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28 lines
1.0 KiB
28 lines
1.0 KiB
.. SPDX-License-Identifier: GPL-2.0 |
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BMIPS DeviceTree Booting |
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Some bootloaders only support a single entry point, at the start of the |
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kernel image. Other bootloaders will jump to the ELF start address. |
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Both schemes are supported; CONFIG_BOOT_RAW=y and CONFIG_NO_EXCEPT_FILL=y, |
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so the first instruction immediately jumps to kernel_entry(). |
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Similar to the arch/arm case (b), a DT-aware bootloader is expected to |
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set up the following registers: |
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a0 : 0 |
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a1 : 0xffffffff |
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a2 : Physical pointer to the device tree block (defined in chapter |
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II) in RAM. The device tree can be located anywhere in the first |
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512MB of the physical address space (0x00000000 - 0x1fffffff), |
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aligned on a 64 bit boundary. |
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Legacy bootloaders do not use this convention, and they do not pass in a |
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DT block. In this case, Linux will look for a builtin DTB, selected via |
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CONFIG_DT_*. |
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This convention is defined for 32-bit systems only, as there are not |
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currently any 64-bit BMIPS implementations.
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