xref: /openbmc/u-boot/arch/nds32/cpu/n1213/start.S (revision a381bcf5) 
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#include <asm-offsets.h>
13#include <config.h>
14#include <common.h>
15#include <asm/macro.h>
16
17/*
18 * Jump vector table for EVIC mode
19 */
20#define ENA_DCAC		2UL
21#define DIS_DCAC		~ENA_DCAC
22#define ICAC_MEM_KBF_ISET	(0x07)	 	! I Cache sets per way
23#define ICAC_MEM_KBF_IWAY	(0x07<<3)	! I cache ways
24#define ICAC_MEM_KBF_ISZ	(0x07<<6)	! I cache line size
25#define DCAC_MEM_KBF_DSET	(0x07)		! D Cache sets per way
26#define DCAC_MEM_KBF_DWAY	(0x07<<3)	! D cache ways
27#define DCAC_MEM_KBF_DSZ	(0x07<<6)	! D cache line size
28
29#define PSW			$ir0
30#define EIT_INTR_PSW		$ir1		! interruption $PSW
31#define EIT_PREV_IPSW		$ir2		! previous $IPSW
32#define EIT_IVB			$ir3		! intr vector base address
33#define EIT_EVA			$ir4		! MMU related Exception VA reg
34#define EIT_PREV_EVA		$ir5		! previous $eva
35#define EIT_ITYPE		$ir6		! interruption type
36#define EIT_PREV_ITYPE		$ir7		! prev intr type
37#define EIT_MACH_ERR		$ir8		! machine error log
38#define EIT_INTR_PC		$ir9		! Interruption PC
39#define EIT_PREV_IPC		$ir10		! previous $IPC
40#define EIT_OVL_INTR_PC		$ir11		! overflow interruption PC
41#define EIT_PREV_P0		$ir12		! prev $P0
42#define EIT_PREV_P1		$ir13		! prev $p1
43#define CR_ICAC_MEM		$cr1		! I-cache/memory config reg
44#define CR_DCAC_MEM		$cr2		! D-cache/memory config reg
45#define MR_CAC_CTL		$mr8
46
47.globl _start
48
49_start:	j	reset
50	j	tlb_fill
51	j	tlb_not_present
52	j	tlb_misc
53	j	tlb_vlpt_miss
54	j	machine_error
55	j	debug
56	j	general_exception
57	j	syscall
58	j	internal_interrupt		! H0I
59	j	internal_interrupt		! H1I
60	j	internal_interrupt		! H2I
61	j	internal_interrupt		! H3I
62	j	internal_interrupt		! H4I
63	j	internal_interrupt		! H5I
64	j	software_interrupt		! S0I
65
66	.balign 16
67
68/*
69 * Andesboot Startup Code (reset vector)
70 *
71 *	1.	bootstrap
72 *		1.1 reset - start of u-boot
73 *		1.2 to superuser mode - as is when reset
74 *		1.4 Do lowlevel_init
75 *			- (this will jump out to lowlevel_init.S in SoC)
76 *			- (lowlevel_init)
77 *		1.3 Turn off watchdog timer
78 *			- (this will jump out to watchdog.S in SoC)
79 *			- (turnoff_watchdog)
80 *	2.	Do critical init when reboot (not from mem)
81 *	3.	Relocate andesboot to ram
82 *	4.	Setup stack
83 *	5.	Jump to second stage (board_init_r)
84 */
85
86/* Note: TEXT_BASE is defined by the (board-dependent) linker script */
87.globl _TEXT_BASE
88_TEXT_BASE:
89	.word	CONFIG_SYS_TEXT_BASE
90
91/*
92 * These are defined in the board-specific linker script.
93 * Subtracting _start from them lets the linker put their
94 * relative position in the executable instead of leaving
95 * them null.
