Input: unified force feedback support for memoryless devices

Consolidate core implementing memoryless devices in one module; added
support for gain and envelopes and periodic => rumble conversion.

Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

4 files changed, 534 insertions, 0 deletions

diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index 58223b5d842a..96232313b1b9 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -24,6 +24,20 @@ config INPUT
 
 if INPUT
 
+config INPUT_FF_MEMLESS
+        tristate "Support for memoryless force-feedback devices"
+        default n
+        ---help---
+          Say Y here if you have memoryless force-feedback input device
+          such as Logitech WingMan Force 3D, ThrustMaster FireStorm Dual
+          Power 2, or similar. You will also need to enable hardware-specific
+          driver.
+
+          If unsure, say N.
+
+          To compile this driver as a module, choose M here: the
+          module will be called ff-memless.
+
 comment "Userland interfaces"
 
 config INPUT_MOUSEDEV
diff --git a/drivers/input/Makefile b/drivers/input/Makefile
index abdc9d435705..a005b1df5f1a 100644
--- a/drivers/input/Makefile
+++ b/drivers/input/Makefile
@@ -7,6 +7,8 @@
 obj-$(CONFIG_INPUT)             += input-core.o
 input-core-objs := input.o ff-core.o
 
+obj-$(CONFIG_INPUT_FF_MEMLESS)  += ff-memless.o
+
 obj-$(CONFIG_INPUT_MOUSEDEV)    += mousedev.o
 obj-$(CONFIG_INPUT_JOYDEV)      += joydev.o
 obj-$(CONFIG_INPUT_EVDEV)       += evdev.o
diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c
new file mode 100644
index 000000000000..cd8b7297e6df
--- /dev/null
+++ b/drivers/input/ff-memless.c
@@ -0,0 +1,515 @@
+/*
+ *  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);
diff --git a/include/linux/input.h b/include/linux/input.h
index 81c6ea5afedb..d8b0c5610c04 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -1169,5 +1169,8 @@ int input_ff_event(struct input_dev *dev, unsigned int type, unsigned int code,
 int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, struct file *file);
 int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);
 
+int input_ff_create_memless(struct input_dev *dev, void *data,
+                int (*play_effect)(struct input_dev *, void *, struct ff_effect *));
+
 #endif
 #endif