Add support for more FAT partitions; support for SD cards greater than 4Gb; TSC2007 touchscreen driver improvements

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4092 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -2202,3 +2202,11 @@
 	  PIC32 port is almost complete but still not ready for prime time.
 
 6.12 2011-xx-xx Gregory Nutt <gnutt@nuttx.org>
+
+	* fs/fat/fs_fat32util.c and fs_fat32.h: Logic extended to look in up to
+	  four partitions for a valid FAT file system.
+	* drivers/input/tsc2007.c: Add support for 8-bit conversions; make sure
+	  that A/D converters are active before requesting conversions.
+	* drivers/mmcsd0/mmcsd_sdio.c: Increase capacity variable from size_t
+	  to uin64_t (if available) so that SD cards with capacities greater
+	  than 4Gb can be supported.

arch/arm/src/armv7-m/up_svcall.c

@@ -202,7 +202,7 @@ static inline void dispatch_syscall(uint32_t *regs)
 #endif
     }
 
-  /* Set up the return vaue.  First, check if a context switch occurred. 
+  /* Set up the return value.  First, check if a context switch occurred. 
    * In this case, regs will no longer be the same as current_regs.  In
    * the case of a context switch, we will have to save the return value
    * in the TCB where it can be returned later when the task is restarted.

drivers/input/tsc2007.c

@@ -91,6 +91,29 @@
 #define DEV_FORMAT   "/dev/input%d"
 #define DEV_NAMELEN  16
 
+/* Commands *****************************************************************/
+
+#define TSC2007_SETUP           (TSC2007_CMD_FUNC_SETUP)
+#ifdef CONFIG_TSC2007_8BIT
+#  define TSC2007_ACTIVATE_Y    (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YON)
+#  define TSC2007_MEASURE_Y     (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YPOS)
+#  define TSC2007_ACTIVATE_X    (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_XON)
+#  define TSC2007_MEASURE_X     (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_XPOS)
+#  define TSC2007_ACTIVATE_Z    (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YXON)
+#  define TSC2007_MEASURE_Z1    (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z1POS)
+#  define TSC2007_MEASURE_Z2    (TSC2007_CMD_8BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z2POS)
+#  define TSC2007_ENABLE_PENIRQ (TSC2007_CMD_8BIT | TSC2007_CMD_PWRDN_IRQEN)
+#else
+#  define TSC2007_ACTIVATE_Y    (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YON)
+#  define TSC2007_MEASURE_Y     (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YPOS)
+#  define TSC2007_ACTIVATE_X    (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_XON)
+#  define TSC2007_MEASURE_X     (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_XPOS)
+#  define TSC2007_ACTIVATE_Z    (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YXON)
+#  define TSC2007_MEASURE_Z1    (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z1POS)
+#  define TSC2007_MEASURE_Z2    (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z2POS)
+#  define TSC2007_ENABLE_PENIRQ (TSC2007_CMD_12BIT | TSC2007_CMD_PWRDN_IRQEN)
+#endif
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -156,6 +179,7 @@ static int tsc2007_sample(FAR struct tsc2007_dev_s *priv,
                           FAR struct tsc2007_sample_s *sample);
 static int tsc2007_waitsample(FAR struct tsc2007_dev_s *priv,
                               FAR struct tsc2007_sample_s *sample);
+static int tsc2007_activate(FAR struct tsc2007_dev_s *priv, uint8_t cmd);
 static int tsc2007_transfer(FAR struct tsc2007_dev_s *priv, uint8_t cmd);
 static void tsc2007_worker(FAR void *arg);
 static int tsc2007_interrupt(int irq, FAR void *context);
@@ -377,6 +401,48 @@ errout:
   return ret;
 }
 