96 */
97#ifdef CONFIG_USE_IRQ
98/* IRQ stack memory (calculated at run-time) */
99.globl IRQ_STACK_START
100IRQ_STACK_START:
101	.word 0x0badc0de
102
103/* IRQ stack memory (calculated at run-time) */
104.globl FIQ_STACK_START
105FIQ_STACK_START:
106	.word 0x0badc0de
107#endif
108
109/* IRQ stack memory (calculated at run-time) + 8 bytes */
110.globl IRQ_STACK_START_IN
111IRQ_STACK_START_IN:
112	.word 0x0badc0de
113
114/*
115 * The bootstrap code of nds32 core
116 */
117
118reset:
119set_ivb:
120	li	$r0, 0x0
121
122	/* turn on BTB */
123	mtsr	$r0, $misc_ctl
124	/* set IVIC, vector size: 4 bytes, base: 0x0 */
125	mtsr	$r0, $ivb
126
127load_lli:
128#ifndef CONFIG_SKIP_LOWLEVEL_INIT
129	jal	load_lowlevel_init
130	jral	$p0
131#endif
132
133/*
134 * Set the N1213 (Whitiger) core to superuser mode
135 * According to spec, it is already when reset
136 */
137turnoff_wtdog:
138#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
139	jal	load_turnoff_watchdog
140	jral	$p0
141#endif
142
143/*
144 * Do CPU critical regs init only at reboot,
145 * not when booting from ram
146 */
147#ifdef CONFIG_INIT_CRITICAL
148	bal	cpu_init_crit		! Do CPU critical regs init
149#endif
150
151/*
152 * Set stackpointer in internal RAM to call board_init_f
153 * $sp must be 8-byte alignment for ABI compliance.
154 */
155call_board_init_f:
156	li		$sp, CONFIG_SYS_INIT_SP_ADDR
157	li		$r10, GD_SIZE	/* get GD size */
158	sub		$sp, $sp, $r10	/* GD start addr */
159	move	$r10, $sp
160	li		$r0, 0x00000000
161
162#ifdef __PIC__
163#ifdef __NDS32_N1213_43U1H__
164/* __NDS32_N1213_43U1H__ implies NDS32 V0 ISA */
165	la	$r15, board_init_f	! store function address into $r15
166#endif
167#endif
168	j	board_init_f		! jump to board_init_f() in lib/board.c
169
170/*
171 * void relocate_code (addr_sp, gd, addr_moni)
172 *
173 * This "function" does not return, instead it continues in RAM
174 * after relocating the monitor code.
175 *
176 */
177.globl	relocate_code
178relocate_code:
179	move	$r4, $r0		/* save addr_sp */
180	move	$r5, $r1		/* save addr of gd */
181	move	$r6, $r2		/* save addr of destination */
182
183/* Set up the stack */
184stack_setup:
185	move	$sp, $r4
186
187	la	$r0, _start
188
189	beq	$r0, $r6, clear_bss	/* skip relocation */
190
191	move	$r1, $r6		/* r1 <- scratch for copy_loop */
192	la	$r3, __bss_start
193	sub	$r3, $r3, $r0		/* r3 <- __bss_start_ofs */
194	add	$r2, $r0, $r3		/* r2 <- source end address */
195
196copy_loop:
197	lwi.p	$r7, [$r0], #4
198	swi.p	$r7, [$r1], #4
199	blt	$r0, $r2, copy_loop
200
201/*
202 * fix relocations related issues
203 */
204fix_relocations:
205	l.w	$r0, _TEXT_BASE		/* r0 <- Text base */
206	sub	$r9, $r6, $r0		/* r9 <- relocation offset */
207
208fix_got:
209/*
210 * Now we want to update GOT.
211 *
212 * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object
213 * generated by GNU ld. Skip these reserved entries from relocation.
