xref: /openbmc/linux/arch/mips/kernel/bmips_vec.S (revision 588b48ca) 
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, bmips_smp_entry
92
93#if defined(CONFIG_CPU_BMIPS5000)
94	mfc0	k0, CP0_PRID
95	li	k1, PRID_IMP_BMIPS5000
96	andi	k0, 0xff00
97	bne	k0, k1, 1f
98
99	/* if we're not on core 0, this must be the SMP boot signal */
100	li	k1, (3 << 25)
101	mfc0	k0, $22
102	and	k0, k1
103	bnez	k0, bmips_smp_entry
1041:
105#endif /* CONFIG_CPU_BMIPS5000 */
106#endif /* CONFIG_SMP */
107
108	/* nope, it's just a regular NMI */
109	SAVE_ALL
110	move	a0, sp
111
112	/* clear EXL, ERL, BEV so that TLB refills still work */
113	mfc0	k0, CP0_STATUS
114	li	k1, ST0_ERL | ST0_EXL | ST0_BEV | ST0_IE
115	or	k0, k1
116	xor	k0, k1
117	mtc0	k0, CP0_STATUS
118	BARRIER
119
120	/* jump to the NMI handler function */
121	la	k0, nmi_handler
122	jr	k0
123
124	RESTORE_ALL
125	.set	arch=r4000
126	eret
127
128/***********************************************************************
129 * CPU1 reset vector (used for the initial boot only)
130 * This is still part of bmips_reset_nmi_vec().
131 ***********************************************************************/
132
133#ifdef CONFIG_SMP
134
135bmips_smp_entry:
136
137	/* set up CP0 STATUS; enable FPU */
138	li	k0, 0x30000000
139	mtc0	k0, CP0_STATUS
140	BARRIER
141
142	/* set local CP0 CONFIG to make kseg0 cacheable, write-back */
143	mfc0	k0, CP0_CONFIG
144	ori	k0, 0x07
145	xori	k0, 0x04
146	mtc0	k0, CP0_CONFIG
147
148	mfc0	k0, CP0_PRID
149	andi	k0, 0xff00
150#if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380)
151	li	k1, PRID_IMP_BMIPS43XX
152	bne	k0, k1, 2f
153
154	/* initialize CPU1's local I-cache */
155	li	k0, 0x80000000
156	li	k1, 0x80010000
157	mtc0	zero, $28
158	mtc0	zero, $28, 1
159	BARRIER
160
1611:	cache	Index_Store_Tag_I, 0(k0)
162	addiu	k0, 16
163	bne	k0, k1, 1b
164
165	b	3f
1662:
167#endif /* CONFIG_CPU_BMIPS4350 || CONFIG_CPU_BMIPS4380 */
168#if defined(CONFIG_CPU_BMIPS5000)
169	/* set exception vector base */
170	li	k1, PRID_IMP_BMIPS5000
171	bne	k0, k1, 3f
172
173	la	k0, ebase
174	lw	k0, 0(k0)
175	mtc0	k0, $15, 1
176	BARRIER
177#endif /* CONFIG_CPU_BMIPS5000 */
1783:
179	/* jump back to kseg0 in case we need to remap the kseg1 area */
180	la	k0, 1f
181	jr	k0
1821:
183	la	k0, bmips_enable_xks01
184	jalr	k0
185
186	/* use temporary stack to set up upper memory TLB */
187	li	sp, BMIPS_WARM_RESTART_VEC
188	la	k0, plat_wired_tlb_setup
189	jalr	k0
190
191	/* switch to permanent stack and continue booting */
192
193	.global bmips_secondary_reentry
194bmips_secondary_reentry:
195	la	k0, bmips_smp_boot_sp
196	lw	sp, 0(k0)
197	la	k0, bmips_smp_boot_gp
198	lw	gp, 0(k0)
199	la	k0, start_secondary
200	jr	k0
201
202#endif /* CONFIG_SMP */
203
204	.align	4
205	.global bmips_reset_nmi_vec_end
206bmips_reset_nmi_vec_end:
207
208END(bmips_reset_nmi_vec)
209
210	.set	pop
211	.previous
212
213/***********************************************************************
214 * CPU1 warm restart vector (used for second and subsequent boots).
215 * Also used for S2 standby recovery (PM).
216 * This entire function gets copied to (BMIPS_WARM_RESTART_VEC)
217 ***********************************************************************/
218
219LEAF(bmips_smp_int_vec)
220
221	.align	4
222	mfc0	k0, CP0_STATUS
223	ori	k0, 0x01
224	xori	k0, 0x01
225	mtc0	k0, CP0_STATUS
226	eret
227
228	.align	4
229	.global bmips_smp_int_vec_end
230bmips_smp_int_vec_end:
231
232END(bmips_smp_int_vec)
233
234/***********************************************************************
235 * XKS01 support
236 * Certain CPUs support extending kseg0 to 1024MB.
237 ***********************************************************************/
238
239LEAF(bmips_enable_xks01)
240
241#if defined(CONFIG_XKS01)
242	mfc0	t0, CP0_PRID
243	andi	t2, t0, 0xff00
244#if defined(CONFIG_CPU_BMIPS4380)
245	li	t1, PRID_IMP_BMIPS43XX
246	bne	t2, t1, 1f
247
248	andi	t0, 0xff
249	addiu	t1, t0, -PRID_REV_BMIPS4380_HI
250	bgtz	t1, 2f
251	addiu	t0, -PRID_REV_BMIPS4380_LO
252	bltz	t0, 2f
253
254	mfc0	t0, $22, 3
255	li	t1, 0x1ff0
256	li	t2, (1 << 12) | (1 << 9)
257	or	t0, t1
258	xor	t0, t1
259	or	t0, t2
260	mtc0	t0, $22, 3
261	BARRIER
262	b	2f
2631:
264#endif /* CONFIG_CPU_BMIPS4380 */
265#if defined(CONFIG_CPU_BMIPS5000)
266	li	t1, PRID_IMP_BMIPS5000
267	bne	t2, t1, 2f
268
269	mfc0	t0, $22, 5
270	li	t1, 0x01ff
271	li	t2, (1 << 8) | (1 << 5)
272	or	t0, t1
273	xor	t0, t1
274	or	t0, t2
275	mtc0	t0, $22, 5
276	BARRIER
277#endif /* CONFIG_CPU_BMIPS5000 */
2782:
279#endif /* defined(CONFIG_XKS01) */
280
281	jr	ra
282
283END(bmips_enable_xks01)
284
285	.previous
286