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1.. SPDX-License-Identifier: GPL-2.02 3BMIPS DeviceTree Booting4------------------------5 6 Some bootloaders only support a single entry point, at the start of the7 kernel image. Other bootloaders will jump to the ELF start address.8 Both schemes are supported; CONFIG_BOOT_RAW=y and CONFIG_NO_EXCEPT_FILL=y,9 so the first instruction immediately jumps to kernel_entry().10 11 Similar to the arch/arm case (b), a DT-aware bootloader is expected to12 set up the following registers:13 14 a0 : 015 16 a1 : 0xffffffff17 18 a2 : Physical pointer to the device tree block (defined in chapter19 II) in RAM. The device tree can be located anywhere in the first20 512MB of the physical address space (0x00000000 - 0x1fffffff),21 aligned on a 64 bit boundary.22 23 Legacy bootloaders do not use this convention, and they do not pass in a24 DT block. In this case, Linux will look for a builtin DTB, selected via25 CONFIG_DT_*.26 27 This convention is defined for 32-bit systems only, as there are not28 currently any 64-bit BMIPS implementations.29