forked from OERV-BSP/u-boot
7187408553
Switch boards that use CFG_PRAM to TEGRA_PRAM. Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
75 lines
2.3 KiB
ReStructuredText
75 lines
2.3 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
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U-Boot for the Nvidia Tegra Note 7
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==================================
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Quick Start
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-----------
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- Build U-Boot
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- Boot U-Boot by loading it into RAM (coldboot)
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- Chainloading U-Boot from the vendor bootloader
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- Boot
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Build U-Boot
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------------
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U-Boot can be built in two forms: U-Boot with SPL, which is used for booting
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by loading directly into RAM and U-Boot without SPL, which can be flashed
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and chainloaded from the vendor bootloader.
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To build U-Boot with SPL proseed:
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.. code-block:: bash
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$ export CROSS_COMPILE=arm-none-eabi-
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$ make tegratab_defconfig
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$ make
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After the build succeeds, you will obtain the final ``u-boot-dtb-tegra.bin``
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file, ready for cold booting by loading into RAM.
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To build U-Boot without SPL adjust tegratab_defconfig:
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.. code-block::
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CONFIG_TEXT_BASE=0x80A00000
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CONFIG_SKIP_LOWLEVEL_INIT=y
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# CONFIG_OF_BOARD_SETUP is not set
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CONFIG_TEGRA_PRAM=y
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After the build succeeds, you will obtain the final ``u-boot-dtb.bin`` file,
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ready for booting with fastboot boot or which can be further processed into
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a flashable boot.img.
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Boot U-Boot by loading it into RAM (coldboot)
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---------------------------------------------
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Done fairly simply by using fusee-tools (using run_bootloader.sh) and placing
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``u-boot-dtb-tegra.bin`` generated on the previous step into fusee-tools dir.
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This method requires constant access to the host PC or payloader and can fully
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eliminate influence of the vendor bootloader onto the boot process.
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.. code-block:: bash
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$ ./run_bootloader.sh -s T114 -t ./bct/tegratab.bct
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Chainloading U-Boot from the vendor bootloader
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----------------------------------------------
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``u-boot-dtb.bin`` has to be further packed into Android boot image form,
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where ``u-boot-dtb.bin`` acts as kernel, while dtb and ramdisk parts should
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not be included. Then the generated boot image can be flashed into the /boot
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partition of the tablet using vendor bootloader's fastboot and will act as
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the bootloader of the last stage.
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Boot
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----
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In both cases after U-Boot obtains control it performs search of extlinux.conf
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first on the dock USB device is available, then on MicroSD card if available
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and lastly on eMMC. If none of the devices above are present, then the device
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is turned off.
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If during boot of U-Boot Volume Down button is pressed, the device will enter
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U-Boot bootmenu.
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