DESK-MX6UL-L/Deployment/Standalone boot

History
Version	Issue Date	Notes
1.0.1	Jun 2021	First DESK release
2.0.0	Feb 2022	DESK 3.0.0 release

Standalone boot

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.

The following programming examples are intended for laboratory usage or for preliminary deployment strategy. 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 a <SOM> to boot in standalone mode, without the need of a system microSD card or an NFS server, with two options:

• booting with NOR and NAND internal storage
  • in this configuration the primary boot images will be fetched from NOR flash storage, while the root file system will be fetched from NAND flash
• booting with NAND only
  • in this configuration the whole system will boot without the need of a NOR flash storage, all images and the root file system will be fetched from NAND flash

Program boot images into NOR flash

U-Boot

Update to the latest U-Boot version allows usage of u-boot environment variables available.

=> run load_spl
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/SPL'.
Load address: 0x80800000
Loading: #########
         1.8 MiB/s
done
Bytes transferred = 44032 (ac00 hex)
=> run spi_update_spl
SF: Detected is25lp256 with page size 256 Bytes, erase size 64 KiB, total 32 MiB
SF: 65536 bytes @ 0x0 Erased: OK
device 0 offset 0x400, size 0xac00
SF: 44032 bytes @ 0x400 Written: OK
=> run load_uboot
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/u-boot.img'.
Load address: 0x80800000
Loading: #################################################################
         ##############################################
         1.8 MiB/s
done
Bytes transferred = 564844 (89e6c hex)
=> run spi_update_uboot
SF: Detected is25lp256 with page size 256 Bytes, erase size 64 KiB, total 32 MiB
SF: 589824 bytes @ 0x10000 Erased: OK
device 0 offset 0x10000, size 0x89e6c
SF: 564844 bytes @ 0x10000 Written: OK

kernel image and device tree

We assume that the following environment variables are present in U-Boot:

loadk=tftpboot ${loadaddr} ${serverip}:${bootfile}
loadfdt=tftpboot ${fdtaddr} ${serverip}:${fdtfile}
spi_updatek=sf erase 200000 800000; sf write ${loadaddr} 200000 ${filesize}
spi_updatefdt=sf erase 180000 80000; sf write ${fdtaddr} 180000 ${filesize}
spi_loadk=sf read ${loadaddr} 200000 800000
spi_loadfdt=sf read ${fdtaddr} 180000 80000
spi_nand=sf probe; run spi_loadk spi_loadfdt nandargs addcons addmisc; if run configid_fixupfdt; then bootm ${loadaddr} - ${fdtaddr}; fi

• Update the bootfile and fdtfile environment variables to fit the filename as found inside the TFTP server.
• Program kernel and device tree on NOR flash with the following U-Boot command

sf probe; run loadk spi_updatek loadfdt spi_updatefdt

E.g.:

=> sf probe; run loadk spi_updatek loadfdt spi_updatefdt
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/uImage'.
Load address: 0x80800000
Loading: #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         ########################################
         1.9 MiB/s
done
Bytes transferred = 8189464 (7cf618 hex)
SF: 8388608 bytes @ 0x200000 Erased: OK
device 0 offset 0x200000, size 0x7cf618
SF: 8189464 bytes @ 0x200000 Written: OK
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/imx6ul-axelulite.dtb'.
Load address: 0x83000000
Loading: #######
         1.5 MiB/s
done
Bytes transferred = 32518 (7f06 hex)
SF: 524288 bytes @ 0x180000 Erased: OK
device 0 offset 0x180000, size 0x7f06
SF: 32518 bytes @ 0x180000 Written: OK

Reboot the system and configure U-Boot to apply the new configuration

=> setenv bootcmd run spi_nand
=> saveenv

Program boot images into NAND flash

U-Boot

U-Boot on NAND flash must be programmed using NXP kobs-ng utility: this tool is required for writing the correct U-Boot image on NAND storing all information needed by bootrom to identify the NAND as a boot device.

Here below an example:

