// SPDX-License-Identifier: GPL-2.0-only
/*
 * exynos-nocp.c - Exynos NoC (Network On Chip) Probe support
 *
 * Copyright (c) 2016 Samsung Electronics Co., Ltd.
 * Author : Chanwoo Choi <cw00.choi@samsung.com>
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/devfreq-event.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#include "exynos-nocp.h"

struct exynos_nocp {
        struct devfreq_event_dev *edev;
        struct devfreq_event_desc desc;

        struct device *dev;

        struct regmap *regmap;
        struct clk *clk;
};

/*
 * The devfreq-event ops structure for nocp probe.
 */
static int exynos_nocp_set_event(struct devfreq_event_dev *edev)
{
        struct exynos_nocp *nocp = devfreq_event_get_drvdata(edev);
        int ret;

        /* Disable NoC probe */
        ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
                                NOCP_MAIN_CTL_STATEN_MASK, 0);
        if (ret < 0) {
                dev_err(nocp->dev, "failed to disable the NoC probe device\n");
                return ret;
        }

        /* Set a statistics dump period to 0 */
        ret = regmap_write(nocp->regmap, NOCP_STAT_PERIOD, 0x0);
        if (ret < 0)
                goto out;

        /* Set the IntEvent fields of *_SRC */
        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_0_SRC,
                                NOCP_CNT_SRC_INTEVENT_MASK,
                                NOCP_CNT_SRC_INTEVENT_BYTE_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_1_SRC,
                                NOCP_CNT_SRC_INTEVENT_MASK,
                                NOCP_CNT_SRC_INTEVENT_CHAIN_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_2_SRC,
                                NOCP_CNT_SRC_INTEVENT_MASK,
                                NOCP_CNT_SRC_INTEVENT_CYCLE_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_3_SRC,
                                NOCP_CNT_SRC_INTEVENT_MASK,
                                NOCP_CNT_SRC_INTEVENT_CHAIN_MASK);
        if (ret < 0)
                goto out;


        /* Set an alarm with a max/min value of 0 to generate StatALARM */
        ret = regmap_write(nocp->regmap, NOCP_STAT_ALARM_MIN, 0x0);
        if (ret < 0)
                goto out;

        ret = regmap_write(nocp->regmap, NOCP_STAT_ALARM_MAX, 0x0);
        if (ret < 0)
                goto out;

        /* Set AlarmMode */
        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_0_ALARM_MODE,
                                NOCP_CNT_ALARM_MODE_MASK,
                                NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_1_ALARM_MODE,
                                NOCP_CNT_ALARM_MODE_MASK,
                                NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_2_ALARM_MODE,
                                NOCP_CNT_ALARM_MODE_MASK,
                                NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
        if (ret < 0)
                goto out;

        ret = regmap_update_bits(nocp->regmap, NOCP_COUNTERS_3_ALARM_MODE,
                                NOCP_CNT_ALARM_MODE_MASK,
                                NOCP_CNT_ALARM_MODE_MIN_MAX_MASK);
        if (ret < 0)
                goto out;

        /* Enable the measurements by setting AlarmEn and StatEn */
        ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
                        NOCP_MAIN_CTL_STATEN_MASK | NOCP_MAIN_CTL_ALARMEN_MASK,
                        NOCP_MAIN_CTL_STATEN_MASK | NOCP_MAIN_CTL_ALARMEN_MASK);
        if (ret < 0)
                goto out;

        /* Set GlobalEN */
        ret = regmap_update_bits(nocp->regmap, NOCP_CFG_CTL,
                                NOCP_CFG_CTL_GLOBALEN_MASK,
                                NOCP_CFG_CTL_GLOBALEN_MASK);
        if (ret < 0)
                goto out;

        /* Enable NoC probe */
        ret = regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
                                NOCP_MAIN_CTL_STATEN_MASK,
                                NOCP_MAIN_CTL_STATEN_MASK);
        if (ret < 0)
                goto out;

        return 0;

out:
        /* Reset NoC probe */
        if (regmap_update_bits(nocp->regmap, NOCP_MAIN_CTL,
                                NOCP_MAIN_CTL_STATEN_MASK, 0)) {
                dev_err(nocp->dev, "Failed to reset NoC probe device\n");
        }

        return ret;
}

static int exynos_nocp_get_event(struct devfreq_event_dev *edev,
                                struct devfreq_event_data *edata)
{
        struct exynos_nocp *nocp = devfreq_event_get_drvdata(edev);
        unsigned int counter[4];
        int ret;

