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 move s2, a2 # save destination address in s2
52 li t0, CONFIG_SYS_MONITOR_BASE
53 sub t6, s2, t0 # t6 <-- relocation offset
56 lw t2, -12(t3) # t2 <-- __image_copy_end
59 add gp, t6 # adjust gp
64 * t2 = source end address
73 /* If caches were enabled, we would have to flush them here. */
77 addi t1, t0, CONFIG_SYS_DCACHE_SIZE
79 cache INDEX_WRITEBACK_INV_D, 0(t0)
81 addi t0, CONFIG_SYS_CACHELINE_SIZE
87 addi t1, t0, CONFIG_SYS_ICACHE_SIZE
89 cache INDEX_INVALIDATE_I, 0(t0)
91 addi t0, CONFIG_SYS_CACHELINE_SIZE
94 mfc0 t0, CP0_CONFIG, 7
97 mtc0 t0, CP0_CONFIG, 7
100 /* Jump to where we've relocated ourselves */
101 addi t0, s2, in_ram - _start
106 .word __rel_dyn_start
107 .word __image_copy_end
108 .word _GLOBAL_OFFSET_TABLE_
109 .word num_got_entries
113 * Now we want to update GOT.
115 * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
116 * generated by GNU ld. Skip these reserved entries from relocation.
118 lw t3, -4(t0) # t3 <-- num_got_entries
119 lw t4, -8(t0) # t4 <-- _GLOBAL_OFFSET_TABLE_
120 add t4, t6 # t4 now holds relocated _G_O_T_
121 addi t4, t4, 8 # skipping first two entries
133 /* Update dynamic relocations */
134 lw t1, -16(t0) # t1 <-- __rel_dyn_start
135 lw t2, -20(t0) # t2 <-- __rel_dyn_end
137 b 2f # skip first reserved entry
141 lw t3, -4(t1) # t3 <-- relocation info
144 bnez t3, 2f # skip non R_MIPS_REL32 entries
147 lw t3, -8(t1) # t3 <-- location to fix up in FLASH
149 lw t4, 0(t3) # t4 <-- original pointer
150 add t4, t6 # t4 <-- adjusted pointer
152 add t3, t6 # t3 <-- location to fix up in RAM
157 addi t1, 8 # each rel.dyn entry is 8 bytes
162 * GOT is now relocated. Thus __bss_start and __bss_end can be
163 * accessed directly via $gp.
165 la t1, __bss_start # t1 <-- __bss_start
166 la t2, __bss_end # t2 <-- __bss_end
173 move a0, a1 # a0 <-- gd