forked from luck/tmp_suning_uos_patched
033919e0f8
When removing module ir_lirc_codec I got this deadlock warning. Fix this by introducing a separate mutex to protect access to available_protocols instead of using ir_raw_handler_lock for this purpose. ====================================================== [ INFO: possible circular locking dependency detected ] 4.7.0-next-20160729 #1 Not tainted ------------------------------------------------------- rmmod/2542 is trying to acquire lock: (&dev->lock){+.+.+.}, at: [<ffffffffa03b1267>] ir_raw_handler_unregister+0x77/0xd0 [rc_core] but task is already holding lock: (ir_raw_handler_lock){+.+.+.}, at: [<ffffffffa03b1212>] ir_raw_handler_unregister+0x22/0xd0 [rc_core] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (ir_raw_handler_lock){+.+.+.}: [<ffffffff810ab1f2>] lock_acquire+0xb2/0x1e0 [<ffffffff815c087f>] mutex_lock_nested+0x5f/0x360 [<ffffffffa03b1403>] ir_raw_get_allowed_protocols+0x13/0x30 [rc_core] [<ffffffffa03af8ea>] store_protocols+0x2fa/0x480 [rc_core] [<ffffffff8143e143>] dev_attr_store+0x13/0x20 [<ffffffff81213c50>] sysfs_kf_write+0x40/0x50 [<ffffffff81212f60>] kernfs_fop_write+0x150/0x1e0 [<ffffffff81197613>] __vfs_write+0x23/0x120 [<ffffffff81198740>] vfs_write+0xb0/0x190 [<ffffffff81199a34>] SyS_write+0x44/0xa0 [<ffffffff815c55a5>] entry_SYSCALL_64_fastpath+0x18/0xa8 -> #0 (&dev->lock){+.+.+.}: [<ffffffff810aac8c>] __lock_acquire+0x10fc/0x1270 [<ffffffff810ab1f2>] lock_acquire+0xb2/0x1e0 [<ffffffff815c087f>] mutex_lock_nested+0x5f/0x360 [<ffffffffa03b1267>] ir_raw_handler_unregister+0x77/0xd0 [rc_core] [<ffffffffa03c8c05>] ir_lirc_codec_exit+0x10/0x12 [ir_lirc_codec] [<ffffffff810e1b88>] SyS_delete_module+0x168/0x220 [<ffffffff815c55a5>] entry_SYSCALL_64_fastpath+0x18/0xa8 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(ir_raw_handler_lock); lock(&dev->lock); lock(ir_raw_handler_lock); lock(&dev->lock); *** DEADLOCK *** 1 lock held by rmmod/2542: #0: (ir_raw_handler_lock){+.+.+.}, at: [<ffffffffa03b1212>] ir_raw_handler_unregister+0x22/0xd0 [rc_core] stack backtrace: CPU: 0 PID: 2542 Comm: rmmod Not tainted 4.7.0-next-20160729 #1 Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015 0000000000000000 ffff88006e607cc0 ffffffff812715f5 ffffffff8232b230 ffffffff8232b230 ffff88006e607d00 ffffffff810a846e 00000000790107f0 ffff880079010818 ffff8800790107f0 1efeb9f4f0dd2e6f ffff880079010000 Call Trace: [<ffffffff812715f5>] dump_stack+0x68/0x93 [<ffffffff810a846e>] print_circular_bug+0x1be/0x210 [<ffffffff810aac8c>] __lock_acquire+0x10fc/0x1270 [<ffffffff810bcead>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [<ffffffff810ab1f2>] lock_acquire+0xb2/0x1e0 [<ffffffffa03b1267>] ? ir_raw_handler_unregister+0x77/0xd0 [rc_core] [<ffffffff815c087f>] mutex_lock_nested+0x5f/0x360 [<ffffffffa03b1267>] ? ir_raw_handler_unregister+0x77/0xd0 [rc_core] [<ffffffff810a980e>] ? trace_hardirqs_on_caller+0xee/0x1b0 [<ffffffffa03b1267>] ir_raw_handler_unregister+0x77/0xd0 [rc_core] [<ffffffffa03c8c05>] ir_lirc_codec_exit+0x10/0x12 [ir_lirc_codec] [<ffffffff810e1b88>] SyS_delete_module+0x168/0x220 [<ffffffff815c55a5>] entry_SYSCALL_64_fastpath+0x18/0xa8 Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
361 lines
9.4 KiB
C
361 lines
9.4 KiB
C
/* rc-ir-raw.c - handle IR pulse/space events
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*
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* Copyright (C) 2010 by Mauro Carvalho Chehab
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation version 2 of the License.
