spi_flash: support for firmware upgrades via SD Card

This module connects directly to MCU's previously flashed with Klipper, uploads Klipper firmware to an attached SD Card, and performs a device reset to intiate the bootloader's update process.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

scripts/spi_flash/fatfs_api.c

@@ -0,0 +1,232 @@
+// Python CFFI bindings for fatfs
+//
+// Copyright (C) 2021 Eric Callahan <arksine.code@gmail.com>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <string.h>                     // memset
+#include <stdlib.h>                     // malloc
+#include "fatfs_api.h"                  // python-fatfs prototypes
+#include "../../lib/fatfs/ff.h"         // fatfs APIs
+#include "../../lib/fatfs/diskio.h"     // fatfs media APIs (callbacks)
+
+/* Callbacks */
+static uint8_t (*python_disk_status)(void) = 0;
+static uint8_t (*python_disk_initialize)(void) = 0;
+static uint8_t (*python_disk_read)(uint8_t* buff, uint32_t sector,
+                                   unsigned int count) = 0;
+static uint8_t (*python_disk_write)(const uint8_t* buff, uint32_t sector,
+                                    unsigned int count) = 0;
+static uint8_t (*python_disk_ioctl)(uint8_t cmd, void* buff) = 0;
+static uint32_t (*python_fattime)(void) = 0;
+
+void __visible
+fatfs_set_callbacks(
+    uint8_t (*status_callback)(void),
+    uint8_t (*init_callback)(void),
+    uint8_t (*read_callback)(uint8_t*, uint32_t, unsigned int),
+    uint8_t (*write_callback)(const uint8_t*, uint32_t, unsigned int),
+    uint8_t (*ioctl_callback)(uint8_t, void*),
+    uint32_t (*fattime_callback)(void)
+)
+{
+    python_disk_status = status_callback;
+    python_disk_initialize = init_callback;
+    python_disk_read = read_callback;
+    python_disk_write = write_callback;
+    python_disk_ioctl = ioctl_callback;
+    python_fattime = fattime_callback;
+}
+
+void __visible
+fatfs_clear_callbacks(void)
+{
+    python_disk_status = 0;
+    python_disk_initialize = 0;
+    python_disk_read = 0;
+    python_disk_write = 0;
+    python_disk_ioctl = 0;
+    python_fattime = 0;
+}
+
+/*  Callbacks from fatfs to python.  These methods are used to  */
+/*  Access access the SD Card APIs                              */
+
+/*  Get FAT Time  */
+DWORD
+get_fattime(void)
+{
+    if (python_fattime == 0)
+    {
+        // Return a default FATTIME of 1/1/2021
+        return 41 << 25 | 1 << 21 | 1 << 16;
+    }
+    return python_fattime();
+}
+
+DSTATUS
+disk_status(BYTE pdrv)
+{
+    if (python_disk_status != 0)
+        return python_disk_status();
+
+    return STA_NOINIT;
+}
+
+DSTATUS
+disk_initialize(BYTE pdrv)
+{
+    if (python_disk_initialize != 0)
+        return python_disk_initialize();
+    return STA_NOINIT;
+}
+
+
+DRESULT
+disk_read(BYTE pdrv, BYTE *buff, LBA_t sector, UINT count)
+{
+    if (python_disk_read != 0)
+        return python_disk_read(buff, sector, count);
+    return RES_NOTRDY;
+}
+
+
+DRESULT
+disk_write(BYTE pdrv, const BYTE *buff, LBA_t sector, UINT count)
+{
+    if (python_disk_write != 0)
+        return python_disk_write(buff, sector, count);
+    return RES_NOTRDY;
+}
+
+DRESULT
+disk_ioctl(BYTE pdrv, BYTE cmd, void *buff)
+{
+    if (python_disk_ioctl != 0)
+        return python_disk_ioctl(cmd, buff);
+    return RES_NOTRDY;
+}
+
+/*  Python-FatFS Interface Functions  */
+
+// Wrapper around the FatFS FIL struct.  FIL is type defined
+// anonymously, thus can't be forward declared and poses
+// challenges with CFFI.
+struct ff_file {
+    FIL fobj;
+};
+static FATFS fs;
+
+uint8_t __visible
+fatfs_mount(void)
+{
+    FRESULT res;
+    memset(&fs, 0, sizeof(fs));
+    res = f_mount(&fs, "", 1);
+    return res;
+}
+
+uint8_t __visible
+fatfs_unmount(void)
+{
+    FRESULT res;
+    res = f_unmount("");
+    memset(&fs, 0, sizeof(fs));
+    return res;
+}
+
+struct ff_file* __visible
+fatfs_open(const char* path, uint8_t mode)
+{
+    FRESULT res;
+    struct ff_file* fhdl = malloc(sizeof(*fhdl));
+    memset(fhdl, 0, sizeof(*fhdl));
+    res = f_open(&(fhdl->fobj), path, mode);
+    if (res != FR_OK) {
+        free(fhdl);
+        fhdl = NULL;
+    }
+    return fhdl;
+}
+
+uint8_t __visible
+fatfs_close(struct ff_file* fhdl)
+{
+    FRESULT res;
+    res = f_close(&(fhdl->fobj));
+    free(fhdl);
+    return res;
+}
+
+int __visible
+fatfs_read(struct ff_file* fhdl, void* rbuf, uint16_t btr)
+{
+    FRESULT res;
+    UINT bytes_read;
+    res = f_read(&(fhdl->fobj), rbuf, btr, &bytes_read);
+    if (res != FR_OK) {
+        return -res;
+    }
+    return bytes_read;
+}
+
+int __visible
+fatfs_write(struct ff_file* fhdl, const void* wbuf, uint16_t btw)
+{
+    FRESULT res;
+    UINT bytes_written;
+    res = f_write(&(fhdl->fobj), wbuf, btw, &bytes_written);
+    if (bytes_written < btw) {
+        return -res;
+    }
+    return bytes_written;
+}
+
+// Remove a file or director
+uint8_t __visible
+fatfs_remove(const char* path)
+{
+    FRESULT res;
+    res = f_unlink(path);
+    return res;
+}
+
+uint8_t __visible
+fatfs_get_fstats(struct ff_file_info* finfo, const char* path)
+{
+    FRESULT res;
+    FILINFO nfo;
+    res = f_stat(path, &nfo);
+    if (res == FR_OK)
+        memcpy(finfo, &nfo, sizeof(nfo));
+    return res;
+}
+
+uint8_t __visible
+fatfs_get_disk_info(struct ff_disk_info* dinfo)
+{
+    FRESULT res;
+    res = f_getlabel("", dinfo->label, &(dinfo->serial_number));
+    if (res != FR_OK)
+        return res;
+    dinfo->fs_type = fs.fs_type;
+    return res;
+}
+
+uint8_t __visible
+fatfs_list_dir(struct ff_file_info* flist, uint8_t max_size, char* path)
+{
+    FRESULT res;
+    DIR dir;
+    FILINFO nfo;
+    res = f_opendir(&dir, path);
+    if (res == FR_OK) {
+        for (uint8_t i=0; i < max_size; i++) {
+            res = f_readdir(&dir, &nfo);
+            if (res != FR_OK ||nfo.fname[0] == 0)
+                break;
+            memcpy(&(flist[i]), &nfo, sizeof(nfo));
+        }
+    }
+    return FR_OK;
+}