For some applications, we need to reduce the CPU Frequency, but if you are not familiar with our BSP or our devices probably you need some help to do some configurations.   In this post, I will share the configuration to set up lower frequencies (100MHz, 200MHz, 400Mhz, 600MHz, 800MHz, and 1000MHz) on iMX8MP, iMX8MN, and iMX8MM.   Note: Works on Kernel 6.1.xx (not tested on oldest BSP)   1- We have to modify the PLL driver to set the proper parameters to lower frequencies. The file to modify is "clk-pll14xx.c" adding the following lines:   https://github.com/nxp-imx/linux-imx/blob/770c5fe2c1d1529fae21b7043911cd50c6cf087e/drivers/clk/imx/clk-pll14xx.c#L57   static const struct imx_pll14xx_rate_table imx_pll1416x_tbl[] = { PLL_1416X_RATE(1800000000U, 225, 3, 0), PLL_1416X_RATE(1600000000U, 200, 3, 0), PLL_1416X_RATE(1500000000U, 375, 3, 1), PLL_1416X_RATE(1400000000U, 350, 3, 1), PLL_1416X_RATE(1200000000U, 300, 3, 1), PLL_1416X_RATE(1000000000U, 250, 3, 1), PLL_1416X_RATE(800000000U, 200, 3, 1), PLL_1416X_RATE(750000000U, 250, 2, 2), PLL_1416X_RATE(700000000U, 350, 3, 2), PLL_1416X_RATE(600000000U, 300, 3, 2), + PLL_1416X_RATE(400000000U, 200, 3, 2), + PLL_1416X_RATE(200000000U, 200, 3, 3), + PLL_1416X_RATE(100000000U, 200, 3, 4), };   2- Once the pll driver has been modified, only we have to add the values on the opp-table according to the device that you will use.   2.1- For iMX 8MP:   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mp.dtsi         a53_opp_table: opp-table { compatible = "operating-points-v2"; opp-shared; + opp-100000000 { + opp-hz = /bits/ 64 <100000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-200000000 { + opp-hz = /bits/ 64 <200000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-400000000 { + opp-hz = /bits/ 64 <400000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-600000000 { + opp-hz = /bits/ 64 <600000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-800000000 { + opp-hz = /bits/ 64 <800000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0x8a0>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>;   2.2 For iMX8MM:   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mm.dtsi     a53_opp_table: opp-table { compatible = "operating-points-v2"; opp-shared; + opp-100000000 { + opp-hz = /bits/ 64 <100000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-200000000 { + opp-hz = /bits/ 64 <200000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-400000000 { + opp-hz = /bits/ 64 <400000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-600000000 { + opp-hz = /bits/ 64 <600000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-800000000 { + opp-hz = /bits/ 64 <800000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xe>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; opp-1200000000 { opp-hz = /bits/ 64 <1200000000>;   2.3- For iMX8MN:   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mn.dtsi   compatible = "operating-points-v2"; opp-shared; + opp-100000000 { + opp-hz = /bits/ 64 <100000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + + opp-200000000 { + opp-hz = /bits/ 64 <200000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + + opp-400000000 { + opp-hz = /bits/ 64 <400000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + + opp-600000000 { + opp-hz = /bits/ 64 <600000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + + opp-800000000 { + opp-hz = /bits/ 64 <800000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + + opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <850000>; + opp-supported-hw = <0xb00>, <0x7>; + clock-latency-ns = <150000>; + opp-suspend; + }; + opp-1200000000 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <850000>;   After that, you should note the changes under Linux.   These commands return information about the system and the current settings.   • The kernel is pre-configured to support only certain frequencies. The list of frequencies currently supported can be obtained from: cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies   • To get the available scaling governors: cat /sys/devices/system/cpu/*/cpufreq/scaling_available_governors   • To check the current CPU frequency: cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_cur_freq   The frequency is displayed depending on the governor set.   • To check the maximum frequency: cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_max_freq   • To check the minimum frequency: cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_min_freq   These commands set a constant CPU frequency:   • Use the maximum frequency: echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor   • Use the current frequency to be the constant frequency: echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor   • The following two commands set the scaling governor to a specified frequency, if that frequency is supported.   If the frequency is not supported, the closest supported frequency is used:   echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo <frequency> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed    

