xref: /openbmc/u-boot/arch/nds32/cpu/n1213/start.S (revision 6bd041f0) 
1/*
2 *	Andesboot - Startup Code for Whitiger core
3 *
4 *	Copyright (C) 2006	Andes Technology Corporation
5 *	Copyright (C) 2006	Shawn Lin <nobuhiro@andestech.com>
6 *	Copyright (C) 2011	Macpaul Lin <macpaul@andestech.com>
7 *				Greentime Hu <greentime@andestech.com>
8 *
9 * SPDX-License-Identifier:	GPL-2.0+
10 */
11
12.pic
13
14#include <asm-offsets.h>
15#include <config.h>
16#include <common.h>
17#include <asm/macro.h>
18
19/*
20 * Jump vector table for EVIC mode
21 */
22#define ENA_DCAC		2UL
23#define DIS_DCAC		~ENA_DCAC
24#define ICAC_MEM_KBF_ISET	(0x07)	 	! I Cache sets per way
25#define ICAC_MEM_KBF_IWAY	(0x07<<3)	! I cache ways
26#define ICAC_MEM_KBF_ISZ	(0x07<<6)	! I cache line size
27#define DCAC_MEM_KBF_DSET	(0x07)		! D Cache sets per way
28#define DCAC_MEM_KBF_DWAY	(0x07<<3)	! D cache ways
29#define DCAC_MEM_KBF_DSZ	(0x07<<6)	! D cache line size
30
31#define PSW			$ir0
32#define EIT_INTR_PSW		$ir1		! interruption $PSW
33#define EIT_PREV_IPSW		$ir2		! previous $IPSW
34#define EIT_IVB			$ir3		! intr vector base address
35#define EIT_EVA			$ir4		! MMU related Exception VA reg
36#define EIT_PREV_EVA		$ir5		! previous $eva
37#define EIT_ITYPE		$ir6		! interruption type
38#define EIT_PREV_ITYPE		$ir7		! prev intr type
39#define EIT_MACH_ERR		$ir8		! machine error log
40#define EIT_INTR_PC		$ir9		! Interruption PC
41#define EIT_PREV_IPC		$ir10		! previous $IPC
42#define EIT_OVL_INTR_PC		$ir11		! overflow interruption PC
43#define EIT_PREV_P0		$ir12		! prev $P0
44#define EIT_PREV_P1		$ir13		! prev $p1
45#define CR_ICAC_MEM		$cr1		! I-cache/memory config reg
46#define CR_DCAC_MEM		$cr2		! D-cache/memory config reg
47#define MR_CAC_CTL		$mr8
48
49.globl _start
50
51_start:	j	reset
52	j	tlb_fill
53	j	tlb_not_present
54	j	tlb_misc
55	j	tlb_vlpt_miss
56	j	machine_error
57	j	debug
58	j	general_exception
59	j	syscall
60	j	internal_interrupt		! H0I
61	j	internal_interrupt		! H1I
62	j	internal_interrupt		! H2I
63	j	internal_interrupt		! H3I
64	j	internal_interrupt		! H4I
65	j	internal_interrupt		! H5I
66	j	software_interrupt		! S0I
67
68	.balign 16
69
70/*
71 * Andesboot Startup Code (reset vector)
72 *
73 *	1.	bootstrap
74 *		1.1 reset - start of u-boot
75 *		1.2 to superuser mode - as is when reset
76 *		1.4 Do lowlevel_init
77 *			- (this will jump out to lowlevel_init.S in SoC)
78 *			- (lowlevel_init)
79 *		1.3 Turn off watchdog timer
80 *			- (this will jump out to watchdog.S in SoC)
81 *			- (turnoff_watchdog)
82 *	2.	Do critical init when reboot (not from mem)
83 *	3.	Relocate andesboot to ram
84 *	4.	Setup stack
85 *	5.	Jump to second stage (board_init_r)
86 */
87
88/* Note: TEXT_BASE is defined by the (board-dependent) linker script */
89.globl _TEXT_BASE
90_TEXT_BASE:
91	.word	CONFIG_SYS_TEXT_BASE
92
93/* IRQ stack memory (calculated at run-time) + 8 bytes */
94.globl IRQ_STACK_START_IN
95IRQ_STACK_START_IN:
96	.word 0x0badc0de
97
98/*
99 * The bootstrap code of nds32 core
100 */
101
102reset:
103
104/*
105 *  gp = ~0            for burn mode
106 *     = ~load_address for load mode
107 */
108reset_gp:
109	.relax_hint 0
110	sethi   $gp, hi20(_GLOBAL_OFFSET_TABLE_-8)
111	.relax_hint 0
112	ori     $gp, $gp, lo12(_GLOBAL_OFFSET_TABLE_-4)
113	add5.pc $gp
114
115set_ivb:
116	li	$r0, 0x0
117
118	/* turn on BTB */
119	mtsr	$r0, $misc_ctl
120	/* set IVIC, vector size: 4 bytes, base: 0x0 */
121	mtsr	$r0, $ivb
122
123#ifndef CONFIG_SKIP_LOWLEVEL_INIT
124	jal	lowlevel_init
125/*
126 *  gp = ~VMA          for burn mode
127 *     = ~load_address for load mode
128 */
129update_gp:
130	.relax_hint 0
131	sethi   $gp, hi20(_GLOBAL_OFFSET_TABLE_-8)
132	.relax_hint 0
133	ori     $gp, $gp, lo12(_GLOBAL_OFFSET_TABLE_-4)
134	add5.pc $gp
135#endif
136
137/*
138 *  do critical initializations first (shall be in short time)
139 *  do self_relocation ASAP.
