/*
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* Copyright (c) 2016 AllWinner Technology Co., Ltd. <www.allwinnertech.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/etherdevice.h>
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#include <linux/netdevice.h>
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#include <net/netlink.h>
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#include <net/sock.h>
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#include <linux/workqueue.h>
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#include <linux/types.h>
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#define EVT_MAX_SIZE 256
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#define NETLINK_PCM_SUNXI 31
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#undef SUNXI_NETLINK_TEST
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enum {
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SNDRV_PCM_NETLINK_CLOSE,
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SNDRV_PCM_NETLINK_START,
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SNDRV_PCM_NETLINK_NOUSE,
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};
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#ifdef SUNXI_NETLINK_TEST
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static void sunxi_netlink_period(struct work_struct *ws);
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DECLARE_DELAYED_WORK(writer_work, sunxi_netlink_period);
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#endif
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struct evt_entry {
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struct list_head list;
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char evt_data[EVT_MAX_SIZE];
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int size;
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};
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struct xrun_event {
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int ref_cnt;
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struct sock *sock;
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struct list_head evtq;
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spinlock_t evt_lock;
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struct list_head freeq;
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struct work_struct ws;
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};
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struct pcm_netlink_status {
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int pid;
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int status;
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struct mutex mutex_lock;
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};
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static struct xrun_event pcm_event;
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static struct pcm_netlink_status pcm_netlink;
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static void free_event_entry(struct evt_entry *e)
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{
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kfree(e);
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}
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static inline struct evt_entry *alloc_evt_entry(void)
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{
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return kmalloc(sizeof(struct evt_entry), GFP_ATOMIC);
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}
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static struct evt_entry *get_evt_entry(void)
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{
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struct evt_entry *e;
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if (list_empty(&pcm_event.freeq))
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e = alloc_evt_entry();
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else {
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e = list_entry(pcm_event.freeq.next, struct evt_entry, list);
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list_del(&e->list);
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}
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return e;
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}
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static void put_evt_entry(struct evt_entry *e)
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{
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list_add_tail(&e->list, &pcm_event.freeq);
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}
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static int netlink_send(struct sock *sock, int group,
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u16 type, void *msg, int len)
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{
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struct sk_buff *skb = NULL;
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struct nlmsghdr *nlh;
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int ret = 0;
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skb = nlmsg_new(len, GFP_ATOMIC);
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if (!skb) {
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kfree_skb(skb);
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return -EMSGSIZE;
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}
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nlh = nlmsg_put(skb, 0, 0, type, len, 0);
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if (!nlh) {
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kfree_skb(skb);
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return -EMSGSIZE;
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}
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memcpy(nlmsg_data(nlh), msg, len);
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NETLINK_CB(skb).portid = 0;
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NETLINK_CB(skb).dst_group = 0;
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if (pcm_netlink.status > SNDRV_PCM_NETLINK_CLOSE) {
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ret = netlink_unicast(sock, skb, pcm_netlink.pid, GFP_ATOMIC);
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if (ret < 0)
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pcm_netlink.status = SNDRV_PCM_NETLINK_CLOSE;
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}
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return ret;
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}
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static void _pcm_event_send(struct work_struct *work)
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{
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unsigned long flags;
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struct evt_entry *e;
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spin_lock_irqsave(&pcm_event.evt_lock, flags);
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while (!list_empty(&pcm_event.evtq)) {
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e = list_entry(pcm_event.evtq.next, struct evt_entry, list);
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spin_unlock_irqrestore(&pcm_event.evt_lock, flags);
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netlink_send(pcm_event.sock, 0, 0, e->evt_data, e->size);
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spin_lock_irqsave(&pcm_event.evt_lock, flags);
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list_del(&e->list);
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put_evt_entry(e);
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}
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spin_unlock_irqrestore(&pcm_event.evt_lock, flags);
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}
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static void netlink_rcv(struct sk_buff *skb)
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{
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struct nlmsghdr *nlh;
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int pid;
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nlh = (struct nlmsghdr *)skb->data;
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pid = nlh->nlmsg_pid; /*pid of sending process */
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/* user start capture? */
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if (!strncmp(nlmsg_data(nlh), "start", 5)) {
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pcm_netlink.pid = pid;
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pcm_netlink.status = SNDRV_PCM_NETLINK_START;
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}
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if (!strncmp(nlmsg_data(nlh), "close", 5))
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pcm_netlink.status = SNDRV_PCM_NETLINK_CLOSE;
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#ifdef SUNXI_NETLINK_TEST
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if (pcm_netlink.status)
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schedule_delayed_work(&writer_work, 5 * HZ);
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#endif
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}
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static void printk_convert(struct evt_entry *e, const char *fmt, va_list args)
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{
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e->size = vscnprintf(e->evt_data, EVT_MAX_SIZE, fmt, args);
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/* mark and strip a trailing newline */
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if (e->size && e->evt_data[e->size - 1] == '\n')
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e->size--;
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}
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void sunxi_netlink_printd(const char *fmt, ...)