1. Intro   This document contains instructions to run run the SAI low power audio demo on the i.MX 8M Plus EVK. Here, the  RPSMG to allows audio to be passed from the A53 cluster running Linux to the M7 core. The latter controls the on board WM8960 audio codec,  which is connected to a 3.5 mm audio jack that allow us to play music using headphones. I will show the necessary steps to make the demo work and will add some GStreamer examples to demonstrate the demo's capabilities.   TBD: update this with a nice diagram that depicts the A53 and M7 RPMSG channel. 2. Requirements   Hardware  MX 8M Plus EVK Headphones with 3.5 mm audio jack Type-C power supply for i.MX 8M Plus EVK Micro USB to USB adapter cable Software  A recent prebuilt Linux BSP image from NXP.com ( we tested this on 5.15.35 and 5.15.5 releases) Windows 10 or Ubuntu 20.04 Workstation MCUXpresso SDK for i.MX 8M Plus ( available from:  Welcome | MCUXpresso SDK Builder (nxp.com)) 3. Reference documentation for this example   MCUXpresso SDK   [1] Getting Started with MCUXpresso SDK for EVK-MIMX8MP     Available within the MCUXpresso SDK package:  \{INSTALL PATH}\SDK_X_X_X_EVK-MIMX8MP\docs    [2] SAI low power audio README file Contains instructions for the SAI Low Power Audio Demo.  Available within the MCUXpresso SDK package: \{INSTALL PATH}\SDK_X_X_X_EVK-MIMX8MP\boards\evkmimx8mp\demo_apps\sai_low_power_audio   4. Downloading a pre-built Linux BSP image for the i.MX 8M Plus   I will make use of the prebuilt Linux Image for the i.MX 8M Plus EVK for demonstrating the demo works.  At the moment of writing this time, I used the 5.15.32 release, although there are older releases like 5.10.5 that I tested and proved to work with no issues. This SAI Low Power Audio Demo shall work for other processors on the i.MX 8M family. Although specific instructions ( e.g. load address for M-core binary load) might require some adaptation. For M-core load address, please refer to the specific MCUXpresso SDK documentation for each processor. The prebuilt Linux image (5.15.32) for the i.MX 8M Plus EVK can be downloaded from here: https://www.nxp.com/webapp/Download?colCode=L5.15.32_2.0.0_MX8MP&appType=license You can download other releases from here: Embedded Linux for i.MX Applications Processors | NXP Semiconductors . Select a version and a board and select download. 5. Flashing the BSP image   If you are using an Ubuntu 20.04 workstation, I recommend you to flash the image using dd. For this, you can refer to the i.MX Linux User's Guide: Section - 4.3.2 Copying the full SD card image - https://www.nxp.com/docs/en/user-guide/IMX_LINUX_USERS_GUIDE.pdf sudo dd if=.wic of=/dev/sdx bs=1M && sync NOTE: when using dd, ALWAYS, double check the of device that you are about to writing. Messing up with another location or partition will harm your system   If you are following this document on a Windows machine: You can use the Universal Update Utility (UUU) to flash your image on either the board's eMMC or SD card. Document named UUU.pdf shall serve as your reference guide for further instructions and flashing examples. It is available along with UUU binary here: https://github.com/NXPmicro/mfgtools/releases Two examples are shown below for your convenience:                                     SD card flash                                                 uuu -b sd_all bootloader rootfs.sdcard.bz2                                     eMMC flash                                                 uuu -b emmc_all bootloader rootfs.sdcard.bz2        uuu uuu.auto NOTE: UUU is also compatible with Ubuntu NOTE: there are other engineers who like to use BalenaEtcher for flashing their BSP images. I have tested it and works on both Ubuntu and Windows 10 machines.   