140 */
141
142/*
143 * Set the N1213 (Whitiger) core to superuser mode
144 * According to spec, it is already when reset
145 */
146#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
147	jal	turnoff_watchdog
148#endif
149
150/*
151 * Do CPU critical regs init only at reboot,
152 * not when booting from ram
153 */
154#ifdef CONFIG_INIT_CRITICAL
155	jal	cpu_init_crit		! Do CPU critical regs init
156#endif
157
158/*
159 * Set stackpointer in internal RAM to call board_init_f
160 * $sp must be 8-byte alignment for ABI compliance.
161 */
162call_board_init_f:
163	li		$sp, CONFIG_SYS_INIT_SP_ADDR
164	li		$r10, GD_SIZE	/* get GD size */
165	sub		$sp, $sp, $r10	/* GD start addr */
166	move	$r10, $sp
167	li		$r0, 0x00000000
168
169#ifdef __PIC__
170#ifdef __NDS32_N1213_43U1H__
171/* __NDS32_N1213_43U1H__ implies NDS32 V0 ISA */
172	la	$r15, board_init_f	! store function address into $r15
173#endif
174#endif
175	j	board_init_f		! jump to board_init_f() in lib/board.c
176
177/*
178 * void relocate_code (addr_sp, gd, addr_moni)
179 *
180 * This "function" does not return, instead it continues in RAM
181 * after relocating the monitor code.
182 *
183 */
184
185/*
186 *  gp = ~RAM_SIZE - TEXT_SIZE for burn/load mode
187 */
188
189.globl	relocate_code
190relocate_code:
191	move	$r4, $r0		/* save addr_sp */
192	move	$r5, $r1		/* save addr of gd */
193	move	$r6, $r2		/* save addr of destination */
194
195/* Set up the stack */
196stack_setup:
197	move	$sp, $r4
198
199	la	$r0, _start@GOTOFF
200	beq	$r0, $r6, clear_bss	/* skip relocation */
201
202	la	 $r1, _end@GOTOFF
203	move $r2, $r6			/* r2 <- scratch for copy_loop */
204
205copy_loop:
206	lwi.p	$r7, [$r0], #4
207	swi.p	$r7, [$r2], #4
208	blt	$r0, $r1, copy_loop
209
210/*
211 * fix relocations related issues
212 */
213fix_relocations:
214	l.w	$r0, _TEXT_BASE@GOTOFF	/* r0 <- Text base */
215	sub	$r9, $r6, $r0			/* r9 <- relocation offset */
216
217	la  $r7, __rel_dyn_start@GOTOFF
218	add	$r7, $r7, $r9		/* r2 <- rel __got_start in RAM */
219	la  $r8, __rel_dyn_end@GOTOFF
220	add	$r8, $r8, $r9		/* r2 <- rel __got_start in RAM */
221	li  $r3, #0x2a /* R_NDS32_RELATIVE */
2221:
223	lmw.bim $r0, [$r7], $r2 /* r0,r1,r2 <- adr,type,addend */
224	bne $r1, $r3, 2f
225
226	add $r0, $r0, $r9
227	add $r2, $r2, $r9
228	sw  $r2, [$r0]
2292:
230	blt $r7, $r8, 1b
231
232clear_bss:
233	la	$r0, __bss_start@GOTOFF	/* r0 <- rel __bss_start in FLASH */
234	add	$r0, $r0, $r9		/* r0 <- rel __bss_start in FLASH */
235	la	$r1, __bss_end@GOTOFF		/* r1 <- rel __bss_end in RAM */
236	add	$r1, $r1, $r9		/* r0 <- rel __bss_end in RAM */
237	li	$r2, 0x00000000		/* clear */
238
239clbss_l:
240	sw	$r2, [$r0]		/* clear loop... */
241	addi	$r0, $r0, #4
242	bne	$r0, $r1, clbss_l
243
244/*
245 * We are done. Do not return, instead branch to second part of board
246 * initialization, now running from RAM.
