rp2: Add USB MSC support.

It is currently not enabled by default on any board.

ports/rp2/CMakeLists.txt

@@ -105,6 +105,7 @@ set(MICROPY_SOURCE_PORT
     rp2_pio.c
     tusb_port.c
     uart.c
+    msc_disk.c
 )
 
 set(MICROPY_SOURCE_QSTR

ports/rp2/boards/PICO/mpconfigboard.h

@@ -1,3 +1,6 @@
 // Board and hardware specific configuration
 #define MICROPY_HW_BOARD_NAME                   "Raspberry Pi Pico"
 #define MICROPY_HW_FLASH_STORAGE_BYTES          (1408 * 1024) 
+
+// Enable USB Mass Storage with FatFS filesystem.
+//#define MICROPY_HW_USB_MSC  (1)

ports/rp2/main.c

@@ -116,7 +116,11 @@ int main(int argc, char **argv) {
         #endif
 
         // Execute _boot.py to set up the filesystem.
+        #if MICROPY_VFS_FAT && MICROPY_HW_USB_MSC
+        pyexec_frozen_module("_boot_fat.py");
+        #else
         pyexec_frozen_module("_boot.py");
+        #endif
 
         // Execute user scripts.
         int ret = pyexec_file_if_exists("boot.py");

ports/rp2/modules/_boot_fat.py

@@ -0,0 +1,15 @@
+import os
+import machine, rp2
+
+
+# Try to mount the filesystem, and format the flash if it doesn't exist.
+bdev = rp2.Flash()
+try:
+    vfs = os.VfsFat(bdev)
+    os.mount(vfs, "/")
+except:
+    os.VfsFat.mkfs(bdev)
+    vfs = os.VfsFat(bdev)
+os.mount(vfs, "/")
+
+del os, bdev, vfs

ports/rp2/mpconfigport.h

@@ -30,8 +30,10 @@
 #include "hardware/spi.h"
 #include "hardware/sync.h"
 #include "pico/binary_info.h"
-
 #include "mpconfigboard.h"
+#if MICROPY_HW_USB_MSC
+#include "hardware/flash.h"
+#endif
 
 // Board and hardware specific configuration
 #define MICROPY_HW_MCU_NAME                     "RP2040"
@@ -107,10 +109,22 @@
 #define MICROPY_FATFS_ENABLE_LFN                (1)
 #define MICROPY_FATFS_LFN_CODE_PAGE             437 /* 1=SFN/ANSI 437=LFN/U.S.(OEM) */
 #define MICROPY_FATFS_RPATH                     (2)
+#if MICROPY_HW_USB_MSC
+#define MICROPY_FATFS_USE_LABEL                 (1)
+#define MICROPY_FATFS_MULTI_PARTITION           (1)
+// Set FatFS block size to flash sector size to avoid caching
+// the flash sector in memory to support smaller block sizes.
+#define MICROPY_FATFS_MAX_SS                    (FLASH_SECTOR_SIZE)
+#endif
 
+#if MICROPY_VFS_FAT && MICROPY_HW_USB_MSC
+#define mp_type_fileio mp_type_vfs_fat_fileio
+#define mp_type_textio mp_type_vfs_fat_textio
+#elif MICROPY_VFS_LFS2
 // Use VfsLfs2's types for fileio/textio
 #define mp_type_fileio mp_type_vfs_lfs2_fileio
 #define mp_type_textio mp_type_vfs_lfs2_textio
+#endif
 
 // Use VFS's functions for import stat and builtin open
 #define mp_import_stat mp_vfs_import_stat

