| /* |
| * Startup Code for MIPS32 XBURST CPU-core |
| * |
| * Copyright (c) 2010 Xiangfu Liu <xiangfu@sharism.cc> |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| */ |
| |
| #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 |
| |
| move s2, a2 # save destination address in s2 |
| |
| li t0, CONFIG_SYS_MONITOR_BASE |
| sub t6, s2, 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, s2, 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, s2 |
| |
| .end relocate_code |