--- /dev/null
+/*
+ * Force feedback support for memoryless devices
+ *
+ * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
+ * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
+ */
+
+/*
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* #define DEBUG */
+
+#define debug(format, arg...) pr_debug("ff-memless: " format "\n", ## arg)
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+
+#include "fixp-arith.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
+MODULE_DESCRIPTION("Force feedback support for memoryless devices");
+
+/* Number of effects handled with memoryless devices */
+#define FF_MEMLESS_EFFECTS 16
+
+/* Envelope update interval in ms */
+#define FF_ENVELOPE_INTERVAL 50
+
+#define FF_EFFECT_STARTED 0
+#define FF_EFFECT_PLAYING 1
+#define FF_EFFECT_ABORTING 2
+
+struct ml_effect_state {
+ struct ff_effect *effect;
+ unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
+ int count; /* loop count of the effect */
+ unsigned long play_at; /* start time */
+ unsigned long stop_at; /* stop time */
+ unsigned long adj_at; /* last time the effect was sent */
+};
+
+struct ml_device {
+ void *private;
+ struct ml_effect_state states[FF_MEMLESS_EFFECTS];
+ int gain;
+ struct timer_list timer;
+ spinlock_t timer_lock;
+ struct input_dev *dev;
+
+ int (*play_effect)(struct input_dev *dev, void *data,
+ struct ff_effect *effect);
+};
+
+static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
+{
+ static const struct ff_envelope empty_envelope;
+
+ switch (effect->type) {
+ case FF_PERIODIC:
+ return &effect->u.periodic.envelope;
+ case FF_CONSTANT:
+ return &effect->u.constant.envelope;
+ default:
+ return &empty_envelope;
+ }
+}
+
+/*
+ * Check for the next time envelope requires an update on memoryless devices
+ */
+static unsigned long calculate_next_time(struct ml_effect_state *state)
+{
+ const struct ff_envelope *envelope = get_envelope(state->effect);
+ unsigned long attack_stop, fade_start, next_fade;
+
+ if (envelope->attack_length) {
+ attack_stop = state->play_at +
+ msecs_to_jiffies(envelope->attack_length);
+ if (time_before(state->adj_at, attack_stop))
+ return state->adj_at +
+ msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
+ }
+
+ if (state->effect->replay.length) {
+ if (envelope->fade_length) {
+ /* check when fading should start */
+ fade_start = state->stop_at -
+ msecs_to_jiffies(envelope->fade_length);
+
+ if (time_before(state->adj_at, fade_start))
+ return fade_start;
+
+ /* already fading, advance to next checkpoint */
+ next_fade = state->adj_at +
+ msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
+ if (time_before(next_fade, state->stop_at))
+ return next_fade;
+ }
+
+ return state->stop_at;
+ }
+
+ return state->play_at;
+}
+
+static void ml_schedule_timer(struct ml_device *ml)
+{
+ struct ml_effect_state *state;
+ unsigned long now = jiffies;
+ unsigned long earliest = 0;
+ unsigned long next_at;
+ int events = 0;
+ int i;
+
+ debug("calculating next timer");
+
+ for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
+
+ state = &ml->states[i];
+
+ if (!test_bit(FF_EFFECT_STARTED, &state->flags))
+ continue;
+
+ if (test_bit(FF_EFFECT_PLAYING, &state->flags))
+ next_at = calculate_next_time(state);
+ else
+ next_at = state->play_at;
+
+ if (time_before_eq(now, next_at) &&
+ (++events == 1 || time_before(next_at, earliest)))
+ earliest = next_at;
+ }
+
+ if (!events) {
+ debug("no actions");
+ del_timer(&ml->timer);
+ } else {
+ debug("timer set");
+ mod_timer(&ml->timer, earliest);
+ }
+}
+
+/*
+ * Apply an envelope to a value
+ */
+static int apply_envelope(struct ml_effect_state *state, int value,
+ struct ff_envelope *envelope)
+{
+ struct ff_effect *effect = state->effect;
+ unsigned long now = jiffies;
+ int time_from_level;
+ int time_of_envelope;
+ int envelope_level;
+ int difference;
+
+ if (envelope->attack_length &&
+ time_before(now,
+ state->play_at + msecs_to_jiffies(envelope->attack_length))) {
+ debug("value = 0x%x, attack_level = 0x%x", value,
+ envelope->attack_level);
+ time_from_level = jiffies_to_msecs(now - state->play_at);
+ time_of_envelope = envelope->attack_length;
+ envelope_level = min_t(__s16, envelope->attack_level, 0x7fff);
+
+ } else if (envelope->fade_length && effect->replay.length &&
+ time_after(now,
+ state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
+ time_before(now, state->stop_at)) {
+ time_from_level = jiffies_to_msecs(state->stop_at - now);
+ time_of_envelope = envelope->fade_length;
+ envelope_level = min_t(__s16, envelope->fade_level, 0x7fff);
+ } else
+ return value;
+
+ difference = abs(value) - envelope_level;
+
+ debug("difference = %d", difference);
+ debug("time_from_level = 0x%x", time_from_level);
+ debug("time_of_envelope = 0x%x", time_of_envelope);
+
+ difference = difference * time_from_level / time_of_envelope;
+
+ debug("difference = %d", difference);
+
+ return value < 0 ?