+/****************************************************************************
+ * Name: tsc2007_activate
+ ****************************************************************************/
+
+static int tsc2007_activate(FAR struct tsc2007_dev_s *priv, uint8_t cmd)
+{
+   struct i2c_msg_s msg;
+   uint8_t data;
+   int ret;
+
+  /* Send the setup command (with no ACK) followed by the A/D converter
+   * activation command (ACKed).
+   */
+
+   data = TSC2007_SETUP;
+
+   msg.addr   = priv->config->address; /* 7-bit address */
+   msg.flags  = 0;                     /* Write transaction, beginning with START */
+   msg.buffer = &data;                 /* Transfer from this address */
+   msg.length = 1;                     /* Send one byte following the address */
+ 
+   /* Ignore errors from the setup command (because it is not ACKed) */
+
+   (void)I2C_TRANSFER(priv->i2c, &msg, 1);
+
+   /* Now activate the A/D converter */
+
+   data = cmd;
+
+   msg.addr   = priv->config->address; /* 7-bit address */
+   msg.flags  = 0;                     /* Write transaction, beginning with START */
+   msg.buffer = &data;                 /* Transfer from this address */
+   msg.length = 1;                     /* Send one byte following the address */
+ 
+   ret = I2C_TRANSFER(priv->i2c, &msg, 1);
+   if (ret < 0)
+     {
+       idbg("I2C_TRANSFER failed: %d\n", ret);
+     }
+   return ret;
+}
+
 /****************************************************************************
  * Name: tsc2007_transfer
  ****************************************************************************/
@@ -529,16 +595,17 @@ static void tsc2007_worker(FAR void *arg)
        *  in the cases previously listed."
        */
 
-      y = tsc2007_transfer(priv,
+      (void)tsc2007_activate(priv, TSC2007_ACTIVATE_X);
-                          (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_YPOS));
+      y = tsc2007_transfer(priv, TSC2007_MEASURE_Y);
+
 
       /* "Voltage is then applied to the other axis, and the A/D converter
        *  converts the voltage representing the X position on the screen. This
        *  process provides the X and Y coordinates to the associated processor."
        */
 
-      x = tsc2007_transfer(priv,
+      (void)tsc2007_activate(priv, TSC2007_ACTIVATE_Y);
-                          (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_XPOS));
+      x = tsc2007_transfer(priv, TSC2007_MEASURE_X);
 
       /* "... To determine pen or finger touch, the pressure of the touch must be
        *  determined. ... There are several different ways of performing this
@@ -556,15 +623,14 @@ static void tsc2007_worker(FAR void *arg)
        * Read Z1 and Z2 values.
        */
 
-      z1 = tsc2007_transfer(priv,
+      (void)tsc2007_activate(priv, TSC2007_ACTIVATE_Z);
-                           (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z1POS));
+      z1 = tsc2007_transfer(priv, TSC2007_MEASURE_Z1);
-      z2 = tsc2007_transfer(priv,
+      (void)tsc2007_activate(priv, TSC2007_ACTIVATE_Z);
-                           (TSC2007_CMD_12BIT | TSC2007_CMD_ADCON_IRQDIS | TSC2007_CMD_FUNC_Z2POS));
+      z2 = tsc2007_transfer(priv, TSC2007_MEASURE_Z2);
 
       /* Power down ADC and enable PENIRQ */
 
-     (void)tsc2007_transfer(priv,
+     (void)tsc2007_transfer(priv, TSC2007_ENABLE_PENIRQ);
-                           (TSC2007_CMD_12BIT | TSC2007_CMD_PWRDN_IRQEN));
 
       /* Now calculate the pressure using the first method, reduced to:
        *
@@ -574,21 +640,23 @@ static void tsc2007_worker(FAR void *arg)
       if (z1 == 0)
         {
           idbg("Z1 zero\n");
-          goto errout;
+          pressure = 0;
         }
-
+      else
-      pressure = (x * config->rxplate * (z2 - z1)) / z1;
-      pressure = (pressure + 2048) >> 12;
-
-      ivdbg("Position: (%d,%4d) pressure: %u z1/2: (%d,%d)\n",
-            x, y, pressure, z1, z2);
-
-      /* Ignore out of range caculcations */
-
-      if (pressure > 0x0fff)
         {
-          idbg("Dropped out-of-range pressure: %d\n", pressure);
+          pressure = (x * config->rxplate * (z2 - z1)) / z1;
-          goto errout;
+          pressure = (pressure + 2048) >> 12;
+
+          ivdbg("Position: (%d,%4d) pressure: %u z1/2: (%d,%d)\n",
+                x, y, pressure, z1, z2);
+
+          /* Ignore out of range caculcations */
+
+          if (pressure > 0x0fff)
+            {
+              idbg("Dropped out-of-range pressure: %d\n", pressure);
+              pressure = 0;
+            }
         }
 
       /* Save the measurements */
@@ -878,17 +946,27 @@ static ssize_t tsc2007_read(FAR struct file *filep, FAR char *buffer, size_t len
 
       report->point[0].flags  = TOUCH_UP | TOUCH_ID_VALID;
     }
-  else if (sample.contact == CONTACT_DOWN)
+  else
     {
-      /* First contact */
+      if (sample.contact == CONTACT_DOWN)
+        {
+          /* First contact */
 
