/*
* Loongson2 performance counter driver for oprofile
*
* Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
* Author: Yanhua <yanh@lemote.com>
* Author: Wu Zhangjin <wuzj@lemote.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
*/
#include <linux/init.h>
#include <linux/oprofile.h>
#include <linux/interrupt.h>
#include <loongson.h> /* LOONGSON2_PERFCNT_IRQ */
#include "op_impl.h"
/*
* a patch should be sent to oprofile with the loongson-specific support.
* otherwise, the oprofile tool will not recognize this and complain about
* "cpu_type 'unset' is not valid".
*/
#define LOONGSON2_CPU_TYPE "mips/godson2"
#define LOONGSON2_COUNTER1_EVENT(event) ((event & 0x0f) << 5)
#define LOONGSON2_COUNTER2_EVENT(event) ((event & 0x0f) << 9)
#define LOONGSON2_PERFCNT_EXL (1UL << 0)
#define LOONGSON2_PERFCNT_KERNEL (1UL << 1)
#define LOONGSON2_PERFCNT_SUPERVISOR (1UL << 2)
#define LOONGSON2_PERFCNT_USER (1UL << 3)
#define LOONGSON2_PERFCNT_INT_EN (1UL << 4)
#define LOONGSON2_PERFCNT_OVERFLOW (1ULL << 31)
/* Loongson2 performance counter register */
#define read_c0_perfctrl() __read_64bit_c0_register($24, 0)
#define write_c0_perfctrl(val) __write_64bit_c0_register($24, 0, val)
#define read_c0_perfcnt() __read_64bit_c0_register($25, 0)
#define write_c0_perfcnt(val) __write_64bit_c0_register($25, 0, val)
static struct loongson2_register_config {
unsigned int ctrl;
unsigned long long reset_counter1;
unsigned long long reset_counter2;
int cnt1_enalbed, cnt2_enalbed;
} reg;
DEFINE_SPINLOCK(sample_lock);
static char *oprofid = "LoongsonPerf";
static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
/* Compute all of the registers in preparation for enabling profiling. */
static void loongson2_reg_setup(struct op_counter_config *cfg)
{
unsigned int ctrl = 0;
reg.reset_counter1 = 0;
reg.reset_counter2 = 0;
/* Compute the performance counter ctrl word. */
/* For now count kernel and user mode */
if (cfg[0].enabled) {
ctrl |= LOONGSON2_COUNTER1_EVENT(cfg[0].event);
reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
}
if (cfg[1].enabled) {
ctrl |= LOONGSON2_COUNTER2_EVENT(cfg[1].event);
reg.reset_counter2 = (0x80000000ULL - cfg[1].count);
}
if (cfg[0].enabled || cfg[1].enabled) {
ctrl |= LOONGSON2_PERFCNT_EXL | LOONGSON2_PERFCNT_INT_EN;
if (cfg[0].kernel || cfg[1].kernel)
ctrl |= LOONGSON2_PERFCNT_KERNEL;
if (cfg[0].user || cfg[1].user)
ctrl |= LOONGSON2_PERFCNT_USER;
}
reg.ctrl = ctrl;
reg.cnt1_enalbed = cfg[0].enabled;
reg.cnt2_enalbed = cfg[1].enabled;
}
/* Program all of the registers in preparation for enabling profiling. */
static void loongson2_cpu_setup(void *args)
{
uint64_t perfcount;
perfcount = (reg.reset_counter2 << 32) | reg.reset_counter1;
write_c0_perfcnt(perfcount);
}
static void loongson2_cpu_start(void *args)
{
/* Start all counters on current CPU */
if (reg.cnt1_enalbed || reg.cnt2_enalbed)
write_c0_perfctrl(reg.ctrl);
}
static void loongson2_cpu_stop(void *args)
{
/* Stop all counters on current CPU */
write_c0_perfctrl(0);
memset(®, 0, sizeof(reg));
}
static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
{
uint64_t counter, counter1, counter2;
struct pt_regs *regs = get_irq_regs();
int enabled;
unsigned long flags;
/*
* LOONGSON2 defines two 32-bit performance counters.
* To avoid a race updating the registers we need to stop the counters
* while we're messing with
* them ...
*/
/* Check whether the irq belongs to me */
enabled = reg.cnt1_enalbed | reg.cnt2_enalbed;
if (!enabled)
return IRQ_NONE;
counter = read_c0_perfcnt();
counter1 = counter & 0xffffffff;
counter2 = counter >> 32;
spin_lock_irqsave(&sample_lock, flags);
if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
if (reg.cnt1_enalbed)
oprofile_add_sample(regs, 0);
counter1 = reg.reset_counter1;
}
if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
if (reg.cnt2_enalbed)
oprofile_add_sample(regs, 1);
counter2 = reg.reset_counter2;
}
spin_unlock_irqrestore(&sample_lock, flags);
write_c0_perfcnt((counter2 << 32) | counter1);
return IRQ_HANDLED;
}
static int __init loongson2_init(void)
{
return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
IRQF_SHARED, "Perfcounter", oprofid);
}
static void loongson2_exit(void)
{
write_c0_perfctrl(0);
free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
}
struct op_mips_model op_model_loongson2_ops = {
.reg_setup = loongson2_reg_setup,
.cpu_setup = loongson2_cpu_setup,
.init = loongson2_init,
.exit = loongson2_exit,
.cpu_start = loongson2_cpu_start,
.cpu_stop = loongson2_cpu_stop,
.cpu_type = LOONGSON2_CPU_TYPE,
.num_counters = 2
};
