Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

[mirror_ubuntu-bionic-kernel.git] / drivers / media / rc / rc-ir-raw.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
 * @pulse:      true for pulse, false for space
 *
 * 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, bool pulse)
{
        ktime_t                 now;
        DEFINE_IR_RAW_EVENT(ev);
        int                     rc = 0;

        if (!dev->raw)
                return -EINVAL;

        now = ktime_get();
        ev.duration = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
        ev.pulse = !pulse;

        rc = ir_raw_event_store(dev, &ev);

        dev->raw->last_event = now;

        /* timer could be set to timeout (125ms by default) */
        if (!timer_pending(&dev->raw->edge_handle) ||
            time_after(dev->raw->edge_handle.expires,
                       jiffies + msecs_to_jiffies(15))) {
                mod_timer(&dev->raw->edge_handle,
                          jiffies + msecs_to_jiffies(15));
        }

        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
 * @ev:         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 || !dev->raw->thread)
                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_proto)
{
        /* 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;
        mutex_unlock(&dev->lock);
}

/**
 * ir_raw_gen_manchester() - Encode data with Manchester (bi-phase) modulation.
 * @ev:         Pointer to pointer to next free event. *@ev is incremented for
 *              each raw event filled.
 * @max:        Maximum number of raw events to fill.
 * @timings:    Manchester modulation timings.
 * @n:          Number of bits of data.
 * @data:       Data bits to encode.
 *
 * Encodes the @n least significant bits of @data using Manchester (bi-phase)
 * modulation with the timing characteristics described by @timings, writing up
 * to @max raw IR events using the *@ev pointer.
 *
 * Returns:     0 on success.
 *              -ENOBUFS if there isn't enough space in the array to fit the
 *              full encoded data. In this case all @max events will have been
 *              written.
 */
int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
                          const struct ir_raw_timings_manchester *timings,
                          unsigned int n, u64 data)
{
        bool need_pulse;
        u64 i;
        int ret = -ENOBUFS;

        i = BIT_ULL(n - 1);

        if (timings->leader) {
                if (!max--)
                        return ret;
                if (timings->pulse_space_start) {
                        init_ir_raw_event_duration((*ev)++, 1, timings->leader);

                        if (!max--)
                                return ret;
                        init_ir_raw_event_duration((*ev), 0, timings->leader);
                } else {
                        init_ir_raw_event_duration((*ev), 1, timings->leader);
                }
                i >>= 1;
        } else {
                /* continue existing signal */
                --(*ev);
        }
        /* from here on *ev will point to the last event rather than the next */

        while (n && i > 0) {
                need_pulse = !(data & i);
                if (timings->invert)
                        need_pulse = !need_pulse;
                if (need_pulse == !!(*ev)->pulse) {
                        (*ev)->duration += timings->clock;
                } else {
                        if (!max--)
                                goto nobufs;
                        init_ir_raw_event_duration(++(*ev), need_pulse,
                                                   timings->clock);
                }

                if (!max--)
                        goto nobufs;
                init_ir_raw_event_duration(++(*ev), !need_pulse,
                                           timings->clock);
                i >>= 1;
        }

        if (timings->trailer_space) {
                if (!(*ev)->pulse)
                        (*ev)->duration += timings->trailer_space;
                else if (!max--)
                        goto nobufs;
                else
                        init_ir_raw_event_duration(++(*ev), 0,
                                                   timings->trailer_space);
        }

        ret = 0;
nobufs:
        /* point to the next event rather than last event before returning */
        ++(*ev);
        return ret;
}
EXPORT_SYMBOL(ir_raw_gen_manchester);

/**
 * ir_raw_gen_pd() - Encode data to raw events with pulse-distance modulation.
 * @ev:         Pointer to pointer to next free event. *@ev is incremented for
 *              each raw event filled.
 * @max:        Maximum number of raw events to fill.
 * @timings:    Pulse distance modulation timings.
 * @n:          Number of bits of data.
 * @data:       Data bits to encode.
 *
 * Encodes the @n least significant bits of @data using pulse-distance
 * modulation with the timing characteristics described by @timings, writing up
 * to @max raw IR events using the *@ev pointer.
 *
 * Returns:     0 on success.
 *              -ENOBUFS if there isn't enough space in the array to fit the
 *              full encoded data. In this case all @max events will have been
 *              written.
 */
int ir_raw_gen_pd(struct ir_raw_event **ev, unsigned int max,
                  const struct ir_raw_timings_pd *timings,
                  unsigned int n, u64 data)
{
        int i;
        int ret;
        unsigned int space;

        if (timings->header_pulse) {
                ret = ir_raw_gen_pulse_space(ev, &max, timings->header_pulse,
                                             timings->header_space);
                if (ret)
                        return ret;
        }

        if (timings->msb_first) {
                for (i = n - 1; i >= 0; --i) {
                        space = timings->bit_space[(data >> i) & 1];
                        ret = ir_raw_gen_pulse_space(ev, &max,
                                                     timings->bit_pulse,
                                                     space);
                        if (ret)
                                return ret;
                }
        } else {
                for (i = 0; i < n; ++i, data >>= 1) {
                        space = timings->bit_space[data & 1];
                        ret = ir_raw_gen_pulse_space(ev, &max,
                                                     timings->bit_pulse,
                                                     space);
                        if (ret)
                                return ret;
                }
        }

        ret = ir_raw_gen_pulse_space(ev, &max, timings->trailer_pulse,
                                     timings->trailer_space);
        return ret;
}
EXPORT_SYMBOL(ir_raw_gen_pd);