-      report->point[0].flags  = TOUCH_DOWN | TOUCH_ID_VALID | TOUCH_POS_VALID | TOUCH_PRESSURE_VALID;
+          report->point[0].flags  = TOUCH_DOWN | TOUCH_ID_VALID | TOUCH_POS_VALID;
-    }
+        }
-  else /* if (sample->contact == CONTACT_MOVE) */
+      else /* if (sample->contact == CONTACT_MOVE) */
-    {
+        {
-      /* Movement of the same contact */
+          /* Movement of the same contact */
 
-      report->point[0].flags  = TOUCH_MOVE | TOUCH_ID_VALID | TOUCH_POS_VALID | TOUCH_PRESSURE_VALID;
+          report->point[0].flags  = TOUCH_MOVE | TOUCH_ID_VALID | TOUCH_POS_VALID;
+        }
+
+      /* A pressure measurement of zero means that pressure is not available */
+
+      if (report->point[0].pressure != 0)
+        {
+          report->point[0].flags  |= TOUCH_PRESSURE_VALID;
+        }
     }
 
   ret = SIZEOF_TOUCH_SAMPLE_S(1);
@@ -1163,7 +1241,7 @@ int tsc2007_register(FAR struct i2c_dev_s *dev,
    * waiting for a touch event.
    */
 
-  ret = tsc2007_transfer(priv, (TSC2007_CMD_12BIT | TSC2007_CMD_PWRDN_IRQEN));
+  ret = tsc2007_transfer(priv, TSC2007_ENABLE_PENIRQ);
   if (ret < 0)
     {
       idbg("tsc2007_transfer failed: %d\n", ret);

drivers/mmcsd/mmcsd_sdio.c

@@ -38,6 +38,7 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+#include <nuttx/compiler.h>
 
 #include <sys/types.h>
 #include <sys/ioctl.h>
@@ -128,11 +129,15 @@ struct mmcsd_state_s
 
   /* Memory card geometry (extracted from the CSD) */
 
-  uint8_t  blockshift;               /* Log2 of blocksize */
+  uint8_t  blockshift;             /* Log2 of blocksize */
   uint16_t blocksize;              /* Read block length (== block size) */
-  size_t nblocks;                  /* Number of blocks */
+  uint32_t nblocks;                /* Number of blocks */
-  size_t capacity;                 /* Total capacity of volume */
 
+#ifdef CONFIG_HAVE_LONG_LONG
+  uint64_t capacity;               /* Total capacity of volume */
+#else
+  uint32_t capacity;               /* Total capacity of volume (Limited to 4Gb) */
+#endif
   /* Read-ahead and write buffering support */
 
 #if defined(CONFIG_FS_WRITEBUFFER) || defined(CONFIG_FS_READAHEAD)
@@ -635,7 +640,11 @@ static void mmcsd_decodeCSD(FAR struct mmcsd_state_s *priv, uint32_t csd[4])
        */
 
       uint32_t csize                 = ((csd[1] & 0x3f) << 16) | (csd[2] >> 16);
+#ifdef CONFIG_HAVE_LONG_LONG
+      priv->capacity                 = ((uint64_t)(csize + 1)) << 19;
+#else
       priv->capacity                 = (csize + 1) << 19;
+#endif
       priv->blockshift               = 9;
       priv->blocksize                = 1 << 9;
       priv->nblocks                  = priv->capacity >> 9;
@@ -802,8 +811,9 @@ static void mmcsd_decodeCSD(FAR struct mmcsd_state_s *priv, uint32_t csd[4])
   fvdbg("  FILE_FORMAT: %d ECC: %d (MMC) CRC: %d\n",
         decoded.fileformat, decoded.mmcecc, decoded.crc);
 
-  fvdbg("Capacity: %dKb, Block size: %db, nblocks: %d wrprotect: %d\n",
+  fvdbg("Capacity: %luKb, Block size: %db, nblocks: %d wrprotect: %d\n",
-         priv->capacity / 1024, priv->blocksize, priv->nblocks, priv->wrprotect);
+         (unsigned long)(priv->capacity / 1024), priv->blocksize,
+         priv->nblocks, priv->wrprotect);
 #endif
 }
 
