mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-03 17:40:04 +00:00
![Heiner Kallweit](/assets/img/avatar_default.png)
I think we can get rid of the spinlock protecting the kthread from being interrupted by a wakeup in certain parts. Even with the current implementation of the kthread the only lost wakeup scenario could happen if the wakeup occurs between the kfifo_len check and setting the state to TASK_INTERRUPTIBLE. In the changed version we could lose a wakeup if it occurs between processing the fifo content and setting the state to TASK_INTERRUPTIBLE. This scenario is covered by an additional check for available events in the fifo and setting the state to TASK_RUNNING in this case. In addition the changed version flushes the kfifo before ending when the kthread is stopped. With this patch we gain: - Get rid of the spinlock - Simplify code - Don't grep / release the mutex for each individual event but just once for the complete fifo content. This reduces overhead if a driver e.g. triggers processing after writing the content of a hw fifo to the kfifo. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
339 lines
8.9 KiB
C
339 lines
8.9 KiB
C
/* rc-ir-raw.c - handle IR pulse/space events
|
|
*
|
|
* Copyright (C) 2010 by Mauro Carvalho Chehab
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation version 2 of the License.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/kthread.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/sched.h>
|
|
#include "rc-core-priv.h"
|
|
|
|
/* Used to keep track of IR raw clients, protected by ir_raw_handler_lock */
|
|
static LIST_HEAD(ir_raw_client_list);
|
|
|
|
/* Used to handle IR raw handler extensions */
|
|
static DEFINE_MUTEX(ir_raw_handler_lock);
|
|
static LIST_HEAD(ir_raw_handler_list);
|
|
static atomic64_t available_protocols = ATOMIC64_INIT(0);
|
|
|
|
static int ir_raw_event_thread(void *data)
|
|
{
|
|
struct ir_raw_event ev;
|
|
struct ir_raw_handler *handler;
|
|
struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
|
|
|
|
while (1) {
|
|
mutex_lock(&ir_raw_handler_lock);
|
|
while (kfifo_out(&raw->kfifo, &ev, 1)) {
|
|
list_for_each_entry(handler, &ir_raw_handler_list, list)
|
|
if (raw->dev->enabled_protocols &
|
|
handler->protocols || !handler->protocols)
|
|
handler->decode(raw->dev, ev);
|
|
raw->prev_ev = ev;
|
|
}
|
|
mutex_unlock(&ir_raw_handler_lock);
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
if (kthread_should_stop()) {
|
|
__set_current_state(TASK_RUNNING);
|
|
break;
|
|
} else if (!kfifo_is_empty(&raw->kfifo))
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
schedule();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
|
|
* @dev: the struct rc_dev device descriptor
|
|
* @ev: the struct ir_raw_event descriptor of the pulse/space
|
|
*
|
|
* This routine (which may be called from an interrupt context) stores a
|
|
* pulse/space duration for the raw ir decoding state machines. Pulses are
|
|
* signalled as positive values and spaces as negative values. A zero value
|
|
* will reset the decoding state machines.
|
|
*/
|
|
int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev)
|
|
{
|
|
if (!dev->raw)
|
|
return -EINVAL;
|
|
|
|
IR_dprintk(2, "sample: (%05dus %s)\n",
|
|
TO_US(ev->duration), TO_STR(ev->pulse));
|
|
|
|
if (!kfifo_put(&dev->raw->kfifo, *ev)) {
|
|
dev_err(&dev->dev, "IR event FIFO is full!\n");
|
|
return -ENOSPC;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ir_raw_event_store);
|
|
|
|
/**
|
|
* ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
|
|
* @dev: the struct rc_dev device descriptor
|
|
* @type: the type of the event that has occurred
|
|
*
|
|
* This routine (which may be called from an interrupt context) is used to
|
|
* store the beginning of an ir pulse or space (or the start/end of ir
|
|
* reception) for the raw ir decoding state machines. This is used by
|
|
* hardware which does not provide durations directly but only interrupts
|
|
* (or similar events) on state change.
