eeprom_stm32: implement high density wear leveling (#12567)

* eeprom_stm32: implement wear leveling
Update EECONFIG_MAGIC_NUMBER
eeprom_stm32: check emulated eeprom size is large enough
* eeprom_stm32: Increasing simulated EEPROM density on stm32
* Adding utility script to decode emulated eeprom
* Adding unit tests
* Applying qmk cformat changes
* cleaned up flash mocking
* Fix for stm32eeprom_parser.py checking via signature with wrong base
* Fix for nk65 keyboard

Co-authored-by: Ilya Zhuravlev <whatever@xyz.is>
Co-authored-by: zvecr <git@zvecr.com>

4 files changed, 512 insertions, 0 deletions

diff --git a/tmk_core/common/test/eeprom_stm32_tests.cpp b/tmk_core/common/test/eeprom_stm32_tests.cpp
new file mode 100644
index 0000000000..aa84492b87
--- /dev/null
+++ b/tmk_core/common/test/eeprom_stm32_tests.cpp
@@ -0,0 +1,438 @@
+/* Copyright 2021 by Don Kjer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gtest/gtest.h"
+
+extern "C" {
+#include "flash_stm32.h"
+#include "eeprom_stm32.h"
+#include "eeprom.h"
+}
+
+/* Mock Flash Parameters:
+ *
+ * === Large Layout ===
+ * flash size: 65536
+ * page size: 2048
+ * density pages: 16
+ * Simulated EEPROM size: 16384
+ *
+ * FlashBuf Layout:
+ * [Unused | Compact |  Write Log  ]
+ * [0......|32768......|49152......65535]
+ *
+ * === Tiny Layout ===
+ * flash size: 1024
+ * page size: 512
+ * density pages: 1
+ * Simulated EEPROM size: 256
+ *
+ * FlashBuf Layout:
+ * [Unused | Compact |  Write Log  ]
+ * [0......|512......|768......1023]
+ *
+ */
+
+#define EEPROM_SIZE (FEE_PAGE_SIZE * FEE_DENSITY_PAGES / 2)
+#define LOG_SIZE EEPROM_SIZE
+#define LOG_BASE (MOCK_FLASH_SIZE - LOG_SIZE)
+#define EEPROM_BASE (LOG_BASE - EEPROM_SIZE)
+
+/* Log encoding helpers */
+#define BYTE_VALUE(addr, value) (((addr) << 8) | (value))
+#define WORD_ZERO(addr) (0x8000 | ((addr) >> 1))
+#define WORD_ONE(addr) (0xA000 | ((addr) >> 1))
+#define WORD_NEXT(addr) (0xE000 | (((addr)-0x80) >> 1))
+
+class EepromStm32Test : public testing::Test {
+   public:
+    EepromStm32Test() {}
+    ~EepromStm32Test() {}
+
+   protected:
+    void SetUp() override { EEPROM_Erase(); }
+
+    void TearDown() override {
+#ifdef EEPROM_DEBUG
+        dumpEepromDataBuf();
+#endif
+    }
+};
+
+TEST_F(EepromStm32Test, TestErase) {
+    EEPROM_WriteDataByte(0, 0x42);
+    EEPROM_Erase();
+    EXPECT_EQ(EEPROM_ReadDataByte(0), 0);
+    EXPECT_EQ(EEPROM_ReadDataByte(1), 0);
+}
+
+TEST_F(EepromStm32Test, TestReadGarbage) {
+    uint8_t garbage = 0x3c;
+    for (int i = 0; i < MOCK_FLASH_SIZE; ++i) {
+        garbage ^= 0xa3;
+        garbage += i;
+        FlashBuf[i] = garbage;
+    }
+    EEPROM_Init();  // Just verify we don't crash
+}
+
+TEST_F(EepromStm32Test, TestWriteBadAddress) {
+    EXPECT_EQ(EEPROM_WriteDataByte(EEPROM_SIZE, 0x42), FLASH_BAD_ADDRESS);
+    EXPECT_EQ(EEPROM_WriteDataWord(EEPROM_SIZE - 1, 0xbeef), FLASH_BAD_ADDRESS);
+    EXPECT_EQ(EEPROM_WriteDataWord(EEPROM_SIZE, 0xbeef), FLASH_BAD_ADDRESS);
+}
+
+TEST_F(EepromStm32Test, TestReadBadAddress) {
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE), 0xFF);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 1), 0xFFFF);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE), 0xFFFF);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 4)), 0);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 3)), 0xFF000000);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)EEPROM_SIZE), 0xFFFFFFFF);
+}
+
+TEST_F(EepromStm32Test, TestReadByte) {
+    /* Direct compacted-area baseline: Address < 0x80 */
+    FlashBuf[EEPROM_BASE + 2] = ~0xef;
+    FlashBuf[EEPROM_BASE + 3] = ~0xbe;