+ -(difference + envelope_level) : (difference + envelope_level);
+}
+
+/*
+ * Return the type the effect has to be converted into (memless devices)
+ */
+static int get_compatible_type(struct ff_device *ff, int effect_type)
+{
+
+ if (test_bit(effect_type, ff->ffbit))
+ return effect_type;
+
+ if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
+ return FF_RUMBLE;
+
+ printk(KERN_ERR
+ "ff-memless: invalid type in get_compatible_type()\n");
+
+ return 0;
+}
+
+/*
+ * Combine two effects and apply gain.
+ */
+static void ml_combine_effects(struct ff_effect *effect,
+ struct ml_effect_state *state,
+ int gain)
+{
+ struct ff_effect *new = state->effect;
+ unsigned int strong, weak, i;
+ int x, y;
+ fixp_t level;
+
+ switch (new->type) {
+ case FF_CONSTANT:
+ i = new->direction * 360 / 0xffff;
+ level = fixp_new16(apply_envelope(state,
+ new->u.constant.level,
+ &new->u.constant.envelope));
+ x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
+ y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
+ /*
+ * here we abuse ff_ramp to hold x and y of constant force
+ * If in future any driver wants something else than x and y
+ * in s8, this should be changed to something more generic
+ */
+ effect->u.ramp.start_level =
+ max(min(effect->u.ramp.start_level + x, 0x7f), -0x80);
+ effect->u.ramp.end_level =
+ max(min(effect->u.ramp.end_level + y, 0x7f), -0x80);
+ break;
+
+ case FF_RUMBLE:
+ strong = new->u.rumble.strong_magnitude * gain / 0xffff;
+ weak = new->u.rumble.weak_magnitude * gain / 0xffff;
+ effect->u.rumble.strong_magnitude =
+ min(strong + effect->u.rumble.strong_magnitude,
+ 0xffffU);
+ effect->u.rumble.weak_magnitude =
+ min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
+ break;
+
+ case FF_PERIODIC:
+ i = apply_envelope(state, abs(new->u.periodic.magnitude),
+ &new->u.periodic.envelope);
+
+ /* here we also scale it 0x7fff => 0xffff */
+ i = i * gain / 0x7fff;
+
+ effect->u.rumble.strong_magnitude =
+ min(i + effect->u.rumble.strong_magnitude, 0xffffU);
+ effect->u.rumble.weak_magnitude =
+ min(i + effect->u.rumble.weak_magnitude, 0xffffU);
+ break;
+
+ default:
+ printk(KERN_ERR "ff-memless: invalid type in ml_combine_effects()\n");
+ break;
+ }
+
+}
+
+
+/*
+ * Because memoryless devices have only one effect per effect type active
+ * at one time we have to combine multiple effects into one
+ */
+static int ml_get_combo_effect(struct ml_device *ml,
+ unsigned long *effect_handled,
+ struct ff_effect *combo_effect)
+{
+ struct ff_effect *effect;
+ struct ml_effect_state *state;
+ int effect_type;
+ int i;
+
+ memset(combo_effect, 0, sizeof(struct ff_effect));
+
+ for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
+ if (__test_and_set_bit(i, effect_handled))
+ continue;
+
+ state = &ml->states[i];
+ effect = state->effect;
+
+ if (!test_bit(FF_EFFECT_STARTED, &state->flags))
+ continue;
+
+ if (time_before(jiffies, state->play_at))
+ continue;
+
+ /*
+ * here we have started effects that are either
+ * currently playing (and may need be aborted)
+ * or need to start playing.
