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	Improve the README by adding instructions on how to boot using Falcon mode, which allows the SPL to load the kernel directly, without using U-Boot proper. Signed-off-by: Fabio Estevam <festevam@gmail.com> Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
		
			
				
	
	
		
			160 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			160 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
How to update U-Boot on pico-imx7d board
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----------------------------------------
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Required software on the host PC:
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- imx_usb_loader: https://github.com/boundarydevices/imx_usb_loader
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Build U-Boot for pico:
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$ make mrproper
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$ make pico-imx7d_defconfig
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$ make
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This generates the SPL and u-boot-dtb.img binaries.
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1. Loading U-Boot via USB Serial Download Protocol
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Note: This method is convenient for development purposes.
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If the eMMC has already a U-Boot flashed with DFU support then
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the user can go to step 2 below in order to update U-Boot.
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Put pico board in USB download mode (refer to the PICO-iMX7D Quick Start Guide
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page 3)
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Connect a USB to serial adapter between the host PC and pico.
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Connect a USB cable between the OTG pico port and the host PC.
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Note: Some computers may be a bit strict with USB current draw and will
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shut down their ports if the draw is too high. The solution for that is
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to use an externally powered USB hub between the board and the host computer.
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Open a terminal program such as minicom.
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Copy SPL and u-boot-dtb.img to the imx_usb_loader folder.
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Load the SPL binary via USB:
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$ sudo ./imx_usb SPL
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Load the u-boot-dtb.img binary via USB:
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$ sudo ./imx_usb u-boot-dtb.img
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Then U-Boot starts and its messages appear in the console program.
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Use the default environment variables:
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=> env default -f -a
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=> saveenv
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2. Flashing U-Boot into the eMMC
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Run the DFU agent so we can flash the new images using dfu-util tool:
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=> dfu 0 mmc 0
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Flash SPL and u-boot-dtb.img into the eMMC running the following commands on a PC:
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$ sudo dfu-util -D SPL -a spl
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$ sudo dfu-util -D u-boot-dtb.img -a u-boot
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Remove power from the pico board.
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Put pico board into normal boot mode.
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Power up the board and the new updated U-Boot should boot from eMMC.
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Booting in Falcon mode
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======================
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Generate a uImage kernel:
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$ make imx_v6_v7_defconfig (Using the default imx_v6_v7_defconfig configuration
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just for an example. In order to boot faster the user should customize the
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defconfig by only enabling the minimal required drivers).
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$ make -j4 uImage LOADADDR=0x80008000
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$ cp arch/arm/boot/uImage /tftpboot
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$ cp arch/arm/boot/dts/imx7d-pico-pi.dtb /tftpboot
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In the U-Boot prompt:
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Setup the server and board IP addresses:
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=> setenv serverip 192.168.0.10
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=> setenv ipaddr 192.168.0.11
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Get the dtb file:
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=> tftp ${fdt_addr} imx7d-pico-pi.dtb
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Get the kernel:
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=> tftp ${loadaddr} uImage
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Write the kernel at 2MB offset:
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=> mmc write ${loadaddr} 0x1000 0x5000
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Setup the bootargs:
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=> setenv bootargs 'console=ttymxc4,115200 root=/dev/mmcblk2p1 rootfstype=ext4 rootwait rw'
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Prepare args:
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=> spl export fdt ${loadaddr} - ${fdt_addr}
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## Booting kernel from Legacy Image at 80800000 ...
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   Image Name:   Linux-5.2.14
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   Image Type:   ARM Linux Kernel Image (uncompressed)
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   Data Size:    9077544 Bytes = 8.7 MiB
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   Load Address: 80008000
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   Entry Point:  80008000
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   Verifying Checksum ... OK
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## Flattened Device Tree blob at 83000000
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   Booting using the fdt blob at 0x83000000
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   Loading Kernel Image
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   Using Device Tree in place at 83000000, end 8300b615
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subcommand not supported
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subcommand not supported
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   Using Device Tree in place at 83000000, end 8300e615
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Argument image is now in RAM: 0x83000000
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=>
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Write 1MB of args data (0x800 sectors) to 1MB offset (0x800 sectors):
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=> mmc write ${fdt_addr} 0x800 0x800
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In order to boot with Falcon mode, activate the CONFIG_SPL_OS_BOOT
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option in the defconfig
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--- a/configs/pico-imx7d_defconfig
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+++ b/configs/pico-imx7d_defconfig
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@@ -67,3 +67,4 @@ CONFIG_USB_GADGET_VENDOR_NUM=0x0525
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 CONFIG_USB_GADGET_PRODUCT_NUM=0xa4a5
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 CONFIG_CI_UDC=y
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 CONFIG_VIDEO=y
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+CONFIG_SPL_OS_BOOT=y
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Then rebuild U-Boot:
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$ make pico-imx7d_defconfig
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$ make -j4
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Launch UMS:
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=> ums 0 mmc 0
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Flash the new binaries:
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$ sudo dd if=SPL of=/dev/sdX bs=1k seek=1; sync
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$ sudo dd if=u-boot-dtb.img  of=/dev/sdX bs=1k seek=69; sync
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And then SPL binary will load and jump directly to the kernel:
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U-Boot SPL 2019.10-rc3-00284-g001c8ea94a-dirty (Sep 10 2019 - 12:46:01 -0300)
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Trying to boot from MMC1
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[    0.000000] Booting Linux on physical CPU 0x0
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[    0.000000] Linux version 5.2.14 (fabio@fabio-OptiPlex-7010) (gcc version 7.4.0 (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04.1)) #30 SMP Wed Sep 10 12:36:27 -03 2019
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[    0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
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[    0.000000] CPU: div instructions available: patching division code
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[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
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[    0.000000] OF: fdt: Machine model: TechNexion PICO-IMX7D Board and PI baseboard
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...
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