97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/*
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* AT91 Power Management
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*
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* Copyright (C) 2005 David Brownell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef __ARCH_ARM_MACH_AT91_PM
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#define __ARCH_ARM_MACH_AT91_PM
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#include <mach/at91_ramc.h>
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#include <mach/at91rm9200_sdramc.h>
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/*
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* The AT91RM9200 goes into self-refresh mode with this command, and will
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* terminate self-refresh automatically on the next SDRAM access.
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*
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* Self-refresh mode is exited as soon as a memory access is made, but we don't
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* know for sure when that happens. However, we need to restore the low-power
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* mode if it was enabled before going idle. Restoring low-power mode while
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* still in self-refresh is "not recommended", but seems to work.
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*/
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static inline void at91rm9200_standby(void)
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{
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u32 lpr = at91_ramc_read(0, AT91RM9200_SDRAMC_LPR);
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asm volatile(
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"b 1f\n\t"
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".align 5\n\t"
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"1: mcr p15, 0, %0, c7, c10, 4\n\t"
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" str %0, [%1, %2]\n\t"
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" str %3, [%1, %4]\n\t"
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" mcr p15, 0, %0, c7, c0, 4\n\t"
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" str %5, [%1, %2]"
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:
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: "r" (0), "r" (AT91_BASE_SYS), "r" (AT91RM9200_SDRAMC_LPR),
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"r" (1), "r" (AT91RM9200_SDRAMC_SRR),
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"r" (lpr));
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}
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/* We manage both DDRAM/SDRAM controllers, we need more than one value to
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* remember.
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*/
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static inline void at91sam9g45_standby(void)
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{
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/* Those two values allow us to delay self-refresh activation
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* to the maximum. */
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u32 lpr0, lpr1;
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u32 saved_lpr0, saved_lpr1;
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saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
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lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
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lpr1 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;
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saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
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lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
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lpr0 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;
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/* self-refresh mode now */
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at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);
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at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);
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cpu_do_idle();
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at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
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at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
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}
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#ifdef CONFIG_SOC_AT91SAM9263
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/*
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* FIXME either or both the SDRAM controllers (EB0, EB1) might be in use;
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* handle those cases both here and in the Suspend-To-RAM support.
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*/
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#warning Assuming EB1 SDRAM controller is *NOT* used
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#endif
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static inline void at91sam9_standby(void)
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{
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u32 saved_lpr, lpr;
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saved_lpr = at91_ramc_read(0, AT91_SDRAMC_LPR);
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lpr = saved_lpr & ~AT91_SDRAMC_LPCB;
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at91_ramc_write(0, AT91_SDRAMC_LPR, lpr |
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AT91_SDRAMC_LPCB_SELF_REFRESH);
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cpu_do_idle();
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at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr);
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}
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#endif
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