/*
 * 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/cpu.h>
#include <linux/smp.h>
#include <linux/proc_fs.h>
#include <linux/oprofile.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <irq.h>
#include <loongson.h>
#include "op_impl.h"

#define LOONGSON3_PERFCNT_OVERFLOW	(1ULL << 63)

#define LOONGSON3_PERFCTRL_EXL		(1UL << 0)
#define LOONGSON3_PERFCTRL_KERNEL	(1UL << 1)
#define LOONGSON3_PERFCTRL_SUPERVISOR	(1UL << 2)
#define LOONGSON3_PERFCTRL_USER		(1UL << 3)
#define LOONGSON3_PERFCTRL_ENABLE	(1UL << 4)
#define LOONGSON3_PERFCTRL_W		(1UL << 30)
#define LOONGSON3_PERFCTRL_M		(1UL << 31)
#define LOONGSON3_PERFCTRL_EVENT(idx, event) \
	(((event) & (idx ? 0x0f : 0x3f)) << 5)

/* Loongson-3 PerfCount performance counter1 register */
#define read_c0_perflo1() __read_64bit_c0_register($25, 0)
#define write_c0_perflo1(val) __write_64bit_c0_register($25, 0, val)
#define read_c0_perfhi1() __read_64bit_c0_register($25, 1)
#define write_c0_perfhi1(val) __write_64bit_c0_register($25, 1, val)

/* Loongson-3 PerfCount performance counter2 register */
#define read_c0_perflo2() __read_64bit_c0_register($25, 2)
#define write_c0_perflo2(val) __write_64bit_c0_register($25, 2, val)
#define read_c0_perfhi2() __read_64bit_c0_register($25, 3)
#define write_c0_perfhi2(val) __write_64bit_c0_register($25, 3, val)

static int (*save_perf_irq)(void);

static struct loongson3_register_config {
	unsigned int control1;
	unsigned int control2;
	unsigned long long reset_counter1;
	unsigned long long reset_counter2;
	int ctr1_enable, ctr2_enable;
} reg;

static void reset_counters(void *arg)
{
	write_c0_perfhi1(0);
	write_c0_perfhi2(0);
	write_c0_perflo1(0xc0000000);
	write_c0_perflo2(0x40000000);
}

/* Compute all of the registers in preparation for enabling profiling. */
static void loongson3_reg_setup(struct op_counter_config *ctr)
{
	unsigned int control1 = 0;
	unsigned int control2 = 0;

	reg.reset_counter1 = 0;
	reg.reset_counter2 = 0;
	/* Compute the performance counter control word. */
	/* For now count kernel and user mode */
	if (ctr[0].enabled) {
		control1 |= LOONGSON3_PERFCTRL_EVENT(0, ctr[0].event) |
					LOONGSON3_PERFCTRL_ENABLE;
		if (ctr[0].kernel)
			control1 |= LOONGSON3_PERFCTRL_KERNEL;
		if (ctr[0].user)
			control1 |= LOONGSON3_PERFCTRL_USER;
		reg.reset_counter1 = 0x8000000000000000ULL - ctr[0].count;
	}

	if (ctr[1].enabled) {
		control2 |= LOONGSON3_PERFCTRL_EVENT(1, ctr[1].event) |
					LOONGSON3_PERFCTRL_ENABLE;
		if (ctr[1].kernel)
			control2 |= LOONGSON3_PERFCTRL_KERNEL;
		if (ctr[1].user)
			control2 |= LOONGSON3_PERFCTRL_USER;
		reg.reset_counter2 = 0x8000000000000000ULL - ctr[1].count;
	}

	if (ctr[0].enabled)
		control1 |= LOONGSON3_PERFCTRL_EXL;
	if (ctr[1].enabled)
		control2 |= LOONGSON3_PERFCTRL_EXL;

	reg.control1 = control1;
	reg.control2 = control2;
	reg.ctr1_enable = ctr[0].enabled;
	reg.ctr2_enable = ctr[1].enabled;
}

/* Program all of the registers in preparation for enabling profiling. */
static void loongson3_cpu_setup(void *args)
{
	uint64_t perfcount1, perfcount2;

	perfcount1 = reg.reset_counter1;
	perfcount2 = reg.reset_counter2;
	write_c0_perfhi1(perfcount1);
	write_c0_perfhi2(perfcount2);
}

static void loongson3_cpu_start(void *args)
{
	/* Start all counters on current CPU */
	reg.control1 |= (LOONGSON3_PERFCTRL_W|LOONGSON3_PERFCTRL_M);
	reg.control2 |= (LOONGSON3_PERFCTRL_W|LOONGSON3_PERFCTRL_M);

	if (reg.ctr1_enable)
		write_c0_perflo1(reg.control1);
	if (reg.ctr2_enable)
		write_c0_perflo2(reg.control2);
}

static void loongson3_cpu_stop(void *args)
{
	/* Stop all counters on current CPU */
	write_c0_perflo1(0xc0000000);
	write_c0_perflo2(0x40000000);
	memset(&reg, 0, sizeof(reg));
}

static int loongson3_perfcount_handler(void)
{
	unsigned long flags;
	uint64_t counter1, counter2;
	uint32_t cause, handled = IRQ_NONE;
	struct pt_regs *regs = get_irq_regs();

	cause = read_c0_cause();
	if (!(cause & CAUSEF_PCI))
		return handled;

	counter1 = read_c0_perfhi1();
	counter2 = read_c0_perfhi2();

	local_irq_save(flags);

	if (counter1 & LOONGSON3_PERFCNT_OVERFLOW) {
		if (reg.ctr1_enable)
			oprofile_add_sample(regs, 0);
		counter1 = reg.reset_counter1;
	}
	if (counter2 & LOONGSON3_PERFCNT_OVERFLOW) {
		if (reg.ctr2_enable)
			oprofile_add_sample(regs, 1);
		counter2 = reg.reset_counter2;
	}

	local_irq_restore(flags);

	write_c0_perfhi1(counter1);
	write_c0_perfhi2(counter2);

	if (!(cause & CAUSEF_TI))
		handled = IRQ_HANDLED;

	return handled;
}

static int loongson3_cpu_callback(struct notifier_block *nfb,
	unsigned long action, void *hcpu)
{
	switch (action) {
	case CPU_STARTING:
	case CPU_STARTING_FROZEN:
		write_c0_perflo1(reg.control1);
		write_c0_perflo2(reg.control2);
		break;
	case CPU_DYING:
	case CPU_DYING_FROZEN:
		write_c0_perflo1(0xc0000000);
		write_c0_perflo2(0x40000000);
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block loongson3_notifier_block = {
	.notifier_call = loongson3_cpu_callback
};

static int __init loongson3_init(void)
{
	on_each_cpu(reset_counters, NULL, 1);
	register_hotcpu_notifier(&loongson3_notifier_block);
	save_perf_irq = perf_irq;
	perf_irq = loongson3_perfcount_handler;

	return 0;
}

static void loongson3_exit(void)
{
	on_each_cpu(reset_counters, NULL, 1);
	unregister_hotcpu_notifier(&loongson3_notifier_block);
	perf_irq = save_perf_irq;
}

struct op_mips_model op_model_loongson3_ops = {
	.reg_setup	= loongson3_reg_setup,
	.cpu_setup	= loongson3_cpu_setup,
	.init		= loongson3_init,
	.exit		= loongson3_exit,
	.cpu_start	= loongson3_cpu_start,
	.cpu_stop	= loongson3_cpu_stop,
	.cpu_type	= "mips/loongson3",
	.num_counters	= 2
};