TS-TPC-7990 U-boot Sections
This platform uses U-Boot as the bootloader to launch the full operating system. The i.MX6 processor loads U-Boot from the on-board 8 MiB SPI flash. U-Boot provides support for loading data from various mediums; this allows booting a kernel from SD, eMMC, SATA, NFS, or USB. U-Boot is a general purpose bootloader that is capable of booting into common Linux distributions, Android, Windows, or custom software OSes.
On a normal boot the output should be similar to the output below:
U-Boot 2015.04-07932-g68f7575230 (Apr 12 2017 - 10:16:39) CPU: Freescale i.MX6SOLO rev1.1 at 792 MHz CPU: Temperature 59 C Reset cause: WDOG Board: TS-TPC-7990 REV B I2C: ready DRAM: 1 GiB MMC: FSL_SDHC: 0, FSL_SDHC: 1 SF: Detected N25Q64 with page size 256 Bytes, erase size 4 KiB, total 8 MiB auto-detected panel LXD-WSVGA Display: LXD-WSVGA (1024x600) In: serial Out: serial Err: serial FPGA Rev: 8 SilabRev: 6 Net: using phy at 1 FEC [PRIME] SF: Detected N25Q64 with page size 256 Bytes, erase size 4 KiB, total 8 MiB SF: 7655 bytes @ 0x200000 Read: OK Booting from eMMC ...
By default the unit will boot to SD or eMMC depending on the status of the "SD boot" jumper on startup. If the jumper is set it boots to SD, otherwise the unit will boot to eMMC. Other boot options like SATA, Network, USB, will require customizing the U-Boot environment.
U-Boot Environment
The eMMC flash contains both the U-Boot executable binary and U-Boot environment. Our default build has 2 MiB of environment space which can be used for variables and boot scripts. The following commands are examples of how to manipulate the U-Boot environment:
# Print all environment variables
env print -a
# Sets the variable bootdelay to 5 seconds
env set bootdelay 5;
# Variables can also contain commands
env set hellocmd 'led red on; echo Hello world; led green on;'
# Execute commands saved in a variable
env run hellocmd;