• boot the system via SD on NFS
• uses a rfs with kobs-ng utility available on it (e.g. DAVE's rfs provided with DESK-MX6UL-L)
• copy the related U-Boot image file on nfs /home/root (for example)
• execute kobs-ng passing the parameters for flashing U-Boot on NAND

root@desk-mx6ul-axelulite:~# kobs-ng -x -v -w desk-mx6ul-l-3.0.0_mx6uldesk_axelulite_SPL
MTD CONFIG:
  chip_0_device_path = "/dev/mtd0"
  chip_1_device_path = "(null)"
  search_exponent = 2
  data_setup_time = 80
  data_hold_time = 60
  address_setup_time = 25
  data_sample_time = 6
  row_address_size = 3
  column_address_size = 2
  read_command_code1 = 0
  read_command_code2 = 48
  boot_stream_major_version = 1
  boot_stream_minor_version = 0
  boot_stream_sub_version = 0
  ncb_version = 3
  boot_stream_1_address = 0
  boot_stream_2_address = 0
  secondary_boot_stream_off_in_MB = 64
	 -- We add the 1k-padding to the uboot.
.tmp_kobs_ng: verifying using key '00000000000000000000000000000000'
.tmp_kobs_ng: is a valid bootstream for key '00000000000000000000000000000000'
mtd: use new bch layout raw access mode
mtd: opening: "/dev/mtd0"
NFC geometry :
	ECC Strength       : 2
	Page Size in Bytes : 2071
	Metadata size      : 10
	ECC Chunk Size in byte : 512
	ECC Chunk count        : 4
	Block Mark Byte Offset : 2028
	Block Mark Bit Offset  : 2
====================================================
mtd: opened '/dev/mtd0' - '(null)'
mtd: max_boot_stream_size_in_bytes = 524288
mtd: boot_stream_size_in_bytes = 45056
mtd: boot_stream_size_in_pages = 22
mtd: #1 0x00100000 - 0x00180000 (0x0010b000)
mtd: #2 0x00180000 - 0x00200000 (0x0018b000)
FCB
  m_u32Checksum = 0x00000000
  m_u32FingerPrint = 0x20424346
  m_u32Version = 0x01000000
  m_NANDTiming.m_u8DataSetup = 80
  m_NANDTiming.m_u8DataHold = 60
  m_NANDTiming.m_u8AddressSetup = 25
  m_NANDTiming.m_u8DSAMPLE_TIME = 6
  m_u32PageDataSize = 2048
  m_u32TotalPageSize = 2112
  m_u32SectorsPerBlock = 64
  m_u32NumberOfNANDs = 0
  m_u32TotalInternalDie = 0
  m_u32CellType = 0
  m_u32EccBlockNEccType = 1
  m_u32EccBlock0Size = 512
  m_u32EccBlockNSize = 512
  m_u32EccBlock0EccType = 1
  m_u32MetadataBytes = 10
  m_u32NumEccBlocksPerPage = 3
  m_u32EccBlockNEccLevelSDK = 0
  m_u32EccBlock0SizeSDK = 0
  m_u32EccBlockNSizeSDK = 0
  m_u32EccBlock0EccLevelSDK = 0
  m_u32NumEccBlocksPerPageSDK = 0
  m_u32MetadataBytesSDK = 0
  m_u32EraseThreshold = 0
  m_u32Firmware1_startingPage = 512
  m_u32Firmware2_startingPage = 768
  m_u32PagesInFirmware1 = 22
  m_u32PagesInFirmware2 = 22
  m_u32DBBTSearchAreaStartAddress = 256
  m_u32BadBlockMarkerByte = 2028
  m_u32BadBlockMarkerStartBit = 2
  m_u32BBMarkerPhysicalOffset = 2048
  m_u32BCHType = 0
  m_NANDTMTiming.m_u32TMTiming2_ReadLatency = 0
  m_NANDTMTiming.m_u32TMTiming2_PreambleDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_CEDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_PostambleDelay = 0
  m_NANDTMTiming.m_u32TMTiming2_CmdAddPause = 0
  m_NANDTMTiming.m_u32TMTiming2_DataPause = 0
  m_NANDTMTiming.m_u32TMSpeed = 0
  m_NANDTMTiming.m_u32TMTiming1_BusyTimeout = 0
  m_u32DISBBM = 0
  m_u32BBMarkerPhysicalOffsetInSpareData = 0
  m_u32OnfiSyncEnable = 0
  m_NANDONFITiming.m_u32ONFISpeed = 0
  m_NANDONFITiming.m_u32ONFITiming_ReadLatency = 0
  m_NANDONFITiming.m_u32ONFITiming_CEDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_PreambleDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_PostambleDelay = 0
  m_NANDONFITiming.m_u32ONFITiming_CmdAddPause = 0
  m_NANDONFITiming.m_u32ONFITiming_DataPause = 0
  m_NANDONFITiming.m_u32ONFITiming_BusyTimeout = 0
  m_u32DISBBSearch = 0
  m_u32RandomizerEnable = 0
  m_u32ReadRetryEnable = 0
  m_u32ReadRetrySeqLength = 0
DBBT
  m_u32Checksum = 0x00000000
  m_u32FingerPrint = 0x54424244
  m_u32Version = 0x01000000
  m_u32DBBTNumOfPages = 0
Firmware: image #0 @ 0x100000 size 0xb000 - available 0x80000
Firmware: image #1 @ 0x180000 size 0xb000 - available 0x80000
-------------- Start to write the [ FCB ] -----
mtd: erasing @0:0x0-0x20000
mtd: Writing FCB0 [ @0:0x0 ] (840) *
mtd: erasing @0:0x20000-0x40000
mtd: Writing FCB1 [ @0:0x20000 ] (840) *
mtd: erasing @0:0x40000-0x60000
mtd: Writing FCB2 [ @0:0x40000 ] (840) *
mtd: erasing @0:0x60000-0x80000
mtd: Writing FCB3 [ @0:0x60000 ] (840) *
mtd_commit_bcb(FCB): status 0

