summaryrefslogtreecommitdiffstats
path: root/arch/frv/kernel/cmode.S
blob: 81ba28ad2207158f080914a1e4e91fa5b7efd6aa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/* cmode.S: clock mode management
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Woodhouse (dwmw2@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/ptrace.h>
#include <asm/errno.h>
#include <asm/cache.h>
#include <asm/spr-regs.h>

#define __addr_MASK	0xfeff9820	/* interrupt controller mask */

#define __addr_SDRAMC	0xfe000400	/* SDRAM controller regs */
#define SDRAMC_DSTS	0x28		/* SDRAM status */
#define SDRAMC_DSTS_SSI	0x00000001	/* indicates that the SDRAM is in self-refresh mode */
#define SDRAMC_DRCN	0x30		/* SDRAM refresh control */
#define SDRAMC_DRCN_SR	0x00000001	/* transition SDRAM into self-refresh mode */
#define __addr_CLKC	0xfeff9a00
#define CLKC_SWCMODE	0x00000008
#define __addr_LEDS	0xe1200004

.macro li v r
	sethi.p		%hi(\v),\r
	setlo		%lo(\v),\r
.endm

	.text
	.balign		4


###############################################################################
#
# Change CMODE
# - void frv_change_cmode(int cmode)
#
###############################################################################
	.globl		frv_change_cmode
        .type		frv_change_cmode,@function

.macro	LEDS v
#ifdef DEBUG_CMODE
	setlos	#~\v,gr10
	sti	gr10,@(gr11,#0)
	membar
#endif
.endm

frv_change_cmode:
	movsg		lr,gr9
#ifdef DEBUG_CMODE
	li		__addr_LEDS,gr11
#endif
	dcef		@(gr0,gr0),#1

	# Shift argument left by 24 bits to fit in SWCMODE register later.
	slli		gr8,#24,gr8

	# (1) Set '0' in the PSR.ET bit, and prohibit interrupts.
	movsg		psr,gr14
	andi		gr14,#~PSR_ET,gr3
	movgs		gr3,psr

#if 0 // Fujitsu recommend to skip this and will update docs.
	# (2) Set '0' to all bits of the MASK register of the interrupt
	#     controller, and mask interrupts.
	li		__addr_MASK,gr12
	ldi		@(gr12,#0),gr13
	li		0xffff0000,gr4
	sti		gr4,@(gr12,#0)
#endif

	# (3) Stop the transfer function of DMAC. Stop all the bus masters
	#     to access SDRAM and the internal resources.

	# (already done by caller)

	# (4) Preload a series of following instructions to the instruction
	#     cache.
	li		#__cmode_icache_lock_start,gr3
	li		#__cmode_icache_lock_end,gr4

1:	icpl		gr3,gr0,#1
	addi		gr3,#L1_CACHE_BYTES,gr3
	cmp		gr4,gr3,icc0
	bhi		icc0,#0,1b

	# Set up addresses in regs for later steps.
	setlos		SDRAMC_DRCN_SR,gr3
	li		__addr_SDRAMC,gr4
	li		__addr_CLKC,gr5
	ldi		@(gr5,#0),gr6
	li		#0x80000000,gr7
	or		gr6,gr7,gr6

	bra		__cmode_icache_lock_start

	.balign	L1_CACHE_BYTES
__cmode_icache_lock_start:

	# (5) Flush the content of all caches by the DCEF instruction.
	dcef		@(gr0,gr0),#1

	# (6) Execute loading the dummy for SDRAM.
	ldi		@(gr9,#0),gr0

	# (7) Set '1' to the DRCN.SR bit, and change SDRAM to the
	#     self-refresh mode. Execute the dummy load to all memory
	#     devices set to cacheable on the external bus side in parallel
	#     with this.
	sti		gr3,@(gr4,#SDRAMC_DRCN)

	# (8) Execute memory barrier instruction (MEMBAR).
	membar

	# (9) Read the DSTS register repeatedly until '1' stands in the
	#     DSTS.SSI field.
1:	ldi		@(gr4,#SDRAMC_DSTS),gr3
	andicc		gr3,#SDRAMC_DSTS_SSI,gr3,icc0
	beq		icc0,#0,1b

	# (10) Execute memory barrier instruction (MEMBAR).
	membar

#if 1
	# (11) Set the value of CMODE that you want to change to
	#      SWCMODE.SWCM[3:0].
	sti		gr8,@(gr5,#CLKC_SWCMODE)

	# (12) Set '1' to the CLKC.SWEN bit. In that case, do not change
	#      fields other than SWEN of the CLKC register.
	sti		gr6,@(gr5,#0)
#endif
	# (13) Execute the instruction just after the memory barrier
	# instruction that executes the self-loop 256 times. (Meanwhile,
	# the CMODE switch is done.)
	membar
	setlos		#256,gr7
2:	subicc		gr7,#1,gr7,icc0
	bne		icc0,#2,2b

	LEDS	0x36

	# (14) Release the self-refresh of SDRAM.
	sti		gr0,@(gr4,#SDRAMC_DRCN)

	# Wait for it...
3:	ldi		@(gr4,#SDRAMC_DSTS),gr3
	andicc		gr3,#SDRAMC_DSTS_SSI,gr3,icc0
	bne		icc0,#2,3b

#if 0
	li		0x0100000,gr10
4:	subicc		gr10,#1,gr10,icc0

	bne		icc0,#0,4b
#endif

__cmode_icache_lock_end:

	li		#__cmode_icache_lock_start,gr3
	li		#__cmode_icache_lock_end,gr4

4:	icul		gr3
	addi		gr3,#L1_CACHE_BYTES,gr3
	cmp		gr4,gr3,icc0
	bhi		icc0,#0,4b

#if 0 // Fujitsu recommend to skip this and will update docs.
	# (15) Release the interrupt mask setting of the MASK register of
	# the interrupt controller if necessary.
	sti		gr13,@(gr12,#0)
#endif
	# (16) Set  1' in the PSR.ET bit, and permit interrupt.
	movgs		gr14,psr

	bralr

	.size		frv_change_cmode, .-frv_change_cmode