+    /* Direct compacted-area baseline: Address >= 0x80 */
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 2] = ~0x78;
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 1] = ~0x56;
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataByte(2), 0xef);
+    EXPECT_EQ(EEPROM_ReadDataByte(3), 0xbe);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 2), 0x78);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 1), 0x56);
+    /* Write Log byte value */
+    FlashBuf[LOG_BASE]     = 0x65;
+    FlashBuf[LOG_BASE + 1] = 3;
+    /* Write Log word value */
+    *(uint16_t*)&FlashBuf[LOG_BASE + 2] = WORD_NEXT(EEPROM_SIZE - 2);
+    *(uint16_t*)&FlashBuf[LOG_BASE + 4] = ~0x9abc;
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataByte(2), 0xef);
+    EXPECT_EQ(EEPROM_ReadDataByte(3), 0x65);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 2), 0xbc);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 1), 0x9a);
+}
+
+TEST_F(EepromStm32Test, TestWriteByte) {
+    /* Direct compacted-area baseline: Address < 0x80 */
+    EEPROM_WriteDataByte(2, 0xef);
+    EEPROM_WriteDataByte(3, 0xbe);
+    /* Direct compacted-area baseline: Address >= 0x80 */
+    EEPROM_WriteDataByte(EEPROM_SIZE - 2, 0x78);
+    EEPROM_WriteDataByte(EEPROM_SIZE - 1, 0x56);
+    /* Check values */
+    /* First write in each aligned word should have been direct */
+    EXPECT_EQ(FlashBuf[EEPROM_BASE + 2], (uint8_t)~0xef);
+    EXPECT_EQ(FlashBuf[EEPROM_BASE + EEPROM_SIZE - 2], (uint8_t)~0x78);
+
+    /* Second write per aligned word requires a log entry */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE], BYTE_VALUE(3, 0xbe));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 2], WORD_NEXT(EEPROM_SIZE - 1));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 4], (uint16_t)~0x5678);
+}
+
+TEST_F(EepromStm32Test, TestByteRoundTrip) {
+    /* Direct compacted-area: Address < 0x80 */
+    EEPROM_WriteDataWord(0, 0xdead);
+    EEPROM_WriteDataByte(2, 0xef);
+    EEPROM_WriteDataByte(3, 0xbe);
+    /* Direct compacted-area: Address >= 0x80 */
+    EEPROM_WriteDataByte(EEPROM_SIZE - 2, 0x78);
+    EEPROM_WriteDataByte(EEPROM_SIZE - 1, 0x56);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataByte(0), 0xad);
+    EXPECT_EQ(EEPROM_ReadDataByte(1), 0xde);
+    EXPECT_EQ(EEPROM_ReadDataByte(2), 0xef);
+    EXPECT_EQ(EEPROM_ReadDataByte(3), 0xbe);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 2), 0x78);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 1), 0x56);
+    /* Write log entries */
+    EEPROM_WriteDataByte(2, 0x80);
+    EEPROM_WriteDataByte(EEPROM_SIZE - 2, 0x3c);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataByte(2), 0x80);
+    EXPECT_EQ(EEPROM_ReadDataByte(3), 0xbe);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 2), 0x3c);
+    EXPECT_EQ(EEPROM_ReadDataByte(EEPROM_SIZE - 1), 0x56);
+}
+
+TEST_F(EepromStm32Test, TestReadWord) {
+    /* Direct compacted-area baseline: Address < 0x80 */
+    FlashBuf[EEPROM_BASE + 0] = ~0xad;
+    FlashBuf[EEPROM_BASE + 1] = ~0xde;
+    /* Direct compacted-area baseline: Address >= 0x80 */
+    FlashBuf[EEPROM_BASE + 200]             = ~0xcd;
+    FlashBuf[EEPROM_BASE + 201]             = ~0xab;
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 4] = ~0x34;
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 3] = ~0x12;
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 2] = ~0x78;
+    FlashBuf[EEPROM_BASE + EEPROM_SIZE - 1] = ~0x56;
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0), 0xdead);
