* Patch by Daniel Engström, 13 Nov 2002:
  Add support for i386 architecture and AMD SC520 board

* Patch by Pierre Aubert, 12 Nov 2002:
  Add support for DOS filesystem and booting from DOS floppy disk
diff --git a/fs/fdos/subdir.c b/fs/fdos/subdir.c
new file mode 100644
index 0000000..5911f2e
--- /dev/null
+++ b/fs/fdos/subdir.c
@@ -0,0 +1,348 @@
+/*
+ * (C) Copyright 2002
+ * Stäubli Faverges - <www.staubli.com>
+ * Pierre AUBERT  p.aubert@staubli.com
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <config.h>
+#include <malloc.h>
+
+#if (CONFIG_COMMANDS & CFG_CMD_FDOS)
+
+#include "dos.h"
+#include "fdos.h"
+
+static int cache_sect;
+static unsigned char cache [SZ_STD_SECTOR];
+
+
+#define min(x,y) ((x)<(y)?(x):(y))
+
+static int descend (Slot_t *parent,
+             Fs_t *fs,
+                    char *path);
+
+/*-----------------------------------------------------------------------------
+ * init_subdir -- 
+ *-----------------------------------------------------------------------------
+ */
+void init_subdir (void)
+{
+    cache_sect = -1;
+}
+/*-----------------------------------------------------------------------------
+ * basename -- 
+ *-----------------------------------------------------------------------------
+ */
+char *basename (char *name)
+{
+    register char *cptr;
+
+    if (!name || !*name) {
+        return ("");
+    }
+    
+    for (cptr= name; *cptr++; );
+    while (--cptr >= name) {
+	if (*cptr == '/')    {
+            return (cptr + 1);
+	}
+    }
+    return(name);
+}
+/*-----------------------------------------------------------------------------
+ * root_map -- 
+ *-----------------------------------------------------------------------------
+ */
+static int root_map (Fs_t *fs, Slot_t *file, int where, int *len)
+{
+    *len = min (*len, fs -> dir_len * SZ_STD_SECTOR - where);
+    if (*len < 0 ) {
+        *len = 0;
+        return (-1);
+    }
+    return fs -> dir_start * SZ_STD_SECTOR + where;
+}
+/*-----------------------------------------------------------------------------
+ * normal_map -- 
+ *-----------------------------------------------------------------------------
+ */
+static int normal_map (Fs_t *fs, Slot_t *file, int where, int *len)
+{
+    int offset;
+    int NrClu;
+    unsigned short RelCluNr;
+    unsigned short CurCluNr;
+    unsigned short NewCluNr;
+    unsigned short AbsCluNr;
+    int clus_size;
+
+    clus_size = fs -> cluster_size * SZ_STD_SECTOR;
+    offset = where % clus_size;
+
+    *len = min (*len, file -> FileSize - where);
+
+    if (*len < 0 ) {
+        *len = 0;
+        return (0);
+    }
+
+    if (file -> FirstAbsCluNr < 2){
+        *len = 0;
+        return (0);
+    }
+
+    RelCluNr = where / clus_size;
+	
+    if (RelCluNr >= file -> PreviousRelCluNr){
+        CurCluNr = file -> PreviousRelCluNr;
+        AbsCluNr = file -> PreviousAbsCluNr;
+    } else {
+        CurCluNr = 0;
+        AbsCluNr = file -> FirstAbsCluNr;
+    }
+
+
+    NrClu = (offset + *len - 1) / clus_size;
+    while (CurCluNr <= RelCluNr + NrClu) {
+        if (CurCluNr == RelCluNr){
+            /* we have reached the beginning of our zone. Save
+             * coordinates */
+            file -> PreviousRelCluNr = RelCluNr;
+            file -> PreviousAbsCluNr = AbsCluNr;
+        }
+        NewCluNr = fat_decode (fs, AbsCluNr);
+        if (NewCluNr == 1 || NewCluNr == 0) {
+            PRINTF("Fat problem while decoding %d %x\n", 
+                    AbsCluNr, NewCluNr);
+            return (-1);
+        }
+        if (CurCluNr == RelCluNr + NrClu) {
+            break;
+        }
+
+        if (CurCluNr < RelCluNr && NewCluNr == FAT12_END) {
+            *len = 0;
+            return 0;
+        }
+
+        if (CurCluNr >= RelCluNr && NewCluNr != AbsCluNr + 1)
+            break;
+        CurCluNr++;
+        AbsCluNr = NewCluNr;
+    }
+
+    *len = min (*len, (1 + CurCluNr - RelCluNr) * clus_size - offset);
+
+    return (((file -> PreviousAbsCluNr - 2) * fs -> cluster_size +
+             fs -> dir_start + fs -> dir_len) *
+            SZ_STD_SECTOR + offset);
+}
+/*-----------------------------------------------------------------------------
+ * open_subdir -- open the subdir containing the file
+ *-----------------------------------------------------------------------------
+ */
+int open_subdir (File_t *desc)
+{
+    char *pathname;
+    char *tmp, *s, *path;
+    char terminator;
+    
+    if ((pathname = (char *)malloc (MAX_PATH)) == NULL) {
+        return (-1);
+    }
+    
+    strcpy (pathname, desc -> name);
+    
+    /* Suppress file name                                                    */
