/*
 * Copyright 2011,2016 Freescale Semiconductor, Inc.
 * Copyright 2011 Linaro Ltd.
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/hrtimer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/perf_event.h>
#include <linux/slab.h>

#include "common.h"

#define MMDC_MAPSR		0x404
#define BP_MMDC_MAPSR_PSD	0
#define BP_MMDC_MAPSR_PSS	4

#define MMDC_MDMISC		0x18
#define BM_MMDC_MDMISC_DDR_TYPE	0x18
#define BP_MMDC_MDMISC_DDR_TYPE	0x3

#define TOTAL_CYCLES		0x0
#define BUSY_CYCLES		0x1
#define READ_ACCESSES		0x2
#define WRITE_ACCESSES		0x3
#define READ_BYTES		0x4
#define WRITE_BYTES		0x5

/* Enables, resets, freezes, overflow profiling*/
#define DBG_DIS			0x0
#define DBG_EN			0x1
#define DBG_RST			0x2
#define PRF_FRZ			0x4
#define CYC_OVF			0x8
#define PROFILE_SEL		0x10

#define MMDC_MADPCR0	0x410
#define MMDC_MADPSR0	0x418
#define MMDC_MADPSR1	0x41C
#define MMDC_MADPSR2	0x420
#define MMDC_MADPSR3	0x424
#define MMDC_MADPSR4	0x428
#define MMDC_MADPSR5	0x42C

#define MMDC_NUM_COUNTERS	6

#define MMDC_FLAG_PROFILE_SEL	0x1

#define to_mmdc_pmu(p) container_of(p, struct mmdc_pmu, pmu)

static enum cpuhp_state cpuhp_mmdc_state;
static int ddr_type;

struct fsl_mmdc_devtype_data {
	unsigned int flags;
};

static const struct fsl_mmdc_devtype_data imx6q_data = {
};

static const struct fsl_mmdc_devtype_data imx6qp_data = {
	.flags = MMDC_FLAG_PROFILE_SEL,
};

static const struct of_device_id imx_mmdc_dt_ids[] = {
	{ .compatible = "fsl,imx6q-mmdc", .data = (void *)&imx6q_data},
	{ .compatible = "fsl,imx6qp-mmdc", .data = (void *)&imx6qp_data},
	{ /* sentinel */ }
};

#ifdef CONFIG_PERF_EVENTS

static DEFINE_IDA(mmdc_ida);

PMU_EVENT_ATTR_STRING(total-cycles, mmdc_pmu_total_cycles, "event=0x00")
PMU_EVENT_ATTR_STRING(busy-cycles, mmdc_pmu_busy_cycles, "event=0x01")
PMU_EVENT_ATTR_STRING(read-accesses, mmdc_pmu_read_accesses, "event=0x02")
PMU_EVENT_ATTR_STRING(write-accesses, mmdc_pmu_write_accesses, "config=0x03")
PMU_EVENT_ATTR_STRING(read-bytes, mmdc_pmu_read_bytes, "event=0x04")
PMU_EVENT_ATTR_STRING(read-bytes.unit, mmdc_pmu_read_bytes_unit, "MB");
PMU_EVENT_ATTR_STRING(read-bytes.scale, mmdc_pmu_read_bytes_scale, "0.000001");
PMU_EVENT_ATTR_STRING(write-bytes, mmdc_pmu_write_bytes, "event=0x05")
PMU_EVENT_ATTR_STRING(write-bytes.unit, mmdc_pmu_write_bytes_unit, "MB");
PMU_EVENT_ATTR_STRING(write-bytes.scale, mmdc_pmu_write_bytes_scale, "0.000001");

struct mmdc_pmu {
	struct pmu pmu;
	void __iomem *mmdc_base;
	cpumask_t cpu;
	struct hrtimer hrtimer;
	unsigned int active_events;
	struct device *dev;
	struct perf_event *mmdc_events[MMDC_NUM_COUNTERS];
	struct hlist_node node;
	struct fsl_mmdc_devtype_data *devtype_data;
};

