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_PPC_BOOK3S_32) 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 */ 103