It is very common that FAT code is using following pattern:
if (disk_{read|write}() < 0)
return -1;
Up till now the above code was dead, since disk_{read|write) could only
return value >= 0.
As a result some errors from medium layer (i.e. eMMC/SD) were not caught.
The above behavior was caused by block_{read|write|erase} declared at
struct block_dev_desc (@part.h). It returns unsigned long, where 0
indicates error and > 0 indicates that medium operation was correct.
This patch as error regards 0 returned from block_{read|write|erase}
when nr_blocks is grater than zero. Read/Write operation with nr_blocks=0
should return 0 and hence is not considered as an error.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Test HW: Odroid XU3 - Exynos 5433
Now that we have a new header file for cache-aligned allocation, we should
move the stack-based allocation macro there also.
Signed-off-by: Simon Glass <sjg@chromium.org>
The FAT code contains a special case to parse the root directory. This
is needed since the root directory location/layout on disk is special
cased for FAT12/16. In particular, the location and size of the FAT12/16
root directory is hard-coded and contiguous, whereas all FAT12/16 non-root
directories, and all FAT32 directories, are stored in a non-contiguous
fashion, with the layout represented by a linked-list of clusters in the
FAT.
If a file path contains ../ (for example /extlinux/../bcm2835-rpi-cm.dtb),
it is possible to need to parse the root directory for the first element
in the path (requiring application of the special case), then a sub-
directory (in the general way), then re-parse the root directory (again
requiring the special case). However, the current code in U-Boot only
applies the special case for the very first path element, and never for
any later path element. When reparsing the root directory without
applying the special case, any file in a sector (or cluster?) other than
the first sector/cluster of the root directory will not be found.
This change modifies the non-root-dir-parsing loop of do_fat_read_at()
to detect if it's walked back to the root directory, and if so, jumps
back to the special case code that handles parsing of the root directory.
This change was tested using sandbox by executing:
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/.."
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/../"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/../backup"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/../backup/"
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/../backup/.."
./u-boot -c "host bind 0 ../sd-p1.bin; ls host 0:0 /extlinux/../backup/../"
./u-boot -c "host bind 0 ../sd-p1.bin; load host 0:0 0 /bcm2835-rpi-cm.dtb"
./u-boot -c "host bind 0 ../sd-p1.bin; load host 0:0 0 /extlinux/../bcm2835-rpi-cm.dtb"
./u-boot -c "host bind 0 ../sd-p1.bin; load host 0:0 0 /backup/../bcm2835-rpi-cm.dtb"
./u-boot -c "host bind 0 ../sd-p1.bin; load host 0:0 0 /extlinux/..backup/../bcm2835-rpi-cm.dtb"
./u-boot -c "host bind 0 ../sd-p1.bin; load host 0:0 0 /extlinux/../backup/../bcm2835-rpi-cm.dtb"
(/extlinux and /backup are in different sectors so trigger some different
cases, and bcm2835-rpi-cm.dtb is in a sector of the root directory other
than the first).
In all honesty, this change is a bit of a hack, using goto and all.
However, as demonstrated above it appears to work well in practice, is
quite minimal, likely doesn't introduce any risk of regressions, and
hopefully doesn't introduce any maintenance issues.
The correct fix would be to collapse the root and non-root loops in
do_fat_read_at() and get_dentfromdir() into a single loop that has a
small special-case when moving from one sector to the next, to handle
the layout difference of root/non-root directories. AFAIK all other
aspects of directory parsing are identical. However, that's a much
larger change which needs significantly more thought before it's
implemented.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
The present fat implementation ignores FAT16 long name
directory entries which aren't placed in a single sector.
This was becouse of the buffer was always filled by the
two sectors, and the loop was made also for two sectors.
If some file long name entries are stored in two sectors,
the we have two cases:
Case 1:
Both of sectors are in the buffer - all required data
for long file name is in the buffer.
- Read OK!
