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Diffstat (limited to 'arch/mips/cpu/xburst/start.S')
| -rw-r--r-- | arch/mips/cpu/xburst/start.S | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/arch/mips/cpu/xburst/start.S b/arch/mips/cpu/xburst/start.S new file mode 100644 index 0000000..d2c064b --- /dev/null +++ b/arch/mips/cpu/xburst/start.S @@ -0,0 +1,192 @@ +/* + * Startup Code for MIPS32 XBURST CPU-core + * + * Copyright (c) 2010 Xiangfu Liu <xiangfu@sharism.cc> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <config.h> +#include <version.h> +#include <asm/regdef.h> +#include <asm/mipsregs.h> +#include <asm/addrspace.h> +#include <asm/cacheops.h> + + .set noreorder + + .globl _start + .text +_start: + /* Initialize $gp */ + bal 1f + nop + .word _gp +1: + lw gp, 0(ra) + + /* Set up temporary stack */ + li sp, CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_INIT_SP_OFFSET + + la t9, board_init_f + jr t9 + nop + +/* + * void relocate_code (addr_sp, gd, addr_moni) + * + * This "function" does not return, instead it continues in RAM + * after relocating the monitor code. + * + * a0 = addr_sp + * a1 = gd + * a2 = destination address + */ + .globl relocate_code + .ent relocate_code +relocate_code: + move sp, a0 # set new stack pointer + + li t0, CONFIG_SYS_MONITOR_BASE + sub t6, a2, t0 # t6 <-- relocation offset + + la t3, in_ram + lw t2, -12(t3) # t2 <-- __image_copy_end + move t1, a2 + + add gp, t6 # adjust gp + + /* + * t0 = source address + * t1 = target address + * t2 = source end address + */ +1: + lw t3, 0(t0) + sw t3, 0(t1) + addu t0, 4 + blt t0, t2, 1b + addu t1, 4 + + /* If caches were enabled, we would have to flush them here. */ + + /* flush d-cache */ + li t0, KSEG0 + addi t1, t0, CONFIG_SYS_DCACHE_SIZE +2: + cache INDEX_WRITEBACK_INV_D, 0(t0) + bne t0, t1, 2b + addi t0, CONFIG_SYS_CACHELINE_SIZE + + sync + + /* flush i-cache */ + li t0, KSEG0 + addi t1, t0, CONFIG_SYS_ICACHE_SIZE +3: + cache INDEX_INVALIDATE_I, 0(t0) + bne t0, t1, 3b + addi t0, CONFIG_SYS_CACHELINE_SIZE + + /* Invalidate BTB */ + mfc0 t0, CP0_CONFIG, 7 + nop + ori t0, 2 + mtc0 t0, CP0_CONFIG, 7 + nop + + /* Jump to where we've relocated ourselves */ + addi t0, a2, in_ram - _start + jr t0 + nop + + .word __rel_dyn_end + .word __rel_dyn_start + .word __image_copy_end + .word _GLOBAL_OFFSET_TABLE_ + .word num_got_entries + +in_ram: + /* + * Now we want to update GOT. + * + * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object + * generated by GNU ld. Skip these reserved entries from relocation. + */ + lw t3, -4(t0) # t3 <-- num_got_entries + lw t4, -8(t0) # t4 <-- _GLOBAL_OFFSET_TABLE_ + add t4, t6 # t4 now holds relocated _G_O_T_ + addi t4, t4, 8 # skipping first two entries + li t2, 2 +1: + lw t1, 0(t4) + beqz t1, 2f + add t1, t6 + sw t1, 0(t4) +2: + addi t2, 1 + blt t2, t3, 1b + addi t4, 4 + + /* Update dynamic relocations */ + lw t1, -16(t0) # t1 <-- __rel_dyn_start + lw t2, -20(t0) # t2 <-- __rel_dyn_end + + b 2f # skip first reserved entry + addi t1, 8 + +1: + lw t3, -4(t1) # t3 <-- relocation info + + sub t3, 3 + bnez t3, 2f # skip non R_MIPS_REL32 entries + nop + + lw t3, -8(t1) # t3 <-- location to fix up in FLASH + + lw t4, 0(t3) # t4 <-- original pointer + add t4, t6 # t4 <-- adjusted pointer + + add t3, t6 # t3 <-- location to fix up in RAM + sw t4, 0(t3) + +2: + blt t1, t2, 1b + addi t1, 8 # each rel.dyn entry is 8 bytes + + /* + * Clear BSS + * + * GOT is now relocated. Thus __bss_start and __bss_end can be + * accessed directly via $gp. + */ + la t1, __bss_start # t1 <-- __bss_start + la t2, __bss_end # t2 <-- __bss_end + +1: + sw zero, 0(t1) + blt t1, t2, 1b + addi t1, 4 + + move a0, a1 # a0 <-- gd + la t9, board_init_r + jr t9 + move a1, a2 + + .end relocate_code |
