Add littlefs lib and example.

apps/CMakeLists.txt

@@ -2,4 +2,5 @@
 add_subdirectory(tcp_server)
 add_subdirectory(adc_dma_chain)
 add_subdirectory(piccolosdr)
-add_subdirectory(barometer)
+add_subdirectory(barometer)
+add_subdirectory(filesystem)

apps/filesystem/CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(pico-filesystem)
+
+add_executable(filesystem test.c)
+
+target_link_libraries(filesystem LINK_PUBLIC littlefs)
+
+pico_add_extra_outputs(filesystem)
+
+pico_enable_stdio_usb(filesystem 1)
+pico_enable_stdio_uart(filesystem 0)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

apps/filesystem/test.c

@@ -0,0 +1,85 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "hardware/flash.h"
+#include "pico/stdio.h"
+#include "pico/stdlib.h"
+
+#include <lfs.h>
+#include <lfs_rp2040.h>
+
+// variables used by the filesystem
+lfs_t lfs;
+lfs_file_t file;
+
+// configuration of the filesystem is provided by this struct
+const struct lfs_config cfg = {
+    // block device operations
+    .read  = lfs_rp2040_read,
+    .prog  = lfs_rp2040_prog,
+    .erase = lfs_rp2040_erase,
+    .sync  = lfs_rp2040_sync,
+
+    // block device configuration
+    .read_size = FLASH_PAGE_SIZE,
+    .prog_size = FLASH_PAGE_SIZE,
+    .block_size = FLASH_SECTOR_SIZE,
+    .block_count = 128,
+    .cache_size = FLASH_PAGE_SIZE,
+
+    .lookahead_size = 16,
+    .block_cycles = 500,
+};
+
+uint storage_get_flash_capacity() {
+    uint8_t rxbuf[4];
+    uint8_t txbuf[] = {0x9f};
+    flash_do_cmd(txbuf, rxbuf, 4);
+    return 1 << rxbuf[3];
+}
+
+// entry point
+int main(void) {
+    stdio_init_all();
+    
+    while (getchar_timeout_us(0) != 'X') {
+        sleep_ms(10);
+    }
+
+    printf("%d\n", storage_get_flash_capacity());
+
+    printf("Hello from Pi Pico!\n");
+
+    // mount the filesystem
+    int err = lfs_mount(&lfs, &cfg);
+
+    printf("%d\n\n", err);
+
+    return 0;
+
+    // reformat if we can't mount the filesystem
+    // this should only happen on the first boot
+    if (err) {
+        lfs_format(&lfs, &cfg);
+        lfs_mount(&lfs, &cfg);
+    }
+
+    // read current count
+    uint32_t boot_count = 0;
+    lfs_file_open(&lfs, &file, "boot_count", LFS_O_RDWR | LFS_O_CREAT);
+    lfs_file_read(&lfs, &file, &boot_count, sizeof(boot_count));
+
+    // update boot count
+    boot_count += 1;
+    lfs_file_rewind(&lfs, &file);
+    lfs_file_write(&lfs, &file, &boot_count, sizeof(boot_count));
+
+    // remember the storage is not updated until the file is closed successfully
+    lfs_file_close(&lfs, &file);
+
+    // release any resources we were using
+    lfs_unmount(&lfs);
+
+    // print the boot count
+    printf("boot_count: %d\n", boot_count);
+}

lib/CMakeLists.txt

@@ -1,3 +1,4 @@
 add_subdirectory(bmp180)
 add_subdirectory(bmp390)
 add_subdirectory(usb_network_stack)
+add_subdirectory(littlefs)

lib/littlefs/CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.12)
+
+add_library(littlefs ./lfs_rp2040.c
+                     ./littlefs/lfs.c
+                     ./littlefs/lfs_util.c)
+
+target_link_libraries(littlefs
+    pico_stdlib
+    pico_stdio
+    hardware_flash
+)
+
+target_include_directories(littlefs PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}
+                                           ${CMAKE_CURRENT_SOURCE_DIR}/littlefs)

lib/littlefs/lfs_rp2040.c

@@ -0,0 +1,30 @@
+#include "lfs_rp2040.h"
+
+// Read a region in a block. Negative error codes are propagated
+// to the user.
+int lfs_rp2040_read(const struct lfs_config *c, lfs_block_t block,
+                    lfs_off_t off, void *buffer, lfs_size_t size) {
+    return 0;
+}
+
+// Program a region in a block. The block must have previously
+// been erased. Negative error codes are propagated to the user.
+// May return LFS_ERR_CORRUPT if the block should be considered bad.
+int lfs_rp2040_prog(const struct lfs_config *c, lfs_block_t block,
+                    lfs_off_t off, const void *buffer, lfs_size_t size) {
+    return 0;
+}
+
+// Erase a block. A block must be erased before being programmed.
+// The state of an erased block is undefined. Negative error codes
+// are propagated to the user.
+// May return LFS_ERR_CORRUPT if the block should be considered bad.
+int lfs_rp2040_erase(const struct lfs_config *c, lfs_block_t block) {
+    return 0;
+}
+
+// Sync the state of the underlying block device. Negative error codes
+// are propagated to the user.
+int lfs_rp2040_sync(const struct lfs_config *c) {
+    return 0;
+}

lib/littlefs/lfs_rp2040.h

@@ -0,0 +1,28 @@
+#ifndef LFS_RP2040_H
+#define LFS_RP2040_H
+
+#include <lfs.h>
+#include <lfs_util.h>
+
+// Read a region in a block. Negative error codes are propagated
+// to the user.
+int lfs_rp2040_read(const struct lfs_config *c, lfs_block_t block,
+                    lfs_off_t off, void *buffer, lfs_size_t size);
+
+// Program a region in a block. The block must have previously
+// been erased. Negative error codes are propagated to the user.
+// May return LFS_ERR_CORRUPT if the block should be considered bad.
+int lfs_rp2040_prog(const struct lfs_config *c, lfs_block_t block,
+                    lfs_off_t off, const void *buffer, lfs_size_t size);
+
+// Erase a block. A block must be erased before being programmed.
+// The state of an erased block is undefined. Negative error codes
+// are propagated to the user.
+// May return LFS_ERR_CORRUPT if the block should be considered bad.
+int lfs_rp2040_erase(const struct lfs_config *c, lfs_block_t block);
+
+// Sync the state of the underlying block device. Negative error codes
+// are propagated to the user.
+int lfs_rp2040_sync(const struct lfs_config *c);
+
+#endif