod
@@ -78,6 +79,8 @@ def do_add_parser(cls, parser):
                             help='Bootloader image to flash')
         parser.add_argument('--esp-flash-partition_table',
                             help='Partition table to flash')
+        parser.add_argument('--esp-encrypt', default=False, action='store_true',
+                            help='Encrypt firmware while flashing (correct efuses required)')
         parser.add_argument('--esp-no-stub', default=False, action='store_true',
                             help='Disable launching the flasher stub, only talk to ROM bootloader')
 
@@ -99,7 +102,7 @@ def do_create(cls, cfg, args):
             flash_freq=args.esp_flash_freq, flash_mode=args.esp_flash_mode,
             espidf=espidf, bootloader_bin=args.esp_flash_bootloader,
             partition_table_bin=args.esp_flash_partition_table,
-            no_stub=args.esp_no_stub)
+            encrypt=args.esp_encrypt, no_stub=args.esp_no_stub)
 
     def do_run(self, command, **kwargs):
         self.require(self.espidf)
@@ -124,6 +127,9 @@ def do_run(self, command, **kwargs):
         cmd_flash.extend(['--flash_freq', self.flash_freq])
         cmd_flash.extend(['--flash_size', self.flash_size])
 
+        if self.encrypt:
+            cmd_flash.extend(['--encrypt'])
+
         if self.bootloader_bin:
             cmd_flash.extend([self.boot_address, self.bootloader_bin])
             if self.partition_table_bin: