Eric Lee / smarc-fsl-linux-kernel

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arch/arm/mach-vexpress/hotplug.c 2.48 KB
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e9882777d   Russell King   ARM: CPU hotplug:... 
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  /*
   *  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 <asm/cacheflush.h>
b3377d186   Nick Bowler   ARM: 7064/1: vexp... 
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  #include <asm/system.h>
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  extern volatile int pen_release;
  
  static inline void cpu_enter_lowpower(void)
  {
  	unsigned int v;
  
  	flush_cache_all();
  	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_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)
  {
  	/*
  	 * there is no power-control hardware on this platform, so all
  	 * we can do is put the core into WFI; this is safe as the calling
  	 * code will have already disabled interrupts
  	 */
  	for (;;) {
b3377d186   Nick Bowler   ARM: 7064/1: vexp... 
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  		wfi();
e9882777d   Russell King   ARM: CPU hotplug:... 
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4a139b647
 
 Will Deacon
 
ARM: versatile: c...




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  		if (pen_release == cpu_logical_map(cpu)) {









e9882777d
 
 Russell King
 
ARM: CPU hotplug:...




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  			/*
  			 * 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)++;
  	}
  }
  
  int platform_cpu_kill(unsigned int cpu)
  {
  	return 1;
  }
  
  /*
   * platform-specific code to shutdown a CPU
   *
   * Called with IRQs disabled
   */
  void platform_cpu_die(unsigned int cpu)
  {
  	int spurious = 0;
  
  	/*
  	 * we're ready for shutdown now, so do it
  	 */
  	cpu_enter_lowpower();
  	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);
  }
  
  int platform_cpu_disable(unsigned int cpu)
  {
  	/*
  	 * we don't allow CPU 0 to be shutdown (it is still too special
  	 * e.g. clock tick interrupts)
  	 */
  	return cpu == 0 ? -EPERM : 0;
  }