|
|
*/
|
|
int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
|
|
{
|
|
ktime_t now;
|
|
s64 delta; /* ns */
|
|
DEFINE_IR_RAW_EVENT(ev);
|
|
int rc = 0;
|
|
int delay;
|
|
|
|
if (!dev->raw)
|
|
return -EINVAL;
|
|
|
|
now = ktime_get();
|
|
delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
|
|
delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
|
|
|
|
/* Check for a long duration since last event or if we're
|
|
* being called for the first time, note that delta can't
|
|
* possibly be negative.
|
|
*/
|
|
if (delta > delay || !dev->raw->last_type)
|
|
type |= IR_START_EVENT;
|
|
else
|
|
ev.duration = delta;
|
|
|
|
if (type & IR_START_EVENT)
|
|
ir_raw_event_reset(dev);
|
|
else if (dev->raw->last_type & IR_SPACE) {
|
|
ev.pulse = false;
|
|
rc = ir_raw_event_store(dev, &ev);
|
|
} else if (dev->raw->last_type & IR_PULSE) {
|
|
ev.pulse = true;
|
|
rc = ir_raw_event_store(dev, &ev);
|
|
} else
|
|
return 0;
|
|
|
|
dev->raw->last_event = now;
|
|
dev->raw->last_type = type;
|
|
return rc;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
|
|
|
|
/**
|
|
* ir_raw_event_store_with_filter() - pass next pulse/space to decoders with some processing
|
|
* @dev: the struct rc_dev device descriptor
|
|
* @type: the type of the event that has occurred
|
|
*
|
|
* This routine (which may be called from an interrupt context) works
|
|
* in similar manner to ir_raw_event_store_edge.
|
|
* This routine is intended for devices with limited internal buffer
|
|
* It automerges samples of same type, and handles timeouts. Returns non-zero
|
|
* if the event was added, and zero if the event was ignored due to idle
|
|
* processing.
|
|
*/
|
|
int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
|
|
{
|
|
if (!dev->raw)
|
|
return -EINVAL;
|
|
|
|
/* Ignore spaces in idle mode */
|
|
if (dev->idle && !ev->pulse)
|
|
return 0;
|
|
else if (dev->idle)
|
|
ir_raw_event_set_idle(dev, false);
|
|
|
|
if (!dev->raw->this_ev.duration)
|
|
dev->raw->this_ev = *ev;
|
|
else if (ev->pulse == dev->raw->this_ev.pulse)
|
|
dev->raw->this_ev.duration += ev->duration;
|
|
else {
|
|
ir_raw_event_store(dev, &dev->raw->this_ev);
|
|
dev->raw->this_ev = *ev;
|
|
}
|
|
|
|
/* Enter idle mode if nessesary */
|
|
if (!ev->pulse && dev->timeout &&
|
|
dev->raw->this_ev.duration >= dev->timeout)
|
|
ir_raw_event_set_idle(dev, true);
|
|
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter);
|
|
|
|
/**
|
|
* ir_raw_event_set_idle() - provide hint to rc-core when the device is idle or not
|
|
* @dev: the struct rc_dev device descriptor
|
|
* @idle: whether the device is idle or not
|
|
*/
|
|
void ir_raw_event_set_idle(struct rc_dev *dev, bool idle)
|
|
{
|
|
if (!dev->raw)
|
|
return;
|
|
|
|
IR_dprintk(2, "%s idle mode\n", idle ? "enter" : "leave");
|
|
|
|
if (idle) {
|
|
dev->raw->this_ev.timeout = true;
|
|
ir_raw_event_store(dev, &dev->raw->this_ev);
|
|
init_ir_raw_event(&dev->raw->this_ev);
|
|
}
|
|
|
|
if (dev->s_idle)
|
|
dev->s_idle(dev, idle);
|
|
|
|
dev->idle = idle;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
|
|
|
|
/**
|
|
* ir_raw_event_handle() - schedules the decoding of stored ir data
|
|
* @dev: the struct rc_dev device descriptor
|
|
*
|
|
* This routine will tell rc-core to start decoding stored ir data.
