feat(p4): montage microSD (SDMMC 1-bit) sur /sdcard

Nouveau composant sd_storage : monte la carte microSD du Freenove en SDMMC
1-bit (CMD=38, CLK=39, D0=40 — pinout FREENOVE_SDMMC_* du firmware Arduino)
sur /sdcard via esp_vfs_fat_sdmmc_mount. Best-effort au boot : carte absente
= non fatal, fallback LittleFS. Lève le plafond LittleFS 5 Mo pour les assets.

Validé sur Freenove : carte ~3839 MiB montée à /sdcard au boot.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

idf_zacus/components/sd_storage/CMakeLists.txt

@@ -0,0 +1,11 @@
+## Zacus sd_storage — microSD (SDMMC 1-bit) FAT mount at /sdcard (P4).
+idf_component_register(
+    SRCS
+        "sd_storage.c"
+    INCLUDE_DIRS
+        "."
+    REQUIRES
+        fatfs
+        sdmmc
+        esp_driver_sdmmc
+)

idf_zacus/components/sd_storage/sd_storage.c

@@ -0,0 +1,74 @@
+#include "sd_storage.h"
+
+#include "esp_log.h"
+#include "esp_vfs_fat.h"
+#include "sdmmc_cmd.h"
+#include "driver/sdmmc_host.h"
+
+static const char *TAG = "sd_storage";
+
+// Freenove ESP32-S3 WROOM N16R8 microSD (SDMMC 1-bit). Mirrors
+// ui_freenove_allinone/include/ui_freenove_config.h FREENOVE_SDMMC_*.
+#define SD_PIN_CMD 38
+#define SD_PIN_CLK 39
+#define SD_PIN_D0  40
+
+static sdmmc_card_t *s_card = NULL;
+
+esp_err_t sd_storage_mount(void) {
+    if (s_card != NULL) {
+        return ESP_OK;
+    }
+
+    const esp_vfs_fat_sdmmc_mount_config_t mount_cfg = {
+        .format_if_mount_failed = false,   // never wipe a user's card
+        .max_files = 5,
+        .allocation_unit_size = 16 * 1024,
+    };
+
+    sdmmc_host_t host = SDMMC_HOST_DEFAULT();
+    host.flags = SDMMC_HOST_FLAG_1BIT;     // Freenove wires D0 only
+    host.max_freq_khz = SDMMC_FREQ_DEFAULT;
+
+    sdmmc_slot_config_t slot = SDMMC_SLOT_CONFIG_DEFAULT();
+    slot.width = 1;
+    slot.clk = SD_PIN_CLK;
+    slot.cmd = SD_PIN_CMD;
+    slot.d0  = SD_PIN_D0;
+    slot.flags |= SDMMC_SLOT_FLAG_INTERNAL_PULLUP;
+
+    esp_err_t err = esp_vfs_fat_sdmmc_mount(SD_STORAGE_MOUNT_POINT, &host,
+                                            &slot, &mount_cfg, &s_card);
+    if (err != ESP_OK) {
+        ESP_LOGW(TAG, "mount failed: %s — no card inserted or wiring issue",
+                 esp_err_to_name(err));
+        s_card = NULL;
+        return err;
+    }
+
+    ESP_LOGI(TAG, "microSD mounted at %s — %lu MiB (%s)",
+             SD_STORAGE_MOUNT_POINT, (unsigned long) sd_storage_capacity_mb(),
+             s_card->cid.name);
+    return ESP_OK;
+}
+
+esp_err_t sd_storage_unmount(void) {
+    if (s_card == NULL) {
+        return ESP_OK;
+    }
+    esp_err_t err = esp_vfs_fat_sdcard_unmount(SD_STORAGE_MOUNT_POINT, s_card);
+    s_card = NULL;
+    return err;
+}
+
+bool sd_storage_ready(void) {
+    return s_card != NULL;
+}
+
+uint32_t sd_storage_capacity_mb(void) {
+    if (s_card == NULL) {
+        return 0U;
+    }
+    uint64_t bytes = (uint64_t) s_card->csd.capacity * s_card->csd.sector_size;
+    return (uint32_t) (bytes / (1024ULL * 1024ULL));
+}

idf_zacus/components/sd_storage/sd_storage.h

@@ -0,0 +1,34 @@
+// Zacus sd_storage — microSD mount for the Freenove ESP32-S3 master.
+//
+// The Freenove WROOM N16R8 exposes the card on the SDMMC peripheral in
+// 1-bit mode (CMD=GPIO38, CLK=GPIO39, D0=GPIO40 — mirrors the Arduino
+// `ui_freenove_allinone` FREENOVE_SDMMC_* pinout). Mounts FAT at /sdcard so
+// media_manager and the asset endpoints can stage large assets off the 5 MB
+// LittleFS partition (P4). Mount is best-effort: a missing card is not fatal.
+#pragma once
+
+#include <stdbool.h>
+#include "esp_err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SD_STORAGE_MOUNT_POINT "/sdcard"
+
+// Mount the microSD card (SDMMC 1-bit) at /sdcard. Returns ESP_OK on success;
+// ESP_ERR_NOT_FOUND / ESP_FAIL when no card is present or wiring is wrong.
+esp_err_t sd_storage_mount(void);
+
+// Unmount and release the card.
+esp_err_t sd_storage_unmount(void);
+
+// True once a card is mounted.
+bool sd_storage_ready(void);
+
+// Card capacity in MiB (0 when not mounted).
+uint32_t sd_storage_capacity_mb(void);
+
+#ifdef __cplusplus
+}
+#endif

idf_zacus/main/CMakeLists.txt

@@ -6,6 +6,7 @@ idf_component_register(
     REQUIRES
         joltwallet__littlefs
         ota_server
+        sd_storage
         media_manager
         npc_engine
         hints_client

idf_zacus/main/main.c

@@ -40,6 +40,7 @@
 
 #include "ota_server.h"
 #include "media_manager.h"
+#include "sd_storage.h"
 #include "npc_engine.h"
 #include "hints_client.h"
 #include "voice_pipeline.h"
@@ -484,6 +485,13 @@ void app_main(void) {
         }
     }
 
+    // P4: best-effort microSD mount (SDMMC 1-bit on /sdcard). A missing card
+    // is non-fatal — assets fall back to LittleFS.
+    if (sd_storage_mount() == ESP_OK) {
+        ESP_LOGI(TAG, "microSD ready (%lu MiB) at %s",
+                 (unsigned long) sd_storage_capacity_mb(), SD_STORAGE_MOUNT_POINT);
+    }
+
     if (mount_littlefs() == ESP_OK) {
         list_littlefs_root();