# Commit environment changes to the SPI flash
# Otherwise changes are lost
env save
# Restore environment to default
env default -a
# Remove a variable
env delete emmcboot
U-Boot Commands
# The most important command is
help
# This can also be used to see more information on a specific command
help i2c
# This is a command added to U-Boot by TS to read the baseboard ID on our
# System on Module devices
bbdetect
echo ${baseboard} ${baseboardid}
# The echo will return something similar to:
# TS-8390 2
# Boots into the binary at $loadaddr. The loaded file needs to have
# the U-Boot header from mkimage. A uImage already contains this.
bootm
# Boots into the binary at $loadaddr, skips the initrd, specifies
# the FDT addrress so Linux knows where to find the device tree
bootm ${loadaddr} - ${fdtaddr}
# Boot a Linux zImage loaded at $loadaddr
bootz
# Boot in to a Linux zImage at $loadaddr, skip initrd, specifies
# the FDT address to Linux knows where to find the device tree
bootz ${loadaddr} - ${fdtaddr}
# Get a DHCP address
dhcp
# This sets ${ipaddr}, ${dnsip}, ${gatewayip}, ${netmask}
# and ${ip_dyn} which can be used to check if the dhcp was successful
# These commands are used for scripting:
false # do nothing, unsuccessfully
true # do nothing, successfully
# This command can set fuses in the processor
# Setting fuses can brick the unit, will void the warranty,
# and should not be done in most cases
fuse
# GPIO can be manipulated from U-Boot. Keep in mind that the IOMUX
# in U-Boot is only setup enough to boot the device, so not all pins will
# be set to GPIO mode out of the box. Boot to the full operating system
# for more GPIO support.
# GPIO are specified in bank and IO in this manual. U-Boot uses a flat numberspace,
# so for bank 2 DIO 25, this would be number (32*1)+25=89
# The formula thus being (32*(bank-1)+dio)=flattened_dio
# Note that on some products, bank 1 is the first bank
# Set 2_25 low
gpio clear 83
# Set 2_25 high
gpio set 83
# Read 2_25
gpio input 83
# Control LEDs
led red on
led green on
led all off
led red toggle
# This command is used to copy a file from most devices
# Load kernel from SD
load mmc 0:1 ${loadaddr} /boot/uImage
# Load Kernel from eMMC
load mmc 1:1 ${loadaddr} /boot/uImage
# Load kernel from USB
usb start
load usb 0:1 ${loadaddr} /boot/uImage
# Load kernel from SATA
sata init
load sata 0:1 ${loadaddr} /boot/uImage
# View the FDT from U-Boot
load mmc 0:1 ${fdtaddr} /boot/imx6q-ts4900.dtb
fdt addr ${fdtaddr}
fdt print
# It is possible to blindly jump to any memory location
# This is similar to bootm, but it does not require
# the use of the U-Boot header
load mmc 0:1 ${loadaddr} /boot/custombinary
go ${loadaddr}
# Browse fat, ext2, ext3, or ext4 filesystems:
ls mmc 0:1 /
# Access memory like devmem in Linux, read/write arbitrary memory
# using mw and md
# write
mw 0x10000000 0xc0ffee00 1
# read
md 0x10000000 1
# Test memory.
mtest
# Check for new SD card
mmc rescan
# Read SD card size
mmc dev 0
mmcinfo
# Read eMMC Size
mmc dev 1
mmcinfo
# The NFS command is like 'load', but used over the network
dhcp
env set serverip 192.168.0.11
nfs ${loadaddr} 192.168.0.11:/path/to/somefile
# Test ICMP
dhcp
ping 192.168.0.11
# Reboot
reset
# SPI access is through the SF command
# Be careful with sf commands since
# this is where U-Boot and the FPGA bitstream exist
# Improper use can render the board unbootable
sf probe
# Delay in seconds
sleep 10
# Load HUSH scripts that have been created with mkimage
load mmc 0:1 ${loadaddr} /boot/ubootscript
source ${loadaddr}
# Most commands have return values that can be used to test
# success, and HUSH scripting supports comparisons like
# test in Bash, but much more minimal
if load mmc 1:1 ${fdtaddr} /boot/uImage;
then echo Loaded Kernel
else
echo Could not find kernel
fi
# Commands can be timed with "time"
time sf probe
# Print U-Boot version/build information
version
Modify Linux Kernel cmdline
The Linux kernel cmdline can be customized by modifying the cmdline_append variable. The variable contents are clobbered when set, so be sure to specify the full desired cmdline string.
env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet
env save
The kernel command line can also be modified from from the on-board Linux. Debian (and other distributions) provide a U-Boot utilities package that contains the tools necessary to create a U-Boot script:
apt-get update && apt-get install u-boot-tools -y
echo "env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet" > /boot/boot.scr
mkimage -A arm -T script -C none -n 'tsimx6 boot script' -d /boot/boot.scr /boot/boot.ub
The boot.scr includes the plain text commands to be run in U-Boot on startup. The mkimage tool adds a checksum and header to this file which can be loaded by U-Boot. The .ub file should not be edited directly.
Booting From NFS
U-Boot includes support for NFS client which can be used to load the kernel, device tree binary, and root filesystem across the network. Our default environment contains the nfsboot command which can be updated to boot NFS on a custom network:
# Set this to your NFS server IP
env set nfsroot 192.168.0.36:/mnt/storage/imx6/
env save
# Boot to NFS once
run nfsboot;
# To make the NFS boot the persistent default
env set bootcmd run nfsboot;
env save
Booting From USB
On startup, U-Boot will attempt to load a script from USB if the U-Boot jumper is on. This can be used for reprogramming the board, or for booting to a kernel and/or filesystem on a USB drive. To make a bootable drive, create a single ext3 partition on a USB drive and copy over a rootfs (in the same manner as is done for an SD card. This is described in depth in the Debian and Yocto sections. Create the /tsinit.ub file in the root of the USB drive. Below is an example of booting to the filesystem on the USB drive:
# Prepare with:
# mkimage -A arm -T script -C none -n 'mx6 usb' -d tsinit.scr tsinit.ub
# DO NOT MANUALLY EDIT THE .UB FILE
if test ${model} = '7990'; then
if load usb ${bootpart} ${loadaddr} /boot/ts7990-fpga.vme; then
fpga load 0 ${loadaddr} ${filesize};
fi;
if test ${pcbrev} != 'a'; then
load usb ${bootpart} ${fdtaddr} /boot/imx6${cpu}-ts7990-${lcd}-revb.dtb;
else
load usb ${bootpart} ${fdtaddr} /boot/imx6${cpu}-ts7990-${lcd}.dtb;
fi;
load usb 0:1 ${loadaddr} ${uimage};
setenv bootargs root=/dev/sda1 rootwait rw ${cmdline_append};
bootm ${loadaddr} - ${fdtaddr};
fi
load usb 0:1 ${loadaddr} /boot/uImage;
setenv bootargs root=/dev/sda1 rootwait rw ${cmdline_append};
bootm ${loadaddr} - ${fdtaddr};
Generate the tsinit.ub file in the same directory, note that u-boot-tools or the equivalent package for a specific distribution will need to be installed:
mkimage -A arm -T script -C none -n 'mx6 usb' -d tsinit.scr tsinit.ub
Set the "U Boot" jumper, insert the USB drive to the device, and apply power.
