[U-Boot] Enable access to FAT filesystem in an ISO9660 El-Torito volume

[U-Boot] Enable access to FAT filesystem in an ISO9660 El-Torito volume

[Kyle Moffett]

The included series of 3 patches fixes several bugs in the FAT code
and the USB storage stack to make it possible to read from a FAT
filesystem image embedded as an "El-Torito boot image" in an ISO9660
volume (IE: a CD or DVD).

This has been tested on the eXMeritus HWW-1U-1A.

[U-Boot] [PATCH 1/3] fs/fat: Fix FAT detection to support non-DOS partition tables

[Kyle Moffett]

The FAT filesystem code currently ends up requiring that the partition
table be a DOS MBR, as it checks for the DOS 0x55 0xAA signature on the
partition table (which may be Mac, EFI, ISO9660, etc) before actually
computing the partition offset.

This fixes support for accessing a FAT filesystem in an ISO9660 boot
volume (El-Torito format) by reordering the filesystem checks and
reading the 0x55 0xAA "DOS boot signature" and FAT/FAT32 magic number
from the first sector of the partition instead of from sector 0.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
---
 fs/fat/fat.c |  123 ++++++++++++++++++++++++++++-----------------------------
 1 files changed, 60 insertions(+), 63 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 9a29458..13bab8f 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -44,49 +44,36 @@ static void downcase (char *str)
 }
 
 static block_dev_desc_t *cur_dev = NULL;
-
-static unsigned long part_offset = 0;
-
-static int cur_part = 1;
-
-#define DOS_PART_TBL_OFFSET	0x1be
-#define DOS_PART_MAGIC_OFFSET	0x1fe
+static unsigned int cur_part_nr = 1;
+static disk_partition_t cur_part_info = {
+	.start = 0,
+	.size = 0,
+	.blksz = 512,
+	.name = "",
+	.type = "",
+};
+
+#define DOS_BOOT_MAGIC_OFFSET	0x1fe
 #define DOS_FS_TYPE_OFFSET	0x36
 #define DOS_FS32_TYPE_OFFSET	0x52
 
-static int disk_read (__u32 startblock, __u32 getsize, __u8 * bufptr)
+static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
 {
-	if (cur_dev == NULL)
+	if (!cur_dev || !cur_dev->block_read)
 		return -1;
 
-	startblock += part_offset;
-
-	if (cur_dev->block_read) {
-		return cur_dev->block_read(cur_dev->dev, startblock, getsize,
-					   (unsigned long *) bufptr);
-	}
-	return -1;
+	return cur_dev->block_read(cur_dev->dev,
+			cur_part_info.start + block, nr_blocks, buf);
 }
 
 int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
 {
 	unsigned char buffer[dev_desc->blksz];
+	unsigned int found_partition = 0;
 
-	if (!dev_desc->block_read)
-		return -1;
+	/* First close any currently found FAT filesystem */
+	cur_dev = NULL;
 