/*
 * Polling period is set to one second, overflow of total-cycles (the fastest
 * increasing counter) takes ten seconds so one second is safe
 */
static unsigned int mmdc_pmu_poll_period_us = 1000000;

module_param_named(pmu_pmu_poll_period_us, mmdc_pmu_poll_period_us, uint,
		S_IRUGO | S_IWUSR);

static ktime_t mmdc_pmu_timer_period(void)
{
	return ns_to_ktime((u64)mmdc_pmu_poll_period_us * 1000);
}

static ssize_t mmdc_pmu_cpumask_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mmdc_pmu *pmu_mmdc = dev_get_drvdata(dev);

	return cpumap_print_to_pagebuf(true, buf, &pmu_mmdc->cpu);
}

static struct device_attribute mmdc_pmu_cpumask_attr =
	__ATTR(cpumask, S_IRUGO, mmdc_pmu_cpumask_show, NULL);

static struct attribute *mmdc_pmu_cpumask_attrs[] = {
	&mmdc_pmu_cpumask_attr.attr,
	NULL,
};

static struct attribute_group mmdc_pmu_cpumask_attr_group = {
	.attrs = mmdc_pmu_cpumask_attrs,
};

static struct attribute *mmdc_pmu_events_attrs[] = {
	&mmdc_pmu_total_cycles.attr.attr,
	&mmdc_pmu_busy_cycles.attr.attr,
	&mmdc_pmu_read_accesses.attr.attr,
	&mmdc_pmu_write_accesses.attr.attr,
	&mmdc_pmu_read_bytes.attr.attr,
	&mmdc_pmu_read_bytes_unit.attr.attr,
	&mmdc_pmu_read_bytes_scale.attr.attr,
	&mmdc_pmu_write_bytes.attr.attr,
	&mmdc_pmu_write_bytes_unit.attr.attr,
	&mmdc_pmu_write_bytes_scale.attr.attr,
	NULL,
};

static struct attribute_group mmdc_pmu_events_attr_group = {
	.name = "events",
	.attrs = mmdc_pmu_events_attrs,
};

PMU_FORMAT_ATTR(event, "config:0-63");
static struct attribute *mmdc_pmu_format_attrs[] = {
	&format_attr_event.attr,
	NULL,
};

static struct attribute_group mmdc_pmu_format_attr_group = {
	.name = "format",
	.attrs = mmdc_pmu_format_attrs,
};

static const struct attribute_group *attr_groups[] = {
	&mmdc_pmu_events_attr_group,
	&mmdc_pmu_format_attr_group,
	&mmdc_pmu_cpumask_attr_group,
	NULL,
};

static u32 mmdc_pmu_read_counter(struct mmdc_pmu *pmu_mmdc, int cfg)
{
	void __iomem *mmdc_base, *reg;

	mmdc_base = pmu_mmdc->mmdc_base;

	switch (cfg) {
	case TOTAL_CYCLES:
		reg = mmdc_base + MMDC_MADPSR0;
		break;
	case BUSY_CYCLES:
		reg = mmdc_base + MMDC_MADPSR1;
		break;
	case READ_ACCESSES:
		reg = mmdc_base + MMDC_MADPSR2;
		break;
	case WRITE_ACCESSES:
		reg = mmdc_base + MMDC_MADPSR3;
		break;
	case READ_BYTES:
		reg = mmdc_base + MMDC_MADPSR4;
		break;
	case WRITE_BYTES:
		reg = mmdc_base + MMDC_MADPSR5;
		break;
	default:
		return WARN_ONCE(1,
			"invalid configuration %d for mmdc counter", cfg);
	}
	return readl(reg);
}

static int mmdc_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
{
	struct mmdc_pmu *pmu_mmdc = hlist_entry_safe(node, struct mmdc_pmu, node);
	int target;

	if (!cpumask_test_and_clear_cpu(cpu, &pmu_mmdc->cpu))
		return 0;

	target = cpumask_any_but(cpu_online_mask, cpu);
	if (target >= nr_cpu_ids)
		return 0;

	perf_pmu_migrate_context(&pmu_mmdc->pmu, cpu, target);
	cpumask_set_cpu(target, &pmu_mmdc->cpu);

	return 0;
}

static bool mmdc_pmu_group_event_is_valid(struct perf_event *event,
					  struct pmu *pmu,
					  unsigned long *used_counters)
{
	int cfg = event->attr.config;

	if (is_software_event(event))
		return true;

	if (event->pmu != pmu)
		return false;

	return !test_and_set_bit(cfg, used_counters);
}

/*
 * Each event has a single fixed-purpose counter, so we can only have a
 * single active event for each at any point in time. Here we just check
 * for duplicates, and rely on mmdc_pmu_event_init to verify that the HW
 * event numbers are valid.
 */
static bool mmdc_pmu_group_is_valid(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;
	struct perf_event *leader = event->group_leader;
	struct perf_event *sibling;
	unsigned long counter_mask = 0;

	set_bit(leader->attr.config, &counter_mask);

	if (event != leader) {
		if (!mmdc_pmu_group_event_is_valid(event, pmu, &counter_mask))
			return false;
	}

	list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
		if (!mmdc_pmu_group_event_is_valid(sibling, pmu, &counter_mask))
			return false;
	}

	return true;
}

static int mmdc_pmu_event_init(struct perf_event *event)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	int cfg = event->attr.config;

