COM iMX6 Bootloader U-Boot

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FAQ

Q: Initialization of MAC address in the bootloader?
A: At the first start, the bootloader reads the MAC address from EEPROM, write it to eFuses and creates env variable ethaddr. The env variable ethaddr could be changed during lifetime to any other MAC address. If you like to get back the original MAC address, please remove ethaddr, save environment and restart the system. In addition to that the env variable ethaddr would be initialized again with eeprom MAC addresss.

Downloads

Enter Bootloader Console

  1. Connect DHCOM UART1 (FF UART) via null modem cable to the RS232 Port of your PC
  2. Start terminal program (e.g. Tera Term) on the Host PC with the following settings:
    Baud rate: 115200
    Data: 8 bit
    Parity: none
    Stop bits: 1 bit
    Flow control: none
  3. Press "del" on the Host PC during Core Module system start to enter bootloader console

U-boot console commands

SPI Flash

SPI Flash Init
sf probe
Example: sf probe
Description: Initializes the OnBoard SPI Flash
SPI Flash Read
sf read <SDRAM address> <SPI Flash address> <Bytes>
Example: sf read 10000000 0 100
Description: Copies 256Bytes from SPI Flash address 0x0 to SDRAM address 0x1000_0000
SPI Flash Write
sf write <SDRAM address> <SPI Flash address> <Bytes>
Example: sf write 10000000 40000 10000
Description: Copies 64kByte from SDRAM address 0x1000_0000 to SPI Flash address 0x4_0000
SPI Flash Erase
sf erase <SPI Flash address> <Bytes>
Example: sf erase 100000 1000
Description: Deletes SPI Flash content from address 0x10_0000 to 0x10_0FFF
Note: The Bytes information needs to be sector size aligned!

SD/MMC Card

Switch between MicroSD, SD Slot and eMMC
mmc dev <Slot number> <Partition number>
Example: mmc dev 0
Description: Switch between SD/MMC Slots: 0 --> SD/MMC Slot, 1 --> MicroSD Slot, 2 --> eMMC Flash
Note eMMC flash partition number: 0 --> User partition, 1 --> Boot partition 1, 2 --> Boot partition 2
Initialize SD/MMC Card
mmc rescan
Description: Initialize new inserted SD Card
Show SD/MMC information
mmcinfo
Description: Shows SD/MMC device information
Device: FSL_SDHC
Manufacturer ID: 45
OEM: 100
Name: SEM08
Tran Speed: 52000000
Rd Block Len: 512
MMC version 4.41
High Capacity: Yes
Capacity: 7.3 GiB
Bus Width: 8-bit
Write to MicroSD, SD Slot and eMMC
mmc write <SDRAM address> <block number> <block count>
Example: mmc write 11000000 5000 400
Description: Write 512kByte (device block size is 512Byte) to the eMMC offset 10MByte.
Read from MicroSD, SD Slot and eMMC
mmc read <SDRAM address> <block number> <block count>
Example: mmc read 11000000 5000 400
Description: Read 512kByte (device block size is 512Byte) from the eMMC offset 10MByte.

FAT - EXT2 - EXT4 - Filesystem

NOTE: All EXT2 commands must also be used for ext4
Show Filesystem information
fatinfo <interface> <device>
Example: fatinfo mmc 1
Interface: MMC
 Device 1: Vendor: Man 094150 Snr 266e068c Rev: 1.0 Prod: AF UD
           Type: Removable Hard Disk
           Capacity: 121.2 MB = 0.1 GB (248320 x 512)
 Partition 1: Filesystem: FAT16 "NO NAME    "
List files
fatls <interface> <device> <directory>
ext2ls <interface> <device> <directory>
Example 1: fatls mmc 1
Example 2: fatls mmc 1 /folder
Load Files from SD Card to SDRAM
fatload <interface> <device> <SDRAM address> <directory+filename>
ext2load <interface> <device> <SDRAM address> <directory+filename>
Example 1: fatload mmc 1 10100000 nk.gz
Example 2: fatload mmc 1 10100000 /folder/nk.gz

Ethernet

Load File via TFTP to SDRAM
tftp <SDRAM address> <directory+filename>
Example: tftp 80100000 nk.gz
Example TFTP Server: "Winagents TFTP Server Manager"
Note: For TFTP download it is necessary to config the ENV variables "ipaddr" and "serverip"
Load File via TFTP to SDRAM using DHCP
dhcp <SDRAM address> <directory+filename>
Example: dhcp 80100000 nk.gz
Example TFTP Server: "Winagents TFTP Server Manager"
Note: It is necessary to config the ENV variable "serverip" with the ip-address of your TFTP-Server
Ping
ping <IP address>
Example: ping 192.168.55.32
Read PHY register via MII interface
mii dump <PHY address> <PHY register>
Example: mii dump 0 0
Remark: The standard MII registers 0-5 are supported by this command. When you are working with a DHCOM i.MX6 module only PHY address "0" is allowed.

Unzip

unzip <source address> <destination address>
Example: unzip 12900000 10100000
Note: The unzip command is supporting the gzip file format.

