xref: /rk3399_rockchip-uboot/arch/mips/cpu/start.S (revision 566ce04de4a2b4c66be8e13751dbb0bfe80117b3) 
1/*
2 *  Startup Code for MIPS32 CPU-core
3 *
4 *  Copyright (c) 2003	Wolfgang Denk <wd@denx.de>
5 *
6 * SPDX-License-Identifier:	GPL-2.0+
7 */
8
9#include <asm-offsets.h>
10#include <config.h>
11#include <asm/asm.h>
12#include <asm/regdef.h>
13#include <asm/mipsregs.h>
14
15#ifndef CONFIG_SYS_INIT_SP_ADDR
16#define CONFIG_SYS_INIT_SP_ADDR	(CONFIG_SYS_SDRAM_BASE + \
17				CONFIG_SYS_INIT_SP_OFFSET)
18#endif
19
20#ifdef CONFIG_32BIT
21# define MIPS_RELOC	3
22# define STATUS_SET	0
23#endif
24
25#ifdef CONFIG_64BIT
26# ifdef CONFIG_SYS_LITTLE_ENDIAN
27#  define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
28	(((r_type) << 24) | ((r_type2) << 16) | ((r_type3) << 8) | (ssym))
29# else
30#  define MIPS64_R_INFO(ssym, r_type3, r_type2, r_type) \
31	((r_type) | ((r_type2) << 8) | ((r_type3) << 16) | (ssym) << 24)
32# endif
33# define MIPS_RELOC	MIPS64_R_INFO(0x00, 0x00, 0x12, 0x03)
34# define STATUS_SET	ST0_KX
35#endif
36
37	/*
38	 * For the moment disable interrupts, mark the kernel mode and
39	 * set ST0_KX so that the CPU does not spit fire when using
40	 * 64-bit addresses.
41	 */
42	.macro	setup_c0_status set clr
43	.set	push
44	mfc0	t0, CP0_STATUS
45	or	t0, ST0_CU0 | \set | 0x1f | \clr
46	xor	t0, 0x1f | \clr
47	mtc0	t0, CP0_STATUS
48	.set	noreorder
49	sll	zero, 3				# ehb
50	.set	pop
51	.endm
52
53	.set noreorder
54
55ENTRY(_start)
56	/* U-Boot entry point */
57	b	reset
58	 nop
59
60	.org 0x10
61#if defined(CONFIG_SYS_XWAY_EBU_BOOTCFG)
62	/*
63	 * Almost all Lantiq XWAY SoC devices have an external bus unit (EBU) to
64	 * access external NOR flashes. If the board boots from NOR flash the
65	 * internal BootROM does a blind read at address 0xB0000010 to read the
66	 * initial configuration for that EBU in order to access the flash
67	 * device with correct parameters. This config option is board-specific.
68	 */
69	.word CONFIG_SYS_XWAY_EBU_BOOTCFG
70	.word 0x0
71#elif defined(CONFIG_MALTA)
72	/*
73	 * Linux expects the Board ID here.
74	 */
75	.word 0x00000420	# 0x420 (Malta Board with CoreLV)
76	.word 0x00000000
77#endif
78
79	.org 0x200
80	/* TLB refill, 32 bit task */
811:	b	1b
82	 nop
83
84	.org 0x280
85	/* XTLB refill, 64 bit task */
861:	b	1b
87	 nop
88
89	.org 0x300
90	/* Cache error exception */
911:	b	1b
92	 nop
93
94	.org 0x380
95	/* General exception */
961:	b	1b
97	 nop
98
99	.org 0x400
100	/* Catch interrupt exceptions */
1011:	b	1b
102	 nop
103
104	.org 0x480
105	/* EJTAG debug exception */
1061:	b	1b
107	 nop
108
109	.align 4
110reset:
111
112	/* Clear watch registers */
113	MTC0	zero, CP0_WATCHLO
114	mtc0	zero, CP0_WATCHHI
115
116	/* WP(Watch Pending), SW0/1 should be cleared */
117	mtc0	zero, CP0_CAUSE
118
119	setup_c0_status STATUS_SET 0
120
121	/* Init Timer */
122	mtc0	zero, CP0_COUNT
123	mtc0	zero, CP0_COMPARE
124
125#ifndef CONFIG_SKIP_LOWLEVEL_INIT
126	mfc0	t0, CP0_CONFIG
127	and	t0, t0, MIPS_CONF_IMPL
128	or	t0, t0, CONF_CM_UNCACHED
129	mtc0	t0, CP0_CONFIG
130#endif
131
132	/*
133	 * Initialize $gp, force pointer sized alignment of bal instruction to
134	 * forbid the compiler to put nop's between bal and _gp. This is
135	 * required to keep _gp and ra aligned to 8 byte.