ports/rp2/msc_disk.c

@@ -0,0 +1,127 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020-2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+#include "tusb.h"
+#if CFG_TUD_MSC
+#include "mpconfigboard.h"
+#include "hardware/flash.h"
+#include "hardware/sync.h"
+#include "pico/stdlib.h"
+
+// This implementation does Not support Flash sector caching.
+#if MICROPY_FATFS_MAX_SS != FLASH_SECTOR_SIZE
+#error MICROPY_FATFS_MAX_SS must be the same size as FLASH_SECTOR_SIZE
+#endif
+
+#define BLOCK_SIZE          (FLASH_SECTOR_SIZE)
+#define BLOCK_COUNT         (MICROPY_HW_FLASH_STORAGE_BYTES / BLOCK_SIZE)
+#define FLASH_BASE_ADDR     (PICO_FLASH_SIZE_BYTES - MICROPY_HW_FLASH_STORAGE_BYTES)
+#define FLASH_MMAP_ADDR     (XIP_BASE + FLASH_BASE_ADDR)
+
+static bool ejected = false;
+
+// Invoked when received SCSI_CMD_INQUIRY
+// Application fill vendor id, product id and revision with string up to 8, 16, 4 characters respectively
+void tud_msc_inquiry_cb(uint8_t lun, uint8_t vendor_id[8], uint8_t product_id[16], uint8_t product_rev[4]) {
+    const char vid[] = "Micropy";
+    const char pid[] = "Mass Storage";
+    const char rev[] = "1.0";
+
+    strncpy((char *)vendor_id,   vid, 8);
+    strncpy((char *)product_id,  pid, 16);
+    strncpy((char *)product_rev, rev, 4);
+}
+
+// Invoked when received Test Unit Ready command.
+// return true allowing host to read/write this LUN e.g SD card inserted
+bool tud_msc_test_unit_ready_cb(uint8_t lun) {
+    if (ejected) {
+        tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x3a, 0x00);
+        return false;
+    }
+    return true;
+}
+
+// Invoked when received SCSI_CMD_READ_CAPACITY_10 and SCSI_CMD_READ_FORMAT_CAPACITY to determine the disk size
+// Application update block count and block size
+void tud_msc_capacity_cb(uint8_t lun, uint32_t *block_count, uint16_t *block_size) {
+    *block_size = BLOCK_SIZE;
+    *block_count = BLOCK_COUNT;
+}
+
+// Invoked when received Start Stop Unit command
+// - Start = 0 : stopped power mode, if load_eject = 1 : unload disk storage
+// - Start = 1 : active mode, if load_eject = 1 : load disk storage
+bool tud_msc_start_stop_cb(uint8_t lun, uint8_t power_condition, bool start, bool load_eject) {
+    if (load_eject) {
+        if (start) {
+            // load disk storage
+            ejected = false;
+        } else {
+            // unload disk storage
+            ejected = true;
+        }
+    }
+    return true;
+}
+
+// Callback invoked when received READ10 command.
+// Copy disk's data to buffer (up to bufsize) and return number of copied bytes.
+int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void *buffer, uint32_t bufsize) {
+    uint32_t count = bufsize / BLOCK_SIZE;
+    memcpy(buffer, (void *)(FLASH_MMAP_ADDR + lba * BLOCK_SIZE), count * BLOCK_SIZE);
+    return count * BLOCK_SIZE;
+}
+
+// Callback invoked when received WRITE10 command.
+// Process data in buffer to disk's storage and return number of written bytes
+int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t *buffer, uint32_t bufsize) {
+    uint32_t count = bufsize / BLOCK_SIZE;
+    uint32_t ints = save_and_disable_interrupts();
+    flash_range_erase(FLASH_BASE_ADDR + lba * BLOCK_SIZE, count * BLOCK_SIZE);
+    flash_range_program(FLASH_BASE_ADDR + lba * BLOCK_SIZE, buffer, count * BLOCK_SIZE);
+    restore_interrupts(ints);
+    return count * BLOCK_SIZE;
+}
+
+// Callback invoked when received an SCSI command not in built-in list below
+// - READ_CAPACITY10, READ_FORMAT_CAPACITY, INQUIRY, MODE_SENSE6, REQUEST_SENSE
+// - READ10 and WRITE10 has their own callbacks
+int32_t tud_msc_scsi_cb(uint8_t lun, uint8_t const scsi_cmd[16], void *buffer, uint16_t bufsize) {
+    int32_t resplen = 0;
+    switch (scsi_cmd[0]) {
+        case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
+            // Sync the logical unit if needed.
+            break;
+
+        default:
+            // Set Sense = Invalid Command Operation
+            tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, 0x20, 0x00);
+            // negative means error -> tinyusb could stall and/or response with failed status
+            resplen = -1;
+            break;
+    }
+    return resplen;
+}
+#endif