Case 2:
The current directory entry is placed at the end of the
second buffered sector. And the next entries are placed
in a sector which is not buffered yet. Then two next
sectors are buffered and the mentioned entry is ignored.
- Read fail!
This commit fixes this issue by:
- read two sectors after loop on each single is done
- keep the last used sector as a first in the buffer
before the read of two next
The commit doesn't affects the fat32 imlementation,
which works good as previous.
Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Mikhail Zolotaryov <lebon@lebon.org.ua>
Cc: Tom Rini <trini@ti.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Suriyan Ramasami <suriyan.r@gmail.com>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Wolfgang Denk <wd@denx.de>
Tested-by: Simon Glass <sjg@chomium.org>
The sandbox/ext4/fat/generic fs commands do not gracefully deal with files
greater than 2GB. Negative values are returned in such cases.
To handle this, the fs functions have been modified to take an additional
parameter of type "* loff_t" which is then populated. The return value
of the fs functions are used only for error conditions.
Signed-off-by: Suriyan Ramasami <suriyan.r@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
[trini: Update board/gdsys/p1022/controlcenterd-id.c,
drivers/fpga/zynqpl.c for changes]
Signed-off-by: Tom Rini <trini@ti.com>
Change the internal FAT functions to use loff_t for offsets.
Signed-off-by: Suriyan Ramasami <suriyan.r@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
[trini: Fix fs/fat/fat.c for min3 updates]
Signed-off-by: Tom Rini <trini@ti.com>
U-Boot has never cared about the type when we get max/min of two
values, but Linux Kernel does. This commit gets min, max, min3, max3
macros synced with the kernel introducing type checks.
Many of references of those macros must be fixed to suppress warnings.
We have two options:
- Use min, max, min3, max3 only when the arguments have the same type
(or add casts to the arguments)
- Use min_t/max_t instead with the appropriate type for the first
argument
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Pavel Machek <pavel@denx.de>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Tested-by: Lukasz Majewski <l.majewski@samsung.com>
[trini: Fixup arch/blackfin/lib/string.c]
Signed-off-by: Tom Rini <trini@ti.com>
These commands may be used to determine the size of a file without
actually reading the whole file content into memory. This may be used
to determine if the file will fit into the memory buffer that will
contain it. In particular, the DFU code will use it for this purpose
in the next commit.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
This hooks into the generic "file exists" support added in an earlier
patch, and provides an implementation for the FAT filesystem.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
It doesn't make a lot of sense to have these methods in fs.c. They are
filesystem-specific, not generic code. Add each to the relevant
filesystem and remove the associated #ifdefs in fs.c.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>
ifdefs in the code are making it harder to read.
The use of simple if(vfat_enabled) makes no more code and is cleaner.
(the code is discarded by the compiler instead of the preprocessor.)
NB: if -O0 is used, the code won't be discarded
and bonus, now the code compiles even if CONFIG_SUPPORT_VFAT is not
defined.
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
toupper/tolower function are already declared, so use them.
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>
In case a function argument is known/fixed size array in C, the argument is
still decoyed as pointer instead ( T f(U n[k]) ~= T fn(U *n) ) and therefore
calling sizeof on the function argument will result in the size of the pointer,
not the size of the array.
The VFAT code contains such a bug, this patch fixes it.
Reported-by: Aaron Williams <Aaron.Williams@cavium.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <tom.rini@gmail.com>
Cc: Aaron Williams <Aaron.Williams@cavium.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
This makes the FAT filesystem API more consistent with other block-based
filesystems. If in the future standard multi-filesystem commands such as
"ls" or "load" are implemented, having FAT work the same way as other
filesystems will be necessary.
Convert cmd_fat.c to the new API, so the code looks more like other files
implementing the same commands for other filesystems.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
cur_part_info.{name,type} are strings. So, we don't need to memset()
the entire thing, just put the NULL-termination in the first byte.