136	 */
137	.align	PTRLOG
138	bal	1f
139	 nop
140	PTR	_gp
1411:
142	PTR_L	gp, 0(ra)
143
144#ifdef CONFIG_MIPS_CM
145	PTR_LA	t9, mips_cm_map
146	jalr	t9
147	 nop
148#endif
149
150#ifndef CONFIG_SKIP_LOWLEVEL_INIT
151# ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
152	/* Initialize any external memory */
153	PTR_LA	t9, lowlevel_init
154	jalr	t9
155	 nop
156# endif
157
158	/* Initialize caches... */
159	PTR_LA	t9, mips_cache_reset
160	jalr	t9
161	 nop
162
163# ifndef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
164	/* Initialize any external memory */
165	PTR_LA	t9, lowlevel_init
166	jalr	t9
167	 nop
168# endif
169#endif
170
171	/* Set up temporary stack */
172	li	t0, -16
173	PTR_LI	t1, CONFIG_SYS_INIT_SP_ADDR
174	and	sp, t1, t0		# force 16 byte alignment
175	PTR_SUBU \
176		sp, sp, GD_SIZE		# reserve space for gd
177	and	sp, sp, t0		# force 16 byte alignment
178	move	k0, sp			# save gd pointer
179#ifdef CONFIG_SYS_MALLOC_F_LEN
180	li	t2, CONFIG_SYS_MALLOC_F_LEN
181	PTR_SUBU \
182		sp, sp, t2		# reserve space for early malloc
183	and	sp, sp, t0		# force 16 byte alignment
184#endif
185	move	fp, sp
186
187	/* Clear gd */
188	move	t0, k0
1891:
190	PTR_S	zero, 0(t0)
191	blt	t0, t1, 1b
192	 PTR_ADDIU t0, PTRSIZE
193
194#ifdef CONFIG_SYS_MALLOC_F_LEN
195	PTR_S	sp, GD_MALLOC_BASE(k0)	# gd->malloc_base offset
196#endif
197
198	move	a0, zero		# a0 <-- boot_flags = 0
199	PTR_LA	t9, board_init_f
200	jr	t9
201	 move	ra, zero
202
203	END(_start)
204
205/*
206 * void relocate_code (addr_sp, gd, addr_moni)
207 *
208 * This "function" does not return, instead it continues in RAM
209 * after relocating the monitor code.