ports/rp2/tusb_config.h

@@ -25,6 +25,8 @@
 #ifndef MICROPY_INCLUDED_RP2_TUSB_CONFIG_H
 #define MICROPY_INCLUDED_RP2_TUSB_CONFIG_H
 
+#include "mpconfigport.h"
+
 #define CFG_TUSB_RHPORT0_MODE   (OPT_MODE_DEVICE)
 
 #define CFG_TUD_CDC             (1)
@@ -32,4 +34,11 @@
 #define CFG_TUD_CDC_RX_BUFSIZE  (256)
 #define CFG_TUD_CDC_TX_BUFSIZE  (256)
 
+#if MICROPY_HW_USB_MSC
+// Board and hardware specific configuration
+#define CFG_TUD_MSC             (1)
+// Set MSC EP buffer size to FatFS block size to avoid partial read/writes (offset arg).
+#define CFG_TUD_MSC_BUFSIZE     (MICROPY_FATFS_MAX_SS)
+#endif
+
 #endif // MICROPY_INCLUDED_RP2_TUSB_CONFIG_H

ports/rp2/tusb_port.c

@@ -34,11 +34,20 @@
 #define MICROPY_HW_USB_PID (0x0005) // RP2 MicroPython
 #endif
 
+#if CFG_TUD_MSC
+#define USBD_DESC_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_MSC_DESC_LEN)
+#else
 #define USBD_DESC_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)
+#endif
 #define USBD_MAX_POWER_MA (250)
 
 #define USBD_ITF_CDC (0) // needs 2 interfaces
+#define USBD_ITF_MSC (2)
+#if CFG_TUD_MSC
+#define USBD_ITF_MAX (3)
+#else
 #define USBD_ITF_MAX (2)
+#endif
 
 #define USBD_CDC_EP_CMD (0x81)
 #define USBD_CDC_EP_OUT (0x02)
@@ -46,11 +55,15 @@
 #define USBD_CDC_CMD_MAX_SIZE (8)
 #define USBD_CDC_IN_OUT_MAX_SIZE (64)
 
+#define EPNUM_MSC_OUT    (0x03)
+#define EPNUM_MSC_IN     (0x83)
+
 #define USBD_STR_0 (0x00)
 #define USBD_STR_MANUF (0x01)
 #define USBD_STR_PRODUCT (0x02)
 #define USBD_STR_SERIAL (0x03)
 #define USBD_STR_CDC (0x04)
+#define USBD_STR_MSC (0x05)
 
 // Note: descriptors returned from callbacks must exist long enough for transfer to complete
 
@@ -77,6 +90,9 @@ static const uint8_t usbd_desc_cfg[USBD_DESC_LEN] = {
 
     TUD_CDC_DESCRIPTOR(USBD_ITF_CDC, USBD_STR_CDC, USBD_CDC_EP_CMD,
         USBD_CDC_CMD_MAX_SIZE, USBD_CDC_EP_OUT, USBD_CDC_EP_IN, USBD_CDC_IN_OUT_MAX_SIZE),
+    #if CFG_TUD_MSC
+    TUD_MSC_DESCRIPTOR(USBD_ITF_MSC, 5, EPNUM_MSC_OUT, EPNUM_MSC_IN, 64),
+    #endif
 };
 
 static const char *const usbd_desc_str[] = {
@@ -84,6 +100,9 @@ static const char *const usbd_desc_str[] = {
     [USBD_STR_PRODUCT] = "Board in FS mode",
     [USBD_STR_SERIAL] = NULL, // generated dynamically
     [USBD_STR_CDC] = "Board CDC",
+    #if CFG_TUD_MSC
+    [USBD_STR_MSC] = "Board MSC",
+    #endif
 };
 
 const uint8_t *tud_descriptor_device_cb(void) {