// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2024-2025 Qualcomm Innovation Center, Inc. All rights reserved.
 */

#include <linux/clk.h>
#include <linux/coresight.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "coresight-ctcu.h"
#include "coresight-priv.h"

DEFINE_CORESIGHT_DEVLIST(ctcu_devs, "ctcu");

#define ctcu_writel(drvdata, val, offset)       __raw_writel((val), drvdata->base + offset)
#define ctcu_readl(drvdata, offset)             __raw_readl(drvdata->base + offset)

/*
 * The TMC Coresight Control Unit utilizes four ATID registers to control the data
 * filter function based on the trace ID for each TMC ETR sink. The length of each
 * ATID register is 32 bits. Therefore, an ETR device has a 128-bit long field
 * in CTCU. Each trace ID is represented by one bit in that filed.
 * e.g. ETR0ATID0 layout, set bit 5 for traceid 5
 *                                           bit5
 * ------------------------------------------------------
 * |   |28|   |24|   |20|   |16|   |12|   |8|  1|4|   |0|
 * ------------------------------------------------------
 *
 * e.g. ETR0:
 * 127                     0 from ATID_offset for ETR0ATID0
 * -------------------------
 * |ATID3|ATID2|ATID1|ATID0|
 */
#define CTCU_ATID_REG_OFFSET(traceid, atid_offset) \
                ((traceid / 32) * 4 + atid_offset)

#define CTCU_ATID_REG_BIT(traceid)      (traceid % 32)
#define CTCU_ATID_REG_SIZE              0x10
#define CTCU_ETR0_ATID0                 0xf8
#define CTCU_ETR1_ATID0                 0x108

static const struct ctcu_etr_config sa8775p_etr_cfgs[] = {
        {
                .atid_offset    = CTCU_ETR0_ATID0,
                .port_num       = 0,
        },
        {
                .atid_offset    = CTCU_ETR1_ATID0,
                .port_num       = 1,
        },
};

static const struct ctcu_config sa8775p_cfgs = {
        .etr_cfgs       = sa8775p_etr_cfgs,
        .num_etr_config = ARRAY_SIZE(sa8775p_etr_cfgs),
};

static void ctcu_program_atid_register(struct ctcu_drvdata *drvdata, u32 reg_offset,
                                       u8 bit, bool enable)
{
        u32 val;

        CS_UNLOCK(drvdata->base);
        val = ctcu_readl(drvdata, reg_offset);
        if (enable)
                val |= BIT(bit);
        else
                val &= ~BIT(bit);

        ctcu_writel(drvdata, val, reg_offset);
        CS_LOCK(drvdata->base);
}

/*
 * __ctcu_set_etr_traceid: Set bit in the ATID register based on trace ID when enable is true.
 * Reset the bit of the ATID register based on trace ID when enable is false.
 *
 * @csdev:      coresight_device of CTCU.
 * @traceid:    trace ID of the source tracer.
 * @port_num:   port number connected to TMC ETR sink.
 * @enable:     True for set bit and false for reset bit.
 *
 * Returns 0 indicates success. Non-zero result means failure.
 */
static int __ctcu_set_etr_traceid(struct coresight_device *csdev, u8 traceid, int port_num,
                                  bool enable)
{
        struct ctcu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
        u32 atid_offset, reg_offset;
        u8 refcnt, bit;

        atid_offset = drvdata->atid_offset[port_num];
        if (atid_offset == 0)
                return -EINVAL;

        bit = CTCU_ATID_REG_BIT(traceid);
        reg_offset = CTCU_ATID_REG_OFFSET(traceid, atid_offset);
        if (reg_offset - atid_offset > CTCU_ATID_REG_SIZE)
                return -EINVAL;

        guard(raw_spinlock_irqsave)(&drvdata->spin_lock);
        refcnt = drvdata->traceid_refcnt[port_num][traceid];
        /* Only program the atid register when the refcnt value is 1 or 0 */
        if ((enable && !refcnt++) || (!enable && !--refcnt))
                ctcu_program_atid_register(drvdata, reg_offset, bit, enable);

        drvdata->traceid_refcnt[port_num][traceid] = refcnt;

        return 0;
}

/*
 * Searching the sink device from helper's view in case there are multiple helper devices
 * connected to the sink device.
 */
static int ctcu_get_active_port(struct coresight_device *sink, struct coresight_device *helper)
{
        struct coresight_platform_data *pdata = helper->pdata;
        int i;

        for (i = 0; i < pdata->nr_inconns; ++i) {
                if (pdata->in_conns[i]->src_dev == sink)
                        return pdata->in_conns[i]->dest_port;
        }

        return -EINVAL;
}

static int ctcu_set_etr_traceid(struct coresight_device *csdev, struct coresight_path *path,
                                bool enable)
{
        struct coresight_device *sink = coresight_get_sink(path);
        u8 traceid = path->trace_id;
        int port_num;