214 */
215	la	$r2, __got_start	/* r2 <- rel __got_start in FLASH */
216	add	$r2, $r2, $r9		/* r2 <- rel __got_start in RAM */
217	la	$r3, __got_end		/* r3 <- rel __got_end in FLASH */
218	add	$r3, $r3, $r9		/* r3 <- rel __got_end in RAM */
219	addi	$r2, $r2, #8		/* skipping first two entries */
220fix_got_loop:
221	lwi	$r0, [$r2]		/* r0 <- location in FLASH to fix up */
222	add	$r0, $r0, $r9		/* r0 <- location fix up to RAM */
223	swi.p	$r0, [$r2], #4		/* r0 <- store fix into .got in RAM */
224	blt	$r2, $r3, fix_got_loop
225
226clear_bss:
227	la	$r0, __bss_start	/* r0 <- rel __bss_start in FLASH */
228	add	$r0, $r0, $r9		/* r0 <- rel __bss_start in FLASH */
229	la	$r1, __bss_end		/* r1 <- rel __bss_end in RAM */
230	add	$r1, $r1, $r9		/* r0 <- rel __bss_end in RAM */
231	li	$r2, 0x00000000		/* clear */
232
233clbss_l:
234	sw	$r2, [$r0]		/* clear loop... */
235	addi	$r0, $r0, #4
236	bne	$r0, $r1, clbss_l
237
238/*
239 * We are done. Do not return, instead branch to second part of board
240 * initialization, now running from RAM.
241 */
242call_board_init_r:
243	la	$r0, board_init_r
244	move	$lp, $r0		/* offset of board_init_r() */
245	add	$lp, $lp, $r9		/* real address of board_init_r() */
246	/* setup parameters for board_init_r */
247	move	$r0, $r5		/* gd_t */
248	move	$r1, $r6		/* dest_addr */
249
250#ifdef __PIC__
251#ifdef __NDS32_N1213_43U1H__		/* NDS32 V0 ISA	*/
252	move	$r15, $lp		/* store function address into $r15 */
253#endif
254#endif
255
256	/* jump to it ... */
257	jr	$lp			/* jump to board_init_r() */
258
259/*
260 * Initialize CPU critical registers
261 *
262 *	1.	Setup control registers
263 *		1.1 Mask all IRQs
264 *		1.2 Flush cache and TLB
265 *		1.3 Disable MMU and cache
266 *	2.	Setup memory timing
267 */
268
269cpu_init_crit:
270
271	move	$r0, $lp		/* push	ra */
272
273	/* Disable Interrupts by clear GIE in $PSW reg */
274	setgie.d
275
276	/* Flush caches and TLB */
277	/* Invalidate caches */
278	bal	invalidate_icac
279	bal	invalidate_dcac
280
281	/* Flush TLB */
282	mfsr	$p0, $MMU_CFG
283	andi	$p0, $p0, 0x3			! MMPS
284	li	$p1, 0x2			! TLB MMU
285	bne	$p0, $p1, 1f
286	tlbop	flushall			! Flush TLB
287
2881:
289	! Disable MMU, Dcache
290	! Whitiger is MMU disabled when reset
291	! Disable the D$
292	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
293	li	$p1, DIS_DCAC
294	and	$p0, $p0, $p1			! Set DC_EN bit
295	mtsr	$p0, MR_CAC_CTL			! write back the $CACHE_CTL reg