-	cur_dev = dev_desc;
-	/* check if we have a MBR (on floppies we have only a PBR) */
-	if (dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *)buffer) != 1) {
-		printf("** Can't read from device %d **\n",
-			dev_desc->dev);
-		return -1;
-	}
-	if (buffer[DOS_PART_MAGIC_OFFSET] != 0x55 ||
-	    buffer[DOS_PART_MAGIC_OFFSET + 1] != 0xaa) {
-		/* no signature found */
-		return -1;
-	}
 #if (defined(CONFIG_CMD_IDE) || \
      defined(CONFIG_CMD_MG_DISK) || \
      defined(CONFIG_CMD_SATA) || \
@@ -94,45 +81,55 @@ int fat_register_device (block_dev_desc_t * dev_desc, int part_no)
      defined(CONFIG_CMD_USB) || \
      defined(CONFIG_MMC) || \
      defined(CONFIG_SYSTEMACE) )
-	{
-		disk_partition_t info;
-
-		/* First we assume there is a MBR */
-		if (!get_partition_info(dev_desc, part_no, &info)) {
-			part_offset = info.start;
-			cur_part = part_no;
-		} else if ((strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET],
-				    "FAT", 3) == 0) ||
-			   (strncmp((char *)&buffer[DOS_FS32_TYPE_OFFSET],
-				    "FAT32", 5) == 0)) {
-			/* ok, we assume we are on a PBR only */
-			cur_part = 1;
-			part_offset = 0;
-		} else {
+
+	/* Read the partition table, if present */
+	if (!get_partition_info(dev_desc, part_no, &cur_part_info)) {
+		cur_dev = dev_desc;
+		cur_part_nr = part_no;
+	}
+#endif
+
+	/* Otherwise it might be a superfloppy (whole-disk FAT filesystem) */
+	if (!cur_dev) {
+		if (part_no != 1) {
 			printf("** Partition %d not valid on device %d **\n",
-				part_no, dev_desc->dev);
+					part_no, dev_desc->dev);
 			return -1;
 		}
+
+		found_partition = 1;
+		cur_dev = dev_desc;
+		cur_part_nr = 1;
+		cur_part_info.start = 0;
+		cur_part_info.size = dev_desc->lba;
+		cur_part_info.blksz = dev_desc->blksz;
+		memset(cur_part_info.name, 0, sizeof(cur_part_info.name));
+		memset(cur_part_info.type, 0, sizeof(cur_part_info.type));
 	}
-#else
-	if ((strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET], "FAT", 3) == 0) ||
-	    (strncmp((char *)&buffer[DOS_FS32_TYPE_OFFSET], "FAT32", 5) == 0)) {
-		/* ok, we assume we are on a PBR only */
-		cur_part = 1;
-		part_offset = 0;
-	} else {
-		/* FIXME we need to determine the start block of the
-		 * partition where the DOS FS resides. This can be done
-		 * by using the get_partition_info routine. For this
-		 * purpose the libpart must be included.
-		 */
-		part_offset = 32;
-		cur_part = 1;
+
+	/* Make sure it has a valid FAT header */
+	if (disk_read(0, 1, buffer) != 1) {
+		cur_dev = NULL;
+		return -1;
 	}
-#endif
-	return 0;
+
+	/* Check if it's actually a DOS volume */
+	if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
+		cur_dev = NULL;
+		return -1;
+	}
+
+	/* Check for FAT12/FAT16/FAT32 filesystem */
+	if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
+		return 0;
+	if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
+		return 0;
+
+	cur_dev = NULL;
+	return -1;
 }
 
+
 /*
  * Get the first occurence of a directory delimiter ('/' or '\') in a string.
  * Return index into string if found, -1 otherwise.
@@ -1170,7 +1167,7 @@ int file_fat_detectfs (void)
 	vol_label[11] = '\0';
 	volinfo.fs_type[5] = '\0';
 
-	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part,
+	printf("Partition %d: Filesystem: %s \"%s\"\n", cur_part_nr,
 		volinfo.fs_type, vol_label);
 
 	return 0;
-- 
1.7.7.3

[U-Boot] [PATCH 2/3] fs/fat: Improve error handling

[Kyle Moffett]

The FAT filesystem fails silently in inexplicable ways when given a
filesystem with a block-size that does not match the device sector size.
In theory this is not an unsupportable combination but requires a major
rewrite of a lot of the filesystem.  Until that occurs, the filesystem
should detect that scenario and display a helpful error message.

This scenario in particular occurred on a 512-byte blocksize FAT fs
stored in an El-Torito boot volume on a CD-ROM (2048-byte sector size).

Additionally, in many circumstances the ->block_read method will not
return a negative number to indicate an error but instead return 0 to
indicate the number of blocks successfully read (IE: None).