6. Preparing the BSP and booting up M7 core  using U-Boot   I am writing this upon the instructions contained on the README file for the low power audio example  [2]. Instructions ready to copy and paste will follow:   Instruct U-Boot to pass to the kernel the rpmsg device tree to enable communication between the A53 cluster and the M7 one: u-boot=>setenv fdtfile imx8mp-evk-rpmsg.dtb u-boot=>saveenv Load the M7 example: u-boot=>setenv mmcargs 'setenv bootargs ${jh_clk} console=${console} root=${mmcroot} snd_pcm.max_alloc_per_card=134217728' u-boot=>saveenv Now, we need to load the M4 with the demo. Refer to [1] for further information. If running the BSP on an SD card, make sure the example binary is listed on the boot partition as follows: fatls mmc 1:1 You shall see something similar to this:             imx8mp_m7_TCM_sai_low_power_audio.bin Open the serial terminal emulator for the M7. Out of the fourth ports listed when we plug the i.MX 8M Plus serial debug cable to the PC, the M7 is typically the last one listed.   All the serial ports available to the workstation when the i.MX 8M Plus serial cable is connected to it. NOTE: you may require to install addtitional COM drivers if you are running on Windows. I like doing the previous step so I can see the result of the next commands issued in U-boot to load the M7 image. fatload mmc 1:1 0x48000000 imx8mp_m7_TCM_sai_low_power_audio.bin; cp.b 0x48000000 0x7e0000 20000; bootaux 0x7e0000 Here is an screenshot that shows how the U-Boot's response should look: U-Boot response when loading the SAI low power audio example to the Cortex M7 That should have prompted the following message on the M7 terminal: M7-core is up!   Now, let’s move to user space! u-boot=> boot 7. Testing the example using a simple GStreamer pipeline   As soon as the O.S. finishes booting. We can see that M7 terminal prompts the following: M7 is now in STOP mode; waiting for some audio to beat the room! Confirm that the WM8960 is listed as audio card as follows: cat /proc/asound/cards             Listing avaialable audio cards. WM8960 should be present. Make note of the list. The wm8960 is listed a the third sound card. This is where I like to differ a bit from [2] and I suggest a quicker test in case of not having an audio file ready. We just simply use GStreamer to play an audiotest source. Please make sure to plug in your headphones onto the board’s 3.5 mm jack before.   The following GStreamer pipeline is using the WM8960 as an audiosink.  gst-launch-1.0 audiotestsrc ! alsasink device=hw:3   NOTE: please be cautious and not put the headphones directly in your head at the first attempt. The sound can be too loud to some people. This is what you should see on the M7 side: Stop the GStreamer pipeline issuing CTRL + C. M7 shall warn you about that: NOTE: you can use the aplay command to play audio as shown on [2]. However, I consider using a testsrc is much quicker and flexible for a quick test.  8. Additional information   Feel free to go ahead and tweak the GStreamer pipeline to change audio test source properties. audiotest src. This command will let you know the available options:            gst-inspect-1.0 audiotestsrc                         NOTE: you can navigate through the displayed list using the “d”key. Press “q’’ to quit. For example:     For example, I am reproducing sound using a different setup based on the list above: gst-launch-1.0 audiotestsrc freq=4000 volume=0.8 wave=8 ! alsasink device=hw:3 9.  Errata and future updates   TBD:     Add an example on how to define the default audio card and play the audio either using gst-play or building the pipeline using filesrc Comment on the limitations of the M7 core regarding sample rate and audio formats  

