| /* |
| * 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 |
| la t3, in_ram |
| lw t2, -12(t3) # t2 <-- uboot_end_data |
| move t1, a2 |
| |
| /* |
| * Fix $gp: |
| * |
| * New $gp = (Old $gp - CONFIG_SYS_MONITOR_BASE) + Destination Address |
| */ |
| move t6, gp |
| sub gp, CONFIG_SYS_MONITOR_BASE |
| add gp, a2 # gp now adjusted |
| sub t6, gp, t6 # t6 <-- relocation offset |
| |
| /* |
| * t0 = source address |
| * t1 = target address |
| * t2 = source end address |
| */ |
| 1: |
| lw t3, 0(t0) |
| sw t3, 0(t1) |
| addu t0, 4 |
| ble 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 _gp |
| .word _GLOBAL_OFFSET_TABLE_ |
| .word uboot_end_data |
| .word uboot_end |
| .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, -16(t0) # t4 <-- _GLOBAL_OFFSET_TABLE_ |
| lw t5, -20(t0) # t5 <-- _gp |
| sub t4, t5 # compute offset |
| add t4, t4, gp # 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 |
| |
| /* Clear BSS */ |
| lw t1, -12(t0) # t1 <-- uboot_end_data |
| lw t2, -8(t0) # t2 <-- uboot_end |
| add t1, t6 # adjust pointers |
| add t2, t6 |
| |
| sub t1, 4 |
| 1: addi t1, 4 |
| bltl t1, t2, 1b |
| sw zero, 0(t1) |
| |
| move a0, a1 # a0 <-- gd |
| la t9, board_init_r |
| jr t9 |
| move a1, a2 |
| |
| .end relocate_code |