210 *
211 * a0 = addr_sp
212 * a1 = gd
213 * a2 = destination address
214 */
215ENTRY(relocate_code)
216	move	sp, a0			# set new stack pointer
217	move	fp, sp
218
219	move	s0, a1			# save gd in s0
220	move	s2, a2			# save destination address in s2
221
222	PTR_LI	t0, CONFIG_SYS_MONITOR_BASE
223	PTR_SUB	s1, s2, t0		# s1 <-- relocation offset
224
225	PTR_LA	t3, in_ram
226	PTR_L	t2, -(3 * PTRSIZE)(t3)	# t2 <-- __image_copy_end
227	move	t1, a2
228
229	PTR_ADD	gp, s1			# adjust gp
230
231	/*
232	 * t0 = source address
233	 * t1 = target address
234	 * t2 = source end address
235	 */
2361:
237	PTR_L	t3, 0(t0)
238	PTR_S	t3, 0(t1)
239	PTR_ADDU t0, PTRSIZE
240	blt	t0, t2, 1b
241	 PTR_ADDU t1, PTRSIZE
242
243	/* If caches were enabled, we would have to flush them here. */
244	PTR_SUB	a1, t1, s2		# a1 <-- size
245	PTR_LA	t9, flush_cache
246	jalr	t9
247	 move	a0, s2			# a0 <-- destination address
248
249	/* Jump to where we've relocated ourselves */
250	PTR_ADDIU t0, s2, in_ram - _start
251	jr	t0
252	 nop
253
254	PTR	__rel_dyn_end
255	PTR	__rel_dyn_start
256	PTR	__image_copy_end
257	PTR	_GLOBAL_OFFSET_TABLE_
258	PTR	num_got_entries
259
260in_ram:
261	/*
262	 * Now we want to update GOT.
263	 *
264	 * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
265	 * generated by GNU ld. Skip these reserved entries from relocation.
266	 */
267	PTR_L	t3, -(1 * PTRSIZE)(t0)	# t3 <-- num_got_entries
268	PTR_L	t8, -(2 * PTRSIZE)(t0)	# t8 <-- _GLOBAL_OFFSET_TABLE_
269	PTR_ADD	t8, s1			# t8 now holds relocated _G_O_T_
270	PTR_ADDIU t8, t8, 2 * PTRSIZE	# skipping first two entries
271	PTR_LI	t2, 2
2721:
273	PTR_L	t1, 0(t8)
274	beqz	t1, 2f
275	 PTR_ADD t1, s1
276	PTR_S	t1, 0(t8)
2772:
278	PTR_ADDIU t2, 1
279	blt	t2, t3, 1b
280	 PTR_ADDIU t8, PTRSIZE
281
282	/* Update dynamic relocations */
283	PTR_L	t1, -(4 * PTRSIZE)(t0)	# t1 <-- __rel_dyn_start
284	PTR_L	t2, -(5 * PTRSIZE)(t0)	# t2 <-- __rel_dyn_end
285
286	b	2f			# skip first reserved entry
287	 PTR_ADDIU t1, 2 * PTRSIZE
288
2891:
290	lw	t8, -4(t1)		# t8 <-- relocation info
291
292	PTR_LI	t3, MIPS_RELOC
293	bne	t8, t3, 2f		# skip non-MIPS_RELOC entries
294	 nop
295
296	PTR_L	t3, -(2 * PTRSIZE)(t1)	# t3 <-- location to fix up in FLASH
297
298	PTR_L	t8, 0(t3)		# t8 <-- original pointer
299	PTR_ADD	t8, s1			# t8 <-- adjusted pointer
300
301	PTR_ADD	t3, s1			# t3 <-- location to fix up in RAM
302	PTR_S	t8, 0(t3)
303
3042:
305	blt	t1, t2, 1b
306	 PTR_ADDIU t1, 2 * PTRSIZE	# each rel.dyn entry is 2*PTRSIZE bytes
307
308	/*
309	 * Clear BSS
310	 *
311	 * GOT is now relocated. Thus __bss_start and __bss_end can be
312	 * accessed directly via $gp.
313	 */
314	PTR_LA	t1, __bss_start		# t1 <-- __bss_start
315	PTR_LA	t2, __bss_end		# t2 <-- __bss_end
316
3171:
318	PTR_S	zero, 0(t1)
319	blt	t1, t2, 1b
320	 PTR_ADDIU t1, PTRSIZE
321
322	move	a0, s0			# a0 <-- gd
323	move	a1, s2
324	PTR_LA	t9, board_init_r
325	jr	t9
326	 move	ra, zero
327
328	END(relocate_code)
329