247 */
248call_board_init_r:
249	la	$r0, board_init_r@GOTOFF
250	move	$lp, $r0		/* offset of board_init_r() */
251	add	$lp, $lp, $r9		/* real address of board_init_r() */
252	/* setup parameters for board_init_r */
253	move	$r0, $r5		/* gd_t */
254	move	$r1, $r6		/* dest_addr */
255
256#ifdef __PIC__
257#ifdef __NDS32_N1213_43U1H__		/* NDS32 V0 ISA	*/
258	move	$r15, $lp		/* store function address into $r15 */
259#endif
260#endif
261
262	/* jump to it ... */
263	jr	$lp			/* jump to board_init_r() */
264
265/*
266 * Initialize CPU critical registers
267 *
268 *	1.	Setup control registers
269 *		1.1 Mask all IRQs
270 *		1.2 Flush cache and TLB
271 *		1.3 Disable MMU and cache
272 *	2.	Setup memory timing
273 */
274
275cpu_init_crit:
276
277	move	$r0, $lp		/* push	ra */
278
279	/* Disable Interrupts by clear GIE in $PSW reg */
280	setgie.d
281
282	/* Flush caches and TLB */
283	/* Invalidate caches */
284	jal	invalidate_icac
285	jal	invalidate_dcac
286
287	/* Flush TLB */
288	mfsr	$p0, $MMU_CFG
289	andi	$p0, $p0, 0x3			! MMPS
290	li	$p1, 0x2			! TLB MMU
291	bne	$p0, $p1, 1f
292	tlbop	flushall			! Flush TLB
293
2941:
295	! Disable MMU, Dcache
296	! Whitiger is MMU disabled when reset
297	! Disable the D$
298	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
299	li	$p1, DIS_DCAC
300	and	$p0, $p0, $p1			! Set DC_EN bit
301	mtsr	$p0, MR_CAC_CTL			! write back the $CACHE_CTL reg
302	isb
303
304	move	$lp, $r0
3052:
306	ret
307
308/*
309 * Invalidate I$
310 */
311invalidate_icac:
312	! read $cr1(I CAC/MEM cfg. reg.) configuration
313	mfsr	$t0, CR_ICAC_MEM
314
315	! Get the ISZ field
316	andi	$p0, $t0, ICAC_MEM_KBF_ISZ
317
318	! if $p0=0, then no I CAC existed
319	beqz	$p0, end_flush_icache
320
321	! get $p0 the index of I$ block
322	srli	$p0, $p0, 6
323
324	! $t1= bit width of I cache line size(ISZ)
325	addi	$t1, $p0, 2
326
327	li	$t4, 1
328	sll	$t5, $t4, $t1			! get $t5 cache line size
329	andi	$p1, $t0, ICAC_MEM_KBF_ISET	! get the ISET field
330	addi	$t2, $p1, 6			! $t2= bit width of ISET
331	andi	$p1, $t0, ICAC_MEM_KBF_IWAY	! get bitfield of Iway
332	srli	$p1, $p1, 3
333	addi	$p1, $p1, 1			! then $p1 is I way number
334	add	$t3, $t2, $t1			! SHIFT
335	sll	$p1, $p1, $t3			! GET the total cache size
336ICAC_LOOP:
337	sub	$p1, $p1, $t5
338	cctl	$p1, L1I_IX_INVAL
339	bnez	$p1, ICAC_LOOP
340end_flush_icache:
341	ret
342
343/*
344 * Invalidate D$
345 */
346invalidate_dcac:
347	! read $cr2(D CAC/MEM cfg. reg.) configuration
348	mfsr	$t0, CR_DCAC_MEM
349
350	! Get the DSZ field
351	andi	$p0, $t0, DCAC_MEM_KBF_DSZ
352
353	! if $p0=0, then no D CAC existed
354	beqz	$p0, end_flush_dcache
355
356	! get $p0 the index of D$ block
357	srli	$p0, $p0, 6
358
359	! $t1= bit width of D cache line size(DSZ)
360	addi	$t1, $p0, 2
361
362	li	$t4, 1
363	sll	$t5, $t4, $t1			! get $t5 cache line size
364	andi	$p1, $t0, DCAC_MEM_KBF_DSET	! get the DSET field
365	addi	$t2, $p1, 6			! $t2= bit width of DSET
366	andi	$p1, $t0, DCAC_MEM_KBF_DWAY	! get bitfield of D way
367	srli	$p1, $p1, 3
368	addi	$p1, $p1, 1			! then $p1 is D way number
369	add	$t3, $t2, $t1			! SHIFT
370	sll	$p1, $p1, $t3			! GET the total cache size
371DCAC_LOOP:
372	sub	$p1, $p1, $t5
373	cctl	$p1, L1D_IX_INVAL
374	bnez	$p1, DCAC_LOOP
375end_flush_dcache:
376	ret
377
378/*
379 * Interrupt handling
380 */
381
382/*
383 * exception handlers
384 */
385	.align	5
386
387.macro	SAVE_ALL
388	! FIXME: Other way to get PC?