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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/export.h>
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#include <linux/kthread.h>
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#include <linux/mutex.h>
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#include <linux/kmod.h>
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#include <linux/sched.h>
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#include <linux/freezer.h>
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#include "rc-core-priv.h"
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/* Used to keep track of IR raw clients, protected by ir_raw_handler_lock */
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static LIST_HEAD(ir_raw_client_list);
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/* Used to handle IR raw handler extensions */
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static DEFINE_MUTEX(ir_raw_handler_lock);
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static LIST_HEAD(ir_raw_handler_list);
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static DEFINE_MUTEX(available_protocols_lock);
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static u64 available_protocols;
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static int ir_raw_event_thread(void *data)
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{
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struct ir_raw_event ev;
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struct ir_raw_handler *handler;
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struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
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while (!kthread_should_stop()) {
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spin_lock_irq(&raw->lock);
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if (!kfifo_len(&raw->kfifo)) {
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set_current_state(TASK_INTERRUPTIBLE);
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if (kthread_should_stop())
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set_current_state(TASK_RUNNING);
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spin_unlock_irq(&raw->lock);
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schedule();
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continue;
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}
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if(!kfifo_out(&raw->kfifo, &ev, 1))
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dev_err(&raw->dev->dev, "IR event FIFO is empty!\n");
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spin_unlock_irq(&raw->lock);
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mutex_lock(&ir_raw_handler_lock);
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list_for_each_entry(handler, &ir_raw_handler_list, list)
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if (raw->dev->enabled_protocols & handler->protocols ||
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!handler->protocols)
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handler->decode(raw->dev, ev);
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raw->prev_ev = ev;
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mutex_unlock(&ir_raw_handler_lock);
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}
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return 0;
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}
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/**
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* ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
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* @dev: the struct rc_dev device descriptor
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* @ev: the struct ir_raw_event descriptor of the pulse/space
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*
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* This routine (which may be called from an interrupt context) stores a
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* pulse/space duration for the raw ir decoding state machines. Pulses are
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* signalled as positive values and spaces as negative values. A zero value
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* will reset the decoding state machines.
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*/
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int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev)
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{
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if (!dev->raw)
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return -EINVAL;
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IR_dprintk(2, "sample: (%05dus %s)\n",
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TO_US(ev->duration), TO_STR(ev->pulse));
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if (!kfifo_put(&dev->raw->kfifo, *ev)) {
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dev_err(&dev->dev, "IR event FIFO is full!\n");
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return -ENOSPC;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(ir_raw_event_store);
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/**
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* ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
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* @dev: the struct rc_dev device descriptor
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* @type: the type of the event that has occurred
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*
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* This routine (which may be called from an interrupt context) is used to
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* store the beginning of an ir pulse or space (or the start/end of ir
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* reception) for the raw ir decoding state machines. This is used by
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* hardware which does not provide durations directly but only interrupts
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* (or similar events) on state change.
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*/
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int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
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{
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ktime_t now;
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s64 delta; /* ns */
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DEFINE_IR_RAW_EVENT(ev);
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int rc = 0;
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int delay;
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if (!dev->raw)
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return -EINVAL;
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now = ktime_get();
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delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
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delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
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/* Check for a long duration since last event or if we're
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* being called for the first time, note that delta can't
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* possibly be negative.
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*/
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if (delta > delay || !dev->raw->last_type)
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type |= IR_START_EVENT;
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else
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ev.duration = delta;
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if (type & IR_START_EVENT)
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ir_raw_event_reset(dev);
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else if (dev->raw->last_type & IR_SPACE) {
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ev.pulse = false;
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rc = ir_raw_event_store(dev, &ev);
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} else if (dev->raw->last_type & IR_PULSE) {
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ev.pulse = true;
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rc = ir_raw_event_store(dev, &ev);
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} else
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return 0;
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dev->raw->last_event = now;
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dev->raw->last_type = type;
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return rc;
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}
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EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
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/**
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* ir_raw_event_store_with_filter() - pass next pulse/space to decoders with some processing
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* @dev: the struct rc_dev device descriptor
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* @type: the type of the event that has occurred
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*
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* This routine (which may be called from an interrupt context) works
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* in similar manner to ir_raw_event_store_edge.
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* This routine is intended for devices with limited internal buffer
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* It automerges samples of same type, and handles timeouts. Returns non-zero
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* if the event was added, and zero if the event was ignored due to idle
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* processing.
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*/
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int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
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{
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if (!dev->raw)
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return -EINVAL;
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/* Ignore spaces in idle mode */
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if (dev->idle && !ev->pulse)
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return 0;
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else if (dev->idle)
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ir_raw_event_set_idle(dev, false);
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if (!dev->raw->this_ev.duration)
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dev->raw->this_ev = *ev;
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else if (ev->pulse == dev->raw->this_ev.pulse)
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dev->raw->this_ev.duration += ev->duration;
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else {
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ir_raw_event_store(dev, &dev->raw->this_ev);
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dev->raw->this_ev = *ev;
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}
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/* Enter idle mode if nessesary */
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if (!ev->pulse && dev->timeout &&
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dev->raw->this_ev.duration >= dev->timeout)
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ir_raw_event_set_idle(dev, true);
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return 1;
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}
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EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter);
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/**
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* ir_raw_event_set_idle() - provide hint to rc-core when the device is idle or not
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* @dev: the struct rc_dev device descriptor
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* @idle: whether the device is idle or not
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*/
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void ir_raw_event_set_idle(struct rc_dev *dev, bool idle)
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{
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if (!dev->raw)
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return;
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IR_dprintk(2, "%s idle mode\n", idle ? "enter" : "leave");
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if (idle) {
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dev->raw->this_ev.timeout = true;
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ir_raw_event_store(dev, &dev->raw->this_ev);
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init_ir_raw_event(&dev->raw->this_ev);
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}
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if (dev->s_idle)
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dev->s_idle(dev, idle);
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dev->idle = idle;
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}
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EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
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/**
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* ir_raw_event_handle() - schedules the decoding of stored ir data
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* @dev: the struct rc_dev device descriptor
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*
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* This routine will tell rc-core to start decoding stored ir data.