@@ -2759,7 +2769,7 @@ static int mmcsd_probe(FAR struct mmcsd_state_s *priv)
             if (ret == OK)
               {
                 /* Yes...  */
-
+
                 fvdbg("Capacity: %lu Kbytes\n", (unsigned long)(priv->capacity / 1024));
                 priv->mediachanged = true;
 

fs/fat/fs_fat32.h

@@ -129,10 +129,12 @@
  */
                               /* 446@0: Generally unused and zero; but may
                                * include IDM Boot Manager menu entry at 8@394 */
+#define PART_ENTRY(n)    (446+((n) << 4)) /* n = 0,1,2,3 */
 #define PART_ENTRY1       446 /* 16@446: Partition table, first entry */
 #define PART_ENTRY2       462 /* 16@462: Partition table, second entry */
-                              /* 32@478: Unused, should be zero */
+#define PART_ENTRY3       478 /* 16@478: Partition table, third entry */
-#define PART_SIGNATURE        /* 2@510: Valid partitions have 0x55aa here */
+#define PART_ENTRY4       494 /* 16@494: Partition table, fourth entry */
+#define PART_SIGNATURE    510 /* 2@510: Valid partitions have 0x55aa here */
 
 /****************************************************************************
  * These offsets describes one partition table entry.  NOTE that ent entries
@@ -147,6 +149,26 @@
 #define PART_STARTSECTOR    8  /* 4@8:  Starting sector */
 #define PART_SIZE          12  /* 4@12: Partition size (in sectors) */
 
+/****************************************************************************
+ * Partition table types.
+ */
+
+#define PART_TYPE_NONE      0  /* No partition */
+#define PART_TYPE_FAT12     1  /* FAT12 */
+#define PART_TYPE_FAT16A    4  /* FAT16 (Partition smaller than 32MB) */
+#define PART_TYPE_EXT       5  /* Extended MS-DOS Partition */
+#define PART_TYPE_FAT16B    6  /* FAT16 (Partition larger than 32MB) */
+#define PART_TYPE_FAT32    11  /* FAT32 (Partition up to 2048Gb) */
+#define PART_TYPE_FAT32X   12  /* Same as 11, but uses LBA1 0x13 extensions */
+#define PART_TYPE_FAT16X   14  /* Same as 6, but uses LBA1 0x13 extensions */
+#define PART_TYPE_EXTX     15  /* Same as 5, but uses LBA1 0x13 extensions */
+
+/****************************************************************************
+ * Each FAT "short" 8.3 file name directory entry is 32-bytes long.
+ *
+ * Sizes and limits
+ */
+
 /****************************************************************************
  * Each FAT "short" 8.3 file name directory entry is 32-bytes long.
  *
@@ -329,8 +351,11 @@
 #define MBR_GETBOOTSIG16(p)       UBYTE_VAL(p,BS16_BOOTSIG)
 #define MBR_GETBOOTSIG32(p)       UBYTE_VAL(p,BS32_BOOTSIG)
 
+#define PART_GETTYPE(n,p)         UBYTE_VAL(p,PART_ENTRY(n)+PART_TYPE)
 #define PART1_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY1+PART_TYPE)
 #define PART2_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY2+PART_TYPE)
+#define PART3_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY3+PART_TYPE)
+#define PART4_GETTYPE(p)          UBYTE_VAL(p,PART_ENTRY4+PART_TYPE)
 
 #define DIR_GETATTRIBUTES(p)      UBYTE_VAL(p,DIR_ATTRIBUTES)
 #define DIR_GETNTRES(p)           UBYTE_VAL(p,DIR_NTRES)
@@ -351,8 +376,11 @@
 #define MBR_PUTBOOTSIG16(p,v)     UBYTE_PUT(p,BS16_BOOTSIG,v)
 #define MBR_PUTBOOTSIG32(p,v)     UBYTE_PUT(p,BS32_BOOTSIG,v)
 
+#define PART_PUTTYPE(n,p,v)       UBYTE_PUT(p,PART_ENTRY(n)+PART_TYPE,v)
 #define PART1_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY1+PART_TYPE,v)
 #define PART2_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY2+PART_TYPE,v)
+#define PART3_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY3+PART_TYPE,v)
+#define PART4_PUTTYPE(p,v)        UBYTE_PUT(p,PART_ENTRY4+PART_TYPE,v)
 