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{
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va_list args;
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struct evt_entry *e;
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unsigned long flags;
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spin_lock_irqsave(&pcm_event.evt_lock, flags);
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e = get_evt_entry();
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if (!e) {
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pr_err("pcm netlink memory not available\n");
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spin_unlock_irqrestore(&pcm_event.evt_lock, flags);
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return;
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}
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va_start(args, fmt);
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printk_convert(e, fmt, args);
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va_end(args);
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list_add_tail(&e->list, &pcm_event.evtq);
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spin_unlock_irqrestore(&pcm_event.evt_lock, flags);
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schedule_work(&pcm_event.ws);
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}
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#ifdef SUNXI_NETLINK_TEST
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static void sunxi_netlink_period(struct work_struct *ws)
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{
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static int count = 1;
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sunxi_netlink_printd("hello form the pcm netlink test: %d\n", count);
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schedule_delayed_work(&writer_work, msecs_to_jiffies(10));
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}
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#endif
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int sunxi_netlink_init(void)
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{
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struct netlink_kernel_cfg cfg = {
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.input = netlink_rcv,
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};
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if (!pcm_event.ref_cnt) {
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pcm_event.sock = netlink_kernel_create(&init_net,
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NETLINK_PCM_SUNXI, &cfg);
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if (!pcm_event.sock) {
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pr_err("netlink create failed\n");
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return -EMSGSIZE;
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}
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if (pcm_event.sock) {
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INIT_LIST_HEAD(&pcm_event.evtq);
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INIT_LIST_HEAD(&pcm_event.freeq);
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INIT_WORK(&pcm_event.ws, _pcm_event_send);
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spin_lock_init(&pcm_event.evt_lock);
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}
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pcm_netlink.status = SNDRV_PCM_NETLINK_CLOSE;
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}
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if (pcm_event.sock) {
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pcm_event.ref_cnt++;
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pr_debug("Creating PCM netlink successfully\n");
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return 0;
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}
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pr_debug("Creating PCM netlink is failed\n");
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return -EBUSY;
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}
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static void sunxi_netlink_exit(void)
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{
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struct evt_entry *e, *temp;
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unsigned long flags;
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if (pcm_event.sock && --pcm_event.ref_cnt == 0) {
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spin_lock_irqsave(&pcm_event.evt_lock, flags);
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list_for_each_entry_safe(e, temp, &pcm_event.evtq, list) {
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list_del(&e->list);
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free_event_entry(e);
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}
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list_for_each_entry_safe(e, temp, &pcm_event.freeq, list) {
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list_del(&e->list);
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free_event_entry(e);
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}
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spin_unlock_irqrestore(&pcm_event.evt_lock, flags);
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netlink_kernel_release(pcm_event.sock);
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pcm_event.sock = NULL;
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}
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}
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module_init(sunxi_netlink_init);
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module_exit(sunxi_netlink_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("wolfgang huang <huangjinhui@allwinnertech.com>");
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MODULE_DESCRIPTION("sunxi netlink interface");
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MODULE_ALIAS("sunxi_netlink");
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