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kernel/linux-imx6_3.14.28/arch/arm/mach-exynos/hotplug.c 3.13 KB
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  /* linux arch/arm/mach-exynos4/hotplug.c
   *
   *  Cloned from linux/arch/arm/mach-realview/hotplug.c
   *
   *  Copyright (C) 2002 ARM Ltd.
   *  All Rights Reserved
   *
   * 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 <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/smp.h>
  #include <linux/io.h>
  
  #include <asm/cacheflush.h>
  #include <asm/cp15.h>
  #include <asm/smp_plat.h>
  
  #include <plat/cpu.h>
  
  #include "common.h"
  #include "regs-pmu.h"
  
  static inline void cpu_enter_lowpower_a9(void)
  {
  	unsigned int v;
  
  	asm volatile(
  	"	mcr	p15, 0, %1, c7, c5, 0
  "
  	"	mcr	p15, 0, %1, c7, c10, 4
  "
  	/*
  	 * Turn off coherency
  	 */
  	"	mrc	p15, 0, %0, c1, c0, 1
  "
  	"	bic	%0, %0, %3
  "
  	"	mcr	p15, 0, %0, c1, c0, 1
  "
  	"	mrc	p15, 0, %0, c1, c0, 0
  "
  	"	bic	%0, %0, %2
  "
  	"	mcr	p15, 0, %0, c1, c0, 0
  "
  	  : "=&r" (v)
  	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
  	  : "cc");
  }
  
  static inline void cpu_enter_lowpower_a15(void)
  {
  	unsigned int v;
  
  	asm volatile(
  	"	mrc	p15, 0, %0, c1, c0, 0
  "
  	"	bic	%0, %0, %1
  "
  	"	mcr	p15, 0, %0, c1, c0, 0
  "
  	  : "=&r" (v)
  	  : "Ir" (CR_C)
  	  : "cc");
  
  	flush_cache_louis();
  
  	asm volatile(
  	/*
  	* Turn off coherency
  	*/
  	"	mrc	p15, 0, %0, c1, c0, 1
  "
  	"	bic	%0, %0, %1
  "
  	"	mcr	p15, 0, %0, c1, c0, 1
  "
  	: "=&r" (v)
  	: "Ir" (0x40)
  	: "cc");
  
  	isb();
  	dsb();
  }
  
  static inline void cpu_leave_lowpower(void)
  {
  	unsigned int v;
  
  	asm volatile(
  	"mrc	p15, 0, %0, c1, c0, 0
  "
  	"	orr	%0, %0, %1
  "
  	"	mcr	p15, 0, %0, c1, c0, 0
  "
  	"	mrc	p15, 0, %0, c1, c0, 1
  "
  	"	orr	%0, %0, %2
  "
  	"	mcr	p15, 0, %0, c1, c0, 1
  "
  	  : "=&r" (v)
  	  : "Ir" (CR_C), "Ir" (0x40)
  	  : "cc");
  }
  
  static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
  {
  	for (;;) {
  
  		/* make cpu1 to be turned off at next WFI command */
  		if (cpu == 1)
  			__raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
  
  		/*
  		 * here's the WFI
  		 */
  		asm(".word	0xe320f003
  "
  		    :
  		    :
  		    : "memory", "cc");
  
  		if (pen_release == cpu_logical_map(cpu)) {
  			/*
  			 * OK, proper wakeup, we're done
  			 */
  			break;
  		}
  
  		/*
  		 * Getting here, means that we have come out of WFI without
  		 * having been woken up - this shouldn't happen
  		 *
  		 * Just note it happening - when we're woken, we can report
  		 * its occurrence.
  		 */
  		(*spurious)++;
  	}
  }
  
  /*
   * platform-specific code to shutdown a CPU
   *
   * Called with IRQs disabled
   */
  void __ref exynos_cpu_die(unsigned int cpu)
  {
  	int spurious = 0;
  	int primary_part = 0;
  
  	/*
  	 * we're ready for shutdown now, so do it.
  	 * Exynos4 is A9 based while Exynos5 is A15; check the CPU part
  	 * number by reading the Main ID register and then perform the
  	 * appropriate sequence for entering low power.
  	 */
  	asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(primary_part) : : "cc");
  	if ((primary_part & 0xfff0) == 0xc0f0)
  		cpu_enter_lowpower_a15();
  	else
  		cpu_enter_lowpower_a9();
  
  	platform_do_lowpower(cpu, &spurious);
  
  	/*
  	 * bring this CPU back into the world of cache
  	 * coherency, and then restore interrupts
  	 */
  	cpu_leave_lowpower();
  
  	if (spurious)
  		pr_warn("CPU%u: %u spurious wakeup calls
  ", cpu, spurious);
  }