xref: /openbmc/linux/arch/arm/mach-sa1100/sleep.S (revision 171f1bc7)
1/*
2 * SA11x0 Assembler Sleep/WakeUp Management Routines
3 *
4 * Copyright (c) 2001 Cliff Brake <cbrake@accelent.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License.
8 *
9 * History:
10 *
11 * 2001-02-06: Cliff Brake         Initial code
12 *
13 * 2001-08-29:	Nicolas Pitre	Simplified.
14 *
15 * 2002-05-27:	Nicolas Pitre	Revisited, more cleanup and simplification.
16 *				Storage is on the stack now.
17 */
18
19#include <linux/linkage.h>
20#include <asm/assembler.h>
21#include <mach/hardware.h>
22
23		.text
24/*
25 * sa1100_finish_suspend()
26 *
27 * Causes sa11x0 to enter sleep state
28 *
29 */
30
31ENTRY(sa1100_finish_suspend)
32	@ disable clock switching
33	mcr	p15, 0, r1, c15, c2, 2
34
35        @ Adjust memory timing before lowering CPU clock
36	@ Clock speed adjustment without changing memory timing makes
37	@ CPU hang in some cases
38        ldr     r0, =MDREFR
39        ldr     r1, [r0]
40        orr     r1, r1, #MDREFR_K1DB2
41        str     r1, [r0]
42
43	@ delay 90us and set CPU PLL to lowest speed
44	@ fixes resume problem on high speed SA1110
45	mov	r0, #90
46	bl	__udelay
47	ldr	r0, =PPCR
48	mov	r1, #0
49	str	r1, [r0]
50	mov	r0, #90
51	bl	__udelay
52
53	/*
54	 * SA1110 SDRAM controller workaround.  register values:
55	 *
56	 * r0  = &MSC0
57	 * r1  = &MSC1
58	 * r2  = &MSC2
59	 * r3  = MSC0 value
60	 * r4  = MSC1 value
61	 * r5  = MSC2 value
62	 * r6  = &MDREFR
63	 * r7  = first MDREFR value
64	 * r8  = second MDREFR value
65	 * r9  = &MDCNFG
66	 * r10 = MDCNFG value
67	 * r11 = third MDREFR value
68	 * r12 = &PMCR
69	 * r13 = PMCR value (1)
70	 */
71
72	ldr	r0, =MSC0
73	ldr	r1, =MSC1
74	ldr	r2, =MSC2
75
76	ldr	r3, [r0]
77	bic	r3, r3, #FMsk(MSC_RT)
78	bic	r3, r3, #FMsk(MSC_RT)<<16
79
80	ldr	r4, [r1]
81	bic	r4, r4, #FMsk(MSC_RT)
82	bic	r4, r4, #FMsk(MSC_RT)<<16
83
84	ldr	r5, [r2]
85	bic	r5, r5, #FMsk(MSC_RT)
86	bic	r5, r5, #FMsk(MSC_RT)<<16
87
88	ldr	r6, =MDREFR
89
90	ldr	r7, [r6]
91bic	r7, r7, #0x0000FF00
92bic	r7, r7, #0x000000F0
93orr	r8, r7, #MDREFR_SLFRSH
94
95	ldr	r9, =MDCNFG
96	ldr	r10, [r9]
97	bic	r10, r10, #(MDCNFG_DE0+MDCNFG_DE1)
98	bic	r10, r10, #(MDCNFG_DE2+MDCNFG_DE3)
99
100	bic	r11, r8, #MDREFR_SLFRSH
101	bic	r11, r11, #MDREFR_E1PIN
102
103	ldr	r12, =PMCR
104
105	mov	r13, #PMCR_SF
106
107	b	sa1110_sdram_controller_fix
108
109	.align 5
110sa1110_sdram_controller_fix:
111
112	@ Step 1 clear RT field of all MSCx registers
113	str 	r3, [r0]
114	str	r4, [r1]
115	str	r5, [r2]
116
117	@ Step 2 clear DRI field in MDREFR
118	str	r7, [r6]
119
120	@ Step 3 set SLFRSH bit in MDREFR
121	str	r8, [r6]
122
123	@ Step 4 clear DE bis in MDCNFG
124	str	r10, [r9]
125
126	@ Step 5 clear DRAM refresh control register
127	str	r11, [r6]
128
129	@ Wow, now the hardware suspend request pins can be used, that makes them functional for
130	@ about 7 ns out of the	entire time that the CPU is running!
131
132	@ Step 6 set force sleep bit in PMCR
133
134	str	r13, [r12]
135
13620:	b	20b			@ loop waiting for sleep
137