+    EXPECT_EQ(EEPROM_ReadDataWord(200), 0xabcd);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 4), 0x1234);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 2), 0x5678);
+    /* Write Log word zero-encoded */
+    *(uint16_t*)&FlashBuf[LOG_BASE] = WORD_ZERO(200);
+    /* Write Log word one-encoded */
+    *(uint16_t*)&FlashBuf[LOG_BASE + 2] = WORD_ONE(EEPROM_SIZE - 4);
+    /* Write Log word value */
+    *(uint16_t*)&FlashBuf[LOG_BASE + 4] = WORD_NEXT(EEPROM_SIZE - 2);
+    *(uint16_t*)&FlashBuf[LOG_BASE + 6] = ~0x9abc;
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(200), 0);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 4), 1);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 2), 0x9abc);
+}
+
+TEST_F(EepromStm32Test, TestWriteWord) {
+    /* Direct compacted-area: Address < 0x80 */
+    EEPROM_WriteDataWord(0, 0xdead);  // Aligned
+    EEPROM_WriteDataWord(3, 0xbeef);  // Unaligned
+    /* Direct compacted-area: Address >= 0x80 */
+    EEPROM_WriteDataWord(200, 0xabcd);  // Aligned
+    EEPROM_WriteDataWord(203, 0x9876);  // Unaligned
+    EEPROM_WriteDataWord(EEPROM_SIZE - 4, 0x1234);
+    EEPROM_WriteDataWord(EEPROM_SIZE - 2, 0x5678);
+    /* Write Log word zero-encoded */
+    EEPROM_WriteDataWord(EEPROM_SIZE - 4, 0);
+    /* Write Log word one-encoded */
+    EEPROM_WriteDataWord(EEPROM_SIZE - 2, 1);
+    /* Write Log word value aligned */
+    EEPROM_WriteDataWord(200, 0x4321);  // Aligned
+    /* Write Log word value unaligned */
+    EEPROM_WriteDataByte(202, 0x3c);    // Set neighboring byte
+    EEPROM_WriteDataWord(203, 0xcdef);  // Unaligned
+    /* Check values */
+    /* Direct compacted-area */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[EEPROM_BASE], (uint16_t)~0xdead);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[EEPROM_BASE + 3], (uint16_t)~0xbeef);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[EEPROM_BASE + 200], (uint16_t)~0xabcd);
+    EXPECT_EQ(FlashBuf[EEPROM_BASE + 203], (uint8_t)~0x76);
+    EXPECT_EQ(FlashBuf[EEPROM_BASE + 204], (uint8_t)~0x98);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[EEPROM_BASE + EEPROM_SIZE - 4], (uint16_t)~0x1234);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[EEPROM_BASE + EEPROM_SIZE - 2], (uint16_t)~0x5678);
+    /* Write Log word zero-encoded */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE], WORD_ZERO(EEPROM_SIZE - 4));
+    /* Write Log word one-encoded */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 2], WORD_ONE(EEPROM_SIZE - 2));
+    /* Write Log word value aligned */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 4], WORD_NEXT(200));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 6], (uint16_t)~0x4321);
+    /* Write Log word value unaligned */
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 8], WORD_NEXT(202));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 10], (uint16_t)~0x763c);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 12], WORD_NEXT(202));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 14], (uint16_t)~0xef3c);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 16], WORD_NEXT(204));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 18], (uint16_t)~0x00cd);
+}
+
+TEST_F(EepromStm32Test, TestWordRoundTrip) {
+    /* Direct compacted-area: Address < 0x80 */
+    EEPROM_WriteDataWord(0, 0xdead);  // Aligned
+    EEPROM_WriteDataWord(3, 0xbeef);  // Unaligned
+    /* Direct compacted-area: Address >= 0x80 */
+    EEPROM_WriteDataWord(200, 0xabcd);  // Aligned
+    EEPROM_WriteDataWord(203, 0x9876);  // Unaligned
+    EEPROM_WriteDataWord(EEPROM_SIZE - 4, 0x1234);
+    EEPROM_WriteDataWord(EEPROM_SIZE - 2, 0x5678);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0), 0xdead);