296	isb
297
298	move	$lp, $r0
2992:
300	ret
301
302#ifndef CONFIG_SKIP_LOWLEVEL_INIT
303load_lowlevel_init:
304	la  $r6, lowlevel_init
305	la  $r7, load_lli + 4
306	sub $p0, $r6, $r7
307	add $p0, $p0, $lp
308ret
309#endif
310
311#ifndef CONFIG_SKIP_TRUNOFF_WATCHDOG
312load_turnoff_watchdog:
313	la  $r6, turnoff_watchdog
314	la  $r7, turnoff_wtdog + 4
315	sub $p0, $r6, $r7
316	add $p0, $p0, $lp
317ret
318#endif
319
320/*
321 * Invalidate I$
322 */
323invalidate_icac:
324	! read $cr1(I CAC/MEM cfg. reg.) configuration
325	mfsr	$t0, CR_ICAC_MEM
326
327	! Get the ISZ field
328	andi	$p0, $t0, ICAC_MEM_KBF_ISZ
329
330	! if $p0=0, then no I CAC existed
331	beqz	$p0, end_flush_icache
332
333	! get $p0 the index of I$ block
334	srli	$p0, $p0, 6
335
336	! $t1= bit width of I cache line size(ISZ)
337	addi	$t1, $p0, 2
338
339	li	$t4, 1
340	sll	$t5, $t4, $t1			! get $t5 cache line size
341	andi	$p1, $t0, ICAC_MEM_KBF_ISET	! get the ISET field
342	addi	$t2, $p1, 6			! $t2= bit width of ISET
343	andi	$p1, $t0, ICAC_MEM_KBF_IWAY	! get bitfield of Iway
344	srli	$p1, $p1, 3
345	addi	$p1, $p1, 1			! then $p1 is I way number
346	add	$t3, $t2, $t1			! SHIFT
347	sll	$p1, $p1, $t3			! GET the total cache size
348ICAC_LOOP:
349	sub	$p1, $p1, $t5
350	cctl	$p1, L1I_IX_INVAL
351	bnez	$p1, ICAC_LOOP
352end_flush_icache:
353	ret
354
355/*
356 * Invalidate D$
357 */
358invalidate_dcac:
359	! read $cr2(D CAC/MEM cfg. reg.) configuration
360	mfsr	$t0, CR_DCAC_MEM
361
362	! Get the DSZ field
363	andi	$p0, $t0, DCAC_MEM_KBF_DSZ
364
365	! if $p0=0, then no D CAC existed
366	beqz	$p0, end_flush_dcache
367
368	! get $p0 the index of D$ block
369	srli	$p0, $p0, 6
370
371	! $t1= bit width of D cache line size(DSZ)
372	addi	$t1, $p0, 2
373
374	li	$t4, 1
375	sll	$t5, $t4, $t1			! get $t5 cache line size
376	andi	$p1, $t0, DCAC_MEM_KBF_DSET	! get the DSET field
377	addi	$t2, $p1, 6			! $t2= bit width of DSET
378	andi	$p1, $t0, DCAC_MEM_KBF_DWAY	! get bitfield of D way
379	srli	$p1, $p1, 3
380	addi	$p1, $p1, 1			! then $p1 is D way number
381	add	$t3, $t2, $t1			! SHIFT
382	sll	$p1, $p1, $t3			! GET the total cache size
383DCAC_LOOP:
384	sub	$p1, $p1, $t5
385	cctl	$p1, L1D_IX_INVAL
386	bnez	$p1, DCAC_LOOP
387end_flush_dcache:
388	ret
389
390/*
391 * Interrupt handling
392 */
393
394/*
395 * exception handlers
396 */
397	.align	5
398
399.macro	SAVE_ALL
400	! FIXME: Other way to get PC?
401	! FIXME: Update according to the newest spec!!