-------------- Start to write the [ DBBT ] -----
mtd: erasing @0:0x80000-0xa0000
mtd: Writing DBBT0 [ @0:0x80000 ] (800) *
mtd: erasing @0:0xa0000-0xc0000
mtd: Writing DBBT1 [ @0:0xa0000 ] (800) *
mtd: erasing @0:0xc0000-0xe0000
mtd: Writing DBBT2 [ @0:0xc0000 ] (800) *
mtd: erasing @0:0xe0000-0x100000
mtd: Writing DBBT3 [ @0:0xe0000 ] (800) *
mtd_commit_bcb(DBBT): status 0

---------- Start to write the [ .tmp_kobs_ng ]----
mtd: Writting .tmp_kobs_ng: #0 @0: 0x00100000 - 0x0010b000
mtd: erasing @0:0x100000-0x120000
mtd: We write one page for save guard. *
mtd: Writting .tmp_kobs_ng: #1 @0: 0x00180000 - 0x0018b000
mtd: erasing @0:0x180000-0x1a0000
mtd: We write one page for save guard. *
</pre>

then the second <code>mtd1</code> partition can be written using ''nandwrite'':

<pre class="workstation-terminal">
root@desk-mx6ul-axelulite:~# flash_erase /dev/mtd1 0 0
Erasing 128 Kibyte @ 5e0000 -- 100 % complete 
root@desk-mx6ul-axelulite:~# nandwrite -p /dev/mtd1 desk-mx6ul-l-3.0.0_mx6uldesk_axelulite_u-boot.img 
Writing data to block 0 at offset 0x0
Writing data to block 1 at offset 0x20000
Writing data to block 2 at offset 0x40000
Writing data to block 3 at offset 0x60000
Writing data to block 4 at offset 0x80000

kernel image and device tree

We assume that the following environment variables are present in u-boot:

nand_updatek=nand erase.part nand-kernel; nand write ${loadaddr} nand-kernel ${filesize}
nand_updatefdt=nand erase.part nand-fdt; nand write ${fdtaddr} nand-fdt ${filesize}
nand_loadk=nand read ${loadaddr} nand-kernel
nand_loadfdt=nand read ${fdtaddr} nand-fdt
nand_nand=run nand_loadk nand_loadfdt nandargs addcons addmisc; if run configid_fixupfdt; then bootm ${loadaddr} - ${fdtaddr}; fi

• Update the bootfile and fdtfile environment variables to fit the filename as found inside the TFTP server.
• Program kernel and device tree on NAND flash with the following U-Boot command

run loadk nand_updatek loadfdt nand_updatefdt

E.g.:

=> run loadk nand_updatek loadfdt nand_updatefdt
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/uImage'.
Load address: 0x80800000
Loading: #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         ########################################
         1.9 MiB/s
done
Bytes transferred = 8189464 (7cf618 hex)

NAND erase.part: device 0 offset 0xc00000, size 0x800000
Erasing at 0x13e0000 -- 100% complete.
OK

NAND write: device 0 offset 0xc00000, size 0x7cf618
 8189464 bytes written: OK
Using FEC0 device
TFTP from server 192.168.0.13; our IP address is 192.168.0.89
Filename 'lynx/imx6ul-axelulite.dtb'.
Load address: 0x83000000
Loading: #######
         1.8 MiB/s
done
Bytes transferred = 32518 (7f06 hex)

NAND erase.part: device 0 offset 0xa00000, size 0x100000
Erasing at 0xae0000 -- 100% complete.
OK

