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https://github.com/AsahiLinux/u-boot
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118 lines
3.6 KiB
Text
118 lines
3.6 KiB
Text
U-Boot for the Freescale i.MX6q SabreLite board
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===============================================
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This file contains information for the port of U-Boot to the Freescale
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i.MX6q SabreLite board.
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1. Build
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--------
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To build U-Boot for the SabreLite board:
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make mx6qsabrelite_config
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make
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2. Boot from SD card
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--------------------
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The SabreLite boards boot from the SPI NOR flash. These boards need their SPI
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to be reflashed with a small SD card loader to support boot from SD card. The
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board will still boot from SPI NOR, but the loader will in turn request the
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BootROM to load the U-Boot from SD card.
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The SD card loader is available from
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https://wiki.linaro.org/Boards/MX6QSabreLite
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This is provided under a open-source 3-clause BSD license.
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To following procedure can be used to update the SPI-NOR on the SabreLite
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board:
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1. Write this SD card loader onto a large SD card using:
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sudo dd if=iMX6DQ_SPI_to_uSDHC3.bin of=/dev/sXx
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Note: Replace sXx with the device representing the SD card in your system.
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Note: This writes SD card loader at address 0
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2. Put this SD card into the slot for the large SD card (SD3 on the bottom of
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the board). Make sure SW1 switch is at position "00", so that it can boot
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from the fuses.
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3. Power-up the SabreLite, press 'space' to enter command mode in the U-Boot
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(the default one the board is shipped with, starting from the SPI NOR) and
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enter the following commands:
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MX6Q SABRELITE U-Boot > mmc dev 0
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MX6Q SABRELITE U-Boot > mmc read 0x10800000 0 200
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MX6Q SABRELITE U-Boot > sf probe
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MX6Q SABRELITE U-Boot > sf erase 0 0x40000
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MX6Q SABRELITE U-Boot > sf write 0x10800000 0 0x40000
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4. Write the u-boot.imx produced during the U-Boot build to the SD card:
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sudo dd if=u-boot.imx of=/dev/sXx bs=512 seek=2 && sudo sync
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Note: Replace sXx with the device representing the SD card in your system.
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5. Re-insert the SD card back in the slot for the large SD card and power-cycle
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the board.
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Note: The board now boots from full size SD3 on the bottom of the board. NOT
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the micro SD4/BOOT slot on the top of the board. I.e. you have to use
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full size SD cards.
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This information originally taken from:
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https://wiki.linaro.org/Boards/MX6QSabreLite
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3. Boot from SPI NOR
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--------------------
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The SabreLite board can also boot U-Boot directly from the SPI NOR flash:
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1. Power-up the SabreLite, press 'space' to enter command mode in the U-Boot
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and enter the following commands:
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=> mmc dev 0
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=> mmc read 0x10800000 0x400 0x80000
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=> sf probe 0
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=> sf erase 0 0xc0000
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=> sf write 0x10800000 0x400 0x80000
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Note: This procedure assumes you have booted using the desired U-Boot from an
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SD card as prepared in the previous section. Alternative mechanisms, such
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as using tftpboot to copy an alternative U-Boot image into memory can
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also be used.
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4. Recovering SPI-NOR
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---------------------
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In case you somehow do not succeed with this procedure you can upload U-Boot
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via USB:
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1. Download and install the imx_loader following the instructions provided:
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https://github.com/boundarydevices/imx_usb_loader
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2. Connect the board to USB via the USB OTG port.
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3. Make sure SW1 switch is at position "01", so that it can boot from USB OTG.
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4. Power-up the SabreLite and run the imx_loader to upload the U-Boot image:
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sudo imx_usb u-boot.imx
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Note: This will upload and run the U-Boot image in memory, the SPI will not be
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reprogrammed and this procedure will need to be repeated if the board is
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reset.
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5. Use one of previous descriptions to re-flash the SPI-NOR as required.
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6. Ensure SW1 is returned to "00" to boot from the fuses once done.
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