Bitmap

Information
bmp info <Bitmap address> 
Image size    : 800 x 480
Bits per pixel: 8
Compression   : 0
Display
bmp display <Bitmap SDRAM address> [x y]
Note: It is necessary to load bitmap file to memory address with an offset of an odd multiple of +2, since the use of a four-byte alignment will cause alignment exceptions at run-time.

Memory

Display
md[.b, .w, .l] <address> [count]
Example: md.b 80100000 100
Write
mw[.b, .w, .l] <address> <value> [count]
Example: mw.b 80100000 aa 100
Description: Writes the value 0xaa to the next 0x100 bytes from the address 0x8010_0000.
Copy
cp[.b, .w, .l] <source> <destination> <count>

Show DHCOM Settings

settings
Example:
 VALIDATION_ID:    "DH"
 DISPLAY_ID:       0x00
 LENGTH:           0x2c
 X_RESOLUTION:     800 pixel
 Y_RESOLUTION:     480 pixel
 PIXEL_CLOCK:      22200 kHz
 LCD_CONFIG_FLAGS: 0x3e3
 HSW:              64 pixel clocks
 VSW:              2 line clocks
 HFP:              42 pixel clocks
 HBP:              86 pixel clocks
 VFP:              10 line clocks
 VBP:              33 line clocks
 DATALINES:        16
 ACB:              0
 ACBI:             0
 GPIO_DIR:         0x01ff
 GPIO_STATE:       0x0000
 HW_CONFIG_FLAGS:  0x001e

I2C

List available devices
i2c probe 
Valid devices:
0 = DHCOM I2C port 1
1 = DHCOM I2C port 2
2 = i.MX6 OnBoard I2C port
Read
i2c md <I2C address> <start address> <end address>
Example: i2c md 57 10 20
Description: Reads 16 Bytes from the address 0x10 to address 0x20.
Write
i2c mw <I2C address> <I2C register> <Value> <Bytes>
Example: i2c mw 57 0 aa 5
Description: Writes 0xaa to 5 Bytes from the offset 0.

Environment

Show ENV variables
env print 
bootdelay=0
baudrate=38400
ipaddr=192.168.55.230
serverip=192.168.55.36
gatewayip=192.168.55.36
netmask=255.255.255.0
frias=5
kernel=uImage
bootargs=console=ttymxc0,115200 root=/dev/mmcblk0p2
nandbootwince=update;bootwince 00200000
splashimage=0x000c0000
save_ENV_to_flash=setenv ENVinFlash 1; saveenv
ENVinFlash=1
ethaddr=00:04:a3:34:b6:0d
ethact=FEC0
winceimagetype=nk.gz
winceimagesize=00ba55ee
loadaddr=00200000
bootcmd=run nandbootwince
filesize=212050
Environment size: 449/262140 bytes
Set ENV variables
env set <ENV name> <ENV value>
Example: env set ipaddr 192.168.55.2
Note: If you need to edit "bootcmd" it is necessary to insert ";" between the unique commands. You can enter ";" at the command line with "\;".
Save ENV variables
env save
Delete ENV variable
env delete <ENV name>
Revert to default ENV
env default -a
Import ENV from textfile
env import -t <SDRAM address> $filesize
Example:
fatload mmc 0 0x10000000 uEnv.txt
env import -t 0x10000000 $filesize
Important:
The uEnv.txt file should be in unix format. Also make sure that there is an empty line at the end of the file.
bootargs=console=ttyO0,115200n8 root=/dev/mmcblk0p2 mem=128M rootwait
bootcmd=mmc rescan; fatload mmc 0 0x82000000 uImage; bootm 0x82000000
uenvcmd=boot

How to do Updates

Display and Hardware settings

DHCOM settings and Splash bitmap

The DHCOM settings are used to setup display and special hardware parameters. For detailed description please have a look at How to create a settings.bin file.
The DHCOM settings file and the splash bitmap are loaded via the env variables "load_settings_bin" and "load_splash" during startup from boot partition. The default content of these env variables is:
settings_bin_file=default_settings.bin
splash_file=splash.bmp
load_settings_bin=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${settings_bin_file}
load_splash=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${splash_file}
Note: The DHCOM display settings can also be stored in external eeprom (address 0x50 / 7bit I2C address) which is connected to DHCOM I2C1 port. If eeprom is available and DISP_ADPT_EEPRM flag is set to 1, the settings from eeprom override the settings from boot partition!
Next you can see the settings load order:

Display disabled by default

With default u-boot configuration u-boot doesn't initialize the Display interface. This feature can be activated by deleting the "panel" environment variable. But also with deactivated display interface, the bootlaoder reads the display settings and pass the settings to the linux kernel.
panel="no_panel": Display interface is deactiveted in u-boot and backlight is powered off.
panel="RGB": Default DH 4,3" display is selected.
panel=deleted: u-boot initialize display by DH settings file.

Backlight enable GPIO

If ENV variable "panel" is set to "no_panel" the backlight enable GPIO (defined via DHCOM settings file or eeprom settings) will be disabled from the bootloader during startup.
If ENV variable "panel" is deleted, the backlight enable GPIO is activated or deactivated in relation to BL_ON flag of DHCOM settings file.
Note: Supported by U-Boot DH VERSION v0.4.2.5 or higher for iMX6
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