 #define DIR_PUTATTRIBUTES(p,v)    UBYTE_PUT(p,DIR_ATTRIBUTES,v)
 #define DIR_PUTNTRES(p,v)         UBYTE_PUT(p,DIR_NTRES,v)
@@ -378,10 +406,16 @@
 #define MBR_GETVOLID16(p)          fat_getuint32(UBYTE_PTR(p,BS16_VOLID))
 #define MBR_GETVOLID32(p)          fat_getuint32(UBYTE_PTR(p,BS32_VOLID))
 
+#define PART_GETSTARTSECTOR(n,p)   fat_getuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_STARTSECTOR))
+#define PART_GETSIZE(n,p)          fat_getuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_SIZE))
 #define PART1_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY1+PART_STARTSECTOR))
 #define PART1_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY1+PART_SIZE))
 #define PART2_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY2+PART_STARTSECTOR))
 #define PART2_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY2+PART_SIZE))
+#define PART3_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY3+PART_STARTSECTOR))
+#define PART3_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY3+PART_SIZE))
+#define PART4_GETSTARTSECTOR(p)    fat_getuint32(UBYTE_PTR(p,PART_ENTRY4+PART_STARTSECTOR))
+#define PART4_GETSIZE(p)           fat_getuint32(UBYTE_PTR(p,PART_ENTRY4+PART_SIZE))
 
 #define MBR_PUTBYTESPERSEC(p,v)    fat_putuint16(UBYTE_PTR(p,BS_BYTESPERSEC),v)
 #define MBR_PUTROOTENTCNT(p,v)     fat_putuint16(UBYTE_PTR(p,BS_ROOTENTCNT),v)
@@ -389,10 +423,16 @@
 #define MBR_PUTVOLID16(p,v)        fat_putuint32(UBYTE_PTR(p,BS16_VOLID),v)
 #define MBR_PUTVOLID32(p,v)        fat_putuint32(UBYTE_PTR(p,BS32_VOLID),v)
 
+#define PART_PUTSTARTSECTOR(n,p,v) fat_putuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_STARTSECTOR),v)
+#define PART_PUTSIZE(n,p,v)        fat_putuint32(UBYTE_PTR(p,PART_ENTRY(n)+PART_SIZE),v)
 #define PART1_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY1+PART_STARTSECTOR),v)
 #define PART1_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY1+PART_SIZE),v)
 #define PART2_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY2+PART_STARTSECTOR),v)
 #define PART2_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY2+PART_SIZE),v)
+#define PART3_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY3+PART_STARTSECTOR),v)
+#define PART3_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY3+PART_SIZE),v)
+#define PART4_PUTSTARTSECTOR(p,v)  fat_putuint32(UBYTE_PTR(p,PART_ENTRY4+PART_STARTSECTOR),v)
+#define PART4_PUTSIZE(p,v)         fat_putuint32(UBYTE_PTR(p,PART_ENTRY4+PART_SIZE),v)
 
 #ifdef CONFIG_FAT_LFN
 # define LDIR_PTRWCHAR1_5(p)       UBYTE_PTR(p,LDIR_WCHAR1_5)

fs/fat/fs_fat32util.c

@@ -138,6 +138,10 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
   if (MBR_GETSIGNATURE(fs->fs_buffer) != BOOT_SIGNATURE16 ||
       MBR_GETBYTESPERSEC(fs->fs_buffer) != fs->fs_hwsectorsize)
     {
+      fdbg("ERROR: Signature: %04x FS sectorsize: %d HW sectorsize: %d\n",
+            MBR_GETSIGNATURE(fs->fs_buffer), MBR_GETBYTESPERSEC(fs->fs_buffer),
+            fs->fs_hwsectorsize);
+
       return -ENODEV;
     }
 
@@ -172,6 +176,9 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
 
   if (!fs->fs_nfatsects || fs->fs_nfatsects >= fs->fs_hwnsectors)
     {
+      fdbg("ERROR: fs_nfatsects %d fs_hwnsectors: %d\n",
+           fs->fs_nfatsects, fs->fs_hwnsectors);
+
       return -ENODEV;
     }
 
@@ -189,6 +196,9 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
 
   if (!fs->fs_fattotsec || fs->fs_fattotsec > fs->fs_hwnsectors)
     {
+      fdbg("ERROR: fs_fattotsec %d fs_hwnsectors: %d\n",
+           fs->fs_fattotsec, fs->fs_hwnsectors);
+
       return -ENODEV;
     }
 
