[ambz2] Implement reading eFuse

ltchiptool/soc/ambz2/flash.py

@@ -8,15 +8,20 @@
 from ltchiptool.util.streams import ProgressCallback
 from uf2tool import OTAScheme, UploadContext
 
-from .util.ambz2tool import AmbZ2Tool
+from .util.ambz2code import AMBZ2_CODE_EFUSE_READ
+from .util.ambz2tool import (
+    AMBZ2_CODE_ADDR,
+    AMBZ2_DATA_ADDR,
+    AMBZ2_EFUSE_PHYSICAL_SIZE,
+    AmbZ2Tool,
+)
 
 
 class AmebaZ2Flash(SocInterface, ABC):
     amb: Optional[AmbZ2Tool] = None
 
     def flash_get_features(self) -> FlashFeatures:
         return FlashFeatures(
-            can_read_efuse=False,
             can_read_info=False,
         )
 
@@ -82,6 +87,8 @@ def flash_get_size(self, memory: FlashMemoryType = FlashMemoryType.FLASH) -> int
             return 0x200000
         if memory == FlashMemoryType.ROM:
             return 384 * 1024
+        if memory == FlashMemoryType.EFUSE:
+            return AMBZ2_EFUSE_PHYSICAL_SIZE
         raise NotImplementedError("Memory type not readable via UART")
 
     def flash_read_raw(
@@ -94,6 +101,10 @@ def flash_read_raw(
     ) -> Generator[bytes, None, None]:
         self.flash_connect()
         assert self.amb
+        if memory == FlashMemoryType.EFUSE:
+            self.amb.register_write_bytes(AMBZ2_CODE_ADDR, AMBZ2_CODE_EFUSE_READ)
+            self.amb.memory_boot(AMBZ2_CODE_ADDR, force_find=True)
+            offset |= AMBZ2_DATA_ADDR
         gen = self.amb.memory_read(
             offset=offset,
             length=length,

ltchiptool/soc/ambz2/util/ambz2code.py

@@ -0,0 +1,40 @@
+#  Copyright (c) Kuba Szczodrzyński 2023-11-7.
+
+AMBZ2_CODE_EFUSE_READ = (
+    # push {r3-r5,lr}
+    # movs r5, #0
+    # loop:
+    # ldr r0, EFUSE_CTRL_SETTING
+    # movs r1, r5
+    # ldr r2, read_data
+    # add r2, r5
+    # movs r3, #0xAA
+    # strb r3, [r2]
+    # movs r3, #0
+    # ldr r4, hal_efuse_stubs
+    # adds r4, r4, #8
+    # ldr r4, [r4]
+    # blx r4
+    # ldr r3, read_size
+    # adds r5, r5, #1
+    # cmp r5, r3
+    # bne loop
+    # pop {r3-r5,pc}
+    # EFUSE_CTRL_SETTING: .word 0x33300000
+    # hal_efuse_stubs: .word 0x500
+    # read_size: .word 512
+    # read_data: .word 0x10038000
+    b"\x38\xb5\x00\x25"
+    b"\x07\x48\x29\x00"
+    b"\x09\x4a\x2a\x44"
+    b"\xaa\x23\x13\x70"
+    b"\x00\x23\x05\x4c"
+    b"\x08\x34\x24\x68"
+    b"\xa0\x47\x04\x4b"
+    b"\x6d\x1c\x9d\x42"
+    b"\xf0\xd1\x38\xbd"
+    b"\x00\x00\x30\x33"  # EFUSE_CTRL_SETTING
+    b"\x00\x05\x00\x00"  # hal_efuse_stubs
+    b"\x00\x02\x00\x00"  # read_size
+    b"\x00\x80\x03\x10"  # read_data
+)