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/*
* Low-level Power Management code.
*
* Copyright (C) 2008 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <mach/pm.h>
#include "pm.h"
#include "sdramc.h"
/* Same as 0xfff00000 but fits in a 21 bit signed immediate */
#define PM_BASE -0x100000
/* Keep this close to the irq handlers */
.section .irq.text, "ax", @progbits
/*
* void cpu_enter_idle(void)
*
* Put the CPU into "idle" mode, in which it will consume
* significantly less power.
*
* If an interrupt comes along in the window between
* unmask_interrupts and the sleep instruction below, the
* interrupt code will adjust the return address so that we
* never execute the sleep instruction. This is required
* because the AP7000 doesn't unmask interrupts when entering
* sleep modes; later CPUs may not need this workaround.
*/
.global cpu_enter_idle
.type cpu_enter_idle, @function
cpu_enter_idle:
mask_interrupts
get_thread_info r8
ld.w r9, r8[TI_flags]
bld r9, TIF_NEED_RESCHED
brcs .Lret_from_sleep
sbr r9, TIF_CPU_GOING_TO_SLEEP
st.w r8[TI_flags], r9
unmask_interrupts
sleep CPU_SLEEP_IDLE
.size cpu_enter_idle, . - cpu_enter_idle
/*
* Common return path for PM functions that don't run from
* SRAM.
*/
.global cpu_idle_skip_sleep
.type cpu_idle_skip_sleep, @function
cpu_idle_skip_sleep:
mask_interrupts
ld.w r9, r8[TI_flags]
cbr r9, TIF_CPU_GOING_TO_SLEEP
st.w r8[TI_flags], r9
.Lret_from_sleep:
unmask_interrupts
retal r12
.size cpu_idle_skip_sleep, . - cpu_idle_skip_sleep
#ifdef CONFIG_PM
.section .init.text, "ax", @progbits
.global pm_exception
.type pm_exception, @function
pm_exception:
/*
* Exceptions are masked when we switch to this handler, so
* we'll only get "unrecoverable" exceptions (offset 0.)
*/
sub r12, pc, . - .Lpanic_msg
lddpc pc, .Lpanic_addr
.align 2
.Lpanic_addr:
.long panic
.Lpanic_msg:
.asciz "Unrecoverable exception during suspend\n"
.size pm_exception, . - pm_exception
.global pm_irq0
.type pm_irq0, @function
pm_irq0:
/* Disable interrupts and return after the sleep instruction */
mfsr r9, SYSREG_RSR_INT0
mtsr SYSREG_RAR_INT0, r8
sbr r9, SYSREG_GM_OFFSET
mtsr SYSREG_RSR_INT0, r9
rete
/*
* void cpu_enter_standby(unsigned long sdramc_base)
*
* Enter PM_SUSPEND_STANDBY mode. At this point, all drivers
* are suspended and interrupts are disabled. Interrupts
* marked as 'wakeup' event sources may still come along and
* get us out of here.
*
* The SDRAM will be put into self-refresh mode (which does
* not require a clock from the CPU), and the CPU will be put
* into "frozen" mode (HSB bus stopped). The SDRAM controller
* will automatically bring the SDRAM into normal mode on the
* first access, and the power manager will automatically
* start the HSB and CPU clocks upon a wakeup event.
*
* This code uses the same "skip sleep" technique as above.
* It is very important that we jump directly to
* cpu_after_sleep after the sleep instruction since that's
* where we'll end up if the interrupt handler decides that we
* need to skip the sleep instruction.
*/
.global pm_standby
.type pm_standby, @function
pm_standby:
/*
* interrupts are already masked at this point, and EVBA
* points to pm_exception above.
*/
ld.w r10, r12[SDRAMC_LPR]
sub r8, pc, . - 1f /* return address for irq handler */
mov r11, SDRAMC_LPR_LPCB_SELF_RFR
bfins r10, r11, 0, 2 /* LPCB <- self Refresh */
sync 0 /* flush write buffer */
st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
ld.w r11, r12[SDRAMC_LPR]
unmask_interrupts
sleep CPU_SLEEP_FROZEN
1: mask_interrupts
retal r12
.size pm_standby, . - pm_standby
.global pm_suspend_to_ram
.type pm_suspend_to_ram, @function
pm_suspend_to_ram:
/*
* interrupts are already masked at this point, and EVBA
* points to pm_exception above.
*/
mov r11, 0
cache r11[2], 8 /* clean all dcache lines */
sync 0 /* flush write buffer */
ld.w r10, r12[SDRAMC_LPR]
sub r8, pc, . - 1f /* return address for irq handler */
mov r11, SDRAMC_LPR_LPCB_SELF_RFR
bfins r10, r11, 0, 2 /* LPCB <- self refresh */
st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
ld.w r11, r12[SDRAMC_LPR]
unmask_interrupts
sleep CPU_SLEEP_STOP
1: mask_interrupts
retal r12
.size pm_suspend_to_ram, . - pm_suspend_to_ram
.global pm_sram_end
.type pm_sram_end, @function
pm_sram_end:
.size pm_sram_end, 0
#endif /* CONFIG_PM */
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