Frequently Asked Questions for i.MX6 Linux

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Compiling

U-boot

Please refer to the following sections for details

  • Getting Started / Build Instructions / To build u-boot (LBV3) (LBV5) (LBV6)
  • Customization / Building & updating u-boot manually (LBV3) (LBV5) (LBV6)

Kernel

Please refer to the following sections for details

  • Getting Started / Build Instructions / To build linux kernel (LBV3) (LBV5) (LBV6)
  • Customization / Building & updating kernel/modules/dtb manually (LBV3) (LBV5) (LBV6)

U-boot

Kernel

In Yocto Project, it is called "boot splashscreen", please refer to the each BSP's corresponding official Yocto website (list as below) for details

  • Yocto Project Reference Manual / Other Tips. (LBV3) (LBV5) (LBV6)

SDcard image

To build from prebuilt image, please refer to the following sections for details.

  • Getting Started / Introducing BSP / Prebuilt image (LBV3) (LBV5) (LBV6)

To build from BSP, please refer to the following sections for details.

  • Getting Started / Build Instructions / To build sdcard image (LBV3) (LBV5) (LBV6)

How To Stress Test On a Linux

Perform the command as below:

stress -c 4 -i 4  -d 1 --hdd-bytes 512

How to fix sata can't be detected issue

find ahci_imx.c in kernel source code

drivers/ata/ahci_imx.c

Mark modification as below:

      // else if(IS_RSB_4411)
      // {
      //         sata_gen_phy_reg[0] = 0x059194f6;
      //         sata_gen_phy_reg[1] = 0x059194f6;
      //         sata_gen_phy_reg[2] = 0x059194f6;
      //}
       

This modification are sata si test value, but it may result in some sata disk can't be detected

How To Create One LIV Disk Image of SD Card

The LIV disk image of SD card is used to boot target device up and to install the entire system to on-baord eMMC.

  • Prerequisites
    1. one free loop device
    2. prewritten script, mksd-linux.sh (extracted from mksd-linux.sh.gz)
    3. the built sdcard image (LBV3) (LBV5) (LBV6) (e.g. fsl-image-qt5-imx6qrsb4410a1.sdcard)
    4. 5GB more available disk space for LIV disk image (e.g. 4410A1LIV6000.img & 4410A1LIV6000.img.gz)
  • Commands
$ LODEV=$(sudo losetup -f)
$ MKSD=mksd-linux.sh
$ gunzip -c mksd-linux.sh.gz > ${MKSD}
$ SDCARD=fsl-image-qt5-imx6qrsb4410a1.sdcard
$ LIV=4410A1LIV6000.img
$ cp ${SDCARD} ${LIV}
$ dd if=/dev/zero of=${LIV} bs=1M seek=3700 count=0
$ echo -e "d\n2\nn\np\n2\n24576\n\nw" | sudo fdisk -u ${LIV}
$ sudo losetup -o $((24576*512)) ${LODEV} ${LIV}
$ sudo e2fsck ${LODEV}
$ sudo resize2fs ${LODEV}
$ mkdir -p ~/mnt
$ sudo mount ${LODEV} ~/mnt
$ sudo mkdir ~/mnt/{mk_inand,image}
$ sudo cp ${MKSD} ~/mnt/mk_inand/
$ sudo chmod +x ~/mnt/mk_inand/${MKSD}
$ sudo cp ${SDCARD} ~/mnt/image/
$ sudo umount ~/mnt
$ sudo losetup -d ${LODEV}
$ gzip -c9 ${LIV} > ${LIV}.gz

How To fix "SF: Unsupported DataFlash ID 40" issue

Because we will change new spi flash on new version of the hardware, if you still use the old version u-boot, it can't be recognized.

We remove the compare spi flash id mechanism in the spi flash driver.

So we can use the patch file as belowand recompile it ,then replace the u-boot binary file in our image.

File:0001-Remove-compare-spi-flash-id-mechanism.patch

How To modify u-boot env in rootfs

Just support for Winbond spi flash(JEDEC ID: 0xef:0x40:0x16)

./fw_printenv                    //print all env 
./fw_printenv [env_name]         //print specific env
  • Set env
./fw_setenv [env_name] [value]   //set new env
  • Delete env
./fw_setenv [env_name]


How To Get unique ID for iMX SOC

  • iMX6

OTP Bank0 Word1 - containsthe first word of the UID.

OTP Bank0 Word2 - contains the second word of the UID.

We can refer to iMX6 DRM Chap46.5.10

root@imx6dlebcrs03a1:~# cat /sys/fsl_otp/HW_OCOTP_CFG0
0xea9b8ea3
root@imx6dlebcrs03a1:~# cat /sys/fsl_otp/HW_OCOTP_CFG1
0x200e11d4


  • iMX7
cat /sys/fsl_otp/HW_OCOTP_TESTER0
0xac98b953
cat /sys/fsl_otp/HW_OCOTP_TESTER1
0x67


  • iMX8M
root@imx8mqevk:/# cat /sys/bus/soc/devices/soc0/soc_uid
180959D6F060954C

How To Rotate 90 degree for iMX6 (Yocto )

 root@imx6dlrsb4411a1:~#export DISPLAY=:0
 root@imx6dlrsb4411a1:~#xrandr -o left

Other Features