The i.MX 8QuadXPlus Multisensory Enablement Kit (MEK) is a NXP development platform based on Cortex A-35 + Cortex-M4 cores. Built with high-level integration to support graphics, video, image processing, audio, and voice functions, the i.MX 8X processor family is ideal for safety-certifiable and efficient performance requirements. This tutorial shows how to enable the Cortex-M4 using the MCUXpresso SDK package and loading the binary from the network. NOTE: It is also possible to load the Cortex-M4 image from the SCFW using the imx-mkimage utility. But now we are going to focus on MCUXpresso. Setting up the machine   Install cmake on the host machine: $ sudo apt-get install cmake Download the armgcc toolchain and export the location as ARMGCC_DIR: $ export ARMGCC_DIR=<your_path_to_arm_gcc>/gcc-arm-none-eabi-9-2020q2/ NOTE: The ARMGCC_DIR variable needs to be exported on the terminal used for compilation. To setup the TFTP server on the host machine: Configuring your Host PC for TFTPPermalink   The first step is to install all the prerequisite packages for TFTP: $ sudo apt-get install xinetd tftpd tftp Create a TFTP folder in your desired location with root owner and the “rwx” permission for all users: $ sudo mkdir /tftpboot $ sudo chmod –R 777 /tftpboot $ sudo chown –R root /tftpboot Create a configuration file for the TFTP with the following content. (The server_args parameter must match with the folder created above) $ cat /etc/xinetd.d/tftp service tftp { protocol = udp port = 69 socket_type = dgram wait = yes user = root server = /usr/sbin/in.tftpd server_args = -s /tftpboot disable = no } Restart the xinetd service: $ sudo /etc/init.d/xinetd restart You can place any file at the TFTP folder and load it through U-Boot, you can also create symbolic links from your building directory avoiding to copy and paste your zImage and dtb files every time. Configuring your Host PC for NFSPermalink   Install all the needed packages for NFS: $ sudo apt-get install nfs-kernel-server Create a folder for placing your rootfs: $ mkdir /tftpboot/rfs Add the following line in the end of your /etc/exports file: /tftpboot/rfs *(rw,no_root_squash,no_subtree_check) Restart the NFS service: $ sudo service nfs-kernel-server restart Place your rootfs or create a symbolic link for the NFS folder.    Downloading the SDK Download the MCUXpresso following these steps: Click on “Select Development Board”; Select MEK-MIMX8QX under “Select a Device, Board, or Kit” and click on “Build MCUXpresso SDK” on the right; Select “Host OS” as Linux and “Toolchain/IDE” as GCC ARM Embedded; Add “FreeRTOS” and all the wanted Middleware and hit “Request Build”; Wait for the SDK to build and download the package. Building the image All demos and code examples available on the SDK package are located in the directory <<SDK_dir>>/boards/mekmimx8qx/. This tutorial shows how to build and flash the hello_world demo but similar procedures can be applied for any example (demo, driver, multicore, etc) on the SDK. To build the demo, enter the armgcc folder under the demo directory and make sure that the ARMGCC_DIR variable is set correctly. $ cd ~/SDK_2.3.0_MEK-MIMX8QX/boards/mekmimx8qx/demo_apps/hello_world/armgcc $ export ARMGCC_DIR=<your_path_to_arm_gcc>/gcc-arm-none-eabi-9-2020q2/ Run the build_release.sh script to build the code. $ ./build_release.sh NOTE: If needed, give the script execution permission by running chmod +x build_release.sh. This generates the M4 binary (hello_world.bin) under the release folder. Copy this image to the /tftpboot/ directory on the host PC. NOTE: This procedure shows how to build the M4 image that runs on TCM. To run the image from DDR, use the build_ddr_release.sh script to build the binary under the ddr_release folder. Flashing the image Open two serial consoles, one for /dev/ttyUSB0 for Cortex-A35 to boot Linux, and one for /dev/ttyUSB1 for Cortex-M4 to boot the SDK image. On the A35 console, with a SD Card with U-Boot, stop the booting process and enter the following commands to load the M4 binary to TCM: => dhcp => setenv serverip <ip_from_host_pc> => tftp 0x88000000 hello_world.bin => dcache flush => bootaux 0x88000000 Then the M4 core will load the image to the /dev/ttyUSB1 console.    

