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