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kernel/linux-imx6_3.14.28/arch/arm/mach-at91/pm.h 3.13 KB
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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 <asm/proc-fns.h>
  
  #include <mach/at91_ramc.h>
  #include <mach/at91rm9200_sdramc.h>
  
  #ifdef CONFIG_PM
  extern void at91_pm_set_standby(void (*at91_standby)(void));
  #else
  static inline void at91_pm_set_standby(void (*at91_standby)(void)) { }
  #endif
  
  /*
   * 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
  \t"
  		".align    5
  \t"
  		"1:  mcr    p15, 0, %0, c7, c10, 4
  \t"
  		"    str    %0, [%1, %2]
  \t"
  		"    str    %3, [%1, %4]
  \t"
  		"    mcr    p15, 0, %0, c7, c0, 4
  \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