From 59fa5956724e6f1dea7cec603b6374ec0e4d700c Mon Sep 17 00:00:00 2001
From: Felipe Moura <moura.fmo@gmail.com>
Date: Tue, 15 Sep 2026 20:27:38 -0300
Subject: [PATCH] boards/esp32s3-xiao: wire up board_spiflash_init()

esp32s3-devkit and esp32s3-eye both call board_spiflash_init() from
their bring-up to register the internal SPI flash MTD partition and
mount its file system; esp32s3-xiao never did, so CONFIG_ESP32S3_SPIFLASH
built but no /dev/... MTD partition or mount ever appeared -- same shape
of gap as the IMU, SD, console and Wi-Fi wiring already fixed for this
board.

Guarded with pm_stay(PM_IDLE_DOMAIN, PM_IDLE) the same way the Wi-Fi
bring-up below it is: flash operations run with the cache disabled and
can't tolerate PM_STANDBY's clock gating either.

Confirmed under QEMU's esp32s3 machine: LittleFS mounts, and a counter
file written to it survives a reboot.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
Assisted-by: Claude:claude-sonnet-5
---
 .../esp32s3/esp32s3-xiao/src/esp32s3-xiao.h    | 18 ++++++++++++++++++
 .../esp32s3/esp32s3-xiao/src/esp32s3_bringup.c | 18 ++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3-xiao.h b/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3-xiao.h
index 1413c4ac227..3b9d3c9caba 100644
--- a/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3-xiao.h
+++ b/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3-xiao.h
@@ -115,5 +115,23 @@ int board_lsm6ds3trc_initialize(int devno, int busno);
 int esp_openeth_initialize(void);
 #endif
 
+/****************************************************************************
+ * Name: board_spiflash_init
+ *
+ * Description:
+ *   Initialize the SPI flash MTD partition and mount the file system
+ *   selected by CONFIG_ESP32S3_SPIFLASH_FS on it.  Implemented by the
+ *   shared ESP32-S3 board code in
+ *   boards/xtensa/esp32s3/common/src/esp32s3_board_spiflash.c.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ESP32S3_SPIFLASH
+int board_spiflash_init(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 #endif /* __BOARDS_XTENSA_ESP32S3_ESP32S3_XIAO_SRC_ESP32S3_XIAO_H */
diff --git a/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3_bringup.c b/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3_bringup.c
index 6dc222264d9..53c669687eb 100644
--- a/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3_bringup.c
+++ b/boards/xtensa/esp32s3/esp32s3-xiao/src/esp32s3_bringup.c
@@ -114,6 +114,24 @@ int esp32s3_bringup(void)
     }
 #endif
 
+#ifdef CONFIG_ESP32S3_SPIFLASH
+#  ifdef CONFIG_PM
+  /* Flash ops run with the cache disabled; same PM guard as Wi-Fi below. */
+
+  pm_stay(PM_IDLE_DOMAIN, PM_IDLE);
+#  endif
+
+  ret = board_spiflash_init();
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: Failed to initialize SPI flash: %d\n", ret);
+    }
+
+#  ifdef CONFIG_PM
+  pm_relax(PM_IDLE_DOMAIN, PM_IDLE);
+#  endif
+#endif
+
 #ifdef CONFIG_DEV_GPIO
   ret = esp32s3_gpio_init();
   if (ret < 0)