summaryrefslogtreecommitdiff
path: root/arch/arm/mach-at91/pm.h
blob: 3ed190ce062bd5add5a426e07b1cf6c5d1e5b89a (plain)
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
/*
 * AT91 Power Management
 *
 * Copyright (C) 2005 David Brownell
 *
 * 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.
 */
#ifndef __ARCH_ARM_MACH_AT91_PM
#define __ARCH_ARM_MACH_AT91_PM

#include <asm/proc-fns.h>

#include <mach/at91_ramc.h>
#include <mach/at91rm9200_sdramc.h>

extern void at91_pm_set_standby(void (*at91_standby)(void));

/*
 * The AT91RM9200 goes into self-refresh mode with this command, and will
 * terminate self-refresh automatically on the next SDRAM access.
 *
 * Self-refresh mode is exited as soon as a memory access is made, but we don't
 * know for sure when that happens. However, we need to restore the low-power
 * mode if it was enabled before going idle. Restoring low-power mode while
 * still in self-refresh is "not recommended", but seems to work.
 */

static inline void at91rm9200_standby(void)
{
	u32 lpr = at91_ramc_read(0, AT91RM9200_SDRAMC_LPR);

	asm volatile(
		"b    1f\n\t"
		".align    5\n\t"
		"1:  mcr    p15, 0, %0, c7, c10, 4\n\t"
		"    str    %0, [%1, %2]\n\t"
		"    str    %3, [%1, %4]\n\t"
		"    mcr    p15, 0, %0, c7, c0, 4\n\t"
		"    str    %5, [%1, %2]"
		:
		: "r" (0), "r" (AT91_BASE_SYS), "r" (AT91RM9200_SDRAMC_LPR),
		  "r" (1), "r" (AT91RM9200_SDRAMC_SRR),
		  "r" (lpr));
}

/* We manage both DDRAM/SDRAM controllers, we need more than one value to
 * remember.
 */
static inline void at91_ddr_standby(void)
{
	/* Those two values allow us to delay self-refresh activation
	 * to the maximum. */
	u32 lpr0, lpr1 = 0;
	u32 saved_lpr0, saved_lpr1 = 0;

	if (at91_ramc_base[1]) {
		saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
		lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
		lpr1 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;
	}

	saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
	lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
	lpr0 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;

	/* self-refresh mode now */
	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);
	if (at91_ramc_base[1])
		at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);

	cpu_do_idle();

	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
	if (at91_ramc_base[1])
		at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
}

/* We manage both DDRAM/SDRAM controllers, we need more than one value to
 * remember.
 */
static inline void at91sam9_sdram_standby(void)
{
	u32 lpr0, lpr1 = 0;
	u32 saved_lpr0, saved_lpr1 = 0;

	if (at91_ramc_base[1]) {
		saved_lpr1 = at91_ramc_read(1, AT91_SDRAMC_LPR);
		lpr1 = saved_lpr1 & ~AT91_SDRAMC_LPCB;
		lpr1 |= AT91_SDRAMC_LPCB_SELF_REFRESH;
	}

	saved_lpr0 = at91_ramc_read(0, AT91_SDRAMC_LPR);
	lpr0 = saved_lpr0 & ~AT91_SDRAMC_LPCB;
	lpr0 |= AT91_SDRAMC_LPCB_SELF_REFRESH;

	/* self-refresh mode now */
	at91_ramc_write(0, AT91_SDRAMC_LPR, lpr0);
	if (at91_ramc_base[1])
		at91_ramc_write(1, AT91_SDRAMC_LPR, lpr1);

	cpu_do_idle();

	at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr0);
	if (at91_ramc_base[1])
		at91_ramc_write(1, AT91_SDRAMC_LPR, saved_lpr1);
}

#endif