Add missing initialization of the bootable and uuid fields.
None of these fields are actually used by fat.c. However, since it
stores the entire disk_partition_t, we should make sure that all fields
are valid.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
A future patch will implement the more standard filesystem API
fat_set_blk_dev(). This API has no way to know which partition number
the partition represents. Equally, future DM rework will make the
concept of partition number harder to pass around.
So, simply remove cur_part_nr from fat.c; its only use is in a
diagnostic printf, and the context where it's printed should make it
obvious which partition is referred to anyway (since the partition ID
would come from the user command-line that caused it).
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
The mkcksum() function now takes one parameter, the pointer to
11-byte wide character array, which it then operates on.
Currently, the function is wrongly passed (dir_entry)->name, which
is only 8-byte wide character array. Though by further inspecting
the dir_entry structure, it can be noticed that the name[8] entry
is immediatelly followed by ext[3] entry. Thus, name[8] and ext[3]
in the dir_entry structure actually work as this 11-byte wide array
since they're placed right next to each other by current compiler
behavior.
Depending on this is obviously wrong, thus fix this by correctly
passing both (dir_entry)->name and (dir_entry)->ext to the mkcksum()
function and adjust the function appropriately.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@ti.com>
The recent switch to use get_device_and_partition() from do_fat_ls()
broke the ability to access a FAT filesystem directly on a whole device;
FAT only works within a partition on a device.
This change makes e.g. "fatls mmc 0:0" work; explicitly requesting
partition ID 0 is something that get_device_and_partition() fully
supports. However, fat_register_device() expects partition ID 1 to be
used in the full-disk case; partition ID 1 was previously implicitly
specified when the user didn't actually specify a partition ID. Update
fat_register_device() to expect the correct ID.
This change does imply that if a user explicitly executes "fatls mmc 0:1"
then this will fail, and may be a change in behaviour.
Note that this still prevents "fatls mmc 0:auto" from working. The next
patch will fix that.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
When storage devices contain files larger than the embedded RAM, it is
useful to be able to read these files by chunks, e.g. for a software
update to the embedded NAND Flash from an external storage device (USB
stick, SD card, etc.).
Hence, this patch makes it possible by adding a new FAT API to read
files from a given position. This patch also adds this feature to the
fatload command.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
With:
fatls mmc 0 /dir/file
dir: regular directory
file: regular file
The previous code read the contents of file as if it were directory entries to
list. This patch refuses to list file contents as if it were a folder.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
One call to get_cluster can be factorized with another, so avoid
duplicating code.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
Add a buffer bouncing mechanism to get_cluster. This can be useful
for misaligned applicative buffers passed through get_contents.
This is required for the following patches in the case of data
aligned differently relatively to buffers and clusters.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
With the previous code, the remaining prefetched sectors were read
again after each sector. With this patch, each sector is read only
once, thus making the prefetch useful.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
fatlength is not used after this assignment, so it is useless and can
be removed.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
startblock must be taken into account in order not to read past the
end of the FAT.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
Remove spaces before opening parentheses in function calls.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
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>
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>
Fix build warning: fat.c: In function 'fat_register_device':
fat.c:66:15: warning: variable 'found_partition' set but not used
[-Wunused-but-set-variable]
Signed-off-by: Wolfgang Denk <wd@denx.de>
The VFAT short alias checksum read from a long file name is only overwritten
when another long file name appears in a directory list. Until then it renders
short file names invisible that have the same checksum. Reset the checksum on
first match.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Martin Mueller <martin.mueller5@de.bosch.com>
The DIRENTSPERBLOCK utilizes sizeof() which will return a size_t which has no
fixed size. Therefor use correct length modifer for printf() statement to
prevent compiler warnings.
