LXR linux/arch/powerpc/kernel/pmc.c

   1/*
   2 *  arch/powerpc/kernel/pmc.c
   3 *
   4 *  Copyright (C) 2004 David Gibson, IBM Corporation.
   5 *  Includes code formerly from arch/ppc/kernel/perfmon.c:
   6 *    Author: Andy Fleming
   7 *    Copyright (c) 2004 Freescale Semiconductor, Inc
   8 *
   9 *  This program is free software; you can redistribute it and/or
  10 *  modify it under the terms of the GNU General Public License
  11 *  as published by the Free Software Foundation; either version
  12 *  2 of the License, or (at your option) any later version.
  13 */
  14
  15#include <linux/errno.h>
  16#include <linux/bug.h>
  17#include <linux/spinlock.h>
  18#include <linux/export.h>
  19
  20#include <asm/processor.h>
  21#include <asm/cputable.h>
  22#include <asm/pmc.h>
  23
  24#ifndef MMCR0_PMAO
  25#define MMCR0_PMAO      0
  26#endif
  27
  28static void dummy_perf(struct pt_regs *regs)
  29{
  30#if defined(CONFIG_FSL_EMB_PERFMON)
  31        mtpmr(PMRN_PMGC0, mfpmr(PMRN_PMGC0) & ~PMGC0_PMIE);
  32#elif defined(CONFIG_PPC64) || defined(CONFIG_6xx)
  33        if (cur_cpu_spec->pmc_type == PPC_PMC_IBM)
  34                mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~(MMCR0_PMXE|MMCR0_PMAO));
  35#else
  36        mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_PMXE);
  37#endif
  38}
  39
  40
  41static DEFINE_RAW_SPINLOCK(pmc_owner_lock);
  42static void *pmc_owner_caller; /* mostly for debugging */
  43perf_irq_t perf_irq = dummy_perf;
  44
  45int reserve_pmc_hardware(perf_irq_t new_perf_irq)
  46{
  47        int err = 0;
  48
  49        raw_spin_lock(&pmc_owner_lock);
  50
  51        if (pmc_owner_caller) {
  52                printk(KERN_WARNING "reserve_pmc_hardware: "
  53                       "PMC hardware busy (reserved by caller %p)\n",
  54                       pmc_owner_caller);
  55                err = -EBUSY;
  56                goto out;
  57        }
  58
  59        pmc_owner_caller = __builtin_return_address(0);
  60        perf_irq = new_perf_irq ? new_perf_irq : dummy_perf;
  61
  62 out:
  63        raw_spin_unlock(&pmc_owner_lock);
  64        return err;
  65}
  66EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  67
  68void release_pmc_hardware(void)
  69{
  70        raw_spin_lock(&pmc_owner_lock);
  71
  72        WARN_ON(! pmc_owner_caller);
  73
  74        pmc_owner_caller = NULL;
  75        perf_irq = dummy_perf;
  76
  77        raw_spin_unlock(&pmc_owner_lock);
  78}
  79EXPORT_SYMBOL_GPL(release_pmc_hardware);
  80
  81#ifdef CONFIG_PPC64
  82void power4_enable_pmcs(void)
  83{
  84        unsigned long hid0;
  85
  86        hid0 = mfspr(SPRN_HID0);
  87        hid0 |= 1UL << (63 - 20);
  88
  89        /* POWER4 requires the following sequence */
  90        asm volatile(
  91                "sync\n"
  92                "mtspr     %1, %0\n"
  93                "mfspr     %0, %1\n"
  94                "mfspr     %0, %1\n"
  95                "mfspr     %0, %1\n"
  96                "mfspr     %0, %1\n"
  97                "mfspr     %0, %1\n"
  98                "mfspr     %0, %1\n"
  99                "isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0):
 100                "memory");
 101}
 102#endif /* CONFIG_PPC64 */
 103