/**
 * ir_raw_gen_pl() - Encode data to raw events with pulse-length modulation.
 * @ev:         Pointer to pointer to next free event. *@ev is incremented for
 *              each raw event filled.
 * @max:        Maximum number of raw events to fill.
 * @timings:    Pulse distance modulation timings.
 * @n:          Number of bits of data.
 * @data:       Data bits to encode.
 *
 * Encodes the @n least significant bits of @data using space-distance
 * modulation with the timing characteristics described by @timings, writing up
 * to @max raw IR events using the *@ev pointer.
 *
 * Returns:     0 on success.
 *              -ENOBUFS if there isn't enough space in the array to fit the
 *              full encoded data. In this case all @max events will have been
 *              written.
 */
int ir_raw_gen_pl(struct ir_raw_event **ev, unsigned int max,
                  const struct ir_raw_timings_pl *timings,
                  unsigned int n, u64 data)
{
        int i;
        int ret = -ENOBUFS;
        unsigned int pulse;

        if (!max--)
                return ret;

        init_ir_raw_event_duration((*ev)++, 1, timings->header_pulse);

        if (timings->msb_first) {
                for (i = n - 1; i >= 0; --i) {
                        if (!max--)
                                return ret;
                        init_ir_raw_event_duration((*ev)++, 0,
                                                   timings->bit_space);
                        if (!max--)
                                return ret;
                        pulse = timings->bit_pulse[(data >> i) & 1];
                        init_ir_raw_event_duration((*ev)++, 1, pulse);
                }
        } else {
                for (i = 0; i < n; ++i, data >>= 1) {
                        if (!max--)
                                return ret;
                        init_ir_raw_event_duration((*ev)++, 0,
                                                   timings->bit_space);
                        if (!max--)
                                return ret;
                        pulse = timings->bit_pulse[data & 1];
                        init_ir_raw_event_duration((*ev)++, 1, pulse);
                }
        }

        if (!max--)
                return ret;

        init_ir_raw_event_duration((*ev)++, 0, timings->trailer_space);

        return 0;
}
EXPORT_SYMBOL(ir_raw_gen_pl);

/**
 * ir_raw_encode_scancode() - Encode a scancode as raw events
 *
 * @protocol:           protocol
 * @scancode:           scancode filter describing a single scancode
 * @events:             array of raw events to write into
 * @max:                max number of raw events
 *
 * Attempts to encode the scancode as raw events.
 *
 * Returns:     The number of events written.
 *              -ENOBUFS if there isn't enough space in the array to fit the
 *              encoding. In this case all @max events will have been written.
 *              -EINVAL if the scancode is ambiguous or invalid, or if no
 *              compatible encoder was found.
 */
int ir_raw_encode_scancode(enum rc_proto protocol, u32 scancode,
                           struct ir_raw_event *events, unsigned int max)
{
        struct ir_raw_handler *handler;
        int ret = -EINVAL;
        u64 mask = 1ULL << protocol;

        mutex_lock(&ir_raw_handler_lock);
        list_for_each_entry(handler, &ir_raw_handler_list, list) {
                if (handler->protocols & mask && handler->encode) {
                        ret = handler->encode(protocol, scancode, events, max);
                        if (ret >= 0 || ret == -ENOBUFS)
                                break;
                }
        }
        mutex_unlock(&ir_raw_handler_lock);

        return ret;
}
EXPORT_SYMBOL(ir_raw_encode_scancode);

static void edge_handle(struct timer_list *t)
{
        struct ir_raw_event_ctrl *raw = from_timer(raw, t, edge_handle);
        struct rc_dev *dev = raw->dev;
        ktime_t interval = ktime_sub(ktime_get(), dev->raw->last_event);

        if (ktime_to_ns(interval) >= dev->timeout) {
                DEFINE_IR_RAW_EVENT(ev);

                ev.timeout = true;
                ev.duration = ktime_to_ns(interval);

                ir_raw_event_store(dev, &ev);
        } else {
                mod_timer(&dev->raw->edge_handle,
                          jiffies + nsecs_to_jiffies(dev->timeout -
                                                     ktime_to_ns(interval)));
        }

        ir_raw_event_handle(dev);
}

/*
 * Used to (un)register raw event clients
 */
int ir_raw_event_prepare(struct rc_dev *dev)
{
        static bool raw_init; /* 'false' default value, raw decoders loaded? */

        if (!dev)
                return -EINVAL;

        if (!raw_init) {
                request_module("ir-lirc-codec");
                raw_init = true;
        }

        dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
        if (!dev->raw)
                return -ENOMEM;

        dev->raw->dev = dev;
        dev->change_protocol = change_protocol;
        timer_setup(&dev->raw->edge_handle, edge_handle, 0);
        INIT_KFIFO(dev->raw->kfifo);

        return 0;
}

int ir_raw_event_register(struct rc_dev *dev)
{
        struct ir_raw_handler *handler;
        struct task_struct *thread;

        /*
         * raw transmitters do not need any event registration
         * because the event is coming from userspace
         */
        if (dev->driver_type != RC_DRIVER_IR_RAW_TX) {
                thread = kthread_run(ir_raw_event_thread, dev->raw, "rc%u",
                                     dev->minor);

                if (IS_ERR(thread))
                        return PTR_ERR(thread);

                dev->raw->thread = thread;
        }

        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;
}

void ir_raw_event_free(struct rc_dev *dev)
{
        if (!dev)
                return;

        kfree(dev->raw);
        dev->raw = NULL;
}

void ir_raw_event_unregister(struct rc_dev *dev)
{
        struct ir_raw_handler *handler;

        if (!dev || !dev->raw)
                return;

        kthread_stop(dev->raw->thread);
        del_timer_sync(&dev->raw->edge_handle);

        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);

        ir_raw_event_free(dev);
}

/*
 * 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);