// SPDX-License-Identifier: GPL-2.0-only
/*
 * Firmware loading and handling functions.
 */

#include <linux/sched.h>
#include <linux/firmware.h>
#include <linux/module.h>

#include "dev.h"
#include "decl.h"

static void load_next_firmware_from_table(struct lbs_private *private);

static void lbs_fw_loaded(struct lbs_private *priv, int ret,
        const struct firmware *helper, const struct firmware *mainfw)
{
        unsigned long flags;

        lbs_deb_fw("firmware load complete, code %d\n", ret);

        /* User must free helper/mainfw */
        priv->fw_callback(priv, ret, helper, mainfw);

        spin_lock_irqsave(&priv->driver_lock, flags);
        priv->fw_callback = NULL;
        wake_up(&priv->fw_waitq);
        spin_unlock_irqrestore(&priv->driver_lock, flags);
}

static void do_load_firmware(struct lbs_private *priv, const char *name,
        void (*cb)(const struct firmware *fw, void *context))
{
        int ret;

        lbs_deb_fw("Requesting %s\n", name);
        ret = request_firmware_nowait(THIS_MODULE, true, name,
                        priv->fw_device, GFP_KERNEL, priv, cb);
        if (ret) {
                lbs_deb_fw("request_firmware_nowait error %d\n", ret);
                lbs_fw_loaded(priv, ret, NULL, NULL);
        }
}

static void main_firmware_cb(const struct firmware *firmware, void *context)
{
        struct lbs_private *priv = context;

        if (!firmware) {
                /* Failed to find firmware: try next table entry */
                load_next_firmware_from_table(priv);
                return;
        }

        /* Firmware found! */
        lbs_fw_loaded(priv, 0, priv->helper_fw, firmware);
        if (priv->helper_fw) {
                release_firmware (priv->helper_fw);
                priv->helper_fw = NULL;
        }
        release_firmware (firmware);
}

static void helper_firmware_cb(const struct firmware *firmware, void *context)
{
        struct lbs_private *priv = context;

        if (!firmware) {
                /* Failed to find firmware: try next table entry */
                load_next_firmware_from_table(priv);
                return;
        }

        /* Firmware found! */
        if (priv->fw_iter->fwname) {
                priv->helper_fw = firmware;
                do_load_firmware(priv, priv->fw_iter->fwname, main_firmware_cb);
        } else {
                /* No main firmware needed for this helper --> success! */
                lbs_fw_loaded(priv, 0, firmware, NULL);
                release_firmware(firmware);
        }
}

static void load_next_firmware_from_table(struct lbs_private *priv)
{
        const struct lbs_fw_table *iter;

        if (!priv->fw_iter)
                iter = priv->fw_table;
        else
                iter = ++priv->fw_iter;

        if (priv->helper_fw) {
                release_firmware(priv->helper_fw);
                priv->helper_fw = NULL;
        }

next:
        if (!iter->helper) {
                /* End of table hit. */
                lbs_fw_loaded(priv, -ENOENT, NULL, NULL);
                return;
        }

        if (iter->model != priv->fw_model) {
                iter++;
                goto next;
        }

        priv->fw_iter = iter;
        do_load_firmware(priv, iter->helper, helper_firmware_cb);
}

void lbs_wait_for_firmware_load(struct lbs_private *priv)
{
        wait_event(priv->fw_waitq, priv->fw_callback == NULL);
}

/**
 *  lbs_get_firmware_async - Retrieves firmware asynchronously. Can load
 *  either a helper firmware and a main firmware (2-stage), or just the helper.
 *
 *  @priv:      Pointer to lbs_private instance
 *  @device:    A pointer to &device structure
 *  @card_model: Bus-specific card model ID used to filter firmware table
 *              elements
 *  @fw_table:  Table of firmware file names and device model numbers
 *              terminated by an entry with a NULL helper name
 *  @callback:  User callback to invoke when firmware load succeeds or fails.
 */
int lbs_get_firmware_async(struct lbs_private *priv, struct device *device,
                            u32 card_model, const struct lbs_fw_table *fw_table,
                            lbs_fw_cb callback)
{
        unsigned long flags;

        spin_lock_irqsave(&priv->driver_lock, flags);
        if (priv->fw_callback) {
                lbs_deb_fw("firmware load already in progress\n");
                spin_unlock_irqrestore(&priv->driver_lock, flags);
                return -EBUSY;
        }

        priv->fw_device = device;
        priv->fw_callback = callback;
        priv->fw_table = fw_table;
        priv->fw_iter = NULL;
        priv->fw_model = card_model;
        spin_unlock_irqrestore(&priv->driver_lock, flags);

        lbs_deb_fw("Starting async firmware load\n");
        load_next_firmware_from_table(priv);
        return 0;
}
EXPORT_SYMBOL_GPL(lbs_get_firmware_async);

/**
 *  lbs_get_firmware - Retrieves two-stage firmware
 *
 *  @dev:       A pointer to &device structure
 *  @card_model: Bus-specific card model ID used to filter firmware table
 *              elements
 *  @fw_table:  Table of firmware file names and device model numbers
 *              terminated by an entry with a NULL helper name
 *  @helper:    On success, the helper firmware; caller must free
 *  @mainfw:    On success, the main firmware; caller must free
 *
 * Deprecated: use lbs_get_firmware_async() instead.
 *
 *  returns:            0 on success, non-zero on failure
 */
int lbs_get_firmware(struct device *dev, u32 card_model,
                        const struct lbs_fw_table *fw_table,
                        const struct firmware **helper,
                        const struct firmware **mainfw)
{
        const struct lbs_fw_table *iter;
        int ret;

        BUG_ON(helper == NULL);
        BUG_ON(mainfw == NULL);

        /* Search for firmware to use from the table. */
        iter = fw_table;
        while (iter && iter->helper) {
                if (iter->model != card_model)
                        goto next;

                if (*helper == NULL) {
                        ret = request_firmware(helper, iter->helper, dev);
                        if (ret)
                                goto next;

                        /* If the device has one-stage firmware (ie cf8305) and
                         * we've got it then we don't need to bother with the
                         * main firmware.
                         */
                        if (iter->fwname == NULL)
                                return 0;
                }

                if (*mainfw == NULL) {
                        ret = request_firmware(mainfw, iter->fwname, dev);
                        if (ret) {
                                /* Clear the helper to ensure we don't have
                                 * mismatched firmware pairs.
                                 */
                                release_firmware(*helper);
                                *helper = NULL;
                        }
                }

                if (*helper && *mainfw)
                        return 0;

  next:
                iter++;
        }

        /* Failed */
        release_firmware(*helper);
        *helper = NULL;
        release_firmware(*mainfw);
        *mainfw = NULL;

        return -ENOENT;
}
EXPORT_SYMBOL_GPL(lbs_get_firmware);