From fbb710a4e3f891a59cfa816666e073b91bec0cb4 Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Mon, 7 Jul 2025 16:06:18 +0200
Subject: [PATCH] added TLV code for EEPROM (not used for now).

---
 avr/common/eeprom_tlv.asm | 135 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 avr/common/eeprom_tlv.asm

diff --git a/avr/common/eeprom_tlv.asm b/avr/common/eeprom_tlv.asm
new file mode 100644
index 0000000..23a4709
--- /dev/null
+++ b/avr/common/eeprom_tlv.asm
@@ -0,0 +1,135 @@
+; ***************************************************************************
+; copyright   : (C) 2025 by Martin Preuss
+; email       : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome".                              *
+; * Please see toplevel file COPYING of that project for license details.   *
+; ***************************************************************************
+
+#ifndef AQH_AVR_COMMON_EEPROM_TLV_H
+#define AQH_AVR_COMMON_EEPROM_TLV_H
+
+
+; ---------------------------------------------------------------------------
+; @routine EepromTlv_AddTlv @global
+;
+; @param r16 type (must not be 0xff!)
+; @param r17 length
+; @return CFLAG set if free bytes found, cleared on error
+; @return X EEPROM address of data for TLV (behind TLV header)
+; @clobbers R16, R20, R21, X (R18)
+
+EepromTlv_AddTlv:
+  mov r20, r16
+  mov r21, r17
+  ldi r16, 0xff
+  rcall EepromTlv_FindFirst       ; (R18)
+  brcc EepromTlv_AddTlv_end
+  cpi r17, 0xff
+  brne EepromTlv_AddTlv_clcEnd
+  add xl, r21                     ; wanted size
+  adc xh, r21
+  sub xh, r21
+  rcall Eeprom_CheckAddr          ; check end address
+  brcc EepromTlv_AddTlv_end
+  sub xl, r21
+  sbc xh, r21
+  add xh, r21
+  sbiw xh:xl, 2
+  mov r16, r20                    ; type
+  rcall Eeprom_WriteByte
+  adiw xh:xl, 1
+  mov r16, r21                    ; length
+  rcall Eeprom_WriteByte
+  adiw xh:xl, 1
+  sec
+  rjmp EepromTlv_AddTlv_end
+EepromTlv_AddTlv_clcEnd:
+  clc
+EepromTlv_AddTlv_end:
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine EepromTlv_FindFirst @global
+;
+; Find first matching TLV
+;
+; @param r16 TLV type to find
+; @return CFLAG set if TLV found, cleared otherwise
+; @return r16 type
+; @return r17 length
+; @return X points to begin of TLV data
+; @clobbers r18
+
+EepromTlv_FindFirst:
+  ldi xl, LOW(EEPROM_OFFS_TLV)
+  ldi xh, HIGH(EEPROM_OFFS_TLV)
+  rjmp EepromTlv_Find
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine EepromTlv_Find @global
+;
+; @param r16 TLV type to find
+; @param X EEPROM address to start search
+; @return CFLAG set if TLV found, cleared otherwise
+; @return r16 type
+; @return r17 length
+; @return X points to begin of TLV data
+; @clobbers r18
+
+EepromTlv_Find:
+  mov r18, r16
+EepromTlv_Find_loop:
+    rcall EepromTlv_ReadHeader
+    brcc EepromTlv_Find_notFound
+    cpi r16, r18                   ; the one we wanted?
+    breq EepromTlv_Find_found
+    add xl, r17                    ; skip TLV data
+    adc xh, r17
+    sub xh, r17
+  rjmp EepromTlv_Find_loop
+EepromTlv_Find_notFound:
+  clc
+  rjmp EepromTlv_Find_end
+EepromTlv_Find_found:
+  sec
+EepromTlv_Find_end:
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine EepromTlv_ReadHeader
+;
+; @param X EEPROM address
+; @return CFLAG set if address okay, cleared if out of range
+; @return r16 type
+; @return r17 length (only data length, can be 0)
+; @return X EEPROM address behind TLV header
+; @clobbers none
+
+EepromTlv_ReadHeader:
+  rcall Eeprom_ReadByteIncr   ; read type
+  brcc EepromTlv_ReadHeader
+  adiw xh:xl, 1
+  push r16
+    rcall Eeprom_ReadByteIncr ; read length
+    mov r17, r16
+  pop r16
+  brcc EepromTlv_ReadHeader
+  adiw xh:xl, 1
+  sec
+EepromTlv_ReadHeader:
+  ret
+; @end
+
+
+