2 * Startup Code for MIPS32 XBURST CPU-core
4 * Copyright (c) 2010 Xiangfu Liu <xiangfu@sharism.cc>
6 * SPDX-License-Identifier: GPL-2.0+
11 #include <asm/regdef.h>
12 #include <asm/mipsregs.h>
13 #include <asm/addrspace.h>
14 #include <asm/cacheops.h>
28 /* Set up temporary stack */
29 li sp, CONFIG_SYS_SDRAM_BASE + CONFIG_SYS_INIT_SP_OFFSET
36 * void relocate_code (addr_sp, gd, addr_moni)
38 * This "function" does not return, instead it continues in RAM
39 * after relocating the monitor code.
43 * a2 = destination address
48 move sp, a0 # set new stack pointer
50 li t0, CONFIG_SYS_MONITOR_BASE
51 sub t6, a2, t0 # t6 <-- relocation offset
54 lw t2, -12(t3) # t2 <-- __image_copy_end
57 add gp, t6 # adjust gp
62 * t2 = source end address
71 /* If caches were enabled, we would have to flush them here. */
75 addi t1, t0, CONFIG_SYS_DCACHE_SIZE
77 cache INDEX_WRITEBACK_INV_D, 0(t0)
79 addi t0, CONFIG_SYS_CACHELINE_SIZE
85 addi t1, t0, CONFIG_SYS_ICACHE_SIZE
87 cache INDEX_INVALIDATE_I, 0(t0)
89 addi t0, CONFIG_SYS_CACHELINE_SIZE
92 mfc0 t0, CP0_CONFIG, 7
95 mtc0 t0, CP0_CONFIG, 7
98 /* Jump to where we've relocated ourselves */
99 addi t0, a2, in_ram - _start
104 .word __rel_dyn_start
105 .word __image_copy_end
106 .word _GLOBAL_OFFSET_TABLE_
107 .word num_got_entries
111 * Now we want to update GOT.
113 * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
114 * generated by GNU ld. Skip these reserved entries from relocation.
116 lw t3, -4(t0) # t3 <-- num_got_entries
117 lw t4, -8(t0) # t4 <-- _GLOBAL_OFFSET_TABLE_
118 add t4, t6 # t4 now holds relocated _G_O_T_
119 addi t4, t4, 8 # skipping first two entries
131 /* Update dynamic relocations */
132 lw t1, -16(t0) # t1 <-- __rel_dyn_start
133 lw t2, -20(t0) # t2 <-- __rel_dyn_end
135 b 2f # skip first reserved entry
139 lw t3, -4(t1) # t3 <-- relocation info
142 bnez t3, 2f # skip non R_MIPS_REL32 entries
145 lw t3, -8(t1) # t3 <-- location to fix up in FLASH
147 lw t4, 0(t3) # t4 <-- original pointer
148 add t4, t6 # t4 <-- adjusted pointer
150 add t3, t6 # t3 <-- location to fix up in RAM
155 addi t1, 8 # each rel.dyn entry is 8 bytes
160 * GOT is now relocated. Thus __bss_start and __bss_end can be
161 * accessed directly via $gp.
163 la t1, __bss_start # t1 <-- __bss_start
164 la t2, __bss_end # t2 <-- __bss_end
171 move a0, a1 # a0 <-- gd