// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
 * Copyright (C) 2018-2024 Linaro Ltd.
 */

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/interconnect.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>

#include "linux/soc/qcom/qcom_aoss.h"

#include "ipa.h"
#include "ipa_data.h"
#include "ipa_endpoint.h"
#include "ipa_interrupt.h"
#include "ipa_modem.h"
#include "ipa_power.h"

/**
 * DOC: IPA Power Management
 *
 * The IPA hardware is enabled when the IPA core clock and all the
 * interconnects (buses) it depends on are enabled.  Runtime power
 * management is used to determine whether the core clock and
 * interconnects are enabled, and if not in use to be suspended
 * automatically.
 *
 * The core clock currently runs at a fixed clock rate when enabled,
 * an all interconnects use a fixed average and peak bandwidth.
 */

#define IPA_AUTOSUSPEND_DELAY   500     /* milliseconds */

/**
 * struct ipa_power - IPA power management information
 * @dev:                IPA device pointer
 * @core:               IPA core clock
 * @qmp:                QMP handle for AOSS communication
 * @interconnect_count: Number of elements in interconnect[]
 * @interconnect:       Interconnect array
 */
struct ipa_power {
        struct device *dev;
        struct clk *core;
        struct qmp *qmp;
        u32 interconnect_count;
        struct icc_bulk_data interconnect[] __counted_by(interconnect_count);
};

/* Initialize interconnects required for IPA operation */
static int ipa_interconnect_init(struct ipa_power *power,
                                 const struct ipa_interconnect_data *data)
{
        struct icc_bulk_data *interconnect;
        int ret;
        u32 i;

        /* Initialize our interconnect data array for bulk operations */
        interconnect = &power->interconnect[0];
        for (i = 0; i < power->interconnect_count; i++) {
                /* interconnect->path is filled in by of_icc_bulk_get() */
                interconnect->name = data->name;
                interconnect->avg_bw = data->average_bandwidth;
                interconnect->peak_bw = data->peak_bandwidth;
                data++;
                interconnect++;
        }

        ret = of_icc_bulk_get(power->dev, power->interconnect_count,
                              power->interconnect);
        if (ret)
                return ret;

        /* All interconnects are initially disabled */
        icc_bulk_disable(power->interconnect_count, power->interconnect);

        /* Set the bandwidth values to be used when enabled */
        ret = icc_bulk_set_bw(power->interconnect_count, power->interconnect);
        if (ret)
                icc_bulk_put(power->interconnect_count, power->interconnect);

        return ret;
}

/* Inverse of ipa_interconnect_init() */
static void ipa_interconnect_exit(struct ipa_power *power)
{
        icc_bulk_put(power->interconnect_count, power->interconnect);
}

/* Enable IPA power, enabling interconnects and the core clock */
static int ipa_power_enable(struct ipa *ipa)
{
        struct ipa_power *power = ipa->power;
        int ret;

        ret = icc_bulk_enable(power->interconnect_count, power->interconnect);
        if (ret)
                return ret;

        ret = clk_prepare_enable(power->core);
        if (ret) {
                dev_err(power->dev, "error %d enabling core clock\n", ret);
                icc_bulk_disable(power->interconnect_count,
                                 power->interconnect);
        }

        return ret;
}

/* Inverse of ipa_power_enable() */
static void ipa_power_disable(struct ipa *ipa)
{
        struct ipa_power *power = ipa->power;

        clk_disable_unprepare(power->core);

        icc_bulk_disable(power->interconnect_count, power->interconnect);
}

static int ipa_runtime_suspend(struct device *dev)
{
        struct ipa *ipa = dev_get_drvdata(dev);

        /* Endpoints aren't usable until setup is complete */
        if (ipa->setup_complete) {
                ipa_endpoint_suspend(ipa);
                gsi_suspend(&ipa->gsi);
        }

        ipa_power_disable(ipa);

        return 0;
}

static int ipa_runtime_resume(struct device *dev)
{
        struct ipa *ipa = dev_get_drvdata(dev);
        int ret;

        ret = ipa_power_enable(ipa);
        if (WARN_ON(ret < 0))
                return ret;

        /* Endpoints aren't usable until setup is complete */
        if (ipa->setup_complete) {
                gsi_resume(&ipa->gsi);
                ipa_endpoint_resume(ipa);
        }

        return 0;
}

static int ipa_suspend(struct device *dev)
{
        struct ipa *ipa = dev_get_drvdata(dev);

