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Haavard Skinnemoen7e591282008-02-24 23:24:26 +01001/*
2 * Low-level Power Management code.
3 *
4 * Copyright (C) 2008 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <asm/asm.h>
11#include <asm/asm-offsets.h>
12#include <asm/thread_info.h>
Haavard Skinnemoen3663b732008-08-05 13:57:38 +020013#include <mach/pm.h>
Haavard Skinnemoen7e591282008-02-24 23:24:26 +010014
Haavard Skinnemoen02a00cf2008-02-24 13:51:38 +010015#include "pm.h"
16#include "sdramc.h"
17
18/* Same as 0xfff00000 but fits in a 21 bit signed immediate */
19#define PM_BASE -0x100000
20
Haavard Skinnemoen7e591282008-02-24 23:24:26 +010021 .section .bss, "wa", @nobits
22 .global disable_idle_sleep
23 .type disable_idle_sleep, @object
24disable_idle_sleep:
25 .int 4
26 .size disable_idle_sleep, . - disable_idle_sleep
27
28 /* Keep this close to the irq handlers */
29 .section .irq.text, "ax", @progbits
30
31 /*
32 * void cpu_enter_idle(void)
33 *
34 * Put the CPU into "idle" mode, in which it will consume
35 * significantly less power.
36 *
37 * If an interrupt comes along in the window between
38 * unmask_interrupts and the sleep instruction below, the
39 * interrupt code will adjust the return address so that we
40 * never execute the sleep instruction. This is required
41 * because the AP7000 doesn't unmask interrupts when entering
42 * sleep modes; later CPUs may not need this workaround.
43 */
44 .global cpu_enter_idle
45 .type cpu_enter_idle, @function
46cpu_enter_idle:
47 mask_interrupts
48 get_thread_info r8
49 ld.w r9, r8[TI_flags]
50 bld r9, TIF_NEED_RESCHED
51 brcs .Lret_from_sleep
52 sbr r9, TIF_CPU_GOING_TO_SLEEP
53 st.w r8[TI_flags], r9
54 unmask_interrupts
55 sleep CPU_SLEEP_IDLE
56 .size cpu_idle_sleep, . - cpu_idle_sleep
57
58 /*
59 * Common return path for PM functions that don't run from
60 * SRAM.
61 */
62 .global cpu_idle_skip_sleep
63 .type cpu_idle_skip_sleep, @function
64cpu_idle_skip_sleep:
65 mask_interrupts
66 ld.w r9, r8[TI_flags]
67 cbr r9, TIF_CPU_GOING_TO_SLEEP
68 st.w r8[TI_flags], r9
69.Lret_from_sleep:
70 unmask_interrupts
71 retal r12
72 .size cpu_idle_skip_sleep, . - cpu_idle_skip_sleep
Haavard Skinnemoen02a00cf2008-02-24 13:51:38 +010073
74#ifdef CONFIG_PM
75 .section .init.text, "ax", @progbits
76
77 .global pm_exception
78 .type pm_exception, @function
79pm_exception:
80 /*
81 * Exceptions are masked when we switch to this handler, so
82 * we'll only get "unrecoverable" exceptions (offset 0.)
83 */
84 sub r12, pc, . - .Lpanic_msg
85 lddpc pc, .Lpanic_addr
86
87 .align 2
88.Lpanic_addr:
89 .long panic
90.Lpanic_msg:
91 .asciz "Unrecoverable exception during suspend\n"
92 .size pm_exception, . - pm_exception
93
94 .global pm_irq0
95 .type pm_irq0, @function
96pm_irq0:
97 /* Disable interrupts and return after the sleep instruction */
98 mfsr r9, SYSREG_RSR_INT0
99 mtsr SYSREG_RAR_INT0, r8
100 sbr r9, SYSREG_GM_OFFSET
101 mtsr SYSREG_RSR_INT0, r9
102 rete
103
104 /*
105 * void cpu_enter_standby(unsigned long sdramc_base)
106 *
107 * Enter PM_SUSPEND_STANDBY mode. At this point, all drivers
108 * are suspended and interrupts are disabled. Interrupts
109 * marked as 'wakeup' event sources may still come along and
110 * get us out of here.
111 *
112 * The SDRAM will be put into self-refresh mode (which does
113 * not require a clock from the CPU), and the CPU will be put
114 * into "frozen" mode (HSB bus stopped). The SDRAM controller
115 * will automatically bring the SDRAM into normal mode on the
116 * first access, and the power manager will automatically
117 * start the HSB and CPU clocks upon a wakeup event.
118 *
119 * This code uses the same "skip sleep" technique as above.
120 * It is very important that we jump directly to
121 * cpu_after_sleep after the sleep instruction since that's
122 * where we'll end up if the interrupt handler decides that we
123 * need to skip the sleep instruction.
124 */
125 .global pm_standby
126 .type pm_standby, @function
127pm_standby:
128 /*
129 * interrupts are already masked at this point, and EVBA
130 * points to pm_exception above.
131 */
132 ld.w r10, r12[SDRAMC_LPR]
133 sub r8, pc, . - 1f /* return address for irq handler */
134 mov r11, SDRAMC_LPR_LPCB_SELF_RFR
135 bfins r10, r11, 0, 2 /* LPCB <- self Refresh */
136 sync 0 /* flush write buffer */
Humphrey Bucknell84c4f2f2008-08-29 16:27:00 +0100137 st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
Haavard Skinnemoen02a00cf2008-02-24 13:51:38 +0100138 ld.w r11, r12[SDRAMC_LPR]
139 unmask_interrupts
140 sleep CPU_SLEEP_FROZEN
1411: mask_interrupts
142 retal r12
143 .size pm_standby, . - pm_standby
144
145 .global pm_suspend_to_ram
146 .type pm_suspend_to_ram, @function
147pm_suspend_to_ram:
148 /*
149 * interrupts are already masked at this point, and EVBA
150 * points to pm_exception above.
151 */
152 mov r11, 0
153 cache r11[2], 8 /* clean all dcache lines */
154 sync 0 /* flush write buffer */
155 ld.w r10, r12[SDRAMC_LPR]
156 sub r8, pc, . - 1f /* return address for irq handler */
157 mov r11, SDRAMC_LPR_LPCB_SELF_RFR
158 bfins r10, r11, 0, 2 /* LPCB <- self refresh */
159 st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
160 ld.w r11, r12[SDRAMC_LPR]
161
162 unmask_interrupts
163 sleep CPU_SLEEP_STOP
1641: mask_interrupts
165
166 retal r12
167 .size pm_suspend_to_ram, . - pm_suspend_to_ram
168
169 .global pm_sram_end
170 .type pm_sram_end, @function
171pm_sram_end:
172 .size pm_sram_end, 0
173
174#endif /* CONFIG_PM */