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
  28 static 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
  41 static DEFINE_RAW_SPINLOCK(pmc_owner_lock);
  42 static void *pmc_owner_caller; /* mostly for debugging */
  43 perf_irq_t perf_irq = dummy_perf;
  44
  45 int 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 }
  66 EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  67
  68 void 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 }
  79 EXPORT_SYMBOL_GPL(release_pmc_hardware);
  80
  81 #ifdef CONFIG_PPC64
  82 void 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 */