Software environment: L5.4.47_2.2.0 Hardware i.MX8QXPC0 EVK board In the uuu script we can see the bootloader imx-boot-imx8qxpc0mek-sd.bin-flash is necessary. The default BSP build generate in the yocto project is with the spl, some customers are confused about the how to build the imx-boot-imx8qxpc0mek-sd.bin-flash. Here I give the manually compile way and generate it in yocto. In the yocto generate it is more convenient than the manually compile way. Hope this can do help for you.

Pre-Sales: i.MX8/8X applications in automotive(Chinese Version) https://community.nxp.com/docs/DOC-345825 i.MX8X website design resource guide: (Chinese Version) https://community.nxp.com/docs/DOC-345676 After-Sales: i.MX8X memory configuration&test application notes: (Chinese Version) https://community.nxp.com/docs/DOC-345803 i.MX8X hardware design guide: (Chinese Version) https://community.nxp.com/docs/DOC-346582 i.MX8X_4.19.35_bootloader customization application notes: (Chinese Version) https://community.nxp.com/docs/DOC-345713 i.MX8X_4.19.35_kernal customization application notes: (Chinese Version) https://community.nxp.com/docs/DOC-345714 i.MX8X_4.14.98_bootloader customization application notes: (Chinese Version) https://community.nxp.com/docs/DOC-342448 i.MX8X_4.14.98_kernal customization application notes: (Chinese Version) https://community.nxp.com/docs/DOC-344217 i.MX8X_5.4.24_bootloader customization application notes: (Chinese Version) https://community.nxp.com/docs/DOC-347131

In this article, I will explain how to set up the iMX8M Plus to use the 4K Dart BCON Basler Camera module. Requirements: Evaluation Kit for the i.MX 8M Plus Applications Processor. (i.MX 8M Plus Evaluation Kit | NXP Semiconductors) Basler Camera for i.MX 8M Plus (4K dart BCON for MIPI camera module for i.MX 8M Plus | NXP Semiconductors). Embedded Linux for i.MX Applications Processors (Embedded Linux for i.MX Applications Processors | NXP Semiconductors) (For this example we will use BSP version Linux 5.15.71_2.2.0) Serial Console Emulator Basler Camera Specifications and Manuals: Basler Camera Specifications at this link: Embedded Vision Kits daA3840-30mc-IMX8MP-EVK - Embedded Vision Kits (baslerweb.com). Basler Manual to identify and setting up the hardware at this link: daA3840-30mc-IMX8MP-EVK | Basler Product Documentation (baslerweb.com) Basler Camera Module out-of-box with i.MX 8M Plus Applications Processor. (Video: Basler Camera Module out-of-box with i.MX 8M Plus Applications Processor | NXP Semiconductors) Steps After setting up the hardware we will need to turn on the iMX8M Plus and follow these steps: 1. Stop the boot process on Uboot by pressing any key. 2. Use the following command to list interfaces. => mmc list Output example => FSL_SDHC: 1 (SD) => FSL_SDHC: 2 The above command will show you the device number in this example for SD, the device number is 1. 3. Then use fatls <interface> <device[:partition]> [<directory>] fatls mmc 1:1 (Device 1 : Partition 1) With this command, we will be able to list device tree files. => fatls mmc 1:1 4. Select imx8mp-evk-basler.dtb or imx8mp-evk-dual-basler.dtb and use the command editenv fdtfile.  => editenv fdtfile Output example edit: imx8mp-evk-basler.dtb 5. In edit command line put the selected device tree (*.dtb). 6. Use saveenv command to save environment and continue with the boot process. 7. Using the terminal and go to /opt/imx8-isp/bin and execute the script run.sh. $ ./run.sh -c basler_1080p60 -lm 8. Use the command gst-device-monitor-1.0 to list devices. Here you will find the path to the camera device. $ gst-device-monitor-1.0 Output example Device found: name : VIV class : Video/Source caps : video/x-raw, format=YUY2, width=[ 176, 4096, 16 ], height=[ 144, 3072, 8 ], pixel-aspect-ratio=1/1, framerate={ (fraction)30/1, (fraction)29/1, (fraction)28/1, (fraction)27/1, (fraction)26/1, (fraction)25/1, (fraction)24/1, (fraction)23/1, (fraction)22/1, (fraction)21/1, (fraction)20/1, (fraction)19/1, (fraction)18/1, (fraction)17/1, (fraction)16/1, (fraction)15/1, (fraction)14/1, (fraction)13/1, (fraction)12/1, (fraction)11/1, (fraction)10/1, (fraction)9/1, (fraction)8/1, (fraction)7/1, (fraction)6/1, (fraction)5/1, (fraction)4/1, (fraction)3/1, (fraction)2/1, (fraction)1/1 } ... properties: udev-probed = true device.bus_path = platform-vvcam-video.0 sysfs.path = /sys/devices/platform/vvcam-video.0/video4linux/video2 device.subsystem = video4linux device.product.name = VIV device.capabilities = :capture: device.api = v4l2 device.path = /dev/video2 v4l2.device.driver = viv_v4l2_device v4l2.device.card = VIV v4l2.device.bus_info = platform:viv0 v4l2.device.version = 393473 (0x00060101) v4l2.device.capabilities = 2216693761 (0x84201001) v4l2.device.device_caps = 69206017 (0x04200001) gst-launch-1.0 v4l2src device=/dev/video2 ! ... 9. Finally, use gstreamer to verify proper operation. (With this gstreamer pipeline you will see a new window with the camera output. Then, just rotate the lens to acquire the correct focus) $ gst-launch-1.0 -v v4l2src device=/dev/video2 ! "video/x-raw,format=YUY2,width=1920,height=1080" ! queue ! imxvideoconvert_g2d ! waylandsink Basic description of Gstreamer Pipeline gst-launch-1.0 -v: The option -v enables the verbose mode to get detailed information of process. v4l2src device=/dev/video2: Select input device in this case the camera is on path /dev/video3. "video/x-raw,format=YUY2,width=1920,height=1080": Received format from camera. queue: This command is a buffer between camera recording process and the following image process, this command help us to interface two process and prevent blocking where each process has different speeds, in other words, when a process A is faster than process B. imxvideoconvert_g2d: This proprietary plugin uses hardware acceleration to perform rotation, scaling, and color space conversion on video frames. waylandsink : This command creates its own window and renders the decoded frames processed previously. 10. Result     I hope this article will be helpful. Best regards, Brian.