4021:
403	li	 $r28, 1
404	push $r28
405	mfsr $r28, PSW			! $PSW
406	push $r28
407	mfsr $r28, EIT_EVA		! $ir1 $EVA
408	push $r28
409	mfsr $r28, EIT_ITYPE		! $ir2 $ITYPE
410	push $r28
411	mfsr $r28, EIT_MACH_ERR		! $ir3 Mach Error
412	push $r28
413	mfsr $r28, EIT_INTR_PSW		! $ir5 $IPSW
414	push $r28
415	mfsr $r28, EIT_PREV_IPSW	! $ir6 prev $IPSW
416	push $r28
417	mfsr $r28, EIT_PREV_EVA		! $ir7 prev $EVA
418	push $r28
419	mfsr $r28, EIT_PREV_ITYPE	! $ir8 prev $ITYPE
420	push $r28
421	mfsr $r28, EIT_INTR_PC		! $ir9 Interruption PC
422	push $r28
423	mfsr $r28, EIT_PREV_IPC		! $ir10 prev INTR_PC
424	push $r28
425	mfsr $r28, EIT_OVL_INTR_PC	! $ir11 Overflowed INTR_PC
426	push $r28
427	mfusr $r28, $d1.lo
428	push $r28
429	mfusr $r28, $d1.hi
430	push $r28
431	mfusr $r28, $d0.lo
432	push $r28
433	mfusr $r28, $d0.hi
434	push $r28
435	pushm $r0, $r30		! store $sp-$r31, ra-$r30, $gp-$r29, $r28-$fp
436	addi	$sp, $sp, -4	! make room for implicit pt_regs parameters
437.endm
438
439	.align	5
440tlb_fill:
441	SAVE_ALL
442	move	$r0, $sp			! To get the kernel stack
443	li	$r1, 1				! Determine interruption type
444	bal 	do_interruption
445
446	.align	5
447tlb_not_present:
448	SAVE_ALL
449	move	$r0, $sp			! To get the kernel stack
450	li	$r1, 2				! Determine interruption type
451	bal 	do_interruption
452
453	.align	5
454tlb_misc:
455	SAVE_ALL
456	move	$r0, $sp			! To get the kernel stack
457	li	$r1, 3				! Determine interruption type
458	bal 	do_interruption
459
460	.align	5
461tlb_vlpt_miss:
462	SAVE_ALL
463	move	$r0, $sp			! To get the kernel stack
464	li	$r1, 4				! Determine interruption type
465	bal	do_interruption
466
467	.align	5
468machine_error:
469	SAVE_ALL
470	move	$r0, $sp			! To get the kernel stack
471	li	$r1, 5				! Determine interruption type
472	bal	do_interruption
473
474	.align	5
475debug:
476	SAVE_ALL
477	move	$r0, $sp			! To get the kernel stack
478	li	$r1, 6				! Determine interruption type
479	bal	do_interruption
480
481	.align	5
482general_exception:
483	SAVE_ALL
484	move	$r0, $sp			! To get the kernel stack
485	li	$r1, 7				! Determine interruption type
486	bal	do_interruption
487
488	.align	5
489syscall:
490	SAVE_ALL
491	move	$r0, $sp			! To get the kernel stack
492	li	$r1, 8				! Determine interruption type
493	bal	do_interruption
494
495	.align	5
496internal_interrupt:
497	SAVE_ALL
498	move	$r0, $sp			! To get the kernel stack
499	li	$r1, 9				! Determine interruption type
500	bal	do_interruption
501
502	.align	5
503software_interrupt:
504	SAVE_ALL
505	move	$r0, $sp			! To get the kernel stack
506	li	$r1, 10				! Determine interruption type
507	bal	do_interruption
508
509	.align	5
510
511/*
512 * void reset_cpu(ulong addr);
513 * $r0: input address to jump to
514 */
515.globl reset_cpu
516reset_cpu:
517/* No need to disable MMU because we never enable it */
518
519	bal	invalidate_icac
520	bal	invalidate_dcac
521	mfsr	$p0, $MMU_CFG
522	andi	$p0, $p0, 0x3			! MMPS
523	li	$p1, 0x2			! TLB MMU
524	bne	$p0, $p1, 1f
525	tlbop	flushall			! Flush TLB
5261:
527	mfsr	$p0, MR_CAC_CTL			! Get the $CACHE_CTL reg
528	li	$p1, DIS_DCAC
529	and	$p0, $p0, $p1			! Clear the DC_EN bit
530	mtsr	$p0, MR_CAC_CTL			! Write back the $CACHE_CTL reg
531	br	$r0				! Jump to the input address
532