2 * Startup Code for MIPS32 CPU-core
4 * Copyright (c) 2003 Wolfgang Denk <wd@denx.de>
6 * SPDX-License-Identifier: GPL-2.0+
9 #include <asm-offsets.h>
12 #include <asm/regdef.h>
13 #include <asm/mipsregs.h>
15 #ifndef CONFIG_SYS_MIPS_CACHE_MODE
16 #define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT
19 #ifndef CONFIG_SYS_INIT_SP_ADDR
20 #define CONFIG_SYS_INIT_SP_ADDR (CONFIG_SYS_SDRAM_BASE + \
21 CONFIG_SYS_INIT_SP_OFFSET)
25 * For the moment disable interrupts, mark the kernel mode and
26 * set ST0_KX so that the CPU does not spit fire when using
29 .macro setup_c0_status set clr
32 or t0, ST0_CU0 | \set | 0x1f | \clr
45 /* U-boot entry point */
50 #if defined(CONFIG_SYS_XWAY_EBU_BOOTCFG)
52 * Almost all Lantiq XWAY SoC devices have an external bus unit (EBU) to
53 * access external NOR flashes. If the board boots from NOR flash the
54 * internal BootROM does a blind read at address 0xB0000010 to read the
55 * initial configuration for that EBU in order to access the flash
56 * device with correct parameters. This config option is board-specific.
58 .word CONFIG_SYS_XWAY_EBU_BOOTCFG
60 #elif defined(CONFIG_MALTA)
62 * Linux expects the Board ID here.
64 .word 0x00000420 # 0x420 (Malta Board with CoreLV)
69 /* TLB refill, 32 bit task */
74 /* XTLB refill, 64 bit task */
79 /* Cache error exception */
84 /* General exception */
89 /* Catch interrupt exceptions */
94 /* EJTAG debug exception */
101 /* Clear watch registers */
102 MTC0 zero, CP0_WATCHLO
103 MTC0 zero, CP0_WATCHHI
105 /* WP(Watch Pending), SW0/1 should be cleared */
112 mtc0 zero, CP0_COMPARE
114 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
115 /* CONFIG0 register */
116 li t0, CONF_CM_UNCACHED
121 * Initialize $gp, force pointer sized alignment of bal instruction to
122 * forbid the compiler to put nop's between bal and _gp. This is
123 * required to keep _gp and ra aligned to 8 byte.
132 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
133 /* Initialize any external memory */
134 PTR_LA t9, lowlevel_init
138 /* Initialize caches... */
139 PTR_LA t9, mips_cache_reset
143 /* ... and enable them */
144 li t0, CONFIG_SYS_MIPS_CACHE_MODE
148 /* Set up temporary stack */
150 PTR_LI t1, CONFIG_SYS_INIT_SP_ADDR
151 and sp, t1, t0 # force 16 byte alignment
152 PTR_SUB sp, sp, GD_SIZE # reserve space for gd
153 and sp, sp, t0 # force 16 byte alignment
154 move k0, sp # save gd pointer
155 #ifdef CONFIG_SYS_MALLOC_F_LEN
156 PTR_LI t2, CONFIG_SYS_MALLOC_F_LEN
157 PTR_SUB sp, sp, t2 # reserve space for early malloc
158 and sp, sp, t0 # force 16 byte alignment
169 #ifdef CONFIG_SYS_MALLOC_F_LEN
170 PTR_ADDU t0, k0, GD_MALLOC_BASE # gd->malloc_base offset
174 PTR_LA t9, board_init_f
179 * void relocate_code (addr_sp, gd, addr_moni)
181 * This "function" does not return, instead it continues in RAM
182 * after relocating the monitor code.
186 * a2 = destination address
191 move sp, a0 # set new stack pointer
194 move s0, a1 # save gd in s0
195 move s2, a2 # save destination address in s2
197 PTR_LI t0, CONFIG_SYS_MONITOR_BASE
198 PTR_SUB s1, s2, t0 # s1 <-- relocation offset
201 PTR_L t2, -(3 * PTRSIZE)(t3) # t2 <-- __image_copy_end
204 PTR_ADD gp, s1 # adjust gp
207 * t0 = source address
208 * t1 = target address
209 * t2 = source end address
218 /* If caches were enabled, we would have to flush them here. */
219 PTR_SUB a1, t1, s2 # a1 <-- size
220 PTR_LA t9, flush_cache
222 move a0, s2 # a0 <-- destination address
224 /* Jump to where we've relocated ourselves */
225 PTR_ADDI t0, s2, in_ram - _start
232 PTR _GLOBAL_OFFSET_TABLE_
237 * Now we want to update GOT.
239 * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
240 * generated by GNU ld. Skip these reserved entries from relocation.
242 PTR_L t3, -(1 * PTRSIZE)(t0) # t3 <-- num_got_entries
243 PTR_L t8, -(2 * PTRSIZE)(t0) # t8 <-- _GLOBAL_OFFSET_TABLE_
244 PTR_ADD t8, s1 # t8 now holds relocated _G_O_T_
245 PTR_ADDI t8, t8, 2 * PTRSIZE # skipping first two entries
257 /* Update dynamic relocations */
258 PTR_L t1, -(4 * PTRSIZE)(t0) # t1 <-- __rel_dyn_start
259 PTR_L t2, -(5 * PTRSIZE)(t0) # t2 <-- __rel_dyn_end
261 b 2f # skip first reserved entry
262 PTR_ADDI t1, 2 * PTRSIZE
265 lw t8, -4(t1) # t8 <-- relocation info
268 bne t8, t3, 2f # skip non R_MIPS_REL32 entries
271 PTR_L t3, -(2 * PTRSIZE)(t1) # t3 <-- location to fix up in FLASH
273 PTR_L t8, 0(t3) # t8 <-- original pointer
274 PTR_ADD t8, s1 # t8 <-- adjusted pointer
276 PTR_ADD t3, s1 # t3 <-- location to fix up in RAM
281 PTR_ADDI t1, 2 * PTRSIZE # each rel.dyn entry is 2*PTRSIZE bytes
286 * GOT is now relocated. Thus __bss_start and __bss_end can be
287 * accessed directly via $gp.
289 PTR_LA t1, __bss_start # t1 <-- __bss_start
290 PTR_LA t2, __bss_end # t2 <-- __bss_end
297 move a0, s0 # a0 <-- gd
299 PTR_LA t9, board_init_r