The FAT filesystem should defensively check to ensure that it got all of
the sectors that it asked for when reading.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
---
 fs/fat/fat.c |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 13bab8f..2136cd7 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -282,6 +282,8 @@ get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
 {
 	__u32 idx = 0;
 	__u32 startsect;
+	__u32 nr_sect;
+	int ret;
 
 	if (clustnum > 0) {
 		startsect = mydata->data_begin +
@@ -292,16 +294,19 @@ get_cluster (fsdata *mydata, __u32 clustnum, __u8 *buffer,
 
 	debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
 
-	if (disk_read(startsect, size / mydata->sect_size, buffer) < 0) {
-		debug("Error reading data\n");
+	nr_sect = size / mydata->sect_size;
+	ret = disk_read(startsect, nr_sect, buffer);
+	if (ret != nr_sect) {
+		debug("Error reading data (got %d)\n", ret);
 		return -1;
 	}
 	if (size % mydata->sect_size) {
 		__u8 tmpbuf[mydata->sect_size];
 
 		idx = size / mydata->sect_size;
-		if (disk_read(startsect + idx, 1, tmpbuf) < 0) {
-			debug("Error reading data\n");
+		ret = disk_read(startsect + idx, 1, tmpbuf);
+		if (ret != 1) {
+			debug("Error reading data (got %d)\n", ret);
 			return -1;
 		}
 		buffer += idx * mydata->sect_size;
@@ -810,6 +815,11 @@ do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
 
 	mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
 	mydata->clust_size = bs.cluster_size;
+	if (mydata->sect_size != cur_part_info.blksz) {
+		printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
+				mydata->sect_size, cur_part_info.blksz);
+		return -1;
+	}
 
 	if (mydata->fatsize == 32) {
 		mydata->data_begin = mydata->rootdir_sect -
-- 
1.7.7.3

[U-Boot] [PATCH 3/3] usb_storage: Fix EHCI "out of buffer pointers" with CD-ROM

[Kyle Moffett]

When performing large bulk reads from a CD or DVD using the U-Boot
usb_storage driver, it generates requests of up to 20 blocks at a time.

With a standard 512-byte block size, that is 10240 bytes and within the
limit of U-Boot's EHCI driver (maximum 5 pages at 4k per page).

Unfortunately CD-ROM media has a 2048-byte blocksize, resulting in a
maximum transfer size of 40960 bytes, which does not fit.

Since the EHCI specification is impossibly obtuse and far beyond my
comprehension, I chose to dynamically compute the limit based on the
blocksize.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
---
 common/usb_storage.c |   45 +++++++++++++++++++++++++--------------------
 1 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/common/usb_storage.c b/common/usb_storage.c
index d9a2585..2720b8d 100644
--- a/common/usb_storage.c
+++ b/common/usb_storage.c
@@ -151,6 +151,7 @@ struct us_data {
 	unsigned int	irqpipe;	 	/* pipe for release_irq */
 	unsigned char	irqmaxp;		/* max packed for irq Pipe */
 	unsigned char	irqinterval;		/* Intervall for IRQ Pipe */
+	unsigned long	max_xfer_blk;		/* Max blocks per xfer */
 	ccb		*srb;			/* current srb */
 	trans_reset	transport_reset;	/* reset routine */
 	trans_cmnd	transport;		/* transport routine */
@@ -1041,14 +1042,13 @@ static void usb_bin_fixup(struct usb_device_descriptor descriptor,
 }
 #endif /* CONFIG_USB_BIN_FIXUP */
 
-#define USB_MAX_READ_BLK 20
-
 unsigned long usb_stor_read(int device, unsigned long blknr,
 			    unsigned long blkcnt, void *buffer)
 {
 	unsigned long start, blks, buf_addr;
 	unsigned short smallblks;
 	struct usb_device *dev;
+	struct us_data *ss;
 	int retry, i;
 	ccb *srb = &usb_ccb;
 
@@ -1066,13 +1066,14 @@ unsigned long usb_stor_read(int device, unsigned long blknr,
 		if (dev->devnum == usb_dev_desc[device].target)
 			break;
 	}
+	ss = (struct us_data *)dev->privptr;
 
