xref: /openbmc/linux/arch/mips/kernel/bmips_vec.S (revision b8265621) 
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com)
7 *
8 * Reset/NMI/re-entry vectors for BMIPS processors
9 */
10
11
12#include <asm/asm.h>
13#include <asm/asmmacro.h>
14#include <asm/cacheops.h>
15#include <asm/cpu.h>
16#include <asm/regdef.h>
17#include <asm/mipsregs.h>
18#include <asm/stackframe.h>
19#include <asm/addrspace.h>
20#include <asm/hazards.h>
21#include <asm/bmips.h>
22
23	.macro	BARRIER
24	.set	mips32
25	_ssnop
26	_ssnop
27	_ssnop
28	.set	mips0
29	.endm
30
31/***********************************************************************
32 * Alternate CPU1 startup vector for BMIPS4350
33 *
34 * On some systems the bootloader has already started CPU1 and configured
35 * it to resume execution at 0x8000_0200 (!BEV IV vector) when it is
36 * triggered by the SW1 interrupt.  If that is the case we try to move
37 * it to a more convenient place: BMIPS_WARM_RESTART_VEC @ 0x8000_0380.
38 ***********************************************************************/
39
40LEAF(bmips_smp_movevec)
41	la	k0, 1f
42	li	k1, CKSEG1
43	or	k0, k1
44	jr	k0
45
461:
47	/* clear IV, pending IPIs */
48	mtc0	zero, CP0_CAUSE
49
50	/* re-enable IRQs to wait for SW1 */
51	li	k0, ST0_IE | ST0_BEV | STATUSF_IP1
52	mtc0	k0, CP0_STATUS
53
54	/* set up CPU1 CBR; move BASE to 0xa000_0000 */
55	li	k0, 0xff400000
56	mtc0	k0, $22, 6
57	/* set up relocation vector address based on thread ID */
58	mfc0	k1, $22, 3
59	srl	k1, 16
60	andi	k1, 0x8000
61	or	k1, CKSEG1 | BMIPS_RELO_VECTOR_CONTROL_0
62	or	k0, k1
63	li	k1, 0xa0080000
64	sw	k1, 0(k0)
65
66	/* wait here for SW1 interrupt from bmips_boot_secondary() */
67	wait
68
69	la	k0, bmips_reset_nmi_vec
70	li	k1, CKSEG1
71	or	k0, k1
72	jr	k0
73END(bmips_smp_movevec)
74
75/***********************************************************************
76 * Reset/NMI vector
77 * For BMIPS processors that can relocate their exception vectors, this
78 * entire function gets copied to 0x8000_0000.
79 ***********************************************************************/
80
81NESTED(bmips_reset_nmi_vec, PT_SIZE, sp)
82	.set	push
83	.set	noat
84	.align	4
85
86#ifdef CONFIG_SMP
87	/* if the NMI bit is clear, assume this is a CPU1 reset instead */
88	li	k1, (1 << 19)
89	mfc0	k0, CP0_STATUS
90	and	k0, k1
91	beqz	k0, soft_reset
92
93#if defined(CONFIG_CPU_BMIPS5000)
94	mfc0	k0, CP0_PRID
95	li	k1, PRID_IMP_BMIPS5000
96	/* mask with PRID_IMP_BMIPS5000 to cover both variants */
97	andi	k0, PRID_IMP_BMIPS5000
98	bne	k0, k1, 1f
99
100	/* if we're not on core 0, this must be the SMP boot signal */
101	li	k1, (3 << 25)
102	mfc0	k0, $22
103	and	k0, k1
104	bnez	k0, bmips_smp_entry
1051:
106#endif /* CONFIG_CPU_BMIPS5000 */
107#endif /* CONFIG_SMP */
108
109	/* nope, it's just a regular NMI */
110	SAVE_ALL
111	move	a0, sp
112
113	/* clear EXL, ERL, BEV so that TLB refills still work */
114	mfc0	k0, CP0_STATUS
115	li	k1, ST0_ERL | ST0_EXL | ST0_BEV | ST0_IE
116	or	k0, k1
117	xor	k0, k1
118	mtc0	k0, CP0_STATUS
119	BARRIER
120
121	/* jump to the NMI handler function */
122	la	k0, nmi_handler
123	jr	k0
124
125	RESTORE_ALL
126	.set	arch=r4000
127	eret
128
129#ifdef CONFIG_SMP
130soft_reset:
131
132#if defined(CONFIG_CPU_BMIPS5000)
133	mfc0	k0, CP0_PRID
134	andi	k0, 0xff00
135	li	k1, PRID_IMP_BMIPS5200
136	bne	k0, k1, bmips_smp_entry
137
138        /* if running on TP 1, jump  to  bmips_smp_entry */
139        mfc0    k0, $22
140        li      k1, (1 << 24)
141        and     k1, k0
142        bnez    k1, bmips_smp_entry
143        nop
144
145        /*
146         * running on TP0, can not be core 0 (the boot core).
147         * Check for soft reset.  Indicates a warm boot
148         */
149        mfc0    k0, $12
150        li      k1, (1 << 20)
151        and     k0, k1
152        beqz    k0, bmips_smp_entry
153
154        /*
155         * Warm boot.
156         * Cache init is only done on TP0
157         */
158        la      k0, bmips_5xxx_init
159        jalr    k0
160        nop
161
162        b       bmips_smp_entry
163        nop
164#endif
165
166/***********************************************************************
167 * CPU1 reset vector (used for the initial boot only)
168 * This is still part of bmips_reset_nmi_vec().
