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/*
* 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 <mach/at91_ramc.h>
#include <mach/at91rm9200_sdramc.h>
/*
* 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 at91sam9g45_standby(void)
{
/* Those two values allow us to delay self-refresh activation
* to the maximum. */
u32 lpr0, lpr1;
u32 saved_lpr0, saved_lpr1;
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);
at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);
cpu_do_idle();
at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
}
#ifdef CONFIG_ARCH_AT91SAM9263
/*
* FIXME either or both the SDRAM controllers (EB0, EB1) might be in use;
* handle those cases both here and in the Suspend-To-RAM support.
*/
#warning Assuming EB1 SDRAM controller is *NOT* used
#endif
static inline void at91sam9_standby(void)
{
u32 saved_lpr, lpr;
saved_lpr = at91_ramc_read(0, AT91_SDRAMC_LPR);
lpr = saved_lpr & ~AT91_SDRAMC_LPCB;
at91_ramc_write(0, AT91_SDRAMC_LPR, lpr |
AT91_SDRAMC_LPCB_SELF_REFRESH);
cpu_do_idle();
at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr);
}
#endif
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