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{{Applies To Bora}}
{{Applies To BoraX}}
{{Applies To BoraLite}}
{{InfoBoxBottom}}
{{ImportantMessage|text=For the sake of simplicity, this document does not address the reliability of the partitioning schemes described. This matter is beyond the scope of this document and should take into account several factors such as the intrinsic reliability of NOR/NAND flashes, the estimated usage in terms of read/write operations, etc. For more information related to this subject, please contact [mailto:support-bora@dave.eu the technical support].}}
== History ==
|March 2019
|Added use case #2
|-
|2.0.1
|March 2019
|Added warning about realiability<br>
Added images of case #1's partitioning scheme
|-
|{{oldid|9151|2.0.2}}
|June 2019
|Fixed definition of <code>nandboot2</code> variable<br>
Fixed dump related to the download of the bitstream file
|-
|3.0.0
|Jan 2020
|Update for BELK/BXELK 4.1.0
|}
<section begin=BTELK/>== Introduction Standalone boot==This document shows some examples related to configuring Bora/BoraX /BoraLite for standalone operativity.
We'll explain how to program and configure a [[:Category:BoraX|BoraX]] -based system to boot in standalone mode, without the need of a system microSD card or an NFS server. Only the flash memories available on the SoM itself will be used to store persistently all the software required.
The examples here documented are valid for [[:Category:Bora|Bora]] and for [[:Category:BoraLite|BoraLite]] as well.
{{ImportantMessage|text=It is worth remembering that the examples shown in this article don't make use of any image script. This technique is used by the bootable microSD card delivered along with the kit, instead. For more details, please refer to [[Working_with_the_Yocto_build_system#bootscript|this section]].}} ===Use case #1=======Introduction====
This configuration makes use of one of the most common partitioning schemes, that is:
*The NOR flash acts as boot memory; as such, it contains
**bootrom header and FSBL (or header+U-Boot SPL)
**U-Boot
**U-Boot redundant environment
**Even though these images are not strictly required to boot the system, the NOR flash also contains:***The Linux kernel image***The Linux Device Tree Blob (DTB)***The bitstream file for the Programmable Logic (PL).*The NAND flash contains the a partition devoted to a read/write UBIFS root filesystem (read/write). The resulting flash memory layout is illustrated in the following pictures. [[File:BELK-NOR-flash-partitioning-case1.png|thumb|center|600px|NOR flash partitioning scheme]] [[File:BELK-NAND-flash-partitioning-case1.png|thumb|center|600px|NAND flash partitioning scheme]]
*Once started, the Linux kernel mount the root filesystem from a NAND partition.
=====Testbed=====
This configuration was tested with the following testbed:
*SOM: DBXF4110D2R
*software: [[BELK/BXELK_software_components#BELK_3.0.1_.2F_BXELK_1.0.0|BXELK 1.0.0]]
==== Program the root filesystem in NAND flash ====
This is a common step for both booting options.
* Boot the system via SD or NFS as described into the [[System_boot_and_recovery_via_microSD_card_(BELK/BXELK)|System boot and recovery via microSD card]] and [[Booting_the_system_via_NFS_(BELK/BXELK)|Booting the system via NFS]]
* By default, the NAND is already partitioned to allow booting from NAND-only (see next section) and, thus, some partitions are reserved for FSBL, U-boot and kernel images. Here we won't modify this default configuration. The [[Memory Tecnology Device (MTD)|MTD]] partitions can be dumped with <code>/proc/mtd</code> (the partition's name should be self-explanatory)
<pre class="board-terminal">
root@bora:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00080000 00040000 00020000 "nand-SPLspl"mtd1: 00080000 000c0000 00020000 "nand-uboot"mtd2: 00040000 00020000 "nand-uboot-env1"mtd3: 00040000 00020000 "nand-uboot-env2"mtd4: 00440000 00600000 00020000 "nand-bitstreamfpga"mtd5: 00040000 00080000 00020000 "nand-device-treefdt"mtd6: 00400000 00800000 00020000 "nand-linuxkernel"mtd7: 1f600000 3f000000 00020000 "nand-rootfsubi"
