/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020-2021 The FreeBSD Foundation
 * Copyright (c) 2022 Bjoern A. Zeeb
 *
 * This software was developed by Björn Zeeb under sponsorship from
 * the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/firmware.h>
#include <sys/queue.h>
#include <sys/taskqueue.h>

#include <linux/types.h>
#include <linux/device.h>

#include <linux/firmware.h>
#undef firmware

MALLOC_DEFINE(M_LKPI_FW, "lkpifw", "LinuxKPI firmware");

struct lkpi_fw_task {
        /* Task and arguments for the "nowait" callback. */
        struct task             fw_task;
        gfp_t                   gfp;
        const char              *fw_name;
        struct device           *dev;
        void                    *drv;
        void(*cont)(const struct linuxkpi_firmware *, void *);
};

static int
_linuxkpi_request_firmware(const char *fw_name, const struct linuxkpi_firmware **fw,
    struct device *dev, gfp_t gfp __unused, bool enoentok, bool warn)
{
        const struct firmware *fbdfw;
        struct linuxkpi_firmware *lfw;
        const char *fwimg;
        char *p;
        uint32_t flags;

        if (fw_name == NULL || fw == NULL || dev == NULL) {
                if (fw != NULL)
                        *fw = NULL;
                return (-EINVAL);
        }

        /* Set independent on "warn". To debug, bootverbose is avail. */
        flags = FIRMWARE_GET_NOWARN;

        KASSERT(gfp == GFP_KERNEL, ("%s: gfp %#x\n", __func__, gfp));
        lfw = malloc(sizeof(*lfw), M_LKPI_FW, M_WAITOK | M_ZERO);

        /*
         * Linux can have a path in the firmware which is hard to replicate
         * for auto-firmware-module-loading.
         * On FreeBSD, depending on what people do, the firmware will either
         * be called "fw", or "dir_fw", or "modname_dir_fw".  The latter the
         * driver author has to deal with herself (requesting the special name).
         * We also optionally flatten '/'s and '.'s as some firmware modules do.
         * We probe in the least-of-work order avoiding memory operations.
         * It will be preferred to build the firmware .ko in a well matching
         * way rather than adding more name-mangling-hacks here in the future
         * (though we could if needed).
         */
        /* (1) Try the original name. */
        fbdfw = firmware_get_flags(fw_name, flags);
        /* (2) Try any name removed of path, if we have not yet. */
        if (fbdfw == NULL) {
                fwimg = strrchr(fw_name, '/');
                if (fwimg != NULL)
                        fwimg++;
                if (fwimg == NULL || *fwimg == '\0')
                        fwimg = fw_name;
                if (fwimg != fw_name)
                        fbdfw = firmware_get_flags(fwimg, flags);
        }
        /* (3) Flatten '/', '.' and '-' to '_' and try with adjusted name. */
        if (fbdfw == NULL &&
            (strchr(fw_name, '/') != NULL || strchr(fw_name, '.') != NULL ||
            strchr(fw_name, '-'))) {
                fwimg = strdup(fw_name, M_LKPI_FW);
                if (fwimg != NULL) {
                        while ((p = strchr(fwimg, '/')) != NULL)
                                *p = '_';
                        fbdfw = firmware_get_flags(fwimg, flags);
                        if (fbdfw == NULL) {
                                while ((p = strchr(fwimg, '.')) != NULL)
                                        *p = '_';
                                fbdfw = firmware_get_flags(fwimg, flags);
                        }
                        if (fbdfw == NULL) {
                                while ((p = strchr(fwimg, '-')) != NULL)
                                        *p = '_';
                                fbdfw = firmware_get_flags(fwimg, flags);
                        }
                        free(__DECONST(void *, fwimg), M_LKPI_FW);
                }
        }
        if (fbdfw == NULL) {
                if (enoentok)
                        *fw = lfw;
                else {
                        free(lfw, M_LKPI_FW);
                        *fw = NULL;
                }
                if (warn)
                        device_printf(dev->bsddev,
                            "could not load firmware image '%s'\n",
                            fw_name);
                return (-ENOENT);
        }

        device_printf(dev->bsddev, "successfully loaded firmware image '%s'\n",
            fw_name);
        lfw->fbdfw = fbdfw;
        lfw->data = (const uint8_t *)fbdfw->data;
        lfw->size = fbdfw->datasize;
        *fw = lfw;
        return (0);
}

static void
lkpi_fw_task(void *ctx, int pending)
{
        struct lkpi_fw_task *lfwt;
        const struct linuxkpi_firmware *fw;

        KASSERT(ctx != NULL && pending == 1, ("%s: lfwt %p, pending %d\n",
            __func__, ctx, pending));

        lfwt = ctx;
        if (lfwt->cont == NULL)
                goto out;

        _linuxkpi_request_firmware(lfwt->fw_name, &fw, lfwt->dev,
            lfwt->gfp, true, true);

        /*
         * Linux seems to run the callback if it cannot find the firmware.
         * We call it in all cases as it is the only feedback to the requester.
         */
        lfwt->cont(fw, lfwt->drv);
        /* Do not assume fw is still valid! */

out:
        free(lfwt, M_LKPI_FW);
}

int
linuxkpi_request_firmware_nowait(struct module *mod __unused, bool _t __unused,
    const char *fw_name, struct device *dev, gfp_t gfp, void *drv,
    void(*cont)(const struct linuxkpi_firmware *, void *))
{
        struct lkpi_fw_task *lfwt;
        int error;

        lfwt = malloc(sizeof(*lfwt), M_LKPI_FW, M_WAITOK | M_ZERO);
        lfwt->gfp = gfp;
        lfwt->fw_name = fw_name;
        lfwt->dev = dev;
        lfwt->drv = drv;
        lfwt->cont = cont;
        TASK_INIT(&lfwt->fw_task, 0, lkpi_fw_task, lfwt);
        error = taskqueue_enqueue(taskqueue_thread, &lfwt->fw_task);

        if (error)
                return (-error);
        return (0);
}

int
linuxkpi_request_firmware(const struct linuxkpi_firmware **fw,
    const char *fw_name, struct device *dev)
{

        return (_linuxkpi_request_firmware(fw_name, fw, dev, GFP_KERNEL, false,
            true));
}

int
linuxkpi_firmware_request_nowarn(const struct linuxkpi_firmware **fw,
    const char *fw_name, struct device *dev)
{

        return (_linuxkpi_request_firmware(fw_name, fw, dev, GFP_KERNEL, false,
            false));
}

void
linuxkpi_release_firmware(const struct linuxkpi_firmware *fw)
{

        if (fw == NULL)
                return;

        if (fw->fbdfw)
                firmware_put(fw->fbdfw, FIRMWARE_UNLOAD);
        free(__DECONST(void *, fw), M_LKPI_FW);
}

int
linuxkpi_request_partial_firmware_into_buf(const struct linuxkpi_firmware **fw,
    const char *fw_name, struct device *dev, uint8_t *buf, size_t buflen,
    size_t offset)
{
        const struct linuxkpi_firmware *lfw;
        int error;

        error = linuxkpi_request_firmware(fw, fw_name, dev);
        if (error != 0)
                return (error);

        lfw = *fw;
        if ((offset + buflen) >= lfw->size) {
                linuxkpi_release_firmware(lfw);
                return (-ERANGE);
        }

        memcpy(buf, lfw->data + offset, buflen);

        return (0);
}