169 ***********************************************************************/
170
171bmips_smp_entry:
172
173	/* set up CP0 STATUS; enable FPU */
174	li	k0, 0x30000000
175	mtc0	k0, CP0_STATUS
176	BARRIER
177
178	/* set local CP0 CONFIG to make kseg0 cacheable, write-back */
179	mfc0	k0, CP0_CONFIG
180	ori	k0, 0x07
181	xori	k0, 0x04
182	mtc0	k0, CP0_CONFIG
183
184	mfc0	k0, CP0_PRID
185	andi	k0, 0xff00
186#if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380)
187	li	k1, PRID_IMP_BMIPS43XX
188	bne	k0, k1, 2f
189
190	/* initialize CPU1's local I-cache */
191	li	k0, 0x80000000
192	li	k1, 0x80010000
193	mtc0	zero, $28
194	mtc0	zero, $28, 1
195	BARRIER
196
1971:	cache	Index_Store_Tag_I, 0(k0)
198	addiu	k0, 16
199	bne	k0, k1, 1b
200
201	b	3f
2022:
203#endif /* CONFIG_CPU_BMIPS4350 || CONFIG_CPU_BMIPS4380 */
204#if defined(CONFIG_CPU_BMIPS5000)
205	/* mask with PRID_IMP_BMIPS5000 to cover both variants */
206	li	k1, PRID_IMP_BMIPS5000
207	andi	k0, PRID_IMP_BMIPS5000
208	bne	k0, k1, 3f
209
210	/* set exception vector base */
211	la	k0, ebase
212	lw	k0, 0(k0)
213	mtc0	k0, $15, 1
214	BARRIER
215#endif /* CONFIG_CPU_BMIPS5000 */
2163:
217	/* jump back to kseg0 in case we need to remap the kseg1 area */
218	la	k0, 1f
219	jr	k0
2201:
221	la	k0, bmips_enable_xks01
222	jalr	k0
223
224	/* use temporary stack to set up upper memory TLB */
225	li	sp, BMIPS_WARM_RESTART_VEC
226	la	k0, plat_wired_tlb_setup
227	jalr	k0
228
229	/* switch to permanent stack and continue booting */
230
231	.global bmips_secondary_reentry
232bmips_secondary_reentry:
233	la	k0, bmips_smp_boot_sp
234	lw	sp, 0(k0)
235	la	k0, bmips_smp_boot_gp
236	lw	gp, 0(k0)
237	la	k0, start_secondary
238	jr	k0
239
240#endif /* CONFIG_SMP */
241
242	.align	4
243	.global bmips_reset_nmi_vec_end
244bmips_reset_nmi_vec_end:
245
246END(bmips_reset_nmi_vec)
247
248	.set	pop
249
250/***********************************************************************
251 * CPU1 warm restart vector (used for second and subsequent boots).
252 * Also used for S2 standby recovery (PM).
253 * This entire function gets copied to (BMIPS_WARM_RESTART_VEC)
254 ***********************************************************************/
255
256LEAF(bmips_smp_int_vec)
257
258	.align	4
259	mfc0	k0, CP0_STATUS
260	ori	k0, 0x01
261	xori	k0, 0x01
262	mtc0	k0, CP0_STATUS
263	eret
264
265	.align	4
266	.global bmips_smp_int_vec_end
267bmips_smp_int_vec_end:
268
269END(bmips_smp_int_vec)
270
271/***********************************************************************
272 * XKS01 support
273 * Certain CPUs support extending kseg0 to 1024MB.
274 ***********************************************************************/
275
276LEAF(bmips_enable_xks01)
277
278#if defined(CONFIG_XKS01)
279	mfc0	t0, CP0_PRID
280	andi	t2, t0, 0xff00
281#if defined(CONFIG_CPU_BMIPS4380)
282	li	t1, PRID_IMP_BMIPS43XX
283	bne	t2, t1, 1f
284
285	andi	t0, 0xff
286	addiu	t1, t0, -PRID_REV_BMIPS4380_HI
287	bgtz	t1, 2f
288	addiu	t0, -PRID_REV_BMIPS4380_LO
289	bltz	t0, 2f
290
291	mfc0	t0, $22, 3
292	li	t1, 0x1ff0
293	li	t2, (1 << 12) | (1 << 9)
294	or	t0, t1
295	xor	t0, t1
296	or	t0, t2
297	mtc0	t0, $22, 3
298	BARRIER
299	b	2f
3001:
301#endif /* CONFIG_CPU_BMIPS4380 */
302#if defined(CONFIG_CPU_BMIPS5000)
303	li	t1, PRID_IMP_BMIPS5000
304	/* mask with PRID_IMP_BMIPS5000 to cover both variants */
305	andi	t2, PRID_IMP_BMIPS5000
306	bne	t2, t1, 2f
307
308	mfc0	t0, $22, 5
309	li	t1, 0x01ff
310	li	t2, (1 << 8) | (1 << 5)
311	or	t0, t1
312	xor	t0, t1
313	or	t0, t2
314	mtc0	t0, $22, 5
315	BARRIER
316#endif /* CONFIG_CPU_BMIPS5000 */
3172:
318#endif /* defined(CONFIG_XKS01) */
319
320	jr	ra
321
322END(bmips_enable_xks01)
323