     The following steps allow you to toggle a pin on i.MX 8M Mini EVK, you can use the EVK as not gate, trigger a wake up signal, etc. With an script and modifying the device tree you can read an input and get as output the invert input.   On the Host.   Cloning the Linux kernel repository.   Clone the i.MX Linux Kernel repo to the home directory. cd ~ git clone -b lf-5.10.72-2.2.0 https://source.codeaurora.org/external/imx/linux-imx cd linux-imx/   Patching the device tree.   Open the imx8mm-evk.dtsi file: vim arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi For the purpose of this example, uart3 has to be "disabled" in order to avoid pins conflict, so change "okay" to "disabled": &uart3 {        pinctrl-names = "default";        pinctrl-0 = <&pinctrl_uart3>;        assigned-clocks = <&clk IMX8MM_CLK_UART3>;        assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>;        fsl,uart-has-rtscts;        status = "disabled"; }; Add the following lines in the iomuxc node: &iomuxc {       pinctrl-names = "default";       pinctrl-0 = <&pinctrl_hog>; ​       pinctrl_hog: hoggrp {               fsl,pins = <                       MX8MM_IOMUXC_ECSPI1_SS0_GPIO5_IO9               0x19                       MX8MM_IOMUXC_ECSPI1_MISO_GPIO5_IO8              0x19               >;       };   Build the device tree.   Setup your toolchain, for example: source /opt/fsl-imx-wayland/5.10-hardknott/environment-setup-cortexa53-crypto-poky-linux Generate config file. make imx_v8_defconfig Compile the device tree. make freescale/imx8mm-evk.dtb Copy the .dtb file to the EVK, for example with scp: scp imx8mm-evk.dtb root@<EVK_IP>:/home/root Alternatively, you may copy the .dtb file directly to the FAT32 partition where the Kernel and Device Tree files are located.   On the EVK Board.   Switching the device tree.   To copy the updated device tree to the corresponding partition, first create a directory. mkdir Partition_1 Mount the partition one. mount /dev/mmcblk1p1 Partition_1/ Copy or move the device tree into partition one. cp imx8mm-evk.dtb Partition_1/ Reboot the board. reboot   Create an script.   Use vi: vi toggle.sh Add the following lines: #!/bin/bash ​ echo 136 > /sys/class/gpio/export echo in > /sys/class/gpio/gpio136/direction ​ echo 137 > /sys/class/gpio/export echo out > /sys/class/gpio/gpio137/direction echo 0 > /sys/class/gpio/gpio137/value ​ while : do ​ if [[($(cat /sys/class/gpio/gpio136/value) == "0")]]; then         echo 1 > /sys/class/gpio/gpio137/value else         echo 0 > /sys/class/gpio/gpio137/value        fi ​ done Save the file: :wq Change file permissions: chmod +x toggle.sh   Toggling a pin.   In this example we are using the pin "UART3_CTS" like an input and "UART3_RTS" like an output. To toggle the pin, run the script: ./toggle.sh

