Eric Lee / smarc-fsl-linux-kernel

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arch/arm/mach-msm/hotplug.c 1.85 KB
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9f1890a5d   Jeff Ohlstein   msm: hotplug: sup... 
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  /*
   *  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>
  
  extern volatile int pen_release;
  
  static inline void cpu_enter_lowpower(void)
  {
  	/* Just flush the cache. Changing the coherency is not yet
  	 * available on msm. */
  	flush_cache_all();
  }
  
  static inline void cpu_leave_lowpower(void)
  {
  }
  
  static inline void platform_do_lowpower(unsigned int cpu)
  {
  	/* Just enter wfi for now. TODO: Properly shut off the cpu. */
  	for (;;) {
  		/*
  		 * here's the WFI
  		 */
  		asm("wfi"
  		    :
  		    :
  		    : "memory", "cc");
1d3cfb34f   Will Deacon   ARM: msm: convert... 
39
 
  		if (pen_release == cpu_logical_map(cpu)) {
9f1890a5d   Jeff Ohlstein   msm: hotplug: sup... 
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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
  		 *
  		 * The trouble is, letting people know about this is not really
  		 * possible, since we are currently running incoherently, and
  		 * therefore cannot safely call printk() or anything else
  		 */
  		pr_debug("CPU%u: spurious wakeup call
  ", cpu);
  	}
  }
  
  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)
  {
  	/*
  	 * we're ready for shutdown now, so do it
  	 */
  	cpu_enter_lowpower();
  	platform_do_lowpower(cpu);
  
  	/*
  	 * bring this CPU back into the world of cache
  	 * coherency, and then restore interrupts
  	 */
  	cpu_leave_lowpower();
  }
  
  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;
  }