xref: /openbmc/u-boot/arch/nds32/cpu/n1213/start.S (revision be059e88) 
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/*
94 * These are defined in the board-specific linker script.
95 * Subtracting _start from them lets the linker put their
96 * relative position in the executable instead of leaving
97 * them null.
98 */
99#ifdef CONFIG_USE_IRQ
100/* IRQ stack memory (calculated at run-time) */
101.globl IRQ_STACK_START
102IRQ_STACK_START:
103	.word 0x0badc0de
104
105/* IRQ stack memory (calculated at run-time) */
106.globl FIQ_STACK_START
107FIQ_STACK_START:
108	.word 0x0badc0de
109#endif
110
111/* IRQ stack memory (calculated at run-time) + 8 bytes */
112.globl IRQ_STACK_START_IN
113IRQ_STACK_START_IN:
114	.word 0x0badc0de
115
116/*
117 * The bootstrap code of nds32 core
118 */
119
120reset:
121
122/*
123 *  gp = ~0            for burn mode
124 *     = ~load_address for load mode
125 */
126reset_gp:
127	.relax_hint 0
128	sethi   $gp, hi20(_GLOBAL_OFFSET_TABLE_-8)
129	.relax_hint 0
130	ori     $gp, $gp, lo12(_GLOBAL_OFFSET_TABLE_-4)
131	add5.pc $gp
132
133set_ivb:
134	li	$r0, 0x0
135
136	/* turn on BTB */
137	mtsr	$r0, $misc_ctl
138	/* set IVIC, vector size: 4 bytes, base: 0x0 */
139	mtsr	$r0, $ivb
140
141#ifndef CONFIG_SKIP_LOWLEVEL_INIT
142	jal	lowlevel_init
143/*
144 *  gp = ~VMA          for burn mode
145 *     = ~load_address for load mode
146 */
147update_gp:
148	.relax_hint 0
149	sethi   $gp, hi20(_GLOBAL_OFFSET_TABLE_-8)
150	.relax_hint 0
151	ori     $gp, $gp, lo12(_GLOBAL_OFFSET_TABLE_-4)
152	add5.pc $gp
153#endif
154
155/*
156 *  do critical initializations first (shall be in short time)
157 *  do self_relocation ASAP.
158 */
159
160/*
161 * Set the N1213 (Whitiger) core to superuser mode
162 * According to spec, it is already when reset
163 */
164#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
165	jal	turnoff_watchdog
166#endif
167
168/*
169 * Do CPU critical regs init only at reboot,
170 * not when booting from ram
171 */
172#ifdef CONFIG_INIT_CRITICAL
173	jal	cpu_init_crit		! Do CPU critical regs init
174#endif
175
176/*
177 * Set stackpointer in internal RAM to call board_init_f
178 * $sp must be 8-byte alignment for ABI compliance.
179 */
180call_board_init_f:
181	li		$sp, CONFIG_SYS_INIT_SP_ADDR
182	li		$r10, GD_SIZE	/* get GD size */
183	sub		$sp, $sp, $r10	/* GD start addr */
184	move	$r10, $sp
185	li		$r0, 0x00000000
186
187#ifdef __PIC__
188#ifdef __NDS32_N1213_43U1H__
189/* __NDS32_N1213_43U1H__ implies NDS32 V0 ISA */
190	la	$r15, board_init_f	! store function address into $r15
191#endif
192#endif
193	j	board_init_f		! jump to board_init_f() in lib/board.c
194
195/*
196 * void relocate_code (addr_sp, gd, addr_moni)
197 *
198 * This "function" does not return, instead it continues in RAM
199 * after relocating the monitor code.