+    tmp = basename (pathname);
+    *tmp = '\0';
+
+    /* root directory  init                                                  */
+    desc -> subdir.FirstAbsCluNr = 0;
+    desc -> subdir.FileSize = -1;
+    desc -> subdir.map = root_map;
+    desc -> subdir.dir.attr = ATTR_DIRECTORY;
+    
+    tmp = pathname;
+    for (s = tmp; ; ++s) {
+        if (*s == '/' || *s == '\0') {
+            path = tmp;
+            terminator = *s;
+            *s = '\0';
+            if (s != tmp && strcmp (path,".")) {
+                if (descend (&desc -> subdir, desc -> fs, path) < 0) {
+                    free (pathname);
+                    return (-1);
+                }
+            }
+            if (terminator == 0) {
+                break;
+            }
+            tmp = s + 1;
+        }
+    }
+    free (pathname);
+    return (0);
+}
+/*-----------------------------------------------------------------------------
+ * descend -- 
+ *-----------------------------------------------------------------------------
+ */
+static int descend (Slot_t *parent,
+             Fs_t *fs,
+             char *path)
+{
+    int entry;
+    Slot_t SubDir;
+
+    if(path[0] == '\0' || strcmp (path, ".") == 0) {
+        return (0);
+    }
+    
+
+    entry = 0;
+    if (vfat_lookup (parent,
+                     fs,
+                     &(SubDir.dir),
+                     &entry,
+                     0,
+                     path,
+                     ACCEPT_DIR | SINGLE | DO_OPEN,
+                     0,
+                     &SubDir) == 0) {
+        *parent = SubDir;
+        return (0);
+    }
+
+    if (strcmp(path, "..") == 0) {
+        parent -> FileSize = -1;
+        parent -> FirstAbsCluNr = 0;
+        parent -> map = root_map;
+        return (0);
+    }
+    return (-1);
+}
+/*-----------------------------------------------------------------------------
+ * open_file -- 
+ *-----------------------------------------------------------------------------
+ */
+int open_file (Slot_t *file, Directory_t *dir)
+{
+    int first;
+    unsigned long size;
+
+    first = __le16_to_cpu (dir -> start);
+
+    if(first == 0 &&
+       (dir -> attr & ATTR_DIRECTORY) != 0) {
+        file -> FirstAbsCluNr = 0;
+        file -> FileSize = -1;
+        file -> map = root_map;
+        return (0);
+    }
+	
+    if ((dir -> attr & ATTR_DIRECTORY) != 0) {
+        size = (1UL << 31) - 1;
+    }
+    else {
+        size = __le32_to_cpu (dir -> size);
+    }
+
+    file -> map = normal_map;
+    file -> FirstAbsCluNr = first;
+    file -> PreviousRelCluNr = 0xffff;
+    file -> FileSize = size;
+    return (0);
+}
+/*-----------------------------------------------------------------------------
+ * read_file -- 
+ *-----------------------------------------------------------------------------
+ */
+int read_file (Fs_t *fs,
+               Slot_t *file,
+               char *buf,
+               int where,
+               int len)
+{
+    int pos;
+    int read, nb, sect, offset;
+    
+    pos = file -> map (fs, file, where, &len);
+    if  (pos < 0) {
+        return -1;
+    }
+    if (len == 0) {
+        return (0);
+    }
+
+    /* Compute sector number                                                 */
+    sect = pos / SZ_STD_SECTOR;
+    offset = pos % SZ_STD_SECTOR;
+    read = 0;
+    
+    if (offset) {
+        /* Read doesn't start at the sector beginning. We need to use our    */
+        /* cache                                                             */
+        if (sect != cache_sect) {
+            if (dev_read (cache, sect, 1) < 0) {
+                return (-1);
+            }
+            cache_sect = sect;
+        }
+        nb = min (len, SZ_STD_SECTOR - offset);
+        
+        memcpy (buf, cache + offset, nb);
+        read += nb;
+        len -= nb;
+        sect += 1;
+    }
+
+    if (len > SZ_STD_SECTOR) {
+        nb = (len - 1) / SZ_STD_SECTOR;
+        if (dev_read (buf + read, sect, nb) < 0) {
+            return ((read) ? read : -1);
+        }
+        /* update sector position                                            */
+        sect += nb;
+
+        /* Update byte position                                              */
+        nb *= SZ_STD_SECTOR;
+        read += nb;
+        len -= nb;
+    }
+
+    if (len) {
+        if (sect != cache_sect) {
+            if (dev_read (cache, sect, 1) < 0) {
+                return ((read) ? read : -1);
+                cache_sect = -1;
+            }
+            cache_sect = sect;
+        }
+        
+        memcpy (buf + read, cache, len);
+        read += len;
+    }
+    return (read);
+}
+#endif