From 8f22819d47a1eee0277e248c677637e9f839cd70 Mon Sep 17 00:00:00 2001
From: Nick Brassel <nick@tzarc.org>
Date: Tue, 25 Jan 2022 01:18:05 +1100
Subject: [PATCH] Default EEPROM implementation should be transient when not
 implemented. Removed the equivalent eeprom_teensy fallback. (#16020)

---
 common_features.mk                | 18 ++++++++--
 platforms/chibios/eeprom_teensy.c | 59 +------------------------------
 2 files changed, 17 insertions(+), 60 deletions(-)

diff --git a/common_features.mk b/common_features.mk
index b13f9a45d2..d07c137066 100644
--- a/common_features.mk
+++ b/common_features.mk
@@ -158,47 +158,61 @@ ifeq ($(filter $(EEPROM_DRIVER),$(VALID_EEPROM_DRIVER_TYPES)),)
 else
   OPT_DEFS += -DEEPROM_ENABLE
   ifeq ($(strip $(EEPROM_DRIVER)), custom)
+    # Custom EEPROM implementation -- only needs to implement init/erase/read_block/write_block
     OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_CUSTOM
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
     SRC += eeprom_driver.c
   else ifeq ($(strip $(EEPROM_DRIVER)), i2c)
+    # External I2C EEPROM implementation
     OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_I2C
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
     QUANTUM_LIB_SRC += i2c_master.c
     SRC += eeprom_driver.c eeprom_i2c.c
   else ifeq ($(strip $(EEPROM_DRIVER)), spi)
+    # External SPI EEPROM implementation
     OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_SPI
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
     QUANTUM_LIB_SRC += spi_master.c
     SRC += eeprom_driver.c eeprom_spi.c
   else ifeq ($(strip $(EEPROM_DRIVER)), transient)
+    # Transient EEPROM implementation -- no data storage but provides runtime area for it
     OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_TRANSIENT
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
     SRC += eeprom_driver.c eeprom_transient.c
   else ifeq ($(strip $(EEPROM_DRIVER)), vendor)
+    # Vendor-implemented EEPROM
     OPT_DEFS += -DEEPROM_VENDOR
     ifeq ($(PLATFORM),AVR)
       # Automatically provided by avr-libc, nothing required
     else ifeq ($(PLATFORM),CHIBIOS)
       ifneq ($(filter STM32F3xx_% STM32F1xx_% %_STM32F401xC %_STM32F401xE %_STM32F405xG %_STM32F411xE %_STM32F072xB %_STM32F042x6 %_GD32VF103xB %_GD32VF103x8, $(MCU_SERIES)_$(MCU_LDSCRIPT)),)
+        # Emulated EEPROM
         OPT_DEFS += -DEEPROM_DRIVER
         COMMON_VPATH += $(DRIVER_PATH)/eeprom
         SRC += eeprom_driver.c
         SRC += $(PLATFORM_COMMON_DIR)/eeprom_stm32.c
         SRC += $(PLATFORM_COMMON_DIR)/flash_stm32.c
       else ifneq ($(filter $(MCU_SERIES),STM32L0xx STM32L1xx),)
+        # True EEPROM on STM32L0xx, L1xx
         OPT_DEFS += -DEEPROM_DRIVER
         COMMON_VPATH += $(DRIVER_PATH)/eeprom
         COMMON_VPATH += $(PLATFORM_PATH)/$(PLATFORM_KEY)/$(DRIVER_DIR)/eeprom
         SRC += eeprom_driver.c
         SRC += eeprom_stm32_L0_L1.c
+      else ifneq ($(filter $(MCU_SERIES),KL2x K20x),)
+        # Teensy EEPROM implementations
+        SRC += eeprom_teensy.c
       else
-        # This will effectively work the same as "transient" if not supported by the chip
-        SRC += $(PLATFORM_COMMON_DIR)/eeprom_teensy.c
+        # Fall back to transient, i.e. non-persistent
+        OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_TRANSIENT
+        COMMON_VPATH += $(DRIVER_PATH)/eeprom
+        SRC += eeprom_driver.c eeprom_transient.c
       endif
     else ifeq ($(PLATFORM),ARM_ATSAM)
+      # arm_atsam EEPROM
       SRC += $(PLATFORM_COMMON_DIR)/eeprom.c
     else ifeq ($(PLATFORM),TEST)
+      # Test harness "EEPROM"
       SRC += $(PLATFORM_COMMON_DIR)/eeprom.c
     endif
   endif
diff --git a/platforms/chibios/eeprom_teensy.c b/platforms/chibios/eeprom_teensy.c
index 4aaf665269..2093f9b4b2 100644
--- a/platforms/chibios/eeprom_teensy.c
+++ b/platforms/chibios/eeprom_teensy.c
@@ -524,64 +524,7 @@ void eeprom_write_block(const void *buf, void *addr, uint32_t len) {
 }
 
 #else
-// No EEPROM supported, so emulate it
-
-#    ifndef EEPROM_SIZE
-#        include "eeconfig.h"
-#        define EEPROM_SIZE (((EECONFIG_SIZE + 3) / 4) * 4)  // based off eeconfig's current usage, aligned to 4-byte sizes, to deal with LTO
-#    endif
-__attribute__((aligned(4))) static uint8_t buffer[EEPROM_SIZE];
-
-uint8_t eeprom_read_byte(const uint8_t *addr) {
-    uint32_t offset = (uint32_t)addr;
-    return buffer[offset];
-}
-
-void eeprom_write_byte(uint8_t *addr, uint8_t value) {
-    uint32_t offset = (uint32_t)addr;
-    buffer[offset]  = value;
-}
-
-uint16_t eeprom_read_word(const uint16_t *addr) {
-    const uint8_t *p = (const uint8_t *)addr;
-    return eeprom_read_byte(p) | (eeprom_read_byte(p + 1) << 8);
-}
-
-uint32_t eeprom_read_dword(const uint32_t *addr) {
-    const uint8_t *p = (const uint8_t *)addr;
-    return eeprom_read_byte(p) | (eeprom_read_byte(p + 1) << 8) | (eeprom_read_byte(p + 2) << 16) | (eeprom_read_byte(p + 3) << 24);
-}
-
-void eeprom_read_block(void *buf, const void *addr, size_t len) {
-    const uint8_t *p    = (const uint8_t *)addr;
-    uint8_t *      dest = (uint8_t *)buf;
-    while (len--) {
-        *dest++ = eeprom_read_byte(p++);
-    }
-}
-
-void eeprom_write_word(uint16_t *addr, uint16_t value) {
-    uint8_t *p = (uint8_t *)addr;
-    eeprom_write_byte(p++, value);
-    eeprom_write_byte(p, value >> 8);
-}
-
-void eeprom_write_dword(uint32_t *addr, uint32_t value) {
-    uint8_t *p = (uint8_t *)addr;
-    eeprom_write_byte(p++, value);
-    eeprom_write_byte(p++, value >> 8);
-    eeprom_write_byte(p++, value >> 16);
-    eeprom_write_byte(p, value >> 24);
-}
-
-void eeprom_write_block(const void *buf, void *addr, size_t len) {
-    uint8_t *      p   = (uint8_t *)addr;
-    const uint8_t *src = (const uint8_t *)buf;
-    while (len--) {
-        eeprom_write_byte(p++, *src++);
-    }
-}
-
+#    error Unsupported Teensy EEPROM.
 #endif /* chip selection */
 // The update functions just calls write for now, but could probably be optimized