</pre>
* Format and initialize ''nand-ubi'' partition, which in our case is <code>mtd7</code>, using [[Memory Tecnology Device (MTD)#UBI|UBI]] with:
<preclass="board-terminal">
ubiformat /dev/mtd7
ubiattach -m 7
<pre class="board-terminal">
root@bora:~# ubiformat /dev/mtd7
ubiformat /dev/mtd7ubiformat: mtd7 (nand), size 526385152 1056964608 bytes (5021008.0 MiB), 4016 8064 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 byteslibscan: scanning eraseblock 4015 8063 -- 100 % completeubiformat: 4016 8060 eraseblocks have valid erase counter, mean value is 21ubiformat: 4 bad eraseblocks found, numbers: 8060, 8061, 8062, 8063ubiformat: formatting eraseblock 4015 8063 -- 100 % complete
root@bora:~# ubiattach -m 7
[ 95 275.732434247791] UBIubi0: attaching mtd7 to ubi0[ 100280.930047486952] UBIubi0: scanning is finished[ 100280.954932520370] UBIubi0: attached mtd7 (name "nand-rootfsubi", size 502 1008 MiB) to ubi0[ 100280.961772526302] UBIubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 129024 bytes[ 100280.968534533222] UBIubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048512[ 100280.975248539860] UBIubi0: VID header offset: 2048 512 (aligned 2048512), data offset: 40962048[ 100280.982129546610] UBIubi0: good PEBs: 40168060, bad PEBs: 04, corrupted PEBs: 0[ 100280.988100552720] UBIubi0: user volume: 0, internal volumes: 1, max. volumes count: 128[ 100280.995271559908] UBIubi0: max/mean erase counter: 43/32, WL threshold: 4096, image sequence number: 1955579947857573235[ 101280.004308568946] UBIubi0: available PEBs: 38527900, total reserved PEBs: 164160, PEBs reserved for bad PEB handling: 160156[ 101280.013959578486] UBIubi0: background thread "ubi_bgt0d" started, PID 913983UBI device number 0, total 4016 8060 LEBs (509935616 1039933440 bytes, 486991.3 8 MiB), available 3852 7900 LEBs (489111552 1019289600 bytes, 466972.5 1 MiB), LEB size 126976 129024 bytes (124126.0 KiB)
root@bora:~# ubimkvol /dev/ubi0 -N rootfs -m
Set volume size to 4891115521019289600Volume ID 0, size 3852 7900 LEBs (489111552 1019289600 bytes, 466972.5 1 MiB), LEB size 126976 129024 bytes (124126.0 KiB), dynamic, name "rootfs", alignment 1root@bora:~#
</pre>
* Now mount the UBI volume using [[Memory Tecnology Device (MTD)#UBIFS|UBIFS]] in a temporary directory
<preclass="board-terminal">
mkdir -p /mnt/nand
mount -t ubifs ubi0_0 /mnt/nand
root@bora:~# mkdir -p /mnt/nand
root@bora:~# mount -t ubifs ubi0_0 /mnt/nand
[ 151327.397013559316] UBIFS(ubi0:0): default file-system created[ 151327.402858565925] UBIFS(ubi0:0): background thread "ubifs_bgt0_0" started, PID 918990[ 151327.529438694738] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0, name "rootfs"[ 151327.535395702090] UBIFS(ubi0:0): LEB size: 126976 129024 bytes (124 126 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes[ 151327.544507711995] UBIFS(ubi0:0): FS size: 487079936 1016967168 bytes (464 969 MiB, 3836 7882 LEBs), journal size 24379392 33546240 bytes (23 31 MiB, 192 260 LEBs)[ 151327.554646722998] UBIFS(ubi0:0): reserved for root: 4952683 bytes (4836 KiB)[ 151327.560452729608] UBIFS(ubi0:0): media format: w4/r0 (latest is w4/r0), UUID 447F14800D33F80E-E173E80A-4BE943F7-B5BEBE9E-A3EC1267F99EC2D24C4FCD14, small LPT model
</pre>
* you can now extract the root file system into that directory
<preclass="board-terminal">tar zxvf belk-3.0.1_borajxvf dave-image-devel-bora.tar.gz bz2 . -C /mnt/nand
</pre>
* finally, you need to cleanly umount and detach the MTD partition
<preclass="board-terminal">
umount /mnt/nand/
ubidetach -m 7
<pre class="board-terminal">
root@bora:~# umount /mnt/nand/
[ 385417.604146604700] UBIFS(ubi0:0): un-mount UBI device 0, volume 0[ 385417.608892609362] UBIFS(ubi0:0): background thread "ubifs_bgt0_0" stops
root@bora:~# ubidetach -m 7
[ 387424.671411230219] UBIubi0: detaching mtd7 from ubi0[ 387424.677554238132] UBIubi0: mtd7 is detached from ubi0
root@bora:~#
</pre>
You can now safely reboot or turn off the system.