+    EXPECT_EQ(EEPROM_ReadDataWord(3), 0xbeef);
+    EXPECT_EQ(EEPROM_ReadDataWord(200), 0xabcd);
+    EXPECT_EQ(EEPROM_ReadDataWord(203), 0x9876);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 4), 0x1234);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 2), 0x5678);
+
+    /* Write Log word zero-encoded */
+    EEPROM_WriteDataWord(EEPROM_SIZE - 4, 0);
+    /* Write Log word one-encoded */
+    EEPROM_WriteDataWord(EEPROM_SIZE - 2, 1);
+    /* Write Log word value aligned */
+    EEPROM_WriteDataWord(200, 0x4321);  // Aligned
+    /* Write Log word value unaligned */
+    EEPROM_WriteDataByte(202, 0x3c);    // Set neighboring byte
+    EEPROM_WriteDataWord(203, 0xcdef);  // Unaligned
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(200), 0x4321);
+    EXPECT_EQ(EEPROM_ReadDataByte(202), 0x3c);
+    EXPECT_EQ(EEPROM_ReadDataWord(203), 0xcdef);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 4), 0);
+    EXPECT_EQ(EEPROM_ReadDataWord(EEPROM_SIZE - 2), 1);
+}
+
+TEST_F(EepromStm32Test, TestByteWordBoundary) {
+    /* Direct compacted-area write */
+    EEPROM_WriteDataWord(0x7e, 0xdead);
+    EEPROM_WriteDataWord(0x80, 0xbeef);
+    /* Byte log entry */
+    EEPROM_WriteDataByte(0x7f, 0x3c);
+    /* Word log entry */
+    EEPROM_WriteDataByte(0x80, 0x18);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0x7e), 0x3cad);
+    EXPECT_EQ(EEPROM_ReadDataWord(0x80), 0xbe18);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE], BYTE_VALUE(0x7f, 0x3c));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 2], WORD_NEXT(0x80));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 4], (uint16_t)~0xbe18);
+    /* Byte log entries */
+    EEPROM_WriteDataWord(0x7e, 0xcafe);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0x7e), 0xcafe);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 6], BYTE_VALUE(0x7e, 0xfe));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 8], BYTE_VALUE(0x7f, 0xca));
+    /* Byte and Word log entries */
+    EEPROM_WriteDataWord(0x7f, 0xba5e);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0x7f), 0xba5e);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 10], BYTE_VALUE(0x7f, 0x5e));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 12], WORD_NEXT(0x80));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 14], (uint16_t)~0xbeba);
+    /* Word log entry */
+    EEPROM_WriteDataWord(0x80, 0xf00d);
+    /* Check values */
+    EEPROM_Init();
+    EXPECT_EQ(EEPROM_ReadDataWord(0x80), 0xf00d);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 16], WORD_NEXT(0x80));
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + 18], (uint16_t)~0xf00d);
+}
+
+TEST_F(EepromStm32Test, TestDWordRoundTrip) {
+    /* Direct compacted-area: Address < 0x80 */
+    eeprom_write_dword((uint32_t*)0, 0xdeadbeef);  // Aligned
+    eeprom_write_dword((uint32_t*)9, 0x12345678);  // Unaligned
+    /* Direct compacted-area: Address >= 0x80 */
+    eeprom_write_dword((uint32_t*)200, 0xfacef00d);
+    eeprom_write_dword((uint32_t*)(EEPROM_SIZE - 4), 0xba5eba11);  // Aligned
+    eeprom_write_dword((uint32_t*)(EEPROM_SIZE - 9), 0xcafed00d);  // Unaligned
+    /* Check direct values */
+    EEPROM_Init();
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)0), 0xdeadbeef);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)9), 0x12345678);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)200), 0xfacef00d);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 4)), 0xba5eba11);  // Aligned
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 9)), 0xcafed00d);  // Unaligned