BSP: L5.4.47-2.2.0-rc2 Board: imx8QM B0 HW:  LVDS2HDMI , MIPIDSI2HDMI. It is the porting of i.MX8QM dpu loopback to isi. to the 5.4.y, with the addition of the MIPI-DSI loopback and the HDMI loopback.  Overview of the DC capture configuration: For enabling the capture: only DC 0 Stream 0  and DC 1 Stream 1 can be captured The pixel link Master address should be set to 3 because the Receiver Address at ISI is 3 and can't be changed. To continue displaying the stream, the Receiver Address at LVDS and DSI or HDMI should be changed to 3. It is possible to change the RA by using GPIO of the modules.   Patches: Create V4L2 device enabling the capture of by the ISI of DC loop-backs. Enable ISI capture from DSI 0 / LVDS 1 in 1920x1080 (at the same time.) Enable ISI capture from HDMI in 2840x2160 (half with even pixel) in 1920x2160. While capturing with the ISI, the captured screen continue to be displayed. Remark: Ov5640 cameras are also enabled in the same dtb. So 4 stream in 1920x1080 can be captured at the same time. Installation and gstreamer command: See readme

This article describes how to integrate NXP WiFi & BT module into i.MX platform, some debug tips, how to test, etc. Although it takes i.MX8MM as example, it is also suitable for all i.MX8 serials platform.

  Some our customers want to use the mfgtool to download the images to QSPI and boot up. When download the demo images on our website (Linux 4.1.15) to the QSPI-NOR on IMX7D SABRE-SDB. The error occurred as follows: Is it able to program the QSPI-NOR on i.MX7D SABRE-SDB by using MFG-Tool? Answer is yes. In the above error message we can see that the system can not find and detect the qspi, so it can not excute the following code,<CMD state="body="$ flash_erase /dev/mtd0 0 20">Erasing Boot partition</CMD>Updater" type="push" when use the mfgtool to download the images to the QSPI-NOR . The board i.MX7D SABRE-SDB and default BSP are boot up from EPDC.  Here customer want to boot up from QSPI, When using QSPI, you need to de-populate R388-R391, R396-R399 and populate R392-R395, R299, R300 in your hardware. QSPI signals are muxed with EPDC_D[7:0]. You can see the schematic, details you can see as follow. After hardware modify, you can use the mfgtool2-yocto-mx-sabresd-qspi-nor-mx25l51245g.vbs to download. And then boot up from qspi, boot mode you can refer to the schematic boot up setting. Both software and mfgtool you can download here http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors/i.mx-software-and-tools:IMXSW_HOME. Demo images can documents you can also get.    

On power-up of a system, the bootloader performs initial hardware configuration, and is responsible for loading the Linux kernel in memory. Several bootloaders are available which support i.MX SoCs: Barebox (http://www.barebox.org/) RedBoot (http://ecos.sourceware.org/redboot/) U-Boot (http://www.denx.de/wiki/U-Boot/) Qi (http://wiki.openmoko.org/wiki/Qi)

This is a quick article focused on how to add the support of SFTP on the i.MX devices using Yocto to add that packages.   Refer to the pdf attached.

PCIE IP on i.MX8MM and i.MX8MP is same, customer can follow PCIE test Application note to do compliance test, if eye diagram failed, they can fine turn corresponding regs below: iMX8MMRM.pdf IMX8MPRM.pdf GEN1:             GEN2:                 Related code in kernel Phy-fsl-imx8-pcie.c (kernel-source\drivers\phy\freescale)    3794      2020/11/4 static int imx8_pcie_phy_init(struct phy *phy) { ……          /* Configure TX drive level  */        writel(0x2d, imx8_phy->base + 0x404);          return 0; }   Thanks Lambert

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-343344 

The A53 Debug Console Changing consists in several major updates like: RDC settings, Pinmux, Clocks and Ecosystem Updates.