 	usb_disable_asynch(1); /* asynch transfer not allowed */
 	srb->lun = usb_dev_desc[device].lun;
 	buf_addr = (unsigned long)buffer;
 	start = blknr;
 	blks = blkcnt;
-	if (usb_test_unit_ready(srb, (struct us_data *)dev->privptr)) {
+	if (usb_test_unit_ready(srb, ss)) {
 		printf("Device NOT ready\n   Request Sense returned %02X %02X"
 		       " %02X\n", srb->sense_buf[2], srb->sense_buf[12],
 		       srb->sense_buf[13]);
@@ -1086,19 +1087,18 @@ unsigned long usb_stor_read(int device, unsigned long blknr,
 		/* XXX need some comment here */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_READ_BLK)
-			smallblks = USB_MAX_READ_BLK;
+		if (blks > ss->max_xfer_blk)
+			smallblks = ss->max_xfer_blk;
 		else
 			smallblks = (unsigned short) blks;
 retry_it:
-		if (smallblks == USB_MAX_READ_BLK)
+		if (smallblks == ss->max_xfer_blk)
 			usb_show_progress();
 		srb->datalen = usb_dev_desc[device].blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (usb_read_10(srb, (struct us_data *)dev->privptr, start,
-		    smallblks)) {
+		if (usb_read_10(srb, ss, start, smallblks)) {
 			USB_STOR_PRINTF("Read ERROR\n");
-			usb_request_sense(srb, (struct us_data *)dev->privptr);
+			usb_request_sense(srb, ss);
 			if (retry--)
 				goto retry_it;
 			blkcnt -= blks;
@@ -1113,19 +1113,18 @@ retry_it:
 			start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_READ_BLK)
+	if (blkcnt >= ss->max_xfer_blk)
 		debug("\n");
 	return blkcnt;
 }
 
-#define USB_MAX_WRITE_BLK 20
-
 unsigned long usb_stor_write(int device, unsigned long blknr,
 				unsigned long blkcnt, const void *buffer)
 {
 	unsigned long start, blks, buf_addr;
 	unsigned short smallblks;
 	struct usb_device *dev;
+	struct us_data *ss;
 	int retry, i;
 	ccb *srb = &usb_ccb;
 
@@ -1143,6 +1142,7 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
 		if (dev->devnum == usb_dev_desc[device].target)
 			break;
 	}
+	ss = (struct us_data *)dev->privptr;
 
 	usb_disable_asynch(1); /* asynch transfer not allowed */
 
@@ -1150,7 +1150,7 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
 	buf_addr = (unsigned long)buffer;
 	start = blknr;
 	blks = blkcnt;
-	if (usb_test_unit_ready(srb, (struct us_data *)dev->privptr)) {
+	if (usb_test_unit_ready(srb, ss)) {
 		printf("Device NOT ready\n   Request Sense returned %02X %02X"
 		       " %02X\n", srb->sense_buf[2], srb->sense_buf[12],
 			srb->sense_buf[13]);
@@ -1166,19 +1166,18 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
 		 */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_WRITE_BLK)
-			smallblks = USB_MAX_WRITE_BLK;
+		if (blks > ss->max_xfer_blk)
+			smallblks = ss->max_xfer_blk;
 		else
 			smallblks = (unsigned short) blks;
 retry_it:
-		if (smallblks == USB_MAX_WRITE_BLK)
+		if (smallblks == ss->max_xfer_blk)
 			usb_show_progress();
 		srb->datalen = usb_dev_desc[device].blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (usb_write_10(srb, (struct us_data *)dev->privptr, start,
-		    smallblks)) {
+		if (usb_write_10(srb, ss, start, smallblks)) {
 			USB_STOR_PRINTF("Write ERROR\n");
-			usb_request_sense(srb, (struct us_data *)dev->privptr);
+			usb_request_sense(srb, ss);
 			if (retry--)
 				goto retry_it;
 			blkcnt -= blks;
@@ -1193,7 +1192,7 @@ retry_it:
 			start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_WRITE_BLK)
+	if (blkcnt >= ss->max_xfer_blk)
 		debug("\n");
 	return blkcnt;
 
@@ -1419,6 +1418,12 @@ int usb_stor_get_info(struct usb_device *dev, struct us_data *ss,
 	USB_STOR_PRINTF(" address %d\n", dev_desc->target);
 	USB_STOR_PRINTF("partype: %d\n", dev_desc->part_type);
 
+	/*
+	 * The U-Boot EHCI driver cannot handle more than 4096*5 bytes in a
+	 * transfer without running itself out of qt_buffers.
+	 */
+	ss->max_xfer_blk = (4096*5)/dev_desc->blksz;
+
 	init_part(dev_desc);
 
