| // 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"); |