Platform: Demo images, i.MX8MPlus EVK   Some customer need test ffs gadget function on i.MX8MPlus EVK. Here is demo for ffs test, please connect EVK and Ubuntu PC before test.   Test script: #!/bin/sh # Setup the device (configfs) modprobe libcomposite mkdir -p config mount none config -t configfs cd config/usb_gadget/ mkdir g1 cd g1 echo 0x1fc9 >idVendor echo 0x0146 >idProduct mkdir strings/0x409 echo 12345 >strings/0x409/serialnumber echo "Signal 11" >strings/0x409/manufacturer echo "Test" >strings/0x409/product mkdir configs/c.1 mkdir configs/c.1/strings/0x409 echo "Config1" >configs/c.1/strings/0x409/configuration # Setup functionfs mkdir functions/ffs.usb0 ln -s functions/ffs.usb0 configs/c.1 cd ../../../ mkdir -p ffs mount usb0 ffs -t functionfs cd ffs ffs-test 64 & # from the Linux kernel, with mods! sleep 3 cd .. # Enable the USB device echo 38100000.usb > config/usb_gadget/g1/UDC   EVK log root@imx8mpevk:~# ./test2.sh [ 17.859597] file system registered ffs-test: dbg: ep0: writing descriptors (in v2 format) ffs-test: dbg: ep0: writing strings ffs-test: dbg: ep1: starting ffs-test: dbg: ep2: starting ffs-test: dbg: ep1: starts ffs-test: dbg: ep0: starts ffs-test: dbg: ep2: starts Event BIND Event ENABLE Ubuntu PC log: lzm@lzm-GL552VW:~$ lsusb -D /dev/bus/usb/001/008 Device: ID 1fc9:0146 NXP Semiconductors Test Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.10 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x1fc9 NXP Semiconductors idProduct 0x0146 bcdDevice 6.01 iManufacturer 1 Signal 11 iProduct 2 Test iSerial 3 12345 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0020 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 4 Config1 bmAttributes 0x80 (Bus Powered) MaxPower 2mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 0 bInterfaceProtocol 0 iInterface 5 Source/Sink Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Binary Object Store Descriptor: bLength 5 bDescriptorType 15 wTotalLength 0x0016 bNumDeviceCaps 2 USB 2.0 Extension Device Capability: bLength 7 bDescriptorType 16 bDevCapabilityType 2 bmAttributes 0x0000010e BESL Link Power Management (LPM) Supported BESL value 256 us SuperSpeed USB Device Capability: bLength 10 bDescriptorType 16 bDevCapabilityType 3 bmAttributes 0x00 wSpeedsSupported 0x000f Device can operate at Low Speed (1Mbps) Device can operate at Full Speed (12Mbps) Device can operate at High Speed (480Mbps) Device can operate at SuperSpeed (5Gbps) bFunctionalitySupport 1 Lowest fully-functional device speed is Full Speed (12Mbps) bU1DevExitLat 0 micro seconds bU2DevExitLat 0 micro seconds Device Status: 0x0001 Self Powered  

on Host: libx11-dev libpng-dev libjpeg-dev libxext-dev x11proto-xext-dev qt3-dev-tools-embedded libxtst-dev On Target (i.MX device) alsa-utils libpng tslib

platform: imx8qxp c0 mek OS: yocto 4.19.35_1.1.0 hardware connection: imx8qxp lvds0 => dummy panel ,  lvds1 => it6263 => display   On imx8qxp there are one DPU(display process unit) and one ISI(image subsystem interface), ISI supports input from dpu.   dpu block diagram: note that only dsi0 and lvds0 can be used for loopback. and this patch only test the lvds0, since lvds support dummy panel.   Please see the readme in the attchment for how to enale this feature.   Note: for ISI loopback,  it needs output of 2x GPIO (4x for HDMI-TX or combo PHY) to pixel_link_receiver_address: For iMX8QM: o LVDS: pixel_link_receiver_address[1:0] = do_gpio_dr[7:6]  o MIPI-DSI: pixel_link_receiver_address[1:0] = do_gpio_dr[7:6] o HDMI-TX: odd_pixel_link_receiver_address[1:0] = do_gpio_dr[7:6],even_pixel_link_receiver_address[1:0] = do_gpio_dr[5:4]   For iMX8QXP: o Combo MIPI-DSI / LVDS: pixel_link0_receiver_address[1:0] = do_gpio_dr[7:6], pixel_link1_receiver_address[1:0] = do_gpio_dr[5:4]   

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-343273