MIPS: Loongson: Add oprofile support
[kernel.git] / arch / mips / oprofile / op_model_loongson2.c
1 /*
2  * Loongson2 performance counter driver for oprofile
3  *
4  * Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
5  * Author: Yanhua <yanh@lemote.com>
6  * Author: Wu Zhangjin <wuzj@lemote.com>
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License.  See the file "COPYING" in the main directory of this archive
10  * for more details.
11  *
12  */
13 #include <linux/init.h>
14 #include <linux/oprofile.h>
15 #include <linux/interrupt.h>
16
17 #include <loongson.h>                   /* LOONGSON2_PERFCNT_IRQ */
18 #include "op_impl.h"
19
20 /*
21  * a patch should be sent to oprofile with the loongson-specific support.
22  * otherwise, the oprofile tool will not recognize this and complain about
23  * "cpu_type 'unset' is not valid".
24  */
25 #define LOONGSON2_CPU_TYPE      "mips/godson2"
26
27 #define LOONGSON2_COUNTER1_EVENT(event) ((event & 0x0f) << 5)
28 #define LOONGSON2_COUNTER2_EVENT(event) ((event & 0x0f) << 9)
29
30 #define LOONGSON2_PERFCNT_EXL                   (1UL    <<  0)
31 #define LOONGSON2_PERFCNT_KERNEL                (1UL    <<  1)
32 #define LOONGSON2_PERFCNT_SUPERVISOR    (1UL    <<  2)
33 #define LOONGSON2_PERFCNT_USER                  (1UL    <<  3)
34 #define LOONGSON2_PERFCNT_INT_EN                (1UL    <<  4)
35 #define LOONGSON2_PERFCNT_OVERFLOW              (1ULL   << 31)
36
37 /* Loongson2 performance counter register */
38 #define read_c0_perfctrl() __read_64bit_c0_register($24, 0)
39 #define write_c0_perfctrl(val) __write_64bit_c0_register($24, 0, val)
40 #define read_c0_perfcnt() __read_64bit_c0_register($25, 0)
41 #define write_c0_perfcnt(val) __write_64bit_c0_register($25, 0, val)
42
43 static struct loongson2_register_config {
44         unsigned int ctrl;
45         unsigned long long reset_counter1;
46         unsigned long long reset_counter2;
47         int cnt1_enalbed, cnt2_enalbed;
48 } reg;
49
50 DEFINE_SPINLOCK(sample_lock);
51
52 static char *oprofid = "LoongsonPerf";
53 static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
54 /* Compute all of the registers in preparation for enabling profiling.  */
55
56 static void loongson2_reg_setup(struct op_counter_config *cfg)
57 {
58         unsigned int ctrl = 0;
59
60         reg.reset_counter1 = 0;
61         reg.reset_counter2 = 0;
62         /* Compute the performance counter ctrl word.  */
63         /* For now count kernel and user mode */
64         if (cfg[0].enabled) {
65                 ctrl |= LOONGSON2_COUNTER1_EVENT(cfg[0].event);
66                 reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
67         }
68
69         if (cfg[1].enabled) {
70                 ctrl |= LOONGSON2_COUNTER2_EVENT(cfg[1].event);
71                 reg.reset_counter2 = (0x80000000ULL - cfg[1].count);
72         }
73
74         if (cfg[0].enabled || cfg[1].enabled) {
75                 ctrl |= LOONGSON2_PERFCNT_EXL | LOONGSON2_PERFCNT_INT_EN;
76                 if (cfg[0].kernel || cfg[1].kernel)
77                         ctrl |= LOONGSON2_PERFCNT_KERNEL;
78                 if (cfg[0].user || cfg[1].user)
79                         ctrl |= LOONGSON2_PERFCNT_USER;
80         }
81
82         reg.ctrl = ctrl;
83
84         reg.cnt1_enalbed = cfg[0].enabled;
85         reg.cnt2_enalbed = cfg[1].enabled;
86
87 }
88
89 /* Program all of the registers in preparation for enabling profiling.  */
90
91 static void loongson2_cpu_setup(void *args)
92 {
93         uint64_t perfcount;
94
95         perfcount = (reg.reset_counter2 << 32) | reg.reset_counter1;
96         write_c0_perfcnt(perfcount);
97 }
98
99 static void loongson2_cpu_start(void *args)
100 {
101         /* Start all counters on current CPU */
102         if (reg.cnt1_enalbed || reg.cnt2_enalbed)
103                 write_c0_perfctrl(reg.ctrl);
104 }
105
106 static void loongson2_cpu_stop(void *args)
107 {
108         /* Stop all counters on current CPU */
109         write_c0_perfctrl(0);
110         memset(&reg, 0, sizeof(reg));
111 }
112
113 static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
114 {
115         uint64_t counter, counter1, counter2;
116         struct pt_regs *regs = get_irq_regs();
117         int enabled;
118         unsigned long flags;
119
120         /*
121          * LOONGSON2 defines two 32-bit performance counters.
122          * To avoid a race updating the registers we need to stop the counters
123          * while we're messing with
124          * them ...
125          */
126
127         /* Check whether the irq belongs to me */
128         enabled = reg.cnt1_enalbed | reg.cnt2_enalbed;
129         if (!enabled)
130                 return IRQ_NONE;
131
132         counter = read_c0_perfcnt();
133         counter1 = counter & 0xffffffff;
134         counter2 = counter >> 32;
135
136         spin_lock_irqsave(&sample_lock, flags);
137
138         if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
139                 if (reg.cnt1_enalbed)
140                         oprofile_add_sample(regs, 0);
141                 counter1 = reg.reset_counter1;
142         }
143         if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
144                 if (reg.cnt2_enalbed)
145                         oprofile_add_sample(regs, 1);
146                 counter2 = reg.reset_counter2;
147         }
148
149         spin_unlock_irqrestore(&sample_lock, flags);
150
151         write_c0_perfcnt((counter2 << 32) | counter1);
152
153         return IRQ_HANDLED;
154 }
155
156 static int __init loongson2_init(void)
157 {
158         return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
159                            IRQF_SHARED, "Perfcounter", oprofid);
160 }
161
162 static void loongson2_exit(void)
163 {
164         write_c0_perfctrl(0);
165         free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
166 }
167
168 struct op_mips_model op_model_loongson2_ops = {
169         .reg_setup = loongson2_reg_setup,
170         .cpu_setup = loongson2_cpu_setup,
171         .init = loongson2_init,
172         .exit = loongson2_exit,
173         .cpu_start = loongson2_cpu_start,
174         .cpu_stop = loongson2_cpu_stop,
175         .cpu_type = LOONGSON2_CPU_TYPE,
176         .num_counters = 2
177 };