From e00326a6db6671414b43ee15e092c57ea976102f Mon Sep 17 00:00:00 2001
From: Selene ToyKeeper
Date: Tue, 7 Nov 2023 08:09:10 -0700
Subject: made build fail if eeprom data bigger than MCU's eeprom size

Based on techniques suggested by DurvalMenezes here:
https://github.com/ToyKeeper/anduril/pull/4
---
 fsm/eeprom.h | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

(limited to 'fsm/eeprom.h')

diff --git a/fsm/eeprom.h b/fsm/eeprom.h
index 440d2b3..1e10fd2 100644
--- a/fsm/eeprom.h
+++ b/fsm/eeprom.h
@@ -7,44 +7,49 @@
 #include <avr/eeprom.h>
 
 // set this higher to enable normal eeprom functions
+// TODO: rename to EEPROM_BYTES_NEEDED or similar, to make purpose clearer
 #ifndef EEPROM_BYTES
 #define EEPROM_BYTES 0
 #endif
 
 // set this higher to enable wear-levelled eeprom functions
+// TODO: rename to EEPROM_WL_BYTES_NEEDED or similar, to make purpose clearer
 #ifndef EEPROM_WL_BYTES
 #define EEPROM_WL_BYTES 0
 #endif
 
 #ifdef USE_EEPROM
-// this fails when EEPROM_BYTES is a sizeof()
-//#if EEPROM_BYTES >= (EEPSIZE/2)
-//#error Requested EEPROM_BYTES too big.
-//#endif
-#ifdef EEPROM_OVERRIDE
-uint8_t *eeprom;
-#else
-uint8_t eeprom[EEPROM_BYTES];
-#endif
-uint8_t load_eeprom();  // returns 1 for success, 0 for no data found
-void save_eeprom();
-#define EEP_START (EEPSIZE/2)
+    #ifdef USE_EEPROM_WL
+        // split eeprom in half
+        #define EEP_START  (EEPROM_SIZE/2)
+        BUILD_ASSERT(eep_less_than_half, EEPROM_BYTES <= (EEPROM_SIZE/2));
+    #else
+        // use entire eeprom
+        #define EEP_START  0
+        BUILD_ASSERT(eep_data_fits, EEPROM_BYTES <= EEPROM_SIZE);
+    #endif
+    #ifdef EEPROM_OVERRIDE
+        uint8_t *eeprom;
+    #else
+        uint8_t eeprom[EEPROM_BYTES];
+    #endif
+    uint8_t load_eeprom();  // returns 1 for success, 0 for no data found
+    void save_eeprom();
 #endif
 
 #ifdef USE_EEPROM_WL
-#if EEPROM_WL_BYTES >= (EEPSIZE/4)
-#error Requested EEPROM_WL_BYTES too big.
-#endif
-uint8_t eeprom_wl[EEPROM_WL_BYTES];
-uint8_t load_eeprom_wl();  // returns 1 for success, 0 for no data found
-void save_eeprom_wl();
-#define EEP_WL_SIZE (EEPSIZE/2)
+    #define EEP_WL_SIZE (EEPROM_SIZE/2)
+    // ensure space for at least 2 slots for wear levelling
+    BUILD_ASSERT(eepwl_two_slots_minimum, EEPROM_WL_BYTES <= (EEP_WL_SIZE/2));
+    uint8_t eeprom_wl[EEPROM_WL_BYTES];
+    uint8_t load_eeprom_wl();  // returns 1 for success, 0 for no data found
+    void save_eeprom_wl();
 #endif
 
-#if EEPSIZE > 256
-#define EEP_OFFSET_T uint16_t
+#if EEPROM_SIZE > 256
+    #define EEP_OFFSET_T uint16_t
 #else
-#define EEP_OFFSET_T uint8_t
+    #define EEP_OFFSET_T uint8_t
 #endif
 
 // if this marker isn't found, the eeprom is assumed to be blank
-- 
cgit v1.2.3