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 static void dummy_perf(struct pt_regs *regs) 47 { 48 } 49 #endif 50 51 static DEFINE_SPINLOCK(pmc_owner_lock); 52 static void *pmc_owner_caller; /* mostly for debugging */ 53 perf_irq_t perf_irq = dummy_perf; 54 55 int reserve_pmc_hardware(perf_irq_t new_perf_irq) 56 { 57 int err = 0; 58 59 spin_lock(&pmc_owner_lock); 60 61 if (pmc_owner_caller) { 62 printk(KERN_WARNING "reserve_pmc_hardware: " 63 "PMC hardware busy (reserved by caller %p)\n", 64 pmc_owner_caller); 65 err = -EBUSY; 66 goto out; 67 } 68 69 pmc_owner_caller = __builtin_return_address(0); 70 perf_irq = new_perf_irq ? : dummy_perf; 71 72 out: 73 spin_unlock(&pmc_owner_lock); 74 return err; 75 } 76 EXPORT_SYMBOL_GPL(reserve_pmc_hardware); 77 78 void release_pmc_hardware(void) 79 { 80 spin_lock(&pmc_owner_lock); 81 82 WARN_ON(! pmc_owner_caller); 83 84 pmc_owner_caller = NULL; 85 perf_irq = dummy_perf; 86 87 spin_unlock(&pmc_owner_lock); 88 } 89 EXPORT_SYMBOL_GPL(release_pmc_hardware); 90 91 #ifdef CONFIG_PPC64 92 void power4_enable_pmcs(void) 93 { 94 unsigned long hid0; 95 96 hid0 = mfspr(SPRN_HID0); 97 hid0 |= 1UL << (63 - 20); 98 99 /* POWER4 requires the following sequence */ 100 asm volatile( 101 "sync\n" 102 "mtspr %1, %0\n" 103 "mfspr %0, %1\n" 104 "mfspr %0, %1\n" 105 "mfspr %0, %1\n" 106 "mfspr %0, %1\n" 107 "mfspr %0, %1\n" 108 "mfspr %0, %1\n" 109 "isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0): 110 "memory"); 111 } 112 #endif /* CONFIG_PPC64 */ 113