fat_fs: Add support for variable sector size

Add support for variable sector sizes by exposing _MAX_SS as
CONFIG_FS_FATFS_MAX_SS to Kconfig and adding the GET_SECTOR_SIZE IOCTL.

Signed-off-by: Markus Fuchs <[email protected]>

Author: mrfuchs

README

@@ -23,3 +23,4 @@ _CODE_PAGE	as	CONFIG_FS_FATFS_CODEPAGE
 _FS_READONLY	as	CONFIG_FS_FATFS_READ_ONLY
 _USE_MKFS	as	CONFIG_FS_FATFS_MKFS
 _VOLUMES	as	CONFIG_FS_FATFS_VOLUMES
+_MAX_SS		as	CONFIG_FS_FATFS_MAX_SS

include/ffconf.h

@@ -201,7 +201,11 @@
 
 
 #define	_MIN_SS		512
+#if defined(CONFIG_FS_FATFS_MAX_SS)
+#define	_MAX_SS		CONFIG_FS_FATFS_MAX_SS
+#else
 #define	_MAX_SS		512
+#endif /* defined(CONFIG_FS_FATFS_MAX_SS) */
 /* These options configure the range of sector size to be supported. (512, 1024,
 /  2048 or 4096) Always set both 512 for most systems, all type of memory cards and
 /  harddisk. But a larger value may be required for on-board flash memory and some

zfs_diskio.c

@@ -97,7 +97,8 @@ DRESULT disk_write(BYTE pdrv, const BYTE *buff, DWORD sector, UINT count)
 
 DRESULT disk_ioctl(BYTE pdrv, BYTE cmd, void *buff)
 {
-	int ret =  RES_OK;
+	int ret = RES_OK;
+	uint32_t sector_size = 0;
 
 	__ASSERT(pdrv < ARRAY_SIZE(pdrv_str), "pdrv out-of-range\n");
 
@@ -113,7 +114,21 @@ DRESULT disk_ioctl(BYTE pdrv, BYTE cmd, void *buff)
 		if (disk_access_ioctl(pdrv_str[pdrv],
 				DISK_IOCTL_GET_SECTOR_COUNT, buff) != 0) {
 			ret = RES_ERROR;
-                }
+		}
+		break;
+
+	case GET_SECTOR_SIZE:
+		/* Zephyr's DISK_IOCTL_GET_SECTOR_SIZE returns sector size as a
+		 * 32-bit number while FatFS's GET_SECTOR_SIZE is supposed to
+		 * return a 16-bit number.
+		 */
+		if ((disk_access_ioctl(pdrv_str[pdrv],
+				DISK_IOCTL_GET_SECTOR_SIZE, &sector_size) == 0) &&
+			(sector_size == (uint16_t)sector_size)) {
+			*(uint16_t *)buff = (uint16_t)sector_size;
+		} else {
+			ret = RES_ERROR;
+		}
 		break;
 
 	case GET_BLOCK_SIZE: