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77 lines
2.4 KiB
ArmAsm
77 lines
2.4 KiB
ArmAsm
/*
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* PROJECT: ReactOS Boot Loader
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* LICENSE: BSD - See COPYING.ARM in the top level directory
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* FILE: boot/armllb/boot.s
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* PURPOSE: Implements the entry point for ARM machines
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* PROGRAMMERS: ReactOS Portable Systems Group
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*/
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.title "ARM LLB Entry Point"
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.include "ntoskrnl/include/internal/arm/kxarm.h"
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.include "ntoskrnl/include/internal/arm/ksarm.h"
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NESTED_ENTRY _start
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PROLOG_END _start
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#ifdef _BEAGLE_ // This is only used for TI BootROM on Beagle/Emulator for now
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/*
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* On Beagle, the boot is directly from TI BootROM that reads NAND flash.
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* First word is size of program to load.
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* Second word is load address of program. Since DDR is not initialized,
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* we load to SDRAM at 40200000h. Max 64K.
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*/
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.word 0x8000
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.word 0x40200000
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#elif _ZOOM2_
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/*
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* On ZOOM2, we currently load from u-boot to make bring-up easier.
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*
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* In order to get ATAG and all that goodness, we have to fool u-boot into
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* thinking we are a Linux ARM kernel.
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*
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* So this is a 'fake' uImage-format header, which will make u-boot grok our
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* image and correctly execute it.
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*
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* Note that a data checksum is in the header, but thankfully we can disable
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* the check.
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*
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* There's also a header checksum, but as long as there's no need to modify
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* this header, we can leave it static.
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*
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* Finally, note that the "Image String" is sized as a 32-byte array in the
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* uImage header format. The string chosen below is not only accurate, but
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* also happens to fit exactly in 32 bytes, meaning we don't need to pad.
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*/
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.word 0x56190527 // Header Magic
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.word 0x5E4B8444 // Checksum
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.word 0x483BE54C // Timestamp
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.word 0x0CA10000 // Image size (64K)
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.word 0x00000081 // Load address
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.word 0x40000081 // Entrypoint
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.word 0x90873DD8 // Data Checksum ('setenv verify n' must be set!)
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.byte 5 // Linux OS
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.byte 2 // ARM
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.byte 2 // Kernel
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.byte 0 // No compression
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.ascii "ReactOS ARM Low-Level Bootloader"
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#endif
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/* Load C entrypoint and setup LLB stack */
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ldr lr, L_LlbStartup
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ldr sp, L_BootStackEnd
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bx lr
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ENTRY_END _start
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L_BootStackEnd:
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#ifdef _BEAGLE_ // This is only used for TI BootROM on Beagle/Emulator for now
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.long 0x00010000
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#elif _ZOOM2_ // On ZOOM2 RAM starts at 0x80000000, not 0
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.long 0x81014000
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#else
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#error Stack Address Not Defined
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#endif
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L_LlbStartup:
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.long LlbStartup
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/* EOF */
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