NAND write: device 0 offset 0xa00000, size 0x7f06
 32518 bytes written: OK

Reboot the system and configure U-Boot to apply the new configuration

=> setenv bootcmd run nand_nand
=> saveenv

Program root file system into NAND flash

• boot the system via SD or NFS as described in the Booting from NFS
• by default, the NAND is already partitioned to allow booting from NAND-only (see next section) and, thus, some partitions are reserved for u-boot and kernel images. Here we won't modify this default configuration. The MTD partitions can be dumped with /proc/mtd (the partition's name should be self-explanatory)

root@desk-mx6ul-axelulite:~# cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00200000 00020000 "nand-SPL"
mtd1: 00600000 00020000 "nand-uboot"
mtd2: 00100000 00020000 "nand-env1"
mtd3: 00100000 00020000 "nand-env2"
mtd4: 00100000 00020000 "nand-fdt"
mtd5: 00100000 00020000 "nand-spare"
mtd6: 00800000 00020000 "nand-kernel"
mtd7: 00400000 00020000 "nand-splash"
mtd8: 3e800000 00020000 "nand-ubi"
mtd9: 00010000 00001000 "spi-SPL"
mtd10: 000f0000 00001000 "spi-uboot"
mtd11: 00040000 00001000 "spi-env1"
mtd12: 00040000 00001000 "spi-env2"
mtd13: 00080000 00001000 "spi-dtb"
mtd14: 00800000 00001000 "spi-kernel"
mtd15: 00400000 00001000 "spi-splash"
mtd16: 01200000 00001000 "spi-free"

Please note that MTD partition index may change depending of flash device availability, flash device size, u-boot environment variables or kernel device driver load order. Always take care of looking inside /proc/mtd to match your specific layout

• Format and initialize nand-ubi partition, which in our case is mtd8, using UBI with:

ubiformat /dev/mtd8
ubiattach -m 8
ubimkvol /dev/ubi0 -N rootfs -m

E.g.

root@desk-mx6ul-axelulite:~# ubiformat /dev/mtd8
ubiformat: mtd8 (nand), size 1048576000 bytes (1000.0 MiB), 8000 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
libscan: scanning eraseblock 7999 -- 100 % complete   
ubiformat: 8000 eraseblocks have valid erase counter, mean value is 16
ubiformat: formatting eraseblock 7999 -- 100 % complete  
root@desk-mx6ul-axelulite:~# ubiattach -m 8
UBI device number 0, total 8000 LEBs (1015808000 bytes, 968.7 MiB), available 7836 LEBs (994983936 bytes, 948.8 MiB), LEB size 126976 bytes (124.0 KiB)
root@desk-mx6ul-axelulite:~# ubimkvol /dev/ubi0 -N rootfs -m
Set volume size to 994983936
Volume ID 0, size 7836 LEBs (994983936 bytes, 948.8 MiB), LEB size 126976 bytes (124.0 KiB), dynamic, name "rootfs", alignment 1

• Now mount the UBI volume using UBIFS in a temporary directory

mkdir -p /mnt/nand
mount -t ubifs ubi0_0 /mnt/nand

E.g.:

root@desk-mx6ul-axelulite:~# mkdir -p /mnt/nand
root@desk-mx6ul-axelulite:~# mount -t ubifs ubi0_0 /mnt/nand/
root@desk-mx6ul-axelulite:~# dmesg | tail -n 7
[  201.602548] UBIFS (ubi0:0): Mounting in unauthenticated mode
[  201.602935] UBIFS (ubi0:0): background thread "ubifs_bgt0_0" started, PID 293
[  201.634481] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0, name "rootfs"
[  201.634523] UBIFS (ubi0:0): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[  201.634550] UBIFS (ubi0:0): FS size: 992698368 bytes (946 MiB, 7818 LEBs), journal size 33521664 bytes (31 MiB, 264 LEBs)
[  201.634570] UBIFS (ubi0:0): reserved for root: 4952683 bytes (4836 KiB)
[  201.634596] UBIFS (ubi0:0): media format: w5/r0 (latest is w5/r0), UUID CBE8807E-6A37-400B-9B56-E12B4C034D9E, small LPT model

• you can now extract the root file system into that directory

tar xvjf desk-image-qt5-desk-mx6ul-axelulite.tar.bz2 -C /mnt/nand/

• finally, you need to cleanly umount and detach the MTD partition

umount /mnt/nand/
ubidetach -m 8

E.g.

root@desk-mx6ul-axelulite:~# umount /mnt/nand
root@desk-mx6ul-axelulite:~# ubidetach -m 8
root@desk-mx6ul-axelulite:~# dmesg | tail -n 4
[ 1154.988629] UBIFS (ubi0:0): un-mount UBI device 0
[ 1154.989082] UBIFS (ubi0:0): background thread "ubifs_bgt0_0" stops
[ 1160.907410] ubi0: detaching mtd8
[ 1160.921595] ubi0: mtd8 is detached

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

nandargs=setenv bootargs ubi.mtd=8 root=ubi0_0 rootfstype=ubifs rw

---