==== Program the boot images in NOR flash====
It is assumed that the following U-Boot's environment variables are defined:
<preclass="board-terminal">
fdt_base=0x00780000
fpga_base=0x00180000
spi_loadfdt=sf read ${fdtaddr} ${fdt_base} 0x80000
spi_loadfpga=sf read ${loadaddr} ${fpga_base} 0x600000
</pre>
</pre>
In U-Boot environment please verify that the following default variables are set in order to be able to boot from NOR + NAND
nandargs=setenv bootargs ubi.mtd=7 root=ubi0_0 rootfstype=ubifs rw
spi_nand=sf probe; run program_fpga spi_programfpga spi_loadk spi_loadfdt nandargs addcons addmisc; bootm ${loadaddr} - ${fdtaddr}
</pre>
=> saveenv
</pre>
In this case, the NOR flash is only used to store U-Boot and its environment. All the other images are stored onto the NAND flash. Specifically, the NAND flash has four partitions that are used to store respectively:
*The <code>uImage</code> binary image, which, in turn, consists of the Linux kernel and a [http://www.linuxfromscratch.org/blfs/view/svn/postlfs/initramfs.html <code>initramfs</code> image].**By the way, this is the default format used for the root filesystem generated by as per [[/BELK-TN-006:_Using_PetaLinux_to_Build_BELK/BXELK_Software_Components|PetaLinux]]'s default configuration.
**This partition is associated with the device file <code>/dev/mtd0</code>
*The PL bitstream
*The Device Tree Blob
**This partition is associated with the device file <code>/dev/mtd2</code>
*An auxiliary read/write filesystem used by the user-space applications for several purposes such as data logging.**This partition is associated with the device file <code>/dev/mtd3</code>.
The resulting bootstrap sequence is like the following:
#U-Boot is retrieved from the NOR flash and copied into the SDRAM memory
#U-boot, in turn, reads from the NAND memory the <code>uImage</code>, the bitstream, the DTB, and copies them into the SDRAM memory
#U-Boot starts the Linux kernel
#Finally, the Linux kernel mounts the root filesystem (<code>initramfs</code>) from the SDRAM memory and starts user-space applications and daemons. It is worth remembering that <code>mtd0</code>,<code>mtd1</code>, and <code>mtd2</code> are used as raw partitions while <code>mtd3</code> is associated with a block device in order to mount a filesystem, specifically ''UBIFS''. To handle such filesystem, the Linux kernel must be built with the UBI/UBIFS support enabled and the root filesystem must include the <code>mtd-utils-ubifs</code> package (see the following image).
To setup the desired standalone configuration, several operations need to be carried out. They are detailed in the following sections. It is assumed that the SOM can boot from the NOR flash. If not, please see [[Restoring_U-Boot_on_SPI_NOR_flash_(BELK/BXELK)|this page]]. =====Testbed=====The testbed used to test this configuration consists of the following boards:*SOM: DBXD4110S2R*Carrier board: EVBBX0000C0R*Software: BXELK 4.0.0 + PetaLinux 2017.1 ====Storing the images onto the raw partitions of the NAND memory====Before storing the images onto into the NAND flash, the bitstrem bitstream must be converted. For more details, please refer to [[BELK-AN-008:_Programming_FPGA_Bitstream_with_UProgramming the FPGA Bitstream with U-Boot|this page]]:
<pre class="board-terminal">
$ python /devel/dave/bora-DBRx/fpga/fpga-bit-to-bin.py -f bitstream.bit bitstream.bin
</pre>
Once the U-Boot console is available, the binary files to be stored onto into the NAND flash can be downloaded via TFTP. The size of the partitions illustrated in the previous image determine the offsets to be used use with the <code>nand erase/write</code> commands. The following box shows the full procedure:.
The first file to be stored is <code>uImage</code>:
Downloading and flashing of the bitstream file:
<pre class="board-terminal">
Bora> tftpboot ${loadaddr} borax/bitstream.bitbin
Using ethernet@e000b000 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.81
Filename 'borax/bitstream.bitbin'.
Load address: 0x2080000
Loading: #################################################################
#################################################################
###############################################################
2.6 5 MiB/s
done
Bytes transferred = 5980021 5979916 (5b3f75 5b3f0c hex)
Bora> nand erase 3000000 f00000
15280 bytes written: OK
</pre>
===Setting up the U-Boot environment===
In order to boot the system as desired, the U-Boot environment must be configured properly. The most important variable is <code>nandboot2</code> that can be created as follows:
<pre class="board-terminal">
Bora> setenv nandboot2 'run program_fpga2 loadunand loadfdtnand nandargs2 addip addcons addmisc; run configid_fixupfdt; bootm ${loadaddr} - ${fdtaddr}'
Bora> savee
Saving Environment to SPI Flash...