200 *
201 */
202
203/*
204 *  gp = ~RAM_SIZE - TEXT_SIZE for burn/load mode
205 */
206
207.globl	relocate_code
208relocate_code:
209	move	$r4, $r0		/* save addr_sp */
210	move	$r5, $r1		/* save addr of gd */
211	move	$r6, $r2		/* save addr of destination */
212
213/* Set up the stack */
214stack_setup:
215	move	$sp, $r4
216
217	la	$r0, _start@GOTOFF
218	beq	$r0, $r6, clear_bss	/* skip relocation */
219
220	la	 $r1, _end@GOTOFF
221	move $r2, $r6			/* r2 <- scratch for copy_loop */
222
223copy_loop:
224	lwi.p	$r7, [$r0], #4
225	swi.p	$r7, [$r2], #4
226	blt	$r0, $r1, copy_loop
227
228/*
229 * fix relocations related issues
230 */
231fix_relocations:
232	l.w	$r0, _TEXT_BASE@GOTOFF	/* r0 <- Text base */
233	sub	$r9, $r6, $r0			/* r9 <- relocation offset */
234
235	la  $r7, __rel_dyn_start@GOTOFF
236	add	$r7, $r7, $r9		/* r2 <- rel __got_start in RAM */
237	la  $r8, __rel_dyn_end@GOTOFF
238	add	$r8, $r8, $r9		/* r2 <- rel __got_start in RAM */
239	li  $r3, #0x2a /* R_NDS32_RELATIVE */
2401:
241	lmw.bim $r0, [$r7], $r2 /* r0,r1,r2 <- adr,type,addend */
242	bne $r1, $r3, 2f
243
244	add $r0, $r0, $r9
245	add $r2, $r2, $r9
246	sw  $r2, [$r0]
2472:
248	blt $r7, $r8, 1b
249
250clear_bss:
251	la	$r0, __bss_start@GOTOFF	/* r0 <- rel __bss_start in FLASH */
252	add	$r0, $r0, $r9		/* r0 <- rel __bss_start in FLASH */
253	la	$r1, __bss_end@GOTOFF		/* r1 <- rel __bss_end in RAM */
254	add	$r1, $r1, $r9		/* r0 <- rel __bss_end in RAM */
255	li	$r2, 0x00000000		/* clear */
256
257clbss_l:
258	sw	$r2, [$r0]		/* clear loop... */
259	addi	$r0, $r0, #4
260	bne	$r0, $r1, clbss_l
261
262/*
263 * We are done. Do not return, instead branch to second part of board
264 * initialization, now running from RAM.
265 */
266call_board_init_r:
267	la	$r0, board_init_r@GOTOFF
268	move	$lp, $r0		/* offset of board_init_r() */
269	add	$lp, $lp, $r9		/* real address of board_init_r() */
270	/* setup parameters for board_init_r */
271	move	$r0, $r5		/* gd_t */
272	move	$r1, $r6		/* dest_addr */
273
274#ifdef __PIC__
275#ifdef __NDS32_N1213_43U1H__		/* NDS32 V0 ISA	*/
276	move	$r15, $lp		/* store function address into $r15 */
277#endif
278#endif
279
280	/* jump to it ... */
281	jr	$lp			/* jump to board_init_r() */
282
283/*
284 * Initialize CPU critical registers
285 *
286 *	1.	Setup control registers
287 *		1.1 Mask all IRQs
288 *		1.2 Flush cache and TLB
289 *		1.3 Disable MMU and cache
290 *	2.	Setup memory timing
291 */
292
293cpu_init_crit:
294
295	move	$r0, $lp		/* push	ra */
296
297	/* Disable Interrupts by clear GIE in $PSW reg */
298	setgie.d
299
300	/* Flush caches and TLB */
