1/*
2 * Loongson2 performance counter driver for oprofile
3 *
4 * Copyright (C) 2009 Lemote Inc.
5 * Author: Yanhua <yanh@lemote.com>
6 * Author: Wu Zhangjin <wuzhangjin@gmail.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#include <linux/init.h>
13#include <linux/oprofile.h>
14#include <linux/interrupt.h>
15
16#include <loongson.h>			/* LOONGSON2_PERFCNT_IRQ */
17#include "op_impl.h"
18
19#define LOONGSON2_CPU_TYPE	"mips/loongson2"
20
21#define LOONGSON2_PERFCNT_OVERFLOW		(1ULL	<< 31)
22
23#define LOONGSON2_PERFCTRL_EXL			(1UL	<<  0)
24#define LOONGSON2_PERFCTRL_KERNEL		(1UL	<<  1)
25#define LOONGSON2_PERFCTRL_SUPERVISOR		(1UL	<<  2)
26#define LOONGSON2_PERFCTRL_USER			(1UL	<<  3)
27#define LOONGSON2_PERFCTRL_ENABLE		(1UL	<<  4)
28#define LOONGSON2_PERFCTRL_EVENT(idx, event) \
29	(((event) & 0x0f) << ((idx) ? 9 : 5))
30
31#define read_c0_perfctrl() __read_64bit_c0_register($24, 0)
32#define write_c0_perfctrl(val) __write_64bit_c0_register($24, 0, val)
33#define read_c0_perfcnt() __read_64bit_c0_register($25, 0)
34#define write_c0_perfcnt(val) __write_64bit_c0_register($25, 0, val)
35
36static struct loongson2_register_config {
37	unsigned int ctrl;
38	unsigned long long reset_counter1;
39	unsigned long long reset_counter2;
40	int cnt1_enabled, cnt2_enabled;
41} reg;
42
43static char *oprofid = "LoongsonPerf";
44static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
45
46static void reset_counters(void *arg)
47{
48	write_c0_perfctrl(0);
49	write_c0_perfcnt(0);
50}
51
52static void loongson2_reg_setup(struct op_counter_config *cfg)
53{
54	unsigned int ctrl = 0;
55
56	reg.reset_counter1 = 0;
57	reg.reset_counter2 = 0;
58
59	/*
60	 * Compute the performance counter ctrl word.
61	 * For now, count kernel and user mode.
62	 */
63	if (cfg[0].enabled) {
64		ctrl |= LOONGSON2_PERFCTRL_EVENT(0, cfg[0].event);
65		reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
66	}
67
68	if (cfg[1].enabled) {
69		ctrl |= LOONGSON2_PERFCTRL_EVENT(1, cfg[1].event);
70		reg.reset_counter2 = 0x80000000ULL - cfg[1].count;
71	}
72
73	if (cfg[0].enabled || cfg[1].enabled) {
74		ctrl |= LOONGSON2_PERFCTRL_EXL | LOONGSON2_PERFCTRL_ENABLE;
75		if (cfg[0].kernel || cfg[1].kernel)
76			ctrl |= LOONGSON2_PERFCTRL_KERNEL;
77		if (cfg[0].user || cfg[1].user)
78			ctrl |= LOONGSON2_PERFCTRL_USER;
79	}
80
81	reg.ctrl = ctrl;
82
83	reg.cnt1_enabled = cfg[0].enabled;
84	reg.cnt2_enabled = cfg[1].enabled;
85}
86
87static void loongson2_cpu_setup(void *args)
88{
89	write_c0_perfcnt((reg.reset_counter2 << 32) | reg.reset_counter1);
90}
91
92static void loongson2_cpu_start(void *args)
93{
94	/* Start all counters on current CPU */
95	if (reg.cnt1_enabled || reg.cnt2_enabled)
96		write_c0_perfctrl(reg.ctrl);
97}
98
99static void loongson2_cpu_stop(void *args)
100{
101	/* Stop all counters on current CPU */
102	write_c0_perfctrl(0);
103	memset(&reg, 0, sizeof(reg));
104}
105
106static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
107{
108	uint64_t counter, counter1, counter2;
109	struct pt_regs *regs = get_irq_regs();
110	int enabled;
111
112	/* Check whether the irq belongs to me */
113	enabled = read_c0_perfctrl() & LOONGSON2_PERFCTRL_ENABLE;
114	if (!enabled)
115		return IRQ_NONE;
116	enabled = reg.cnt1_enabled | reg.cnt2_enabled;
117	if (!enabled)
118		return IRQ_NONE;
119
120	counter = read_c0_perfcnt();
121	counter1 = counter & 0xffffffff;
122	counter2 = counter >> 32;
123
124	if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
125		if (reg.cnt1_enabled)
126			oprofile_add_sample(regs, 0);
127		counter1 = reg.reset_counter1;
128	}
129	if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
130		if (reg.cnt2_enabled)
131			oprofile_add_sample(regs, 1);
132		counter2 = reg.reset_counter2;
133	}
134
135	write_c0_perfcnt((counter2 << 32) | counter1);
136
137	return IRQ_HANDLED;
138}
139
140static int __init loongson2_init(void)
141{
142	return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
143			   IRQF_SHARED, "Perfcounter", oprofid);
144}
145
146static void loongson2_exit(void)
147{
148	reset_counters(NULL);
149	free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
150}
151
152struct op_mips_model op_model_loongson2_ops = {
153	.reg_setup = loongson2_reg_setup,
154	.cpu_setup = loongson2_cpu_setup,
155	.init = loongson2_init,
156	.exit = loongson2_exit,
157	.cpu_start = loongson2_cpu_start,
158	.cpu_stop = loongson2_cpu_stop,
159	.cpu_type = LOONGSON2_CPU_TYPE,
160	.num_counters = 2
161};
162