Update U-Boot
| WARNING: | Installing a customer U-Boot binary is not recommended and may cause the unit to fail to boot. |
U-Boot requires a different build for Quad/Dual and Solo/Duallite. Flashing the wrong U-Boot image will cause the board to fail to properly boot. Recovery in this case would require submitting an RMA request.
On a booted unit at the U-Boot console, type "env print ${imx_type}" and this will return the U-Boot build that should be used. Copy the correct u-boot.imx file to the SD card, boot to the U-Boot shell, and run:
mmc dev 0
load mmc 0:1 ${loadaddr} /u-boot.imx
sf probe
sf erase 0 0x80000
sf write ${loadaddr} 0x400 $filesize
U-Boot Development
We do provide our U-Boot sources but we do not recommend rebuilding a custom U-Boot if it can be avoided. Custom built U-Boot binaries will not have the latest up to date settings. Specifically, the largest concern is with RAM timing settings. Memory technology is expanding rapidly and we may need to use different parts through the shipping lifetime of the device itself. If RAM timings change, then we update our factory shipped U-Boot to have the proper settings. A custom U-Boot would need to be re-built if any of these settings change.
Our U-Boot includes a variable "imx_type". If loading a custom U-Boot binary, make sure to check the value of this before writing. If we are forced to update the RAM configuration we will change this variable. We will also send out a product change to anyone who is subscribed to our PCS system.
If you still need to proceed with building a custom U-Boot, use the imx_v2015.04_3.14.52_1.1.0_ga branch from the github here: https://github.com/embeddedTS/u-boot-imx/
On a booted unit at the U-Boot console, type "env print ${imx_type}" and this will return the U-Boot build that should be used and the correct RAM timing.
After that, adjust the following commands to match the build configuration; these commands will build the u-boot.imx binary.
export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-
export DATE=$(date +"%b-%d-%Y")
make ts7990-s-1g-800mhz-i_defconfig
make -j9 u-boot.imx
This will output a u-boot.imx file that can be written to the SPI flash following the instructions in the update U-Boot section.
U-Boot Recovery
We have several variations of the TS-TPC-7990's u-boot which include different RAM configurations for the Quad core, solo commercial, solo industrial, and a few older variants. On a functional board if you run "ech o ${imx_type}" this will show which variant you are running. To recover the system you must get it booting over the USB OTG port.
On startup, the i.MX6 checks the SPI flash for a valid boot header in SPI flash. If it is unable to locate a valid boot header, the CPU falls back to the "serial downloader" which allows the CPU to execute code sent via USB. If the unit has a valid but damaged or incorrect U-Boot binary programmed in to SPI flash, an RMA return will be required in order to properly recover it. Please contact us for assistance with this.
1) Download the U-Boot binary for the correct imx_type variant from the list here: https://files.embeddedTS.com/ts-arm-sbc/ts-7970-linux/u-boot/. See the U-Boot Changelog for information on the changes between released versions.
2) Download and build/install the "imx_usb" loader
3) Apply power to the device.
4) Plug a USB type B cable into the "Device" USB Micro connector on the device and connect it to a host PC.
5) Check 'dmesg' or 'lsusb' on the host PC for a new USB connection. This should show a HID device listing NXP or Freescale as the manufacturer. For example:
hid-generic 0003:15A2:0054.0006: hiddev0,hidraw3: USB HID v1.10 Device [Freescale SemiConductor Inc SE Blank ARIK] on usb-0000:00:14.0-6.4.2/input0
If it does not show the above output, an RMA return will be required in order to properly recover the unit. Please contact us for assistance with this.
6) Plug a USB type B cable into the "Console" USB Micro connector on the device and connect it to a host PC, and open your terminal emulator
7) Install the UBOOT jumper on the 7990 to stop at the u-boot prompt
8) Run 'imx_usb path/to/u-boot.imx' on the host PC
At this point, the USB serial device should show up on the host, opening it will reveal that the unit is stopped at the U-Boot prompt. Follow the steps in Update U-Boot to reinstall U-Boot on the SPI flash.