389	! FIXME: Update according to the newest spec!!
3901:
391	li	 $r28, 1
392	push $r28
393	mfsr $r28, PSW			! $PSW
394	push $r28
395	mfsr $r28, EIT_EVA		! $ir1 $EVA
396	push $r28
397	mfsr $r28, EIT_ITYPE		! $ir2 $ITYPE
398	push $r28
399	mfsr $r28, EIT_MACH_ERR		! $ir3 Mach Error
400	push $r28
401	mfsr $r28, EIT_INTR_PSW		! $ir5 $IPSW
402	push $r28
403	mfsr $r28, EIT_PREV_IPSW	! $ir6 prev $IPSW
404	push $r28
405	mfsr $r28, EIT_PREV_EVA		! $ir7 prev $EVA
406	push $r28
407	mfsr $r28, EIT_PREV_ITYPE	! $ir8 prev $ITYPE
408	push $r28
409	mfsr $r28, EIT_INTR_PC		! $ir9 Interruption PC
410	push $r28
411	mfsr $r28, EIT_PREV_IPC		! $ir10 prev INTR_PC
412	push $r28
413	mfsr $r28, EIT_OVL_INTR_PC	! $ir11 Overflowed INTR_PC
414	push $r28
415	mfusr $r28, $d1.lo
416	push $r28
417	mfusr $r28, $d1.hi
418	push $r28
419	mfusr $r28, $d0.lo
420	push $r28
421	mfusr $r28, $d0.hi
422	push $r28
423	pushm $r0, $r30		! store $sp-$r31, ra-$r30, $gp-$r29, $r28-$fp
424	addi	$sp, $sp, -4	! make room for implicit pt_regs parameters
425.endm
426
427	.align	5
428tlb_fill:
429	SAVE_ALL
430	move	$r0, $sp			! To get the kernel stack
431	li	$r1, 1				! Determine interruption type
432	bal 	do_interruption
433
434	.align	5
435tlb_not_present:
436	SAVE_ALL
437	move	$r0, $sp			! To get the kernel stack
438	li	$r1, 2				! Determine interruption type
439	bal 	do_interruption
440
441	.align	5
442tlb_misc:
443	SAVE_ALL
444	move	$r0, $sp			! To get the kernel stack
445	li	$r1, 3				! Determine interruption type
446	bal 	do_interruption
447
448	.align	5
449tlb_vlpt_miss:
450	SAVE_ALL
451	move	$r0, $sp			! To get the kernel stack
452	li	$r1, 4				! Determine interruption type
453	bal	do_interruption
454
455	.align	5
456machine_error:
457	SAVE_ALL
458	move	$r0, $sp			! To get the kernel stack
459	li	$r1, 5				! Determine interruption type
460	bal	do_interruption
461
462	.align	5
463debug:
464	SAVE_ALL
465	move	$r0, $sp			! To get the kernel stack
466	li	$r1, 6				! Determine interruption type
467	bal	do_interruption
468
469	.align	5
470general_exception:
471	SAVE_ALL
472	move	$r0, $sp			! To get the kernel stack
473	li	$r1, 7				! Determine interruption type
474	bal	do_interruption
475
476	.align	5
477syscall:
478	SAVE_ALL
479	move	$r0, $sp			! To get the kernel stack
480	li	$r1, 8				! Determine interruption type
481	bal	do_interruption
482
483	.align	5
484internal_interrupt:
485	SAVE_ALL
486	move	$r0, $sp			! To get the kernel stack
487	li	$r1, 9				! Determine interruption type
488	bal	do_interruption
489
490	.align	5
491software_interrupt:
492	SAVE_ALL
493	move	$r0, $sp			! To get the kernel stack
494	li	$r1, 10				! Determine interruption type
495	bal	do_interruption
496
497	.align	5
498
499/*
500 * void reset_cpu(ulong addr);
501 * $r0: input address to jump to
502 */
503.globl reset_cpu
504reset_cpu:
505/* No need to disable MMU because we never enable it */
506
507	bal	invalidate_icac
508	bal	invalidate_dcac
509	mfsr	$p0, $MMU_CFG
510	andi	$p0, $p0, 0x3			! MMPS
511	li	$p1, 0x2			! TLB MMU
512	bne	$p0, $p1, 1f
513	tlbop	flushall			! Flush TLB
5141:
515	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
516	li	$p1, DIS_DCAC
517	and	$p0, $p0, $p1			! Clear the DC_EN bit
518	mtsr	$p0, MR_CAC_CTL			! Write back the $CACHE_CTL reg
519	br	$r0				! Jump to the input address
520