        if ((sink == NULL) || !IS_VALID_CS_TRACE_ID(traceid)) {
                dev_err(&csdev->dev, "Invalid sink device or trace ID\n");
                return -EINVAL;
        }

        port_num = ctcu_get_active_port(sink, csdev);
        if (port_num < 0)
                return -EINVAL;

        dev_dbg(&csdev->dev, "traceid is %d\n", traceid);

        return __ctcu_set_etr_traceid(csdev, traceid, port_num, enable);
}

static int ctcu_enable(struct coresight_device *csdev, enum cs_mode mode,
                       struct coresight_path *path)
{
        return ctcu_set_etr_traceid(csdev, path, true);
}

static int ctcu_disable(struct coresight_device *csdev, struct coresight_path *path)
{
        return ctcu_set_etr_traceid(csdev, path, false);
}

static const struct coresight_ops_helper ctcu_helper_ops = {
        .enable = ctcu_enable,
        .disable = ctcu_disable,
};

static const struct coresight_ops ctcu_ops = {
        .helper_ops = &ctcu_helper_ops,
};

static int ctcu_probe(struct platform_device *pdev)
{
        const struct ctcu_etr_config *etr_cfg;
        struct coresight_platform_data *pdata;
        struct coresight_desc desc = { 0 };
        struct device *dev = &pdev->dev;
        const struct ctcu_config *cfgs;
        struct ctcu_drvdata *drvdata;
        void __iomem *base;
        int i, ret;

        desc.name = coresight_alloc_device_name(&ctcu_devs, dev);
        if (!desc.name)
                return -ENOMEM;

        drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata)
                return -ENOMEM;

        pdata = coresight_get_platform_data(dev);
        if (IS_ERR(pdata))
                return PTR_ERR(pdata);
        dev->platform_data = pdata;

        base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
        if (IS_ERR(base))
                return PTR_ERR(base);

        ret = coresight_get_enable_clocks(dev, &drvdata->apb_clk, NULL);
        if (ret)
                return ret;

        cfgs = of_device_get_match_data(dev);
        if (cfgs) {
                if (cfgs->num_etr_config <= ETR_MAX_NUM) {
                        for (i = 0; i < cfgs->num_etr_config; i++) {
                                etr_cfg = &cfgs->etr_cfgs[i];
                                drvdata->atid_offset[i] = etr_cfg->atid_offset;
                        }
                }
        }

        drvdata->base = base;
        drvdata->dev = dev;
        platform_set_drvdata(pdev, drvdata);

        desc.type = CORESIGHT_DEV_TYPE_HELPER;
        desc.subtype.helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_CTCU;
        desc.pdata = pdata;
        desc.dev = dev;
        desc.ops = &ctcu_ops;
        desc.access = CSDEV_ACCESS_IOMEM(base);

        drvdata->csdev = coresight_register(&desc);
        if (IS_ERR(drvdata->csdev))
                return PTR_ERR(drvdata->csdev);

        return 0;
}

static void ctcu_remove(struct platform_device *pdev)
{
        struct ctcu_drvdata *drvdata = platform_get_drvdata(pdev);

        coresight_unregister(drvdata->csdev);
}

static int ctcu_platform_probe(struct platform_device *pdev)
{
        int ret;

        pm_runtime_get_noresume(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        ret = ctcu_probe(pdev);
        pm_runtime_put(&pdev->dev);
        if (ret)
                pm_runtime_disable(&pdev->dev);

        return ret;
}

static void ctcu_platform_remove(struct platform_device *pdev)
{
        struct ctcu_drvdata *drvdata = platform_get_drvdata(pdev);

        if (WARN_ON(!drvdata))
                return;

        ctcu_remove(pdev);
        pm_runtime_disable(&pdev->dev);
}

#ifdef CONFIG_PM
static int ctcu_runtime_suspend(struct device *dev)
{
        struct ctcu_drvdata *drvdata = dev_get_drvdata(dev);

        clk_disable_unprepare(drvdata->apb_clk);

        return 0;
}

static int ctcu_runtime_resume(struct device *dev)
{
        struct ctcu_drvdata *drvdata = dev_get_drvdata(dev);

        return clk_prepare_enable(drvdata->apb_clk);
}
#endif

static const struct dev_pm_ops ctcu_dev_pm_ops = {
        SET_RUNTIME_PM_OPS(ctcu_runtime_suspend, ctcu_runtime_resume, NULL)
};

static const struct of_device_id ctcu_match[] = {
        {.compatible = "qcom,sa8775p-ctcu", .data = &sa8775p_cfgs},
        {}
};

static struct platform_driver ctcu_driver = {
        .probe          = ctcu_platform_probe,
        .remove         = ctcu_platform_remove,
        .driver         = {
                .name   = "coresight-ctcu",
                .of_match_table = ctcu_match,
                .pm     = &ctcu_dev_pm_ops,
                .suppress_bind_attrs = true,
        },
};
module_platform_driver(ctcu_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CoreSight TMC Control Unit driver");