/*

   *  arch/powerpc/kernel/pmc.c

   *
   *  Copyright (C) 2004 David Gibson, IBM Corporation.

   *  Includes code formerly from arch/ppc/kernel/perfmon.c:
   *    Author: Andy Fleming
   *    Copyright (c) 2004 Freescale Semiconductor, Inc

   *
   *  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.
   */

  #include <linux/errno.h>
  #include <linux/spinlock.h>

  #include <linux/export.h>

  
  #include <asm/processor.h>

  #include <asm/cputable.h>

  #include <asm/pmc.h>

  #ifndef MMCR0_PMAO
  #define MMCR0_PMAO	0

  #endif

  static void dummy_perf(struct pt_regs *regs)
  {

  #if defined(CONFIG_FSL_EMB_PERFMON)

  	mtpmr(PMRN_PMGC0, mfpmr(PMRN_PMGC0) & ~PMGC0_PMIE);
  #elif defined(CONFIG_PPC64) || defined(CONFIG_6xx)

  	if (cur_cpu_spec->pmc_type == PPC_PMC_IBM)

  		mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~(MMCR0_PMXE|MMCR0_PMAO));

  #else

  	mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_PMXE);

  #endif

  }

  static DEFINE_RAW_SPINLOCK(pmc_owner_lock);

  static void *pmc_owner_caller; /* mostly for debugging */
  perf_irq_t perf_irq = dummy_perf;
  
  int reserve_pmc_hardware(perf_irq_t new_perf_irq)
  {
  	int err = 0;

  	raw_spin_lock(&pmc_owner_lock);

  
  	if (pmc_owner_caller) {
  		printk(KERN_WARNING "reserve_pmc_hardware: "
  		       "PMC hardware busy (reserved by caller %p)
  ",
  		       pmc_owner_caller);
  		err = -EBUSY;
  		goto out;
  	}
  
  	pmc_owner_caller = __builtin_return_address(0);

  	perf_irq = new_perf_irq ? new_perf_irq : dummy_perf;

  
   out:

  	raw_spin_unlock(&pmc_owner_lock);

  	return err;
  }
  EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  
  void release_pmc_hardware(void)
  {

  	raw_spin_lock(&pmc_owner_lock);

  
  	WARN_ON(! pmc_owner_caller);
  
  	pmc_owner_caller = NULL;
  	perf_irq = dummy_perf;

  	raw_spin_unlock(&pmc_owner_lock);

  }
  EXPORT_SYMBOL_GPL(release_pmc_hardware);

  #ifdef CONFIG_PPC64

  void power4_enable_pmcs(void)
  {
  	unsigned long hid0;

  	hid0 = mfspr(SPRN_HID0);

  	hid0 |= 1UL << (63 - 20);
  
  	/* POWER4 requires the following sequence */
  	asm volatile(
  		"sync
  "
  		"mtspr     %1, %0
  "
  		"mfspr     %0, %1
  "
  		"mfspr     %0, %1
  "
  		"mfspr     %0, %1
  "
  		"mfspr     %0, %1
  "
  		"mfspr     %0, %1
  "
  		"mfspr     %0, %1
  "

  		"isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0):

  		"memory");
  }

  #endif /* CONFIG_PPC64 */