From bedb649edf9a4e0d451daccda72ae35634b80dde Mon Sep 17 00:00:00 2001
From: Stanislav Ponomarev <me@stasponomarev.com>
Date: Tue, 27 Feb 2024 00:26:17 +0400
Subject: [PATCH] esp32/boards/ESP32_GENERIC_S3: Add 4MiB partitioning board
 variant.

Added a 4MiB flash partitioning variant for ESP32S3: adds support for 4MiB
discrete flash boards or ESP32-S3FH4R2 with embedded 4MiB flash based ones.

Tested on the waveshare ESP32-S3 Mini w/ESP32-S3FH4R2.

Signed-off-by: Stanislav Ponomarev <me@stasponomarev.com>
---
 ports/esp32/boards/ESP32_GENERIC_S3/board.json          | 3 ++-
 ports/esp32/boards/ESP32_GENERIC_S3/board.md            | 4 +++-
 ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake | 7 +++++++
 ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.flash_4m  | 4 ++++
 4 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.flash_4m

diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/board.json b/ports/esp32/boards/ESP32_GENERIC_S3/board.json
index 671936c922..c9794dba86 100644
--- a/ports/esp32/boards/ESP32_GENERIC_S3/board.json
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/board.json
@@ -18,6 +18,7 @@
     "url": "https://www.espressif.com/en/products/modules",
     "vendor": "Espressif",
     "variants": {
-        "SPIRAM_OCT": "Support for Octal-SPIRAM"
+        "SPIRAM_OCT": "Support for Octal-SPIRAM",
+        "FLASH_4M": "4MiB flash"
     }
 }
diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/board.md b/ports/esp32/boards/ESP32_GENERIC_S3/board.md
index cc902eeb89..16930c9193 100644
--- a/ports/esp32/boards/ESP32_GENERIC_S3/board.md
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/board.md
@@ -1,7 +1,9 @@
 The following files are firmware that should work on most ESP32-S3-based
-boards with 8MiB of flash, including WROOM and MINI modules.
+boards with 4/8MiB of flash, including WROOM and MINI modules.
 
 This firmware supports configurations with and without SPIRAM (also known as
 PSRAM) and will auto-detect a connected SPIRAM chip at startup and allocate
 the MicroPython heap accordingly. However if your board has Octal SPIRAM, then
 use the "spiram-oct" variant.
+
+If your board has 4MiB flash (including ESP32-S3FH4R2 based ones with embedded flash), then use the "flash-4m" build.
diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake
index c60f1c280a..1f7440353b 100644
--- a/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake
@@ -20,3 +20,10 @@ if(MICROPY_BOARD_VARIANT STREQUAL "SPIRAM_OCT")
         MICROPY_HW_BOARD_NAME="Generic ESP32S3 module with Octal-SPIRAM"
     )
 endif()
+
+if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_4M")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/ESP32_GENERIC_S3/sdkconfig.flash_4m
+    )
+endif()
diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.flash_4m b/ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.flash_4m
new file mode 100644
index 0000000000..c967c46ae6
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.flash_4m
@@ -0,0 +1,4 @@
+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE_8MB=
+
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-4MiB.csv"