 	USB_STOR_PRINTF("partype: %d\n", dev_desc->part_type);
-- 
1.7.7.3

[U-Boot] [PATCH 3/3] usb_storage: Fix EHCI "out of buffer pointers" with CD-ROM

[Mike Frysinger]

On Tuesday 20 December 2011 12:41:14 Kyle Moffett wrote:
> +	/*
> +	 * The U-Boot EHCI driver cannot handle more than 4096*5 bytes in a
> +	 * transfer without running itself out of qt_buffers.
> +	 */
> +	ss->max_xfer_blk = (4096*5)/dev_desc->blksz;

spaces around those operators
-mike
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[U-Boot] [PATCH 1/3] fs/fat: Fix FAT detection to support non-DOS partition tables

[Mike Frysinger]

On Tuesday 20 December 2011 12:41:12 Kyle Moffett wrote:
> --- a/fs/fat/fat.c
> +++ b/fs/fat/fat.c
> 
> +static disk_partition_t cur_part_info = {
> +	.start = 0,
> +	.size = 0,
> +	.blksz = 512,
> +	.name = "",
> +	.type = "",
> +};

there any way we could delay that initialization of blksz to runtime ?  if 
that wasn't there, cur_part_info would be in .bss instead of .data.
-mike
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[U-Boot] [PATCH 1/3] fs/fat: Fix FAT detection to support non-DOS partition tables

[Moffett, Kyle D]

On Dec 20, 2011, at 13:20, Mike Frysinger wrote:
> On Tuesday 20 December 2011 12:41:12 Kyle Moffett wrote:
>> --- a/fs/fat/fat.c
>> +++ b/fs/fat/fat.c
>> 
>> +static disk_partition_t cur_part_info = {
>> +	.start = 0,
>> +	.size = 0,
>> +	.blksz = 512,
>> +	.name = "",
>> +	.type = "",
>> +};
> 
> there any way we could delay that initialization of blksz to runtime ?  if 
> that wasn't there, cur_part_info would be in .bss instead of .data.

I redid this patch several times before I figured out what was going
on and I ended up with both paths fully initializing this struct, so
there's really no need for an initializer at all.

I'll remove it for the next round.

Thanks for the review!

Cheers,
Kyle Moffett

--
Curious about my work on the Debian powerpcspe port?
I'm keeping a blog here: http://pureperl.blogspot.com/

[U-Boot] [PATCH 3/3] usb_storage: Fix EHCI "out of buffer pointers" with CD-ROM

[Moffett, Kyle D]

On Dec 20, 2011, at 13:20, Mike Frysinger wrote:
> On Tuesday 20 December 2011 12:41:14 Kyle Moffett wrote:
>> +	/*
>> +	 * The U-Boot EHCI driver cannot handle more than 4096*5 bytes in a
>> +	 * transfer without running itself out of qt_buffers.
>> +	 */
>> +	ss->max_xfer_blk = (4096*5)/dev_desc->blksz;
> 
> spaces around those operators

Fixed, thanks for the catch!

Cheers,
Kyle Moffett

--
Curious about my work on the Debian powerpcspe port?
I'm keeping a blog here: http://pureperl.blogspot.com/

[U-Boot] [PATCH 3/3] usb_storage: Fix EHCI "out of buffer pointers" with CD-ROM

[Mike Frysinger]

On Tuesday 20 December 2011 13:24:25 Moffett, Kyle D wrote:
> On Dec 20, 2011, at 13:20, Mike Frysinger wrote:
> > On Tuesday 20 December 2011 12:41:14 Kyle Moffett wrote:
> >> +	/*
> >> +	 * The U-Boot EHCI driver cannot handle more than 4096*5 bytes in a
> >> +	 * transfer without running itself out of qt_buffers.
> >> +	 */
> >> +	ss->max_xfer_blk = (4096*5)/dev_desc->blksz;
> > 
> > spaces around those operators
> 
> Fixed, thanks for the catch!

you're too cheery for this list.  i fear you may not last long.  hopefully 
you'll prove me wrong.
-mike
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