sound/pci/ctxfi/ctimap.c

   1 /**
   2  * Copyright (C) 2008, Creative Technology Ltd. All Rights Reserved.
   3  *
   4  * This source file is released under GPL v2 license (no other versions).
   5  * See the COPYING file included in the main directory of this source
   6  * distribution for the license terms and conditions.
   7  *
   8  * @File        ctimap.c
   9  *
  10  * @Brief
  11  * This file contains the implementation of generic input mapper operations
  12  * for input mapper management.
  13  *
  14  * @Author      Liu Chun
  15  * @Date        May 23 2008
  16  *
  17  */
  18
  19 #include "ctimap.h"
  20 #include <linux/slab.h>
  21
  22 int input_mapper_add(struct list_head *mappers, struct imapper *entry,
  23                      int (*map_op)(void *, struct imapper *), void *data)
  24 {
  25         struct list_head *pos, *pre, *head;
  26         struct imapper *pre_ent, *pos_ent;
  27
  28         head = mappers;
  29
  30         if (list_empty(head)) {
  31                 entry->next = entry->addr;
  32                 map_op(data, entry);
  33                 list_add(&entry->list, head);
  34                 return 0;
  35         }
  36
  37         list_for_each(pos, head) {
  38                 pos_ent = list_entry(pos, struct imapper, list);
  39                 if (pos_ent->slot > entry->slot) {
  40                         /* found a position in list */
  41                         break;
  42                 }
  43         }
  44
  45         if (pos != head) {
  46                 pre = pos->prev;
  47                 if (pre == head)
  48                         pre = head->prev;
  49
  50                 __list_add(&entry->list, pos->prev, pos);
  51         } else {
  52                 pre = head->prev;
  53                 pos = head->next;
  54                 list_add_tail(&entry->list, head);
  55         }
  56
  57         pre_ent = list_entry(pre, struct imapper, list);
  58         pos_ent = list_entry(pos, struct imapper, list);
  59
  60         entry->next = pos_ent->addr;
  61         map_op(data, entry);
  62         pre_ent->next = entry->addr;
  63         map_op(data, pre_ent);
  64
  65         return 0;
  66 }
  67
  68 int input_mapper_delete(struct list_head *mappers, struct imapper *entry,
  69                      int (*map_op)(void *, struct imapper *), void *data)
  70 {
  71         struct list_head *next, *pre, *head;
  72         struct imapper *pre_ent, *next_ent;
  73
  74         head = mappers;
  75
  76         if (list_empty(head))
  77                 return 0;
  78
  79         pre = (entry->list.prev == head) ? head->prev : entry->list.prev;
  80         next = (entry->list.next == head) ? head->next : entry->list.next;
  81
  82         if (pre == &entry->list) {
  83                 /* entry is the only one node in mappers list */
  84                 entry->next = entry->addr = entry->user = entry->slot = 0;
  85                 map_op(data, entry);
  86                 list_del(&entry->list);
  87                 return 0;
  88         }
  89
  90         pre_ent = list_entry(pre, struct imapper, list);
  91         next_ent = list_entry(next, struct imapper, list);
  92
  93         pre_ent->next = next_ent->addr;
  94         map_op(data, pre_ent);
  95         list_del(&entry->list);
  96
  97         return 0;
  98 }
  99
 100 void free_input_mapper_list(struct list_head *head)
 101 {
 102         struct imapper *entry;
 103         struct list_head *pos;
 104
 105         while (!list_empty(head)) {
 106                 pos = head->next;
 107                 list_del(pos);
 108                 entry = list_entry(pos, struct imapper, list);
 109                 kfree(entry);
 110         }
 111 }
 112