// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * VIDEO MOTION CODECs internal API for video devices
 *
 * Interface for MJPEG (and maybe later MPEG/WAVELETS) codec's
 * bound to a master device.
 *
 * (c) 2002 Wolfgang Scherr <scherr@net4you.at>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>

#include "videocodec.h"

struct attached_list {
        struct videocodec *codec;
        struct attached_list *next;
};

struct codec_list {
        const struct videocodec *codec;
        int attached;
        struct attached_list *list;
        struct codec_list *next;
};

static struct codec_list *codeclist_top;

/* ================================================= */
/* function prototypes of the master/slave interface */
/* ================================================= */

struct videocodec *videocodec_attach(struct videocodec_master *master)
{
        struct codec_list *h = codeclist_top;
        struct zoran *zr;
        struct attached_list *a, *ptr;
        struct videocodec *codec;
        int res;

        if (!master) {
                pr_err("%s: no data\n", __func__);
                return NULL;
        }

        zr = videocodec_master_to_zoran(master);

        zrdev_dbg(zr, "%s: '%s', flags %lx, magic %lx\n", __func__,
                  master->name, master->flags, master->magic);

        if (!h) {
                zrdev_err(zr, "%s: no device available\n", __func__);
                return NULL;
        }

        while (h) {
                // attach only if the slave has at least the flags
                // expected by the master
                if ((master->flags & h->codec->flags) == master->flags) {
                        zrdev_dbg(zr, "%s: try '%s'\n", __func__, h->codec->name);

                        codec = kmemdup(h->codec, sizeof(struct videocodec), GFP_KERNEL);
                        if (!codec)
                                goto out_kfree;

                        res = strlen(codec->name);
                        snprintf(codec->name + res, sizeof(codec->name) - res, "[%d]", h->attached);
                        codec->master_data = master;
                        res = codec->setup(codec);
                        if (res == 0) {
                                zrdev_dbg(zr, "%s: '%s'\n", __func__, codec->name);
                                ptr = kzalloc_obj(*ptr);
                                if (!ptr)
                                        goto out_kfree;
                                ptr->codec = codec;

                                a = h->list;
                                if (!a) {
                                        h->list = ptr;
                                        zrdev_dbg(zr, "videocodec: first element\n");
                                } else {
                                        while (a->next)
                                                a = a->next;    // find end
                                        a->next = ptr;
                                        zrdev_dbg(zr, "videocodec: in after '%s'\n",
                                                  h->codec->name);
                                }

                                h->attached += 1;
                                return codec;
                        }
                        kfree(codec);
                }
                h = h->next;
        }

        zrdev_err(zr, "%s: no codec found!\n", __func__);
        return NULL;

 out_kfree:
        kfree(codec);
        return NULL;
}

int videocodec_detach(struct videocodec *codec)
{
        struct codec_list *h = codeclist_top;
        struct zoran *zr;
        struct attached_list *a, *prev;
        int res;

        if (!codec) {
                pr_err("%s: no data\n", __func__);
                return -EINVAL;
        }

        zr = videocodec_to_zoran(codec);

        zrdev_dbg(zr, "%s: '%s', type: %x, flags %lx, magic %lx\n", __func__,
                  codec->name, codec->type, codec->flags, codec->magic);

        if (!h) {
                zrdev_err(zr, "%s: no device left...\n", __func__);
                return -ENXIO;
        }

        while (h) {
                a = h->list;
                prev = NULL;
                while (a) {
                        if (codec == a->codec) {
                                res = a->codec->unset(a->codec);
                                if (res >= 0) {
                                        zrdev_dbg(zr, "%s: '%s'\n", __func__,
                                                  a->codec->name);
                                        a->codec->master_data = NULL;
                                } else {
                                        zrdev_err(zr, "%s: '%s'\n", __func__, a->codec->name);
                                        a->codec->master_data = NULL;
                                }
                                if (!prev) {
                                        h->list = a->next;
                                        zrdev_dbg(zr, "videocodec: delete first\n");
                                } else {
                                        prev->next = a->next;
                                        zrdev_dbg(zr, "videocodec: delete middle\n");
                                }
                                kfree(a->codec);
                                kfree(a);
                                h->attached -= 1;
                                return 0;
                        }
                        prev = a;
                        a = a->next;
                }
                h = h->next;
        }

        zrdev_err(zr, "%s: given codec not found!\n", __func__);
        return -EINVAL;
}

int videocodec_register(const struct videocodec *codec)
{
        struct codec_list *ptr, *h = codeclist_top;
        struct zoran *zr;

        if (!codec) {
                pr_err("%s: no data!\n", __func__);
                return -EINVAL;
        }

        zr = videocodec_to_zoran((struct videocodec *)codec);

        zrdev_dbg(zr,
                  "videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
                  codec->name, codec->type, codec->flags, codec->magic);

        ptr = kzalloc_obj(*ptr);
        if (!ptr)
                return -ENOMEM;
        ptr->codec = codec;

        if (!h) {
                codeclist_top = ptr;
                zrdev_dbg(zr, "videocodec: hooked in as first element\n");
        } else {
                while (h->next)
                        h = h->next;    // find the end
                h->next = ptr;
                zrdev_dbg(zr, "videocodec: hooked in after '%s'\n",
                          h->codec->name);
        }

        return 0;
}

int videocodec_unregister(const struct videocodec *codec)
{
        struct codec_list *prev = NULL, *h = codeclist_top;
        struct zoran *zr;

        if (!codec) {
                pr_err("%s: no data!\n", __func__);
                return -EINVAL;
        }

        zr = videocodec_to_zoran((struct videocodec *)codec);

        zrdev_dbg(zr,
                  "videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
                  codec->name, codec->type, codec->flags, codec->magic);

        if (!h) {
                zrdev_err(zr, "%s: no device left...\n", __func__);
                return -ENXIO;
        }

        while (h) {
                if (codec == h->codec) {
                        if (h->attached) {
                                zrdev_err(zr, "videocodec: '%s' is used\n",
                                          h->codec->name);
                                return -EBUSY;
                        }
                        zrdev_dbg(zr, "videocodec: unregister '%s' is ok.\n",
                                  h->codec->name);
                        if (!prev) {
                                codeclist_top = h->next;
                                zrdev_dbg(zr,
                                          "videocodec: delete first element\n");
                        } else {
                                prev->next = h->next;
                                zrdev_dbg(zr,
                                          "videocodec: delete middle element\n");
                        }
                        kfree(h);
                        return 0;
                }
                prev = h;
                h = h->next;
        }

        zrdev_err(zr, "%s: given codec not found!\n", __func__);
        return -EINVAL;
}

int videocodec_debugfs_show(struct seq_file *m)
{
        struct codec_list *h = codeclist_top;
        struct attached_list *a;

        seq_puts(m, "<S>lave or attached <M>aster name  type flags    magic    ");
        seq_puts(m, "(connected as)\n");

        while (h) {
                seq_printf(m, "S %32s %04x %08lx %08lx (TEMPLATE)\n",
                           h->codec->name, h->codec->type,
                              h->codec->flags, h->codec->magic);
                a = h->list;
                while (a) {
                        seq_printf(m, "M %32s %04x %08lx %08lx (%s)\n",
                                   a->codec->master_data->name,
                                      a->codec->master_data->type,
                                      a->codec->master_data->flags,
                                      a->codec->master_data->magic,
                                      a->codec->name);
                        a = a->next;
                }
                h = h->next;
        }

        return 0;
}