+    /* Write Log byte encoded */
+    eeprom_write_dword((uint32_t*)0, 0xdecafbad);
+    eeprom_write_dword((uint32_t*)9, 0x87654321);
+    /* Write Log word encoded */
+    eeprom_write_dword((uint32_t*)200, 1);
+    /* Write Log word value aligned */
+    eeprom_write_dword((uint32_t*)(EEPROM_SIZE - 4), 0xdeadc0de);  // Aligned
+    eeprom_write_dword((uint32_t*)(EEPROM_SIZE - 9), 0x6789abcd);  // Unaligned
+    /* Check log values */
+    EEPROM_Init();
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)0), 0xdecafbad);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)9), 0x87654321);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)200), 1);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 4)), 0xdeadc0de);  // Aligned
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)(EEPROM_SIZE - 9)), 0x6789abcd);  // Unaligned
+}
+
+TEST_F(EepromStm32Test, TestBlockRoundTrip) {
+    char  src0[] = "0123456789abcdef";
+    void* src1   = (void*)&src0[1];
+    /* Various alignments of src & dst, Address < 0x80 */
+    eeprom_write_block(src0, (void*)0, sizeof(src0));
+    eeprom_write_block(src0, (void*)21, sizeof(src0));
+    eeprom_write_block(src1, (void*)40, sizeof(src0) - 1);
+    eeprom_write_block(src1, (void*)61, sizeof(src0) - 1);
+    /* Various alignments of src & dst, Address >= 0x80 */
+    eeprom_write_block(src0, (void*)140, sizeof(src0));
+    eeprom_write_block(src0, (void*)161, sizeof(src0));
+    eeprom_write_block(src1, (void*)180, sizeof(src0) - 1);
+    eeprom_write_block(src1, (void*)201, sizeof(src0) - 1);
+
+    /* Check values */
+    EEPROM_Init();
+
+    char  dstBuf[256] = {0};
+    char* dst0a       = (char*)dstBuf;
+    char* dst0b       = (char*)&dstBuf[20];
+    char* dst1a       = (char*)&dstBuf[41];
+    char* dst1b       = (char*)&dstBuf[61];
+    char* dst0c       = (char*)&dstBuf[80];
+    char* dst0d       = (char*)&dstBuf[100];
+    char* dst1c       = (char*)&dstBuf[121];
+    char* dst1d       = (char*)&dstBuf[141];
+    eeprom_read_block((void*)dst0a, (void*)0, sizeof(src0));
+    eeprom_read_block((void*)dst0b, (void*)21, sizeof(src0));
+    eeprom_read_block((void*)dst1a, (void*)40, sizeof(src0) - 1);
+    eeprom_read_block((void*)dst1b, (void*)61, sizeof(src0) - 1);
+    eeprom_read_block((void*)dst0c, (void*)140, sizeof(src0));
+    eeprom_read_block((void*)dst0d, (void*)161, sizeof(src0));
+    eeprom_read_block((void*)dst1c, (void*)180, sizeof(src0) - 1);
+    eeprom_read_block((void*)dst1d, (void*)201, sizeof(src0) - 1);
+    EXPECT_EQ(strcmp((char*)src0, dst0a), 0);
+    EXPECT_EQ(strcmp((char*)src0, dst0b), 0);
+    EXPECT_EQ(strcmp((char*)src0, dst0c), 0);
+    EXPECT_EQ(strcmp((char*)src0, dst0d), 0);
+    EXPECT_EQ(strcmp((char*)src1, dst1a), 0);
+    EXPECT_EQ(strcmp((char*)src1, dst1b), 0);
+    EXPECT_EQ(strcmp((char*)src1, dst1c), 0);
+    EXPECT_EQ(strcmp((char*)src1, dst1d), 0);
+}
+
+TEST_F(EepromStm32Test, TestCompaction) {
+    /* Direct writes */
+    eeprom_write_dword((uint32_t*)0, 0xdeadbeef);
+    eeprom_write_byte((uint8_t*)4, 0x3c);
+    eeprom_write_word((uint16_t*)6, 0xd00d);
+    eeprom_write_dword((uint32_t*)150, 0xcafef00d);
+    eeprom_write_dword((uint32_t*)200, 0x12345678);
+    /* Fill write log entries */
+    uint32_t i;
+    uint32_t val = 0xd8453c6b;
+    for (i = 0; i < (LOG_SIZE / (sizeof(uint32_t) * 2)); i++) {
+        val ^= 0x593ca5b3;
+        val += i;
+        eeprom_write_dword((uint32_t*)200, val);
+    }
+    /* Check values pre-compaction */
+    EEPROM_Init();
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)0), 0xdeadbeef);