+ */
+ effect_type = get_compatible_type(ml->dev->ff, effect->type);
+ if (combo_effect->type != effect_type) {
+ if (combo_effect->type != 0) {
+ __clear_bit(i, effect_handled);
+ continue;
+ }
+ combo_effect->type = effect_type;
+ }
+
+ if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
+ __clear_bit(FF_EFFECT_PLAYING, &state->flags);
+ __clear_bit(FF_EFFECT_STARTED, &state->flags);
+ } else if (effect->replay.length &&
+ time_after_eq(jiffies, state->stop_at)) {
+
+ __clear_bit(FF_EFFECT_PLAYING, &state->flags);
+
+ if (--state->count <= 0) {
+ __clear_bit(FF_EFFECT_STARTED, &state->flags);
+ } else {
+ state->play_at = jiffies +
+ msecs_to_jiffies(effect->replay.delay);
+ state->stop_at = state->play_at +
+ msecs_to_jiffies(effect->replay.length);
+ }
+ } else {
+ __set_bit(FF_EFFECT_PLAYING, &state->flags);
+ state->adj_at = jiffies;
+ ml_combine_effects(combo_effect, state, ml->gain);
+ }
+ }
+
+ return combo_effect->type != 0;
+}
+
+static void ml_play_effects(struct ml_device *ml)
+{
+ struct ff_effect effect;
+ DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
+
+ memset(handled_bm, 0, sizeof(handled_bm));
+
+ while (ml_get_combo_effect(ml, handled_bm, &effect))
+ ml->play_effect(ml->dev, ml->private, &effect);
+
+ ml_schedule_timer(ml);
+}
+
+static void ml_effect_timer(unsigned long timer_data)
+{
+ struct input_dev *dev = (struct input_dev *)timer_data;
+ struct ml_device *ml = dev->ff->private;
+
+ debug("timer: updating effects");
+
+ spin_lock(&ml->timer_lock);
+ ml_play_effects(ml);
+ spin_unlock(&ml->timer_lock);
+}
+
+static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
+{
+ struct ml_device *ml = dev->ff->private;
+ int i;
+
+ spin_lock_bh(&ml->timer_lock);
+
+ ml->gain = gain;
+
+ for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
+ __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
+
+ ml_play_effects(ml);
+
+ spin_unlock_bh(&ml->timer_lock);
+}
+
+static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
+{
+ struct ml_device *ml = dev->ff->private;
+ struct ml_effect_state *state = &ml->states[effect_id];
+
+ spin_lock_bh(&ml->timer_lock);
+
+ if (value > 0) {
+ debug("initiated play");
+
+ __set_bit(FF_EFFECT_STARTED, &state->flags);
+ state->count = value;
+ state->play_at = jiffies +
+ msecs_to_jiffies(state->effect->replay.delay);
+ state->stop_at = state->play_at +
+ msecs_to_jiffies(state->effect->replay.length);
+ state->adj_at = state->play_at;
+
+ ml_schedule_timer(ml);
+
+ } else {
+ debug("initiated stop");
+
+ if (test_bit(FF_EFFECT_PLAYING, &state->flags))
+ __set_bit(FF_EFFECT_ABORTING, &state->flags);
+ else
+ __clear_bit(FF_EFFECT_STARTED, &state->flags);
+
+ ml_play_effects(ml);
+ }
+
+ spin_unlock_bh(&ml->timer_lock);
+
+ return 0;
+}
+
+static int ml_ff_upload(struct input_dev *dev,
+ struct ff_effect *effect, struct ff_effect *old)
+{
+ struct ml_device *ml = dev->ff->private;
+ struct ml_effect_state *state = &ml->states[effect->id];
+
+ spin_lock_bh(&ml->timer_lock);
+
+ if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
+ __clear_bit(FF_EFFECT_PLAYING, &state->flags);
+ state->play_at = jiffies +
+ msecs_to_jiffies(state->effect->replay.delay);
+ state->stop_at = state->play_at +
+ msecs_to_jiffies(state->effect->replay.length);
+ state->adj_at = state->play_at;
+ ml_schedule_timer(ml);
+ }
+
+ spin_unlock_bh(&ml->timer_lock);
+
+ return 0;
+}
+
+static void ml_ff_destroy(struct ff_device *ff)
+{
+ struct ml_device *ml = ff->private;
+
+ kfree(ml->private);
+}
+
+/**
+ * input_ff_create_memless() - create memoryless FF device
+ * @dev: input device supporting force-feedback
+ * @data: driver-specific data to be passed into @play_effect
+ * @play_effect: driver-specific method for playing FF effect
+ */
+int input_ff_create_memless(struct input_dev *dev, void *data,
+ int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
+{
+ struct ml_device *ml;
+ struct ff_device *ff;
+ int error;
+ int i;
+
+ ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
+ if (!ml)
+ return -ENOMEM;
+
+ ml->dev = dev;
+ ml->private = data;
+ ml->play_effect = play_effect;
+ ml->gain = 0xffff;
+ spin_lock_init(&ml->timer_lock);
+ setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
+
+ set_bit(FF_GAIN, dev->ffbit);
+
+ error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
+ if (error) {
+ kfree(ml);
+ return error;
+ }
+
+ ff = dev->ff;
+ ff->private = ml;
+ ff->upload = ml_ff_upload;
+ ff->playback = ml_ff_playback;
+ ff->set_gain = ml_ff_set_gain;
+ ff->destroy = ml_ff_destroy;
+
+ /* we can emulate periodic effects with RUMBLE */
+ if (test_bit(FF_RUMBLE, ff->ffbit)) {
+ set_bit(FF_PERIODIC, dev->ffbit);
+ set_bit(FF_SINE, dev->ffbit);
+ set_bit(FF_TRIANGLE, dev->ffbit);
+ set_bit(FF_SQUARE, dev->ffbit);
+ }
+
+ for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
+ ml->states[i].effect = &ff->effects[i];
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(input_ff_create_memless);
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