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*/
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void ir_raw_event_handle(struct rc_dev *dev)
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{
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unsigned long flags;
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if (!dev->raw)
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return;
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spin_lock_irqsave(&dev->raw->lock, flags);
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wake_up_process(dev->raw->thread);
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spin_unlock_irqrestore(&dev->raw->lock, flags);
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}
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EXPORT_SYMBOL_GPL(ir_raw_event_handle);
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/* used internally by the sysfs interface */
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u64
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ir_raw_get_allowed_protocols(void)
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{
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u64 protocols;
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mutex_lock(&available_protocols_lock);
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protocols = available_protocols;
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mutex_unlock(&available_protocols_lock);
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return protocols;
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}
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static int change_protocol(struct rc_dev *dev, u64 *rc_type)
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{
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/* the caller will update dev->enabled_protocols */
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return 0;
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}
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static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
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{
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mutex_lock(&dev->lock);
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dev->enabled_protocols &= ~protocols;
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dev->enabled_wakeup_protocols &= ~protocols;
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mutex_unlock(&dev->lock);
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}
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/*
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* Used to (un)register raw event clients
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*/
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int ir_raw_event_register(struct rc_dev *dev)
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{
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int rc;
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struct ir_raw_handler *handler;
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if (!dev)
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return -EINVAL;
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dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
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if (!dev->raw)
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return -ENOMEM;
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dev->raw->dev = dev;
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dev->change_protocol = change_protocol;
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INIT_KFIFO(dev->raw->kfifo);
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spin_lock_init(&dev->raw->lock);
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dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
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"rc%u", dev->minor);
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if (IS_ERR(dev->raw->thread)) {
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rc = PTR_ERR(dev->raw->thread);
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goto out;
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}
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mutex_lock(&ir_raw_handler_lock);
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list_add_tail(&dev->raw->list, &ir_raw_client_list);
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list_for_each_entry(handler, &ir_raw_handler_list, list)
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if (handler->raw_register)
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handler->raw_register(dev);
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mutex_unlock(&ir_raw_handler_lock);
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return 0;
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out:
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kfree(dev->raw);
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dev->raw = NULL;
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return rc;
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}
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void ir_raw_event_unregister(struct rc_dev *dev)
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{
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struct ir_raw_handler *handler;
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if (!dev || !dev->raw)
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return;
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kthread_stop(dev->raw->thread);
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mutex_lock(&ir_raw_handler_lock);
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list_del(&dev->raw->list);
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list_for_each_entry(handler, &ir_raw_handler_list, list)
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if (handler->raw_unregister)
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handler->raw_unregister(dev);
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mutex_unlock(&ir_raw_handler_lock);
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kfree(dev->raw);
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dev->raw = NULL;
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}
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/*
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* Extension interface - used to register the IR decoders
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*/
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int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
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{
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struct ir_raw_event_ctrl *raw;
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mutex_lock(&ir_raw_handler_lock);
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list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
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if (ir_raw_handler->raw_register)
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list_for_each_entry(raw, &ir_raw_client_list, list)
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ir_raw_handler->raw_register(raw->dev);
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mutex_lock(&available_protocols_lock);
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available_protocols |= ir_raw_handler->protocols;
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mutex_unlock(&available_protocols_lock);
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mutex_unlock(&ir_raw_handler_lock);
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return 0;
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}
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EXPORT_SYMBOL(ir_raw_handler_register);
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void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
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{
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struct ir_raw_event_ctrl *raw;
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u64 protocols = ir_raw_handler->protocols;
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mutex_lock(&ir_raw_handler_lock);
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list_del(&ir_raw_handler->list);
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list_for_each_entry(raw, &ir_raw_client_list, list) {
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ir_raw_disable_protocols(raw->dev, protocols);
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if (ir_raw_handler->raw_unregister)
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ir_raw_handler->raw_unregister(raw->dev);
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}
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mutex_lock(&available_protocols_lock);
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available_protocols &= ~protocols;
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mutex_unlock(&available_protocols_lock);
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mutex_unlock(&ir_raw_handler_lock);
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}
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EXPORT_SYMBOL(ir_raw_handler_unregister);
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