+    EXPECT_EQ(eeprom_read_byte((uint8_t*)4), 0x3c);
+    EXPECT_EQ(eeprom_read_word((uint16_t*)6), 0xd00d);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)150), 0xcafef00d);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)200), val);
+    EXPECT_NE(*(uint16_t*)&FlashBuf[LOG_BASE], 0xFFFF);
+    EXPECT_NE(*(uint16_t*)&FlashBuf[LOG_BASE + LOG_SIZE - 2], 0xFFFF);
+    /* Run compaction */
+    eeprom_write_byte((uint8_t*)4, 0x1f);
+    EEPROM_Init();
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)0), 0xdeadbeef);
+    EXPECT_EQ(eeprom_read_byte((uint8_t*)4), 0x1f);
+    EXPECT_EQ(eeprom_read_word((uint16_t*)6), 0xd00d);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)150), 0xcafef00d);
+    EXPECT_EQ(eeprom_read_dword((uint32_t*)200), val);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE], 0xFFFF);
+    EXPECT_EQ(*(uint16_t*)&FlashBuf[LOG_BASE + LOG_SIZE - 2], 0xFFFF);
+}
diff --git a/tmk_core/common/test/flash_stm32_mock.c b/tmk_core/common/test/flash_stm32_mock.c
new file mode 100644
index 0000000000..1b81d81f9a
--- /dev/null
+++ b/tmk_core/common/test/flash_stm32_mock.c
@@ -0,0 +1,50 @@
+/* Copyright 2021 by Don Kjer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <stdbool.h>
+#include "flash_stm32.h"
+
+uint8_t FlashBuf[MOCK_FLASH_SIZE] = {0};
+
+static bool flash_locked = true;
+
+FLASH_Status FLASH_ErasePage(uint32_t Page_Address) {
+    if (flash_locked) return FLASH_ERROR_WRP;
+    Page_Address -= (uintptr_t)FlashBuf;
+    Page_Address -= (Page_Address % FEE_PAGE_SIZE);
+    if (Page_Address >= MOCK_FLASH_SIZE) return FLASH_BAD_ADDRESS;
+    memset(&FlashBuf[Page_Address], '\xff', FEE_PAGE_SIZE);
+    return FLASH_COMPLETE;
+}
+
+FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data) {
+    if (flash_locked) return FLASH_ERROR_WRP;
+    Address -= (uintptr_t)FlashBuf;
+    if (Address >= MOCK_FLASH_SIZE) return FLASH_BAD_ADDRESS;
+    uint16_t oldData = *(uint16_t*)&FlashBuf[Address];
+    if (oldData == 0xFFFF || Data == 0) {
+        *(uint16_t*)&FlashBuf[Address] = Data;
+        return FLASH_COMPLETE;
+    } else {
+        return FLASH_ERROR_PG;
+    }
+}
+
+FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout) { return FLASH_COMPLETE; }
+void         FLASH_Unlock(void) { flash_locked = false; }
+void         FLASH_Lock(void) { flash_locked = true; }
+void         FLASH_ClearFlag(uint32_t FLASH_FLAG) {}
diff --git a/tmk_core/common/test/rules.mk b/tmk_core/common/test/rules.mk
new file mode 100644
index 0000000000..e47e5880c5
--- /dev/null
+++ b/tmk_core/common/test/rules.mk
@@ -0,0 +1,23 @@
+eeprom_stm32_DEFS  := -DFLASH_STM32_MOCKED -DNO_PRINT -DFEE_FLASH_BASE=FlashBuf
+eeprom_stm32_tiny_DEFS := $(eeprom_stm32_DEFS) \
+	-DFEE_MCU_FLASH_SIZE=1 \
+	-DMOCK_FLASH_SIZE=1024 \
+	-DFEE_PAGE_SIZE=512 \
+	-DFEE_DENSITY_PAGES=1
+eeprom_stm32_large_DEFS := $(eeprom_stm32_DEFS) \
+	-DFEE_MCU_FLASH_SIZE=64 \
+	-DMOCK_FLASH_SIZE=65536 \
+	-DFEE_PAGE_SIZE=2048 \
+	-DFEE_DENSITY_PAGES=16
+
+eeprom_stm32_INC := \
+	$(TMK_PATH)/common/chibios/
+eeprom_stm32_tiny_INC := $(eeprom_stm32_INC)
+eeprom_stm32_large_INC := $(eeprom_stm32_INC)
+
+eeprom_stm32_SRC := \
+	$(TMK_PATH)/common/test/eeprom_stm32_tests.cpp \
+	$(TMK_PATH)/common/test/flash_stm32_mock.c \
+	$(TMK_PATH)/common/chibios/eeprom_stm32.c
+eeprom_stm32_tiny_SRC := $(eeprom_stm32_SRC)
+eeprom_stm32_large_SRC := $(eeprom_stm32_SRC)
diff --git a/tmk_core/common/test/testlist.mk b/tmk_core/common/test/testlist.mk
new file mode 100644
index 0000000000..51a9638bb9
--- /dev/null
+++ b/tmk_core/common/test/testlist.mk
@@ -0,0 +1 @@
+TEST_LIST += eeprom_stm32_tiny eeprom_stm32_large