	if (event->attr.type != event->pmu->type)
		return -ENOENT;

	if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
		return -EOPNOTSUPP;

	if (event->cpu < 0) {
		dev_warn(pmu_mmdc->dev, "Can't provide per-task data!\n");
		return -EOPNOTSUPP;
	}

	if (event->attr.exclude_user		||
			event->attr.exclude_kernel	||
			event->attr.exclude_hv		||
			event->attr.exclude_idle	||
			event->attr.exclude_host	||
			event->attr.exclude_guest	||
			event->attr.sample_period)
		return -EINVAL;

	if (cfg < 0 || cfg >= MMDC_NUM_COUNTERS)
		return -EINVAL;

	if (!mmdc_pmu_group_is_valid(event))
		return -EINVAL;

	event->cpu = cpumask_first(&pmu_mmdc->cpu);
	return 0;
}

static void mmdc_pmu_event_update(struct perf_event *event)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;
	u64 delta, prev_raw_count, new_raw_count;

	do {
		prev_raw_count = local64_read(&hwc->prev_count);
		new_raw_count = mmdc_pmu_read_counter(pmu_mmdc,
						      event->attr.config);
	} while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
		new_raw_count) != prev_raw_count);

	delta = (new_raw_count - prev_raw_count) & 0xFFFFFFFF;

	local64_add(delta, &event->count);
}

static void mmdc_pmu_event_start(struct perf_event *event, int flags)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;
	void __iomem *mmdc_base, *reg;
	u32 val;

	mmdc_base = pmu_mmdc->mmdc_base;
	reg = mmdc_base + MMDC_MADPCR0;

	/*
	 * hrtimer is required because mmdc does not provide an interrupt so
	 * polling is necessary
	 */
	hrtimer_start(&pmu_mmdc->hrtimer, mmdc_pmu_timer_period(),
			HRTIMER_MODE_REL_PINNED);

	local64_set(&hwc->prev_count, 0);

	writel(DBG_RST, reg);

	val = DBG_EN;
	if (pmu_mmdc->devtype_data->flags & MMDC_FLAG_PROFILE_SEL)
		val |= PROFILE_SEL;

	writel(val, reg);
}

static int mmdc_pmu_event_add(struct perf_event *event, int flags)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;

	int cfg = event->attr.config;

	if (flags & PERF_EF_START)
		mmdc_pmu_event_start(event, flags);

	if (pmu_mmdc->mmdc_events[cfg] != NULL)
		return -EAGAIN;

	pmu_mmdc->mmdc_events[cfg] = event;
	pmu_mmdc->active_events++;

	local64_set(&hwc->prev_count, mmdc_pmu_read_counter(pmu_mmdc, cfg));

	return 0;
}

static void mmdc_pmu_event_stop(struct perf_event *event, int flags)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	void __iomem *mmdc_base, *reg;

	mmdc_base = pmu_mmdc->mmdc_base;
	reg = mmdc_base + MMDC_MADPCR0;

	writel(PRF_FRZ, reg);
	mmdc_pmu_event_update(event);
}

static void mmdc_pmu_event_del(struct perf_event *event, int flags)
{
	struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
	int cfg = event->attr.config;

	pmu_mmdc->mmdc_events[cfg] = NULL;
	pmu_mmdc->active_events--;

	if (pmu_mmdc->active_events == 0)
		hrtimer_cancel(&pmu_mmdc->hrtimer);

	mmdc_pmu_event_stop(event, PERF_EF_UPDATE);
}

static void mmdc_pmu_overflow_handler(struct mmdc_pmu *pmu_mmdc)
{
	int i;

	for (i = 0; i < MMDC_NUM_COUNTERS; i++) {
		struct perf_event *event = pmu_mmdc->mmdc_events[i];

		if (event)
			mmdc_pmu_event_update(event);
	}
}

static enum hrtimer_restart mmdc_pmu_timer_handler(struct hrtimer *hrtimer)
{
	struct mmdc_pmu *pmu_mmdc = container_of(hrtimer, struct mmdc_pmu,
			hrtimer);

	mmdc_pmu_overflow_handler(pmu_mmdc);
	hrtimer_forward_now(hrtimer, mmdc_pmu_timer_period());

	return HRTIMER_RESTART;
}

static int mmdc_pmu_init(struct mmdc_pmu *pmu_mmdc,
		void __iomem *mmdc_base, struct device *dev)
{
	int mmdc_num;

