Merge pull request #17 from Sani7/bugfix/mkllfs-llfs

Fix/improve llfs and the mkllfs utility

README.md

@@ -6,6 +6,7 @@
  - [Style Guide](#style-guide)
    - [Editor Configuration](#editor-configuration)
  - [Commit Messages Conventions](#commit-messages-conventions)
+ - [Writing File System Data to QSPI Flash](#writing-file-system-data-to-qspi-flash)
  - [Documentation](#documentation)
 
 ## Used Libs, Compiler and Apps
@@ -52,6 +53,10 @@ Implement access right management
 
 The body of a commit message may be used to explain the what and why of a commit.
 
+## Writing File System Data to QSPI Flash
+Please read the [llfs.md](./docs/llfs.md#enabling-the-external-loader-in-stm32cubeide) document for instructions
+on how to enable the external loader in STM32CubeIDE.
+
 ## Documentation
 Documentation is placed in the [docs](docs) folder.
 If your part needs documentation (e.g. how to use tcp cmd interface), add a markdown file in the above-mentioned folder.

docs/llfs.md

@@ -24,6 +24,7 @@ restricting operations solely to read functions.
    - [Reading a file](#reading-a-file)
    - [Getting the number of files](#getting-the-number-of-files)
  - [Using the POSIX file functions](#using-the-posix-file-functions)
+ - [Enabling the external loader in STM32CubeIDE](#enabling-the-external-loader-in-stm32cubeide)
 
 ## Initialization
 Before using the llfs API, or the file related POSIX (fopen, fgetc, ...) functions, the filesystem must be initialized by calling `llfs_init()`.
@@ -161,3 +162,16 @@ The following functions are tested and working, but other functions might also w
  - `rewind`
  - `fstat`
  - `fileno`
+
+## Enabling the external loader in STM32CubeIDE
+In order to write the file system data to the QSPI flash, the external loader must be enabled in STM32CubeIDE.
+This can be done by opening the debug configuration:
+
+![screenshot of step 1](img/ext_loader_step_1.png)
+
+Then, in the `Debugger` tab:
+3. Enable the `External Loader`
+4. Click the `Scan` button
+5. Select the correct loader: `N25Q128A_STM32F746G-DISCO, 0x90000000 ...`
+
+![screenshot of step 2](img/ext_loader_step_2.png)

docs/mkllfs.md

@@ -7,7 +7,7 @@ The llfs filesystem is a flat filesystem, meaning that it does not support direc
 
 The mkllfs utilit can be used to generate the `llfs_data.c` file. The `llfs_data.c` file from a directory with files.
 
-A pre-compiled version can be download: [mkllfs.exe](https://github.com/Sani7/2023-Webservices_And_Applications/releases/tag/v0.2.0)
+A pre-compiled version can be download: [mkllfs.exe](https://github.com/Sani7/2023-Webservices_And_Applications/releases/tag/v0.2.1)
 
 ## Usage
 The mkllfs utility can be used as follows:

mkllfs/main.c

@@ -1,7 +1,7 @@
 /**
  * @file main.c
  * @brief Converts files to a C file that can be used by llfs (linked list file system).
- * @version 0.2.0
+ * @version 0.2.1
  * @author Lorenz C.
  */
 
@@ -10,7 +10,7 @@
 #include <string.h>
 #include "tinydir.h"
 
-#define VERSION      "0.2.0"
+#define VERSION      "0.2.1"
 #define LLFS_VERSION "0.1.1"
 #define MAX_PATH_LEN 256
 
@@ -125,7 +125,7 @@ int main(int argc, char** argv) {
 
     // Make the last file the root file of the llfs
     fprintf(out_file, "\n");
-    fprintf(out_file, "const struct llfs_data_file *llfs_root = &%s;\n", prev_llfs_name);
+    fprintf(out_file, "const struct llfs_data_file *llfs_root =%s%s;\n", (strcmp(prev_llfs_name, "NULL") == 0 ? " " : " &"), prev_llfs_name);
 
     // Print the number of files
     printf("Successfully converted %d files.\r\n", file_count);

project/Core/Src/llfs.c

@@ -10,8 +10,8 @@
 #include <stdio.h>
 #include <string.h>
 #define LOGGER_LEVEL_WARN
-#include "llfs.h"
 #include "log.h"
+#include "llfs.h"
 
 /**
  * @brief The maximum number of files that can be opened concurrently using the POSIX API
@@ -20,8 +20,8 @@
 
 extern struct llfs_data_file* llfs_root;
 const char* TAG = "llfs";
-size_t file_count = 0;
+static size_t file_count = 0;   // Cache for the number of files in the filesystem
-FILE* file_table[POSIX_MAX_FILES];
+static FILE* file_table[POSIX_MAX_FILES];
 
 static int new_file_table_entry(void);
 static int free_file_table_entry(int file_id);
@@ -41,6 +41,14 @@ int8_t llfs_init(void) {
     file_table[STDOUT_FILENO] = stdout;
     file_table[STDERR_FILENO] = stderr;
 
+    // Calculate the number of files in the filesystem and cache it
+    const struct llfs_data_file* file = llfs_root;
+    file_count = 0;
+    while (file != NULL) {
+        file_count++;
+        file = file->next;
+    }
+
     return 0;
 }
 
@@ -57,7 +65,7 @@ size_t llfs_file_list(llfs_file_t* file_list, size_t max_files, char* filter) {
     }
 
     // Iterate over all files in the filesystem
-    while (file != NULL && file_count < max_files) {
+    while (file != NULL && count < max_files) {
         // Filter out files with a filename that does not match the filter
         if (filter != NULL) {
             if (!file_ext_cmp(file->name, filter)) {
@@ -130,13 +138,6 @@ llfs_file_t* llfs_next_file(void** mem, char* filter) {
 }
 
 size_t llfs_file_count(void) {
-    if (file_count == 0) {
-        const struct llfs_data_file* file = llfs_root;
-        while (file != NULL) {
-            file_count++;
-            file = file->next;
-        }
-    }
     return file_count;
 }
 
@@ -218,7 +219,7 @@ int _close(int file_id) {
  * @param len
  * @return
  */
-int _read(int file_id, char* ptr, int len) {
+size_t _read(int file_id, char* ptr, int len) {
     FILE* stream;
     llfs_file_t* llfs_file;
     size_t bytes_read;
@@ -256,7 +257,7 @@ int _read(int file_id, char* ptr, int len) {
     memcpy(ptr, llfs_file->data + stream->_offset, bytes_read);
 
     stream->_offset += (off_t)bytes_read;
-    return (int)bytes_read;
+    return bytes_read;
 }
 
 /**
@@ -281,7 +282,7 @@ int isatty(int file) {
  * @param dir
  * @return
  */
-int _lseek(int file, int ptr, int dir) {
+off_t _lseek(int file, int ptr, int dir) {
     FILE* stream;
 
     if (file == STDIN_FILENO || file == STDOUT_FILENO || file == STDERR_FILENO) {
@@ -310,7 +311,7 @@ int _lseek(int file, int ptr, int dir) {
             return -1;
     }
 
-    return 0;
+    return stream->_offset;
 }
 
 /**
@@ -409,8 +410,6 @@ static FILE* file_id_to_stream(int file_id) {
     return file_table[file_id];
 }
 
-
-
 /**
  * @brief Check if a filename ends with a given extension
  *