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};