@@ -197,6 +207,9 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
   fs->fs_fatresvdseccount = MBR_GETRESVDSECCOUNT(fs->fs_buffer);
   if (fs->fs_fatresvdseccount > fs->fs_hwnsectors)
     {
+      fdbg("ERROR: fs_fatresvdseccount %d fs_hwnsectors: %d\n",
+           fs->fs_fatresvdseccount, fs->fs_hwnsectors);
+
       return -ENODEV;
     }
 
@@ -210,6 +223,9 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
   ndatasectors = fs->fs_fattotsec - fs->fs_fatresvdseccount - ntotalfatsects - rootdirsectors;
   if (ndatasectors > fs->fs_hwnsectors)
     {
+      fdbg("ERROR: ndatasectors %d fs_hwnsectors: %d\n",
+           ndatasectors, fs->fs_hwnsectors);
+
       return -ENODEV;
     }
 
@@ -235,11 +251,14 @@ static int fat_checkbootrecord(struct fat_mountpt_s *fs)
     }
   else if (!notfat32)
     {
-      fs->fs_fsinfo   = fs->fs_fatbase + MBR_GETFSINFO(fs->fs_buffer);
+      fs->fs_fsinfo = fs->fs_fatbase + MBR_GETFSINFO(fs->fs_buffer);
-      fs->fs_type     = FSTYPE_FAT32;
+      fs->fs_type   = FSTYPE_FAT32;
     }
   else
     {
+      fdbg("ERROR: notfat32: %d fs_nclusters: %d\n",
+           notfat32, fs->fs_nclusters);
+
       return -ENODEV;
     }
 
@@ -550,37 +569,63 @@ int fat_mount(struct fat_mountpt_s *fs, bool writeable)
       /* The contents of sector 0 is not a boot record.  It could be a
        * partition, however.  Assume it is a partition and get the offset
        * into the partition table.  This table is at offset MBR_TABLE and is
-       * indexed by 16x the partition number.  Here we support only
+       * indexed by 16x the partition number.
-       * partition 0.
-       *
-       * Check if the partition exists and, if so, get the bootsector for that
-       * partition and see if we can find the boot record there.
        */
 
-      if (PART1_GETTYPE(fs->fs_buffer) == 0)
+       int i;
-        {
+       for (i = 0; i < 4; i++)
-          fdbg("No MBR or partition\n");
+         {
-          goto errout_with_buffer;
+           /* Check if the partition exists and, if so, get the bootsector for that
+            * partition and see if we can find the boot record there.
+            */
+ 
+          uint8_t part = PART_GETTYPE(i, fs->fs_buffer);
+          fvdbg("Partition %d, offset %d, type %d\n", i, PART_ENTRY(i), part);
+
+          if (part == 0)
+            {
+              fvdbg("No partition %d\n", i);
+              continue;
+            }
+
+          /* There appears to be a partition, get the sector number of the
+           * partition (LBA)
+           */
+
+          fs->fs_fatbase = PART_GETSTARTSECTOR(i, fs->fs_buffer);
+
+          /* Read the new candidate boot sector */
+
+          ret = fat_hwread(fs, fs->fs_buffer, fs->fs_fatbase, 1);
+          if (ret < 0)
+            {
+              /* Failed to read the sector */
+
+              goto errout_with_buffer;
+            }
+
+          /* Check if this is a boot record */
+
+          ret = fat_checkbootrecord(fs);
+          if (ret == OK)
+            {
+              /* Break out of the loop if a valid boot record is found */
+
+              fvdbg("MBR found in partition %d\n", i);
+              break;
+            }
+
+          /* Re-read sector 0 so that we can check the next partition */
+
+          fvdbg("Partition %d is not an MBR\n", i);
+          ret = fat_hwread(fs, fs->fs_buffer, 0, 1);
+          if (ret < 0)
+            {
+              goto errout_with_buffer;
+            }
         }
 
-      /* There appears to be a partition, get the sector number of the
+      if (i > 3)
-       * partition (LBA)
-       */
-
-      fs->fs_fatbase = PART1_GETSTARTSECTOR(fs->fs_buffer);
-
-      /* Read the new candidate boot sector */
-
-      ret = fat_hwread(fs, fs->fs_buffer, fs->fs_fatbase, 1);
-      if (ret < 0)
-        {
-          goto errout_with_buffer;
-        }
-
-      /* Check if this is a boot record */
-
-      ret = fat_checkbootrecord(fs);
-      if (ret != OK)
         {
           fdbg("No valid MBR\n");
           goto errout_with_buffer;