Valid environment: 1
</pre>
Another important variable that needs to be changed is <code>mtdparts</code>. It must be set like this in order to tell the kernel how the NAND flash is partitioned:
<pre class="board-terminal">
mtdparts=mtdparts=pl35x-nand:48M(data0),15M(data1),1M(data2),-(data3)
</pre>
Similarly, other variables need to be created such as <code>loadunand</code> and <code>loadfdtnand</code>. The resulting environment should look like this:
<pre class="board-terminal">
</pre>
Please note that the variable <code>bootcmd</code> is set to run the desired boot sequence (<code>nandboot2</code>).
====Formatting the fourth partition of the NAND memory (<code>mtd3</code>)====
After setting up the U-Boot environment, it is possible to start a full bootstrap sequence by issuing the <code>boot</code> command. Please refer to [[#Full bootstrap procedure|this section]] to see the dump of the serial console during the full bootstrap sequence.
Once the system has completed the bootstrap procedure, it is possible to format the <code>mtd3</code> partition in order to store a ''UBIFS'' filesystem.
First of all, check that the NAND's partitions are defined properly:
<pre class="board-terminal">
root@bora-ubi:~# cat /proc/mtd
mtd2: 00100000 00020000 "data2"
mtd3: 3c000000 00020000 "data3"
To format the partition and to mount the newly created filesystem, issue the following commands:
<pre class="board-terminal">
root@bora-ubi:~# ubiformat /dev/mtd3
ubiformat: mtd3 (nand), size 1006632960 bytes (960.0 MiB), 7680 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
[ 6549.244741] ubi0: background thread "ubi_bgt0d" started, PID 1456
UBI device number 0, total 7676 LEBs (990388224 bytes, 944.5 MiB), available 7516 LEBs (969744384 bytes, 924.8 MiB), LEB size 129024 bytes (126.0 KiB)
root@bora-ubi:~# ubimkvol /dev/ubi0 -N data3 -m
Set volume size to 969744384
Volume ID 0, size 7516 LEBs (969744384 bytes, 924.8 MiB), LEB size 129024 bytes (126.0 KiB), dynamic, name "data3", alignment 1
root@bora-ubi:~# mkdir -p /mnt/data3
root@bora-ubi:~# mount -t ubifs ubi0_0 /mnt/data3
[ 6634.342953] UBIFS (ubi0:0): default file-system created
[ 6634.564767] UBIFS (ubi0:0): reserved for root: 4952683 bytes (4836 KiB)
[ 6634.571363] UBIFS (ubi0:0): media format: w4/r0 (latest is w4/r0), UUID 8B1F86F2-F2C3-4292-845F-77D3BF3E212A, small LPT model
</pre>
It is now possible to verify that the filesystem was mounted properly:
<pre class="board-terminal">
root@bora-ubi:~# mount
rootfs on / type rootfs (rw)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000)
ubi0_0 on /mnt/data3 type ubifs (rw,relatime)
</pre>
As expected, the available space on the <code>ubi0_0</code> is less than the raw size of the partition:
<pre class="board-terminal">
root@bora-ubi:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
</pre>
====Full bootstrap procedure====For the reader's convenience, the following box shows the full bootstrap procedure (please, click on the "Expand" link):
<pre class="board-terminal mw-collapsible mw-collapsed">
</pre>
====Additional notes====*<code>mtd0</code>, <code>mtd1</code>, and <code>mtd2</code> are significantly larger than the files they store used in this example. This allows having a spare room to store larger images. For the sake of simplicity, however, U-Boot was configured to read the whole partitions. Obviously, these affect the overall boot time negatively. To optimize it, (see how the <code>loadunand</code>, <code>loadfdtnand</code>, and <code>loadfpga2</code> variables are defined). Obviously, this affect the overall boot time negatively. To optimize it, these variables have to be changed in order to read read just the required amount of data according to the size of the actual stored files.*As stated previously, the root filesystem is <code>initramfs</code> and thus not persistent. Consequently, every it is mountedtime the system boots, the directory <code>/mnt/data3</code> must be createdbefore mounting the ''UBIFS'' file system stored in the NAND flash.<section end=BTELK/>
