drivers/staging/media/zoran/videocodec.c - linux - Git at Google

 // 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>
  */

 #define VIDEOCODEC_VERSION "v0.2"

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

 // kernel config is here (procfs flag)

 #ifdef CONFIG_PROC_FS
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/uaccess.h>
 #endif

 #include "videocodec.h"

 static int debug;
 module_param(debug, int, 0);
 MODULE_PARM_DESC(debug, "Debug level (0-4)");

 #define dprintk(num, format, args...) \
 	do { \
 		if (debug >= num) \
 			printk(format, ##args); \
 	} while (0)

 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 attached_list *a, *ptr;
 	struct videocodec *codec;
 	int res;

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

 	dprintk(2, "%s: '%s', flags %lx, magic %lx\n", __func__,
 		master->name, master->flags, master->magic);

 	if (!h) {
 		pr_err("%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) {
 			dprintk(4, "%s: try '%s'\n", __func__, h->codec->name);

 			if (!try_module_get(h->codec->owner))
 				return NULL;

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

 			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) {
 				dprintk(3, "%s: '%s'\n", __func__, codec->name);
 				ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
 				if (!ptr)
 					goto out_kfree;
 				ptr->codec = codec;

 				a = h->list;
 				if (!a) {
 					h->list = ptr;
 					dprintk(4, "videocodec: first element\n");
 				} else {
 					while (a->next)
 						a = a->next;	// find end
 					a->next = ptr;
 					dprintk(4, "videocodec: in after '%s'\n", h->codec->name);
 				}

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

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

  out_module_put:
 	module_put(h->codec->owner);
  out_kfree:
 	kfree(codec);
 	return NULL;
 }
 EXPORT_SYMBOL(videocodec_attach);

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

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

 	dprintk(2, "%s: '%s', type: %x, flags %lx, magic %lx\n", __func__,
 		codec->name, codec->type, codec->flags, codec->magic);

 	if (!h) {
 		pr_err("%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) {
 					dprintk(3, "%s: '%s'\n", __func__, a->codec->name);
 					a->codec->master_data = NULL;
 				} else {
 					pr_err("%s: '%s'\n", __func__, a->codec->name);
 					a->codec->master_data = NULL;
 				}
 				if (!prev) {
 					h->list = a->next;
 					dprintk(4, "videocodec: delete first\n");
 				} else {
 					prev->next = a->next;
 					dprintk(4, "videocodec: delete middle\n");
 				}
 				module_put(a->codec->owner);
 				kfree(a->codec);
 				kfree(a);
 				h->attached -= 1;
 				return 0;
 			}
 			prev = a;
 			a = a->next;
 		}
 		h = h->next;
 	}

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

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

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

 	dprintk(2,
 		"videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
 		codec->name, codec->type, codec->flags, codec->magic);

 	ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
 		return -ENOMEM;
 	ptr->codec = codec;

 	if (!h) {
 		codeclist_top = ptr;
 		dprintk(4, "videocodec: hooked in as first element\n");
 	} else {
 		while (h->next)
 			h = h->next;	// find the end
 		h->next = ptr;
 		dprintk(4, "videocodec: hooked in after '%s'\n",
 			h->codec->name);
 	}

 	return 0;
 }
 EXPORT_SYMBOL(videocodec_register);

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

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

 	dprintk(2,
 		"videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
 		codec->name, codec->type, codec->flags, codec->magic);

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

 	while (h) {
 		if (codec == h->codec) {
 			if (h->attached) {
 				pr_err("videocodec: '%s' is used\n", h->codec->name);
 				return -EBUSY;
 			}
 			dprintk(3, "videocodec: unregister '%s' is ok.\n",
 				h->codec->name);
 			if (!prev) {
 				codeclist_top = h->next;
 				dprintk(4,
 					"videocodec: delete first element\n");
 			} else {
 				prev->next = h->next;
 				dprintk(4,
 					"videocodec: delete middle element\n");
 			}
 			kfree(h);
 			return 0;
 		}
 		prev = h;
 		h = h->next;
 	}

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

 #ifdef CONFIG_PROC_FS
 static int proc_videocodecs_show(struct seq_file *m, void *v)
 {
 	struct codec_list *h = codeclist_top;
 	struct attached_list *a;

 	seq_printf(m, "<S>lave or attached <M>aster name  type flags    magic    ");
 	seq_printf(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;
 }
 #endif

 /* ===================== */
 /* hook in driver module */
 /* ===================== */
 static int __init videocodec_init(void)
 {
 #ifdef CONFIG_PROC_FS
 	static struct proc_dir_entry *videocodec_proc_entry;
 #endif

 	pr_info("Linux video codec intermediate layer: %s\n", VIDEOCODEC_VERSION);

 #ifdef CONFIG_PROC_FS
 	videocodec_proc_entry = proc_create_single("videocodecs", 0, NULL, proc_videocodecs_show);
 	if (!videocodec_proc_entry)
 		pr_err("videocodec: can't init procfs.\n");
 #endif
 	return 0;
 }

 static void __exit videocodec_exit(void)
 {
 #ifdef CONFIG_PROC_FS
 	remove_proc_entry("videocodecs", NULL);
 #endif
 }

 module_init(videocodec_init);
 module_exit(videocodec_exit);

 MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
 MODULE_DESCRIPTION("Intermediate API module for video codecs "
 		   VIDEOCODEC_VERSION);
 MODULE_LICENSE("GPL");
	// 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>
	*/

	#define VIDEOCODEC_VERSION "v0.2"

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

	// kernel config is here (procfs flag)

	#ifdef CONFIG_PROC_FS
	#include <linux/proc_fs.h>
	#include <linux/seq_file.h>
	#include <linux/uaccess.h>
	#endif

	#include "videocodec.h"

	static int debug;
	module_param(debug, int, 0);
	MODULE_PARM_DESC(debug, "Debug level (0-4)");

	#define dprintk(num, format, args...) \
	do { \
	if (debug >= num) \
	printk(format, ##args); \
	} while (0)

	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 attached_list a, ptr;
	struct videocodec *codec;
	int res;

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

	dprintk(2, "%s: '%s', flags %lx, magic %lx\n", __func__,
	master->name, master->flags, master->magic);

	if (!h) {
	pr_err("%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) {
	dprintk(4, "%s: try '%s'\n", __func__, h->codec->name);

	if (!try_module_get(h->codec->owner))
	return NULL;

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

	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) {
	dprintk(3, "%s: '%s'\n", __func__, codec->name);
	ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
	goto out_kfree;
	ptr->codec = codec;

	a = h->list;
	if (!a) {
	h->list = ptr;
	dprintk(4, "videocodec: first element\n");
	} else {
	while (a->next)
	a = a->next; // find end
	a->next = ptr;
	dprintk(4, "videocodec: in after '%s'\n", h->codec->name);
	}

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

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

	out_module_put:
	module_put(h->codec->owner);
	out_kfree:
	kfree(codec);
	return NULL;
	}
	EXPORT_SYMBOL(videocodec_attach);

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

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

	dprintk(2, "%s: '%s', type: %x, flags %lx, magic %lx\n", __func__,
	codec->name, codec->type, codec->flags, codec->magic);

	if (!h) {
	pr_err("%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) {
	dprintk(3, "%s: '%s'\n", __func__, a->codec->name);
	a->codec->master_data = NULL;
	} else {
	pr_err("%s: '%s'\n", __func__, a->codec->name);
	a->codec->master_data = NULL;
	}
	if (!prev) {
	h->list = a->next;
	dprintk(4, "videocodec: delete first\n");
	} else {
	prev->next = a->next;
	dprintk(4, "videocodec: delete middle\n");
	}
	module_put(a->codec->owner);
	kfree(a->codec);
	kfree(a);
	h->attached -= 1;
	return 0;
	}
	prev = a;
	a = a->next;
	}
	h = h->next;
	}

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

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

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

	dprintk(2,
	"videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
	codec->name, codec->type, codec->flags, codec->magic);

	ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
	return -ENOMEM;
	ptr->codec = codec;

	if (!h) {
	codeclist_top = ptr;
	dprintk(4, "videocodec: hooked in as first element\n");
	} else {
	while (h->next)
	h = h->next; // find the end
	h->next = ptr;
	dprintk(4, "videocodec: hooked in after '%s'\n",
	h->codec->name);
	}

	return 0;
	}
	EXPORT_SYMBOL(videocodec_register);

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

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

	dprintk(2,
	"videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
	codec->name, codec->type, codec->flags, codec->magic);

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

	while (h) {
	if (codec == h->codec) {
	if (h->attached) {
	pr_err("videocodec: '%s' is used\n", h->codec->name);
	return -EBUSY;
	}
	dprintk(3, "videocodec: unregister '%s' is ok.\n",
	h->codec->name);
	if (!prev) {
	codeclist_top = h->next;
	dprintk(4,
	"videocodec: delete first element\n");
	} else {
	prev->next = h->next;
	dprintk(4,
	"videocodec: delete middle element\n");
	}
	kfree(h);
	return 0;
	}
	prev = h;
	h = h->next;
	}

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

	#ifdef CONFIG_PROC_FS
	static int proc_videocodecs_show(struct seq_file m, void v)
	{
	struct codec_list *h = codeclist_top;
	struct attached_list *a;

	seq_printf(m, "<S>lave or attached <M>aster name type flags magic ");
	seq_printf(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;
	}
	#endif

	/* ===================== */
	/* hook in driver module */
	/* ===================== */
	static int __init videocodec_init(void)
	{
	#ifdef CONFIG_PROC_FS
	static struct proc_dir_entry *videocodec_proc_entry;
	#endif

	pr_info("Linux video codec intermediate layer: %s\n", VIDEOCODEC_VERSION);

	#ifdef CONFIG_PROC_FS
	videocodec_proc_entry = proc_create_single("videocodecs", 0, NULL, proc_videocodecs_show);
	if (!videocodec_proc_entry)
	pr_err("videocodec: can't init procfs.\n");
	#endif
	return 0;
	}

	static void __exit videocodec_exit(void)
	{
	#ifdef CONFIG_PROC_FS
	remove_proc_entry("videocodecs", NULL);
	#endif
	}

	module_init(videocodec_init);
	module_exit(videocodec_exit);

	MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
	MODULE_DESCRIPTION("Intermediate API module for video codecs "
	VIDEOCODEC_VERSION);
	MODULE_LICENSE("GPL");