/* * (C) Copyright 2007 Michal Simek * (C) Copyright 2004 Atmark Techno, Inc. * * Michal SIMEK <monstr@monstr.eu> * Yasushi SHOJI <yashi@atmark-techno.com> * * SPDX-License-Identifier: GPL-2.0+ */ #include <asm-offsets.h> #include <config.h> .text .global _start _start: /* * reserve registers: * r10: Stores little/big endian offset for vectors * r2: Stores imm opcode * r3: Stores brai opcode */ mts rmsr, r0 /* disable cache */ #if defined(CONFIG_SPL_BUILD) addi r1, r0, CONFIG_SPL_STACK_ADDR addi r1, r1, -4 /* Decrement SP to top of memory */ #else addi r1, r0, CONFIG_SYS_INIT_SP_OFFSET addi r1, r1, -4 /* Decrement SP to top of memory */ /* Find-out if u-boot is running on BIG/LITTLE endian platform * There are some steps which is necessary to keep in mind: * 1. Setup offset value to r6 * 2. Store word offset value to address 0x0 * 3. Load just byte from address 0x0 * 4a) LITTLE endian - r10 contains 0x2 because it is the smallest * value that's why is on address 0x0 * 4b) BIG endian - r10 contains 0x0 because 0x2 offset is on addr 0x3 */ addik r6, r0, 0x2 /* BIG/LITTLE endian offset */ lwi r7, r0, 0x28 swi r6, r0, 0x28 /* used first unused MB vector */ lbui r10, r0, 0x28 /* used first unused MB vector */ swi r7, r0, 0x28 /* add opcode instruction for 32bit jump - 2 instruction imm & brai */ addi r2, r0, 0xb0000000 /* hex b000 opcode imm */ addi r3, r0, 0xb8080000 /* hew b808 opcode brai */ #ifdef CONFIG_SYS_RESET_ADDRESS /* reset address */ swi r2, r0, 0x0 /* reset address - imm opcode */ swi r3, r0, 0x4 /* reset address - brai opcode */ addik r6, r0, CONFIG_SYS_RESET_ADDRESS sw r6, r1, r0 lhu r7, r1, r10 rsubi r8, r10, 0x2 sh r7, r0, r8 rsubi r8, r10, 0x6 sh r6, r0, r8 #endif #ifdef CONFIG_SYS_USR_EXCEP /* user_vector_exception */ swi r2, r0, 0x8 /* user vector exception - imm opcode */ swi r3, r0, 0xC /* user vector exception - brai opcode */ addik r6, r0, _exception_handler sw r6, r1, r0 /* * BIG ENDIAN memory map for user exception * 0x8: 0xB000XXXX * 0xC: 0xB808XXXX * * then it is necessary to count address for storing the most significant * 16bits from _exception_handler address and copy it to * 0xa address. Big endian use offset in r10=0 that's why is it just * 0xa address. The same is done for the least significant 16 bits * for 0xe address. * * LITTLE ENDIAN memory map for user exception * 0x8: 0xXXXX00B0 * 0xC: 0xXXXX08B8 * * Offset is for little endian setup to 0x2. rsubi instruction decrease * address value to ensure that points to proper place which is * 0x8 for the most significant 16 bits and * 0xC for the least significant 16 bits */ lhu r7, r1, r10 rsubi r8, r10, 0xa sh r7, r0, r8 rsubi r8, r10, 0xe sh r6, r0, r8 #endif /* interrupt_handler */ swi r2, r0, 0x10 /* interrupt - imm opcode */ swi r3, r0, 0x14 /* interrupt - brai opcode */ addik r6, r0, _interrupt_handler sw r6, r1, r0 lhu r7, r1, r10 rsubi r8, r10, 0x12 sh r7, r0, r8 rsubi r8, r10, 0x16 sh r6, r0, r8 /* hardware exception */ swi r2, r0, 0x20 /* hardware exception - imm opcode */ swi r3, r0, 0x24 /* hardware exception - brai opcode */ addik r6, r0, _hw_exception_handler sw r6, r1, r0 lhu r7, r1, r10 rsubi r8, r10, 0x22 sh r7, r0, r8 rsubi r8, r10, 0x26 sh r6, r0, r8 #endif /* BUILD_SPL */ /* Flush cache before enable cache */ addik r5, r0, 0 addik r6, r0, XILINX_DCACHE_BYTE_SIZE flush: bralid r15, flush_cache nop /* enable instruction and data cache */ mfs r12, rmsr ori r12, r12, 0xa0 mts rmsr, r12 clear_bss: /* clear BSS segments */ addi r5, r0, __bss_start addi r4, r0, __bss_end cmp r6, r5, r4 beqi r6, 3f 2: swi r0, r5, 0 /* write zero to loc */ addi r5, r5, 4 /* increment to next loc */ cmp r6, r5, r4 /* check if we have reach the end */ bnei r6, 2b 3: /* jumping to board_init */ #ifndef CONFIG_SPL_BUILD brai board_init_f #else brai board_init_r #endif 1: bri 1b #ifndef CONFIG_SPL_BUILD /* * Read 16bit little endian */ .text .global in16 .ent in16 .align 2 in16: lhu r3, r0, r5 bslli r4, r3, 8 bsrli r3, r3, 8 andi r4, r4, 0xffff or r3, r3, r4 rtsd r15, 8 sext16 r3, r3 .end in16 /* * Write 16bit little endian * first parameter(r5) - address, second(r6) - short value */ .text .global out16 .ent out16 .align 2 out16: bslli r3, r6, 8 bsrli r6, r6, 8 andi r3, r3, 0xffff or r3, r3, r6 sh r3, r0, r5 rtsd r15, 8 or r0, r0, r0 .end out16 #endif