This patch fixes following warning:
---8<---
fat.c: In function 'do_fat_read':
fat.c:879: warning: format '%d' expects type 'int', but argument 4 has type 'long unsigned int'
--->8---
Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
cc: Mike Frysinger <vapier@gentoo.org>
cc: Thomas Chou <thomas@wytron.com.tw>
cc: rjones@nexus-tech.net
cc: kharris@nexus-tech.net
Acked-by: Mike Frysinger <vapier@gentoo.org>
Fix:
fat.c: In function 'fat_register_device':
fat.c:74:19: warning: variable 'info' set but not used
[-Wunused-but-set-variable]
Signed-off-by: Wolfgang Denk <wd@denx.de>
ATTR_VFAT condition requires multiple bits to be set but the present
condition checking in do_fat_read() & get_dentfromdir() ends up
passing on even a single bit being set.
Signed-off-by: J. Vijayanand <vijayanand.jayaraman@in.bosch.com>
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Commit c30a15e "FAT: Add FAT write feature" introduced a compiler
warning. Fix this.
Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Donggeun Kim <dg77.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
In some cases, saving data in RAM as a file with FAT format is required.
This patch allows the file to be written in FAT formatted partition.
The usage is similar with reading a file.
First, fat_register_device function is called before file_fat_write function
in order to set target partition.
Then, file_fat_write function is invoked with desired file name,
start ram address for writing data, and file size.
Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Currently in do_fat_read() when reading FAT sectors, we have to divide down
LINEAR_PREFETCH_SIZE by the sector size, whereas it's defined as 2 sectors
worth of bytes. In order to avoid redundant multiplication/division, introduce
#define PREFETCH_BLOCKS instead of #define LINEAR_PREFETCH_SIZE.
Signed-off-by: Sergei Shtylyov <sshtylyov@mvista.com>
The root directory cluster field only exists in a FAT32 boot sector, so the
'root_cluster' variable in do_fat_read() contains garbage in case of FAT12/16.
Make it contain 0 instead as this is what is passed to get_vfatname() in that
case anyway.
Signed-off-by: Sergei Shtylyov <sshtylyov@mvista.com>
The code multiples the FAT size in sectors by the sector size and then tries to
compare that to the number of sectors in the 'getsize' variable. While fixing
this, also change the initial value of 'getsize' as the division of FATBUFSIZE
by the sector size gets us FATBUFBLOCKS.
Signed-off-by: Sergei Shtylyov <sshtylyov@mvista.com>
Apple iPod nanos have sector sizes of 2 or 4 KiB, which crashes U-Boot when it
tries to read the boot sector into 512-byte buffer situated on stack. Make the
FAT code indifferent to the sector size.
Signed-off-by: Sergei Shtylyov <sshtylyov@mvista.com>
Fat directory handling didn't check reaching the end of the root directory. It
relied on a stop condition based on a directory entry with a name starting with
a '\0' character. This check in itself is wrong ('\0' indicates free entry, not
end_of_directory) but outside the scope of this fix. For FAT32, the end of the
rootdir is reached when the end of the cluster chain is reached. The code didn't
check this condition and started to read an incorrect cluster. This caused a
subsequent read request of a sector outside the range of the usb stick in
use. On its turn, the usb stick protested with a stall handshake.
Both FAT32 and non-FAT32 (FAT16/FAT12) end or rootdir checks have been put in.
Signed-off-by: Erik Hansen <erik@makarta.com>
Last commit 3831530dcb7b71329c272ccd6181f8038b6a6dd0a was intended
"explicitly specify FAT12/16 root directory parsing buffer size, instead
of relying on cluster size". Howver, the underlying function requires
the size of the buffer in blocks, not in bytes, and instead of passing
a double sector size a request for 1024 blocks is sent. This generates
a buffer overflow with overwriting of other structure (in the case seen,
USB structures were overwritten).
Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Mikhail Zolotaryov <lebon@lebon.org.ua>
The U-Boot code has the following bugs related to the processing of Long File
Name (LFN) entries scattered across several clusters/sectors :
1) get_vfatname() function is designed to gather scattered LFN entries by
cluster chain processing - that doesn't work for FAT12/16 root directory.
