initial buildroot for linux 5.15

board/technexion/imx7dpico/readme.txt

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+****************************
+Technexion i.MX7D Pico board
+****************************
+
+This file documents the Buildroot support for the Technexion i.MX7D Pico board.
+
+Build
+=====
+
+First, configure Buildroot for the i.MX7D Pico board:
+
+  make imx7dpico_defconfig
+
+Build all components:
+
+  make
+
+You will find in output/images/ the following files:
+  - imx7d-pico.dtb
+  - rootfs.ext4
+  - rootfs.tar
+  - sdcard.img
+  - u-boot-dtb.img
+  - SPL
+  - zImage
+
+Flash U-Boot and SPL
+=====
+
+Note: This method is convenient for development purposes.
+If the eMMC has already a U-Boot flashed with DFU support then
+the user can go to step 2 below in order to update U-Boot.
+
+Put pico board in USB download mode (refer to the PICO-iMX7D Quick Start Guide
+page 3)
+
+Connect a USB to serial adapter between the host PC and pico.
+
+Connect a USB cable between the OTG pico port and the host PC.
+
+Note: Some computers may be a bit strict with USB current draw and will
+shut down their ports if the draw is too high. The solution for that is
+to use an externally powered USB hub between the board and the host computer.
+
+Open a terminal program such as minicom.
+
+Copy SPL and u-boot-dtb.img to the imx_usb_loader folder.
+
+Load the SPL binary via USB:
+
+$ sudo ./imx_usb SPL
+
+Load the u-boot-dtb.img binary via USB:
+
+$ sudo ./imx_usb u-boot-dtb.img
+
+Then U-Boot starts and its messages appear in the console program.
+
+Use the default environment variables:
+
+=> env default -f -a
+=> saveenv
+
+Run the DFU agent so we can flash the new images using dfu-util tool:
+
+=> dfu 0 mmc 0
+
+Flash SPL and u-boot-dtb.img into the eMMC running the following commands on a PC:
+
+$ sudo dfu-util -D SPL -a spl
+
+$ sudo dfu-util -D u-boot-dtb.img -a u-boot
+
+Remove power from the pico board.
+
+Put pico board into normal boot mode.
+
+Power up the board and the new updated U-Boot should boot from eMMC.
+
+Flash the eMMC
+==============
+
+In the U-Boot prompt lauch:
+
+=> ums 0 mmc 0
+
+This will mount the eMMC content in the host PC as a mass storage device.
+
+To determine the device associated to the eMMC card have a look in the
+/proc/partitions file:
+
+  cat /proc/partitions
+
+Buildroot prepares a bootable "sdcard.img" image in the output/images/
+directory, ready to be dumped on the eMMC card. Launch the following
+command as root:
+
+  dd if=output/images/sdcard.img of=/dev/<your-sd-device>
+
+*** WARNING! This will destroy all the eMMC content. Use with care! ***
+
+For details about the medium image layout, see the definition in
+board/freescale/common/imx/genimage.cfg.template.
+
+Boot the i.MX7D Pico board
+==========================
+
+To boot your newly created system:
+- put a micro USB cable into the Debug USB Port and connect using a terminal
+  emulator at 115200 bps, 8n1;
+- power on the board.
+
+Using Wifi
+==========
+
+# modprobe brcmfmac
+# iwconfig wlan0 essid ACCESSPOINTNAME
+# wpa_passphrase ACCESSPOINTNAME > /etc/wpa.conf
+(enter the wifi password and press enter)
+# wpa_supplicant -Dwext -iwlan0 -c /etc/wpa.conf &
+# udhcpc -i wlan0
+# ping buildroot.org
+
+Enjoy!