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→Program root file system into eMMC flash
== Introduction ==
This document was written and tested with the software/hardware combination described in the history table above. However, it contains general concepts that can be adapted on any DAVE Embedded Systems' Linux platform.
{{ImportantMessage|text=The following programming examples are intended for <b>laboratory usage</b> or for ''preliminary deployment strategy''.<br><br>A complete deployment strategy has to be carefully identifiyed taking into account the overall arguments like: boot speed, safe boot, recovery mechanisms, watchdog supervisor, etc.}}
We'll explain how to program and configure an [[:Category:SDVX |SDVX]] to boot in standalone mode, without the need of a system microSD card or an NFS server, with threee options:
* booting with eMMC only
** in this configuration the whole system will boot without the need of a NOR/NAND flashes storage, all images and the root file system will be fetched from eMMC flash
== Program boot images ...==
{{ImportantMessage|text=Select the proper <code>u-boot</code>, <code>kernel</code> and <code>device tree</code> binary images according to the Axel Lite or Axel ULite SOM used}}
42547 bytes written: OK
=>
</pre>
Reboot the system and configure U-Boot to apply the new configuration
<pre class="board-terminal">
=> setenv bootcmd run nand_nand
=> saveenv
</pre>
===u-Boot===
Update to the latest u-boot version allows usage of u-boot environment variables available.
<pre>
mmc_update=mmc dev; setexpr blocks ${filesize} / 0x200; setexpr blocks ${blocks} + 1; mmc write ${loadaddr} 2 ${blocks}
</pre>
Load u-boot binary form a <code>tftp</code> server:
<pre class="board-terminal">
done
Bytes transferred = 671788 (a402c hex)
=> run mmc_update
switch to partitions #0, OK
mmc2(part 0) is current device (eMMC)
MMC write: dev # 2, block # 2, count 1313 ... 1313 blocks written: OK
=>
</pre>
Load u-boot binary form an <code>SD</code> card:
<pre class="board-terminal">
Hit ENTER within 1 seconds to stop autoboot
=> fatload mmc 0:1 ${loadaddr} sdvx-1.0.1_mx6dlaxel_u-boot.imx
reading sdvx-1.0.1_mx6dlaxel_u-boot.imx
671788 bytes read in 50 ms (12.8 MiB/s)
=> mmc dev 2
switch to partitions #0, OK
mmc2(part 0) is current device (eMMC)
=> run mmc_update
switch to partitions #0, OK
<pre>
mmc_loadk=fatload mmc 0${mmcdev}:1 ${loadaddr} ${bootfile}mmc_loadfdt=fatload mmc 0${mmcdev}:1 ${fdtaddr} ${fdtfile}
mmc_loadsplash=fatload mmc ${mmcdev}:1 ${loadaddr} ${splashfile}; cp.b ${loadaddr} ${splashimage} ${filesize}
mmcargs=setenv bootargs root=${mmcroot}
mmcroot=/dev/mmcblk2p2 rootwait rw
</pre>
<pre class="board-terminal">
root@sdvx-lite:~# mkdir -p /mnt/nand
root@sdvx-lite:~# mount -t ubifs ubi0_0 /mnt/nand
[ 1810.301461] UBIFS: default file-system created
[ 1810.308952] UBIFS: background thread "ubifs_bgt0_0" started, PID 717
[ 1810.452274] UBIFS: mounted UBI device 0, volume 0, name "rootfs"
[ 1810.459421] UBIFS: LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[ 1810.469398] UBIFS: FS size: 992698368 bytes (946 MiB, 7818 LEBs), journal size 33521664 bytes (31 MiB, 264 LEBs)
[ 1810.480976] UBIFS: reserved for root: 4952683 bytes (4836 KiB)
[ 1810.487210] UBIFS: media format: w4/r0 (latest is w4/r0), UUID 99D0F3C6-5955-4B30-9E2D-72202281BD30, small LPT model
</pre>
* you can now extract the root file system into that directory
<pre>
tar xvjf sdvx-1.0.1_image-devel-sdvx-lite.tar.bz2 -C /mnt/nand
</pre>
* finally, you need to cleanly umount and detach the MTD partition
<pre>
umount /mnt/nand/
ubidetach -m 7
</pre>
E.g.
<pre class="board-terminal">
root@sdvx-lite:~# umount /mnt/nand/
[ 2446.743091] UBIFS: un-mount UBI device 0, volume 0
[ 2446.749670] UBIFS: background thread "ubifs_bgt0_0" stops
root@sdvx-lite:~# ubidetach -m 7
[ 2450.738153] UBI: detaching mtd7 from ubi0
[ 2450.759527] UBI: mtd7 is detached from ubi0
</pre>
You can now safely reboot or turn off the system.