|
|
*/
|
|
void ir_raw_event_handle(struct rc_dev *dev)
|
|
{
|
|
if (!dev->raw)
|
|
return;
|
|
|
|
wake_up_process(dev->raw->thread);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ir_raw_event_handle);
|
|
|
|
/* used internally by the sysfs interface */
|
|
u64
|
|
ir_raw_get_allowed_protocols(void)
|
|
{
|
|
return atomic64_read(&available_protocols);
|
|
}
|
|
|
|
static int change_protocol(struct rc_dev *dev, u64 *rc_type)
|
|
{
|
|
/* the caller will update dev->enabled_protocols */
|
|
return 0;
|
|
}
|
|
|
|
static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
|
|
{
|
|
mutex_lock(&dev->lock);
|
|
dev->enabled_protocols &= ~protocols;
|
|
dev->enabled_wakeup_protocols &= ~protocols;
|
|
mutex_unlock(&dev->lock);
|
|
}
|
|
|
|
/*
|
|
* Used to (un)register raw event clients
|
|
*/
|
|
int ir_raw_event_register(struct rc_dev *dev)
|
|
{
|
|
int rc;
|
|
struct ir_raw_handler *handler;
|
|
|
|
if (!dev)
|
|
return -EINVAL;
|
|
|
|
dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
|
|
if (!dev->raw)
|
|
return -ENOMEM;
|
|
|
|
dev->raw->dev = dev;
|
|
dev->change_protocol = change_protocol;
|
|
INIT_KFIFO(dev->raw->kfifo);
|
|
|
|
dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
|
|
"rc%u", dev->minor);
|
|
|
|
if (IS_ERR(dev->raw->thread)) {
|
|
rc = PTR_ERR(dev->raw->thread);
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&ir_raw_handler_lock);
|
|
list_add_tail(&dev->raw->list, &ir_raw_client_list);
|
|
list_for_each_entry(handler, &ir_raw_handler_list, list)
|
|
if (handler->raw_register)
|
|
handler->raw_register(dev);
|
|
mutex_unlock(&ir_raw_handler_lock);
|
|
|
|
return 0;
|
|
|
|
out:
|
|
kfree(dev->raw);
|
|
dev->raw = NULL;
|
|
return rc;
|
|
}
|
|
|
|
void ir_raw_event_unregister(struct rc_dev *dev)
|
|
{
|
|
struct ir_raw_handler *handler;
|
|
|
|
if (!dev || !dev->raw)
|
|
return;
|
|
|
|
kthread_stop(dev->raw->thread);
|
|
|
|
mutex_lock(&ir_raw_handler_lock);
|
|
list_del(&dev->raw->list);
|
|
list_for_each_entry(handler, &ir_raw_handler_list, list)
|
|
if (handler->raw_unregister)
|
|
handler->raw_unregister(dev);
|
|
mutex_unlock(&ir_raw_handler_lock);
|
|
|
|
kfree(dev->raw);
|
|
dev->raw = NULL;
|
|
}
|
|
|
|
/*
|
|
* Extension interface - used to register the IR decoders
|
|
*/
|
|
|
|
int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
|
|
{
|
|
struct ir_raw_event_ctrl *raw;
|
|
|
|
mutex_lock(&ir_raw_handler_lock);
|
|
list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
|
|
if (ir_raw_handler->raw_register)
|
|
list_for_each_entry(raw, &ir_raw_client_list, list)
|
|
ir_raw_handler->raw_register(raw->dev);
|
|
atomic64_or(ir_raw_handler->protocols, &available_protocols);
|
|
mutex_unlock(&ir_raw_handler_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(ir_raw_handler_register);
|
|
|
|
void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
|
|
{
|
|
struct ir_raw_event_ctrl *raw;
|
|
u64 protocols = ir_raw_handler->protocols;
|
|
|
|
mutex_lock(&ir_raw_handler_lock);
|
|
list_del(&ir_raw_handler->list);
|
|
list_for_each_entry(raw, &ir_raw_client_list, list) {
|
|
ir_raw_disable_protocols(raw->dev, protocols);
|
|
if (ir_raw_handler->raw_unregister)
|
|
ir_raw_handler->raw_unregister(raw->dev);
|
|
}
|
|
atomic64_andnot(protocols, &available_protocols);
|
|
mutex_unlock(&ir_raw_handler_lock);
|
|
}
|
|
EXPORT_SYMBOL(ir_raw_handler_unregister);
|