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
dummy_perf(struct pt_regs * regs)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
reserve_pmc_hardware(perf_irq_t new_perf_irq)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
release_pmc_hardware(void)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
power4_enable_pmcs(void)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