301	/* Invalidate caches */
302	jal	invalidate_icac
303	jal	invalidate_dcac
304
305	/* Flush TLB */
306	mfsr	$p0, $MMU_CFG
307	andi	$p0, $p0, 0x3			! MMPS
308	li	$p1, 0x2			! TLB MMU
309	bne	$p0, $p1, 1f
310	tlbop	flushall			! Flush TLB
311
3121:
313	! Disable MMU, Dcache
314	! Whitiger is MMU disabled when reset
315	! Disable the D$
316	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
317	li	$p1, DIS_DCAC
318	and	$p0, $p0, $p1			! Set DC_EN bit
319	mtsr	$p0, MR_CAC_CTL			! write back the $CACHE_CTL reg
320	isb
321
322	move	$lp, $r0
3232:
324	ret
325
326/*
327 * Invalidate I$
328 */
329invalidate_icac:
330	! read $cr1(I CAC/MEM cfg. reg.) configuration
331	mfsr	$t0, CR_ICAC_MEM
332
333	! Get the ISZ field
334	andi	$p0, $t0, ICAC_MEM_KBF_ISZ
335
336	! if $p0=0, then no I CAC existed
337	beqz	$p0, end_flush_icache
338
339	! get $p0 the index of I$ block
340	srli	$p0, $p0, 6
341
342	! $t1= bit width of I cache line size(ISZ)
343	addi	$t1, $p0, 2
344
345	li	$t4, 1
346	sll	$t5, $t4, $t1			! get $t5 cache line size
347	andi	$p1, $t0, ICAC_MEM_KBF_ISET	! get the ISET field
348	addi	$t2, $p1, 6			! $t2= bit width of ISET
349	andi	$p1, $t0, ICAC_MEM_KBF_IWAY	! get bitfield of Iway
350	srli	$p1, $p1, 3
351	addi	$p1, $p1, 1			! then $p1 is I way number
352	add	$t3, $t2, $t1			! SHIFT
353	sll	$p1, $p1, $t3			! GET the total cache size
354ICAC_LOOP:
355	sub	$p1, $p1, $t5
356	cctl	$p1, L1I_IX_INVAL
357	bnez	$p1, ICAC_LOOP
358end_flush_icache:
359	ret
360
361/*
362 * Invalidate D$
363 */
364invalidate_dcac:
365	! read $cr2(D CAC/MEM cfg. reg.) configuration
366	mfsr	$t0, CR_DCAC_MEM
367
368	! Get the DSZ field
369	andi	$p0, $t0, DCAC_MEM_KBF_DSZ
370
371	! if $p0=0, then no D CAC existed
372	beqz	$p0, end_flush_dcache
373
374	! get $p0 the index of D$ block
375	srli	$p0, $p0, 6
376
377	! $t1= bit width of D cache line size(DSZ)
378	addi	$t1, $p0, 2
379
380	li	$t4, 1
381	sll	$t5, $t4, $t1			! get $t5 cache line size
382	andi	$p1, $t0, DCAC_MEM_KBF_DSET	! get the DSET field
383	addi	$t2, $p1, 6			! $t2= bit width of DSET
384	andi	$p1, $t0, DCAC_MEM_KBF_DWAY	! get bitfield of D way
385	srli	$p1, $p1, 3
386	addi	$p1, $p1, 1			! then $p1 is D way number
387	add	$t3, $t2, $t1			! SHIFT
388	sll	$p1, $p1, $t3			! GET the total cache size
389DCAC_LOOP:
390	sub	$p1, $p1, $t5
391	cctl	$p1, L1D_IX_INVAL
392	bnez	$p1, DCAC_LOOP
393end_flush_dcache:
394	ret
395
396/*
397 * Interrupt handling
398 */
399
400/*
401 * exception handlers
402 */
403	.align	5
404
405.macro	SAVE_ALL
406	! FIXME: Other way to get PC?
407	! FIXME: Update according to the newest spec!!
