6 Mass Storage Support (#35)

* [Feature] USB Mass Storage Device

- This allows a USB Mass Storage device to expose the SD card.  Useful for taking off track logs.

NOTE:  I could not get the CDC mode to work once mass storage began, meaning, when you plug into the computer, it won't expose Serial, or ability to flash it.

To get around this limitation, I added a new platform (available in PlatformIO down the bottom bar) to enable a build to disable mass storage in non-release builds.

* [bug] work with windows

Some race condition I don't understand.  If this isn't done before Serial is started/used, we won't see it unless behind a USB hub.  Weird.

* [Feature] Also allow firmware MSC Updates

Adds a new drive (separate from SD card) that operators can update new firmware by a simple drag and drop of a "firmware.bin" file into.

Author: scottyob

platformio.ini

@@ -1,6 +1,9 @@
+[platformio]
+src_dir = src/vario
+
 # Mostly taken from 
 # https://github.com/sivar2311/ESP32-S3-PlatformIO-Flash-and-PSRAM-configurations?tab=readme-ov-file#esp32-s3-fn8
-[env:leaf]
+[env]
 # platform = espressif32  # Old, default platform
 # https://github.com/pioarduino/platform-espressif32
 platform = https://github.com/pioarduino/platform-espressif32/releases/download/stable/platform-espressif32.zip
@@ -28,10 +31,19 @@ lib_deps =
 	; WiFi Manager for configuring WiFi credentials over captive portal 
 	WiFiManager
 
-# build_type = debug  # Might be useful when looking at stack traces
-# Used to take exception traces and decode them to meaningful errors
-monitor_filters = esp32_exception_decoder
+[env:release]
+extends = env
+build_flags = 
+	${env.build_flags}
+	# Enables USB Mass Storage for accessing SD card
+	# NOTE:  Disables Serial for debugging / uploading.
+	-D ENABLE_MASS_STORAGE
 
-[platformio]
-src_dir = src/vario
 
+[env:dev]
+extends = env
+build_flags = 
+	${env.build_flags}
+build_type = debug  # Might be useful when looking at stack traces
+# Used to take exception traces and decode them to meaningful errors
+monitor_filters = esp32_exception_decoder

src/vario/SDcard.cpp

@@ -15,7 +15,12 @@
 bool remountSDCard = false; // flag set if the SD_DETECT pin changes state, so we know to attempt a re-mounting if the card is inserted or removed
 bool SDcardIsPresent = false;
 
+#include "USB.h"
+#include "USBMSC.h"
+#include "FirmwareMSC.h"
 
+FirmwareMSC MSC_Update;
+USBMSC MSC;
 
 void listDir(fs::FS &fs, const char * dirname, uint8_t levels) {
     Serial.printf("Listing directory: %s\n", dirname);
@@ -235,6 +240,54 @@ void SDcard_update() {
     SDcard_detectStateLast = SDcard_detectState;
 }
 
+static int32_t onRead(uint32_t lba, uint32_t offset, void *buffer, uint32_t bufsize) {
+    // Check bufSize is a multiple of block size
+    if (bufsize % 512) {
+        return -1;
+    }
+
+    auto bufferOffset = 0;
+    for(int sector = lba; sector < lba + bufsize / 512; sector++) {
+        if (!SD_MMC.readRAW((uint8_t*)buffer + bufferOffset, sector)) {
+            return -1;
+        }
+        bufferOffset += 512;
+    }
+    
+    return bufsize;
+}
+
+static int32_t onWrite(uint32_t lba, uint32_t offset, uint8_t *buffer, uint32_t bufsize) {
+    // Check bufSize is a multiple of block size
+    if (bufsize % 512) {
+        return -1;
+    }
+
+    auto bufferOffset = 0;
+    for(int sector = lba; sector < lba + bufsize / 512; sector++) {
+        if (!SD_MMC.writeRAW(buffer + bufferOffset, sector)) {
+            return -1;
+        }
+        bufferOffset += 512;
+    }
+    
+    return bufsize;
+}
+
+void SDCard_SetupMassStorage() {
+    Serial.setDebugOutput(true);
+    MSC.vendorID("Leaf");
+    MSC.productID("Leaf_Vario");
+    MSC.productRevision("1.0");
+    MSC.onRead(onRead);
+    MSC.onWrite(onWrite);
+    MSC.isWritable(true);
+    MSC.mediaPresent(true);
+    MSC.begin(SD_MMC.numSectors(), 512);
+    MSC_Update.begin();
+    USB.begin();
+}
+
 bool SDcard_mount() {
     // we may be re-mounting after changing power states (from ON to CHARGE and back to ON). 
     // If the SD card was removed during that process, we need to force-end the SD_MCC object so we can try to restart it, so we can properly tell if re-mounting fails (otherwise the SD_MCC object would falsely persist)
@@ -246,6 +299,9 @@ bool SDcard_mount() {
     } else {
         if (DEBUG_SDCARD) Serial.println("SDcard Mount Success");  
         SDcardIsPresent = true;
+        #ifdef ENABLE_MASS_STORAGE
+        SDCard_SetupMassStorage();
+        #endif
     }
 
     return SDcardIsPresent;

src/vario/SDcard.h

@@ -45,4 +45,6 @@ bool SDcard_createDataFile(String filename);
 void SDcard_writeData(String data);
 void SDcard_closeDataFile(void);
 
+void SDCard_SetupMassStorage(void);
+
 #endif

src/vario/vario.ino

@@ -72,6 +72,10 @@
 /////////////////////////////////////////////////
 void setup() {
 
+  #ifdef ENABLE_MASS_STORAGE
+  SDCard_SetupMassStorage();
+  #endif
+
   // Start USB Serial Debugging Port
     Serial.begin(115200);
     delay(200);