Cross compiling mtd tools

I need to compile mtd-tools for arm, to be precise Xilinx ZynQ z702 which, by the way, a very nice platform for moderately complex projects. The presence of an integrated FPGA is the key aspect of its "all programmable" tag-line. You can find more info on ZynQ HERE

I am currently working on ZynQ derivative and going to test the QSPI flash interface to NOR, and possibly the NAND interface (if the board is wired up). In any case, I need mtd tools because,

• There is no n/w i/f on the target board to download the linux kernel image
• Our linux kernel require to be run from flash (jffs2, jffs2 being the better choice?) root file system, not as a ramfs (ext2/3/4)

During the process, I was referring to MTD compilation notes at this TI page. But TI page is not very clear about cross compilation. So, here are my thoughts and steps I took to get it compiled.

Step 0: Get your cross compilation environment ready

Well, on ZynQ (or any other platform requiring cross compilation), setting up the tool chain is a subject by itself. Here I assume that you have (somehow) setup your cross compilation environment and the tool chain is available to you as ${CROSS_COMPILE}<toolchain binary>

Step1 : Get the source code

Mtd-utils require the following dependencies satisfied for compilation

• zlib (compression)
  • http://zlib.net/zlib-1.2.8.tar.gz – Latest as of the time of writing.
• lzo (compression) (Here is the wikipedia article on LZO)
  • http://www.oberhumer.com/opensource/lzo/download/lzo-2.06.tar.gz – You may want to download a later version
• e2fsprogs (for uuid)
  • http://git.kernel.org/cgit/fs/ext2/e2fsprogs.git – Click on the snapshot link to download. You may want to download a stable release
• mtd-utils
  • http://git.infradead.org/mtd-utils.git – Click on the snapshot link to download. You may want to download a stable release

Once download is complete, gunzip/untar the files into respective directories.

Prepare prefix directory

Zlib, lzo and e2fs progs being dependencies for mtd-utils, you want to keep all these in a place accessible by mtd-utils during compilation. That means, you need to install these libraries and header files. By default, the prefix (/usr/local/...) may not be a good idea because you are compiling these libraries for a different architecture (arm in my case). I have chosen a target prefix directory /export/prj/voler/mtd-utils/; you may choose something similar.

$ echo $CROSS_COMPILE

/export/prj/Xilinx/SDK/2014.2/gnu/arm/lin/bin/arm-xilinx-linux-gnueabi-

[om@hexcore /export/prj/voler/zlib-1.2.8]

$ arm-xilinx-linux-gnueabi-gcc

arm-xilinx-linux-gnueabi-gcc: fatal error: no input files

compilation terminated.

Cross compile Zlib

[om@hexcore /export/prj/voler/zlib-1.2.8]

$ ./configure –prefix=/export/prj/voler/mtd-utils/

This configure does not support cross compiling environment. So, we need to make manual changes to generated Makefile like the following

CC={CROSS_COMPILE}gcc

....

LDSHARED={CROSS_COMPILE}gcc -shared -Wl,-soname,libz.so.1,--version-script,zlib.map

CPP={CROSS_COMPILE}gcc -E

$make

....

[om@hexcore /export/prj/voler/zlib-1.2.8]

$ file /export/prj/voler/mtd-utils/lib/libz.so.1.2.8

/export/prj/voler/mtd-utils/lib/libz.so.1.2.8: ELF 32-bit LSB shared object, ARM, EABI5 version 1 (SYSV), dynamically linked, not stripped

Cross compile lzo

[om@hexcore /export/prj/voler/lzo-2.06]

$ ./configure --host=arm-xilinx-linux-gnueabi --prefix=/export/prj/voler/mtd-utils

configure: WARNING: if you wanted to set the --build type, don't use --host.

If a cross compiler is detected then cross compile mode will be used

configure: Configuring LZO 2.06

....

LZO configuration summary

-------------------------

LZO version : 2.06

configured for host : arm-xilinx-linux-gnueabi

source code location : .

compiler : arm-xilinx-linux-gnueabi-gcc

preprocessor definitions : -DLZO_HAVE_CONFIG_H=1

preprocessor flags :

compiler flags : -g -O2

build static library : yes

build shared library : no

enable i386 assembly code : no

LZO 2.06 configured.

[om@hexcore /export/prj/voler/lzo-2.06]

$ make ; make install

make all-am

----------------------------------------------------------------------

Libraries have been installed in:

/export/prj/voler/mtd-utils/lib

Cross compile e2fsprogs

[om@hexcore /export/prj/voler/e2fsprogs-1.42.11]

$ ./configure --host=arm-xilinx-linux-gnueabi –prefix=/export/prj/voler/mtd-utils

[om@hexcore /export/prj/voler/e2fsprogs-1.42.11]

$ make ; make install

cd lib/uuid/

make install

Cross compile mtd-utils

Mtd-utils has no ./configure script. That means, we need to manually change the Makefile for cross compilation related changes.

PREFIX = /home/temp/mtdutils

CROSS=arm-linux-gnueabi-

ZLIBCPPFLAGS = -I$(PREFIX)/include

ZLIBLDFLAGS = -L$(PREFIX)/lib

LZOCPPFLAGS = -I$(PREFIX)/include

LZOLDFLAGS = -L$(PREFIX)/lib

LDFLAGS += $(ZLIBLDFLAGS) $(LZOLDFLAGS)

# if you want the resulting binaries standalone binaries, add -static here

# LDFLAGS += $(ZLIBLDFLAGS) $(LZOLDFLAGS) -static

CFLAGS ?= -O2 -g $(ZLIBCPPFLAGS) $(LZOCPPFLAGS)

Edit the common.mk file and comment out the PREFIX=/usr line. Then make and install:

[om@hexcore /export/prj/voler/mtd-utils-9f10713]

WITHOUT_XATTR=1 make; make install

(Thanks to http://wiki.beyondlogic.org/index.php/Cross_Compiling_MTD_Utils_for_ARM, I did not have to re-invent this)

Precompiled binaries for ZynQ

Download precompiled binaries for ZynQ / ARM v7 from here :

Binary	Size	Md5sum	sha256sum
mtd-utils.tbz	7676764	622e0d4bc7f3197c9dc0ccf00d93b498	0af126bc948522db9d821 1b9e479f41173c028e105 7bc27a02096957720f6bfb
mtd-utils.static.tbz	11847584	f55e42e81a2e6944fa87aa0f97117ee0	f613c70337be8bbe316567 8715930e9cc004c18218d9 d9ed8f83ecf4acf04f56

A sample run here:

root@zynq:~# mtdinfo

Count of MTD devices: 5

Present MTD devices: mtd0, mtd1, mtd2, mtd3, mtd4

Sysfs interface supported: yes

root@zynq:~# mtdinfo /dev/mtd0

mtd0

Name: qspi-fsbl-uboot

Type: nor

Eraseblock size: 65536 bytes, 64.0 KiB

Amount of eraseblocks: 16 (1048576 bytes, 1024.0 KiB)

Minimum input/output unit size: 1 byte

Sub-page size: 1 byte

Character device major/minor: 90:0

Bad blocks are allowed: false

Device is writable: true