	*pmu_mmdc = (struct mmdc_pmu) {
		.pmu = (struct pmu) {
			.task_ctx_nr    = perf_invalid_context,
			.attr_groups    = attr_groups,
			.event_init     = mmdc_pmu_event_init,
			.add            = mmdc_pmu_event_add,
			.del            = mmdc_pmu_event_del,
			.start          = mmdc_pmu_event_start,
			.stop           = mmdc_pmu_event_stop,
			.read           = mmdc_pmu_event_update,
		},
		.mmdc_base = mmdc_base,
		.dev = dev,
		.active_events = 0,
	};

	mmdc_num = ida_simple_get(&mmdc_ida, 0, 0, GFP_KERNEL);

	return mmdc_num;
}

static int imx_mmdc_remove(struct platform_device *pdev)
{
	struct mmdc_pmu *pmu_mmdc = platform_get_drvdata(pdev);

	cpuhp_state_remove_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node);
	perf_pmu_unregister(&pmu_mmdc->pmu);
	kfree(pmu_mmdc);
	return 0;
}

static int imx_mmdc_perf_init(struct platform_device *pdev, void __iomem *mmdc_base)
{
	struct mmdc_pmu *pmu_mmdc;
	char *name;
	int mmdc_num;
	int ret;
	const struct of_device_id *of_id =
		of_match_device(imx_mmdc_dt_ids, &pdev->dev);

	pmu_mmdc = kzalloc(sizeof(*pmu_mmdc), GFP_KERNEL);
	if (!pmu_mmdc) {
		pr_err("failed to allocate PMU device!\n");
		return -ENOMEM;
	}

	/* The first instance registers the hotplug state */
	if (!cpuhp_mmdc_state) {
		ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
					      "perf/arm/mmdc:online", NULL,
					      mmdc_pmu_offline_cpu);
		if (ret < 0) {
			pr_err("cpuhp_setup_state_multi failed\n");
			goto pmu_free;
		}
		cpuhp_mmdc_state = ret;
	}

	mmdc_num = mmdc_pmu_init(pmu_mmdc, mmdc_base, &pdev->dev);
	if (mmdc_num == 0)
		name = "mmdc";
	else
		name = devm_kasprintf(&pdev->dev,
				GFP_KERNEL, "mmdc%d", mmdc_num);

	pmu_mmdc->devtype_data = (struct fsl_mmdc_devtype_data *)of_id->data;

	hrtimer_init(&pmu_mmdc->hrtimer, CLOCK_MONOTONIC,
			HRTIMER_MODE_REL);
	pmu_mmdc->hrtimer.function = mmdc_pmu_timer_handler;

	cpumask_set_cpu(raw_smp_processor_id(), &pmu_mmdc->cpu);

	/* Register the pmu instance for cpu hotplug */
	cpuhp_state_add_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node);

	ret = perf_pmu_register(&(pmu_mmdc->pmu), name, -1);
	if (ret)
		goto pmu_register_err;

	platform_set_drvdata(pdev, pmu_mmdc);
	return 0;

pmu_register_err:
	pr_warn("MMDC Perf PMU failed (%d), disabled\n", ret);
	cpuhp_state_remove_instance_nocalls(cpuhp_mmdc_state, &pmu_mmdc->node);
	hrtimer_cancel(&pmu_mmdc->hrtimer);
pmu_free:
	kfree(pmu_mmdc);
	return ret;
}

#else
#define imx_mmdc_remove NULL
#define imx_mmdc_perf_init(pdev, mmdc_base) 0
#endif

static int imx_mmdc_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	void __iomem *mmdc_base, *reg;
	u32 val;
	int timeout = 0x400;

	mmdc_base = of_iomap(np, 0);
	WARN_ON(!mmdc_base);

	reg = mmdc_base + MMDC_MDMISC;
	/* Get ddr type */
	val = readl_relaxed(reg);
	ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >>
		 BP_MMDC_MDMISC_DDR_TYPE;

	reg = mmdc_base + MMDC_MAPSR;

	/* Enable automatic power saving */
	val = readl_relaxed(reg);
	val &= ~(1 << BP_MMDC_MAPSR_PSD);
	writel_relaxed(val, reg);

	/* Ensure it's successfully enabled */
	while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
		cpu_relax();

	if (unlikely(!timeout)) {
		pr_warn("%s: failed to enable automatic power saving\n",
			__func__);
		return -EBUSY;
	}

	return imx_mmdc_perf_init(pdev, mmdc_base);
}

int imx_mmdc_get_ddr_type(void)
{
	return ddr_type;
}

static struct platform_driver imx_mmdc_driver = {
	.driver		= {
		.name	= "imx-mmdc",
		.of_match_table = imx_mmdc_dt_ids,
	},
	.probe		= imx_mmdc_probe,
	.remove		= imx_mmdc_remove,
};

static int __init imx_mmdc_init(void)
{
	return platform_driver_register(&imx_mmdc_driver);
}
postcore_initcall(imx_mmdc_init);