In other words, the function expects the following input data:
1.1) FAT32 directory (which is cluster chain based);
OR
1.2) FAT12/16 non-root directory (which is also cluster chain based);
OR
1.3) FAT12/16 root directory (allocated as contiguous sectors area), but
all necessary information MUST be within the input buffer of filesystem cluster
size (thus cluster-chain jump is never initiated).
In order to accomplish the last condition, root directory parsing code in
do_fat_read() uses the following trick: read-out cluster-size block, process
only first sector (512 bytes), then shift 512 forward, read-out cluster-size
block and so on. This works great unless cluster size is equal to 512 bytes
(in a case you have a small partition), or long file name entries are scattered
across three sectors, see 4) for details.
2) Despite of the fact that get_vfatname() supports FAT32 root directory
browsing, do_fat_read() function doesn't send current cluster number correctly,
so root directory look-up doesn't work correctly.
3) get_vfatname() doesn't gather scattered entries correctly also is the case
when all LFN entries are located at the end of the source cluster, but real
directory entry (which must be returned) is at the only beginning of the
next one. No error detected, the resulting directory entry returned contains
a semi-random information (wrong size, wrong start cluster number and so on)
i.e. the entry is not accessible.
4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13
UTF-16 code units) to represent a single long file name i.e. up to 520 bytes.
U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record
may cause buffer overflow / memory corruption.
Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may
take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16
partition) - get_vfatname() function doesn't support such case as well.
The patch attached fixes these problems in the following way:
- keep using 256 bytes buffer for a long file name, but safely prevent a
possible buffer overflow (skip LFN processing, if it contains 10 or more
slots).
- explicitly specify FAT12/16 root directory parsing buffer size, instead
of relying on cluster size. The value used is a double sector size (to store
current sector and the next one). This fixes the first problem and increases
performance on big FAT12/16 partitions;
- send current cluster number (FAT32) to get_vfatname() during root
directory processing;
- use LFN counter to seek the real directory entry in get_vfatname() - fixes the
third problem;
- skip deleted entries in the root directory (to prevent bogus buffer
overflow detection and LFN counter steps).
Note: it's not advised to split up the patch, because a separate part may
operate incorrectly.
Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
On FAT32, instead of fetching the cluster numbers from the FAT, the
code assumed (incorrectly) that the clusters for the root directory
were allocated contiguously. In the result, only the first cluster
could be accessed. At the typical cluster size of 8 sectors this
caused all accesses to files after the first 128 entries to fail -
"fatls" would terminate after 128 files (usually displaying a bogus
file name, occasionally even crashing the system), and "fatload"
would fail to find any files that were not in the first directory
cluster.
Signed-off-by: Wolfgang Denk <wd@denx.de>
"Superfloppy" format (in U-Boot called PBR) did not work for FAT32 as
the file system type string is at a different location. Add support
for FAT32.
Signed-off-by: Wolfgang Denk <wd@denx.de>
The static function compare_sign is only used to compare the fs_type string
and does not do anything more than what strncmp does.
The addition of the trailing '\0' to fs_type, while legal, is not needed
because the it is never printed out and strncmp does not depend on NULL
terminated strings.
Signed-off-by: Tom Rix <Tom.Rix@windriver.com>
Mflash is fusion memory device mainly targeted consumer eletronic and
mobile phone.
Internally, it have nand flash and other hardware logics and supports
some different operation (ATA, IO, XIP) modes.
IO mode is custom mode for the host that doesn't have IDE interface.
(Many mobile targeted SoC doesn't have IDE bus)
This driver support mflash IO mode.
Followings are brief descriptions about IO mode.
1. IO mode based on ATA protocol and uses some custom command. (read
confirm, write confirm)
2. IO mode uses SRAM bus interface.
Signed-off-by: unsik Kim <donari75@gmail.com>