4081:
409	li	 $r28, 1
410	push $r28
411	mfsr $r28, PSW			! $PSW
412	push $r28
413	mfsr $r28, EIT_EVA		! $ir1 $EVA
414	push $r28
415	mfsr $r28, EIT_ITYPE		! $ir2 $ITYPE
416	push $r28
417	mfsr $r28, EIT_MACH_ERR		! $ir3 Mach Error
418	push $r28
419	mfsr $r28, EIT_INTR_PSW		! $ir5 $IPSW
420	push $r28
421	mfsr $r28, EIT_PREV_IPSW	! $ir6 prev $IPSW
422	push $r28
423	mfsr $r28, EIT_PREV_EVA		! $ir7 prev $EVA
424	push $r28
425	mfsr $r28, EIT_PREV_ITYPE	! $ir8 prev $ITYPE
426	push $r28
427	mfsr $r28, EIT_INTR_PC		! $ir9 Interruption PC
428	push $r28
429	mfsr $r28, EIT_PREV_IPC		! $ir10 prev INTR_PC
430	push $r28
431	mfsr $r28, EIT_OVL_INTR_PC	! $ir11 Overflowed INTR_PC
432	push $r28
433	mfusr $r28, $d1.lo
434	push $r28
435	mfusr $r28, $d1.hi
436	push $r28
437	mfusr $r28, $d0.lo
438	push $r28
439	mfusr $r28, $d0.hi
440	push $r28
441	pushm $r0, $r30		! store $sp-$r31, ra-$r30, $gp-$r29, $r28-$fp
442	addi	$sp, $sp, -4	! make room for implicit pt_regs parameters
443.endm
444
445	.align	5
446tlb_fill:
447	SAVE_ALL
448	move	$r0, $sp			! To get the kernel stack
449	li	$r1, 1				! Determine interruption type
450	bal 	do_interruption
451
452	.align	5
453tlb_not_present:
454	SAVE_ALL
455	move	$r0, $sp			! To get the kernel stack
456	li	$r1, 2				! Determine interruption type
457	bal 	do_interruption
458
459	.align	5
460tlb_misc:
461	SAVE_ALL
462	move	$r0, $sp			! To get the kernel stack
463	li	$r1, 3				! Determine interruption type
464	bal 	do_interruption
465
466	.align	5
467tlb_vlpt_miss:
468	SAVE_ALL
469	move	$r0, $sp			! To get the kernel stack
470	li	$r1, 4				! Determine interruption type
471	bal	do_interruption
472
473	.align	5
474machine_error:
475	SAVE_ALL
476	move	$r0, $sp			! To get the kernel stack
477	li	$r1, 5				! Determine interruption type
478	bal	do_interruption
479
480	.align	5
481debug:
482	SAVE_ALL
483	move	$r0, $sp			! To get the kernel stack
484	li	$r1, 6				! Determine interruption type
485	bal	do_interruption
486
487	.align	5
488general_exception:
489	SAVE_ALL
490	move	$r0, $sp			! To get the kernel stack
491	li	$r1, 7				! Determine interruption type
492	bal	do_interruption
493
494	.align	5
495syscall:
496	SAVE_ALL
497	move	$r0, $sp			! To get the kernel stack
498	li	$r1, 8				! Determine interruption type
499	bal	do_interruption
500
501	.align	5
502internal_interrupt:
503	SAVE_ALL
504	move	$r0, $sp			! To get the kernel stack
505	li	$r1, 9				! Determine interruption type
506	bal	do_interruption
507
508	.align	5
509software_interrupt:
510	SAVE_ALL
511	move	$r0, $sp			! To get the kernel stack
512	li	$r1, 10				! Determine interruption type
513	bal	do_interruption
514
515	.align	5
516
517/*
518 * void reset_cpu(ulong addr);
519 * $r0: input address to jump to
520 */
521.globl reset_cpu
522reset_cpu:
523/* No need to disable MMU because we never enable it */
524
525	bal	invalidate_icac
526	bal	invalidate_dcac
527	mfsr	$p0, $MMU_CFG
528	andi	$p0, $p0, 0x3			! MMPS
529	li	$p1, 0x2			! TLB MMU
530	bne	$p0, $p1, 1f
531	tlbop	flushall			! Flush TLB
5321:
533	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
534	li	$p1, DIS_DCAC
535	and	$p0, $p0, $p1			! Clear the DC_EN bit
536	mtsr	$p0, MR_CAC_CTL			! Write back the $CACHE_CTL reg
537	br	$r0				! Jump to the input address
538