        /* Increment the disable depth to ensure that the IRQ won't
         * be re-enabled until the matching _enable call in
         * ipa_resume(). We do this to ensure that the interrupt
         * handler won't run whilst PM runtime is disabled.
         *
         * Note that disabling the IRQ is NOT the same as disabling
         * irq wake. If wakeup is enabled for the IPA then the IRQ
         * will still cause the system to wake up, see irq_set_irq_wake().
         */
        ipa_interrupt_irq_disable(ipa);

        return pm_runtime_force_suspend(dev);
}

static int ipa_resume(struct device *dev)
{
        struct ipa *ipa = dev_get_drvdata(dev);
        int ret;

        ret = pm_runtime_force_resume(dev);

        /* Now that PM runtime is enabled again it's safe
         * to turn the IRQ back on and process any data
         * that was received during suspend.
         */
        ipa_interrupt_irq_enable(ipa);

        return ret;
}

/* Return the current IPA core clock rate */
u32 ipa_core_clock_rate(struct ipa *ipa)
{
        return ipa->power ? (u32)clk_get_rate(ipa->power->core) : 0;
}

static int ipa_power_retention_init(struct ipa_power *power)
{
        struct qmp *qmp = qmp_get(power->dev);

        if (IS_ERR(qmp)) {
                if (PTR_ERR(qmp) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;

                /* We assume any other error means it's not defined/needed */
                qmp = NULL;
        }
        power->qmp = qmp;

        return 0;
}

static void ipa_power_retention_exit(struct ipa_power *power)
{
        qmp_put(power->qmp);
        power->qmp = NULL;
}

/* Control register retention on power collapse */
void ipa_power_retention(struct ipa *ipa, bool enable)
{
        static const char fmt[] = "{ class: bcm, res: ipa_pc, val: %c }";
        struct ipa_power *power = ipa->power;
        int ret;

        if (!power->qmp)
                return;         /* Not needed on this platform */

        ret = qmp_send(power->qmp, fmt, enable ? '1' : '0');
        if (ret)
                dev_err(power->dev, "error %d sending QMP %sable request\n",
                        ret, enable ? "en" : "dis");
}

/* Initialize IPA power management */
struct ipa_power *
ipa_power_init(struct device *dev, const struct ipa_power_data *data)
{
        struct ipa_power *power;
        struct clk *clk;
        size_t size;
        int ret;

        clk = clk_get(dev, "core");
        if (IS_ERR(clk))
                return dev_err_cast_probe(dev, clk, "error getting core clock\n");

        ret = clk_set_rate(clk, data->core_clock_rate);
        if (ret) {
                dev_err(dev, "error %d setting core clock rate to %u\n",
                        ret, data->core_clock_rate);
                goto err_clk_put;
        }

        size = struct_size(power, interconnect, data->interconnect_count);
        power = kzalloc(size, GFP_KERNEL);
        if (!power) {
                ret = -ENOMEM;
                goto err_clk_put;
        }
        power->dev = dev;
        power->core = clk;
        power->interconnect_count = data->interconnect_count;

        ret = ipa_interconnect_init(power, data->interconnect_data);
        if (ret)
                goto err_kfree;

        ret = ipa_power_retention_init(power);
        if (ret)
                goto err_interconnect_exit;

        pm_runtime_set_autosuspend_delay(dev, IPA_AUTOSUSPEND_DELAY);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_enable(dev);

        return power;

err_interconnect_exit:
        ipa_interconnect_exit(power);
err_kfree:
        kfree(power);
err_clk_put:
        clk_put(clk);

        return ERR_PTR(ret);
}

/* Inverse of ipa_power_init() */
void ipa_power_exit(struct ipa_power *power)
{
        struct device *dev = power->dev;
        struct clk *clk = power->core;

        pm_runtime_disable(dev);
        pm_runtime_dont_use_autosuspend(dev);
        ipa_power_retention_exit(power);
        ipa_interconnect_exit(power);
        kfree(power);
        clk_put(clk);
}

const struct dev_pm_ops ipa_pm_ops = {
        .suspend                = ipa_suspend,
        .resume                 = ipa_resume,
        .runtime_suspend        = ipa_runtime_suspend,
        .runtime_resume         = ipa_runtime_resume,
};