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/config.h>
  16 #include <linux/errno.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/module.h>
  19
  20 #include <asm/processor.h>
  21 #include <asm/pmc.h>
  22
  23 #if defined(CONFIG_FSL_BOOKE) && !defined(CONFIG_E200)
  24 static void dummy_perf(struct pt_regs *regs)
  25 {
  26         unsigned int pmgc0 = mfpmr(PMRN_PMGC0);
  27
  28         pmgc0 &= ~PMGC0_PMIE;
  29         mtpmr(PMRN_PMGC0, pmgc0);
  30 }
  31 #elif defined(CONFIG_PPC64) || defined(CONFIG_6xx)
  32
  33 #ifndef MMCR0_PMAO
  34 #define MMCR0_PMAO      0
  35 #endif
  36
  37 /* Ensure exceptions are disabled */
  38 static void dummy_perf(struct pt_regs *regs)
  39 {
  40         unsigned int mmcr0 = mfspr(SPRN_MMCR0);
  41
  42         mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
  43         mtspr(SPRN_MMCR0, mmcr0);
  44 }
  45 #else
  46 /* Ensure exceptions are disabled */
  47 static void dummy_perf(struct pt_regs *regs)
  48 {
  49         unsigned int mmcr0 = mfspr(SPRN_MMCR0);
  50
  51         mmcr0 &= ~(MMCR0_PMXE);
  52         mtspr(SPRN_MMCR0, mmcr0);
  53 }
  54 #endif
  55
  56 static DEFINE_SPINLOCK(pmc_owner_lock);
  57 static void *pmc_owner_caller; /* mostly for debugging */
  58 perf_irq_t perf_irq = dummy_perf;
  59
  60 int reserve_pmc_hardware(perf_irq_t new_perf_irq)
  61 {
  62         int err = 0;
  63
  64         spin_lock(&pmc_owner_lock);
  65
  66         if (pmc_owner_caller) {
  67                 printk(KERN_WARNING "reserve_pmc_hardware: "
  68                        "PMC hardware busy (reserved by caller %p)\n",
  69                        pmc_owner_caller);
  70                 err = -EBUSY;
  71                 goto out;
  72         }
  73
  74         pmc_owner_caller = __builtin_return_address(0);
  75         perf_irq = new_perf_irq ? : dummy_perf;
  76
  77  out:
  78         spin_unlock(&pmc_owner_lock);
  79         return err;
  80 }
  81 EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  82
  83 void release_pmc_hardware(void)
  84 {
  85         spin_lock(&pmc_owner_lock);
  86
  87         WARN_ON(! pmc_owner_caller);
  88
  89         pmc_owner_caller = NULL;
  90         perf_irq = dummy_perf;
  91
  92         spin_unlock(&pmc_owner_lock);
  93 }
  94 EXPORT_SYMBOL_GPL(release_pmc_hardware);
  95
  96 #ifdef CONFIG_PPC64
  97 void power4_enable_pmcs(void)
  98 {
  99         unsigned long hid0;
 100
 101         hid0 = mfspr(SPRN_HID0);
 102         hid0 |= 1UL << (63 - 20);
 103
 104         /* POWER4 requires the following sequence */
 105         asm volatile(
 106                 "sync\n"
 107                 "mtspr     %1, %0\n"
 108                 "mfspr     %0, %1\n"
 109                 "mfspr     %0, %1\n"
 110                 "mfspr     %0, %1\n"
 111                 "mfspr     %0, %1\n"
 112                 "mfspr     %0, %1\n"
 113                 "mfspr     %0, %1\n"
 114                 "isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0):
 115                 "memory");
 116 }
 117 #endif /* CONFIG_PPC64 */