xref: /linux/drivers/watchdog/octeon-wdt-nmi.S (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2007-2017 Cavium, Inc.
4 */
5#include <asm/asm.h>
6#include <asm/regdef.h>
7
8#define CVMSEG_BASE	-32768
9#define CVMSEG_SIZE	6912
10#define SAVE_REG(r)	sd $r, CVMSEG_BASE + CVMSEG_SIZE - ((32 - r) * 8)($0)
11
12        NESTED(octeon_wdt_nmi_stage2, 0, sp)
13	.set 	push
14	.set 	noreorder
15	.set 	noat
16	/* Clear Dcache so cvmseg works right. */
17	cache	1,0($0)
18	/* Use K0 to do a read/modify/write of CVMMEMCTL */
19	dmfc0	k0, $11, 7
20	/* Clear out the size of CVMSEG	*/
21	dins	k0, $0, 0, 6
22	/* Set CVMSEG to its largest value */
23	ori	k0, k0, 0x1c0 | 54
24	/* Store the CVMMEMCTL value */
25	dmtc0	k0, $11, 7
26	/*
27	 * Restore K0 from the debug scratch register, it was saved in
28	 * the boot-vector code.
29	 */
30	dmfc0	k0, $31
31
32	/*
33	 * Save all registers to the top CVMSEG. This shouldn't
34	 * corrupt any state used by the kernel. Also all registers
35	 * should have the value right before the NMI.
36	 */
37	SAVE_REG(0)
38	SAVE_REG(1)
39	SAVE_REG(2)
40	SAVE_REG(3)
41	SAVE_REG(4)
42	SAVE_REG(5)
43	SAVE_REG(6)
44	SAVE_REG(7)
45	SAVE_REG(8)
46	SAVE_REG(9)
47	SAVE_REG(10)
48	SAVE_REG(11)
49	SAVE_REG(12)
50	SAVE_REG(13)
51	SAVE_REG(14)
52	SAVE_REG(15)
53	SAVE_REG(16)
54	SAVE_REG(17)
55	SAVE_REG(18)
56	SAVE_REG(19)
57	SAVE_REG(20)
58	SAVE_REG(21)
59	SAVE_REG(22)
60	SAVE_REG(23)
61	SAVE_REG(24)
62	SAVE_REG(25)
63	SAVE_REG(26)
64	SAVE_REG(27)
65	SAVE_REG(28)
66	SAVE_REG(29)
67	SAVE_REG(30)
68	SAVE_REG(31)
69	/* Write zero to all CVMSEG locations per Core-15169 */
70	dli	a0, CVMSEG_SIZE - (33 * 8)
711:	sd	zero, CVMSEG_BASE(a0)
72	daddiu	a0, a0, -8
73	bgez	a0, 1b
74	nop
75	/* Set the stack to begin right below the registers */
76	dli	sp, CVMSEG_BASE + CVMSEG_SIZE - (32 * 8)
77	/* Load the address of the third stage handler */
78	dla	$25, octeon_wdt_nmi_stage3
79	/* Call the third stage handler */
80	jal	$25
81	/* a0 is the address of the saved registers */
82	 move	a0, sp
83	/* Loop forvever if we get here. */
842:	b	2b
85	nop
86	.set pop
87	END(octeon_wdt_nmi_stage2)
88