        /* Read cycle count */
        ret = regmap_read(nocp->regmap, NOCP_COUNTERS_0_VAL, &counter[0]);
        if (ret < 0)
                goto out;

        ret = regmap_read(nocp->regmap, NOCP_COUNTERS_1_VAL, &counter[1]);
        if (ret < 0)
                goto out;

        ret = regmap_read(nocp->regmap, NOCP_COUNTERS_2_VAL, &counter[2]);
        if (ret < 0)
                goto out;

        ret = regmap_read(nocp->regmap, NOCP_COUNTERS_3_VAL, &counter[3]);
        if (ret < 0)
                goto out;

        edata->load_count = ((counter[1] << 16) | counter[0]);
        edata->total_count = ((counter[3] << 16) | counter[2]);

        dev_dbg(&edev->dev, "%s (event: %ld/%ld)\n", edev->desc->name,
                                        edata->load_count, edata->total_count);

        return 0;

out:
        dev_err(nocp->dev, "Failed to read the counter of NoC probe device\n");

        return ret;
}

static const struct devfreq_event_ops exynos_nocp_ops = {
        .set_event = exynos_nocp_set_event,
        .get_event = exynos_nocp_get_event,
};

static const struct of_device_id exynos_nocp_id_match[] = {
        { .compatible = "samsung,exynos5420-nocp", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, exynos_nocp_id_match);

static struct regmap_config exynos_nocp_regmap_config = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = 4,
        .max_register = NOCP_COUNTERS_3_VAL,
};

static int exynos_nocp_parse_dt(struct platform_device *pdev,
                                struct exynos_nocp *nocp)
{
        struct device *dev = nocp->dev;
        struct device_node *np = dev->of_node;
        struct resource *res;
        void __iomem *base;

        if (!np) {
                dev_err(dev, "failed to find devicetree node\n");
                return -EINVAL;
        }

        nocp->clk = devm_clk_get(dev, "nocp");
        if (IS_ERR(nocp->clk))
                nocp->clk = NULL;

        /* Maps the memory mapped IO to control nocp register */
        base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        exynos_nocp_regmap_config.max_register = resource_size(res) - 4;

        nocp->regmap = devm_regmap_init_mmio(dev, base,
                                        &exynos_nocp_regmap_config);
        if (IS_ERR(nocp->regmap)) {
                dev_err(dev, "failed to initialize regmap\n");
                return PTR_ERR(nocp->regmap);
        }

        return 0;
}

static int exynos_nocp_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct exynos_nocp *nocp;
        int ret;

        nocp = devm_kzalloc(&pdev->dev, sizeof(*nocp), GFP_KERNEL);
        if (!nocp)
                return -ENOMEM;

        nocp->dev = &pdev->dev;

        /* Parse dt data to get resource */
        ret = exynos_nocp_parse_dt(pdev, nocp);
        if (ret < 0) {
                dev_err(&pdev->dev,
                        "failed to parse devicetree for resource\n");
                return ret;
        }

        /* Add devfreq-event device to measure the bandwidth of NoC */
        nocp->desc.ops = &exynos_nocp_ops;
        nocp->desc.driver_data = nocp;
        nocp->desc.name = np->full_name;
        nocp->edev = devm_devfreq_event_add_edev(&pdev->dev, &nocp->desc);
        if (IS_ERR(nocp->edev)) {
                dev_err(&pdev->dev,
                        "failed to add devfreq-event device\n");
                return PTR_ERR(nocp->edev);
        }
        platform_set_drvdata(pdev, nocp);

        ret = clk_prepare_enable(nocp->clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to prepare ppmu clock\n");
                return ret;
        }

        pr_info("exynos-nocp: new NoC Probe device registered: %s\n",
                        dev_name(dev));

        return 0;
}

static void exynos_nocp_remove(struct platform_device *pdev)
{
        struct exynos_nocp *nocp = platform_get_drvdata(pdev);

        clk_disable_unprepare(nocp->clk);
}

static struct platform_driver exynos_nocp_driver = {
        .probe  = exynos_nocp_probe,
        .remove = exynos_nocp_remove,
        .driver = {
                .name   = "exynos-nocp",
                .of_match_table = exynos_nocp_id_match,
        },
};
module_platform_driver(exynos_nocp_driver);

MODULE_DESCRIPTION("Exynos NoC (Network on Chip) Probe driver");
MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_LICENSE("GPL");