In U-Boot environment check the following variable, which must contain the same MTD partition number used above
<pre>
nand_args=setenv bootargs root=ubi0:rootfs rootfstype=ubifs rw ubi.mtd=7
</pre>
== Program root file system into eMMC flash ==
* Boot the system via SD or NFS as described in the e [[SDV04 Embedded Linux Kit (SDVX)#Quick_start_guide|Quick start guide]]
* eMMC device has to be partitioned and properly formatted choosing the <code>file system</code> for each partition
* an example of SD partitioning script is the following one:
=== FAT32 partition ===
<pre>
#!/bin/sh
node=$1
# partition size in MB
BOOTLOAD_RESERVE=8
BOOT_ROM_SIZE=128
RFS_SIZE=2048
# create the SDCARD partition
part=""
echo ${node} | grep mmcblk > /dev/null
if [ "$?" -eq "0" ]; then
part="p"
fi
# print the SD total capacity
total_size=`sfdisk -s ${node}`
total_size=`expr ${total_size} / 1024`
echo SD total size: ${total_size}KB
# calculate partition sizes
boot_start=`expr ${BOOTLOAD_RESERVE} \\* 1024 \\* 1024 / 512`
boot_size=`expr ${BOOT_ROM_SIZE} \\* 1024 \\* 1024 / 512`
rfs_start=`expr ${boot_size} + ${boot_start}`
rfs_size=`expr ${RFS_SIZE} \\* 1024 \\* 1024 / 512`
umount ${node}${part}1 > /dev/null 2>&1
umount ${node}${part}2 > /dev/null 2>&1
# call sfdisk to create partition table
{ echo ${boot_start},${boot_size},0c,-; echo ${rfs_start},${rfs_size},83,-; } | sfdisk --force ${node}
# format the SDCARD partition
echo "formatting boot"
mkfs.vfat -F 32 -n boot ${node}${part}1
echo "formatting rfs"
mkfs.ext4 -F ${node}${part}2 -Lrfs
</pre>
E.g.
<pre class="workstation-terminal">
root@sdvx-lite:~# ./sdcard-partition.sh /dev/mmcblk2
SD total size: 3776KB
[ 1341.905014] mmcblk2: p1 p2
Checking that no-one is using this disk right now ... OK
Disk /dev/mmcblk2: 3.7 GiB, 3959422976 bytes, 7733248 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical):[ 1341.922729] mmcblk2: p1 p2
512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xa77eb3f0
Old situation:
Device Boot Start End Sectors Size Id Type
/dev/mmcblk2p1 2048 264191 262144 128M c W95 FAT32 (LBA)
/dev/mmcblk2p2 264192 4458495 4194304 2G 83 Linux
>>> Created a new DOS disklabel with disk identifier 0xcce0c36f.
Created a new partition 1 of type 'W95 FAT32 (LBA)' and of size 128 MiB.
/dev/mmcblk2p2: Created a new partition 2 of type 'Linux' and of size 2 GiB.
/dev/mmcblk2p3:
New situation:
Device Boot Start End Sectors Size Id Type
/dev/mmcblk2p1 16384 278527 262144 128M c W95 FAT32 (LBA)
/dev/mmcblk2p2 278528 4472831 4194304 2G 83 Linux
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
formatting boot
mkfs.fat 3.0.28 (2015-05-16)
mkfs.fat: warning - lowercase labels might not work properly with DOS or Windows
formatting rfs
mke2fs 1.43-WIP (18-May-2015)
Discarding device blocks: done
Creating filesystem with 524288 4k blocks and 131072 inodes
Filesystem UUID: 9a685543-1af2-4e39-83f3-b8a32248c021
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
root@sdvx-lite:~#
</pre>
* create a mount point and mount the first partition
<pre>
mkdir -p /mnt/emmc
mount /dev/mmcblk2p1 /mnt/emmc
</pre>
* copy kernel, dtb and splash_image files
<pre class="workstation-terminal">
root@sdvx-lite:~# mount /dev/mmcblk2p1 /mnt/emmc
[ 40.988575] FAT-fs (mmcblk2p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
root@sdvx-lite:~# cd /mnt/emmc
root@sdvx-lite:/mnt/emmc# cp /tftpboot/sdvx/linux/sdvx-1.0.1*dtb .
root@sdvx-lite:/mnt/emmc# cp /tftpboot/sdvx/linux/sdvx-1.0.1*uImage .
root@sdvx-lite:/mnt/emmc# cp /tftpboot/sdvx/linux/splash_image.bmp .
root@sdvx-lite:/mnt/emmc# cd
root@sdvx-lite:~# umount /mnt/emmc
</pre>
* now mount the EXT4 volume in the temporary directory
E.g.:
<pre class="workstation-terminal">
root@sdvx-lite:~# mount /dev/mmcblk2p2 /mnt/emmc
[ 1810.899327] EXT4-fs (mmcblk2p2): mounted filesystem with ordered data mode. Opts: (null)
root@sdvx-lite:~# cd /mnt/emmc
root@sdvx-lite:/mnt/emmc#
</pre>
* you can now extract the root file system into that directory
<pre>
tar xvjf sdvx-1.0.1_image-devel-sdvx-lite.tar.bz2
</pre>
* finally, you need to cleanly umount and safely reboot or turn off the system.
<pre class="workstation-terminal">
root@sdvx-lite:/mnt/emmc# cd
root@sdvx-lite:~# umount /mnt/emmc
root@sdvx-lite:~# reboot
</pre>
Reboot the system and configure U-Boot to apply the new configuration
<pre class="workstation-terminal">
=> setenv bootcmd run mmcboot
=> saveenv
</pre>
=== ext4 partition ===
For using an <b>ext4</b> partition also for boot files, it is possibile to change the formatting script:
{ echo ${boot_start},${boot_size},'''83''',-; echo ${rfs_start},${rfs_size},83,-; } | sfdisk --force ${node}
and formatting the first partition using ''mkfs.ext4''
mkfs.ext4 -F ${node}${part}1 -Lboot
then, the u-boot <code>environment</code> has to be properly configured:
<pre class="workstation-terminal">
=> setenv mmc_loadk 'ext4load mmc ${mmcdev}:1 ${loadaddr} ${bootfile}'
=> setenv mmc_loadfdt 'ext4load mmc ${mmcdev}:1 ${fdtaddr} ${fdtfile}'
=> setenv mmc_loadsplash 'ext4load mmc ${mmcdev}:1 ${loadaddr} ${splashfile}; cp.b ${loadaddr} ${splashimage} ${filesize}'
=> saveenv
</pre>