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authorAnssi Hannula <anssi.hannula@gmail.com>2006-07-19 01:40:22 -0400
committerDmitry Torokhov <dtor@insightbb.com>2006-07-19 01:40:22 -0400
commit509ca1a9383601fdc5612d3d3ba5b981f6eb6c8b (patch)
tree4d7b63c2b108510c11a89dc0ea45efe788fed779 /drivers/input/ff-core.c
parentInput: move fixp-arith.h to drivers/input (diff)
downloadlinux-dev-509ca1a9383601fdc5612d3d3ba5b981f6eb6c8b.tar.xz
linux-dev-509ca1a9383601fdc5612d3d3ba5b981f6eb6c8b.zip
Input: implement new force feedback interface
Implement a new force feedback interface, in which all non-driver-specific operations are separated to a common module. This includes handling effect type validations, locking, etc. The effects are now file descriptor specific instead of the previous strange half-process half-fd specific behaviour. The effect memory of devices is not emptied if the root user opens and closes the device while another user is using effects. This is a minor change and most likely no force feedback aware programs are affected by this negatively. Otherwise the userspace interface is left unaltered. Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/ff-core.c')
-rw-r--r--drivers/input/ff-core.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c
new file mode 100644
index 000000000000..35656cadc914
--- /dev/null
+++ b/drivers/input/ff-core.c
@@ -0,0 +1,367 @@
+/*
+ * Force feedback support for Linux input subsystem
+ *
+ * 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-core: " format "\n", ## arg)
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+/*
+ * Check that the effect_id is a valid effect and whether the user
+ * is the owner
+ */
+static int check_effect_access(struct ff_device *ff, int effect_id,
+ struct file *file)
+{
+ if (effect_id < 0 || effect_id >= ff->max_effects ||
+ !ff->effect_owners[effect_id])
+ return -EINVAL;
+
+ if (file && ff->effect_owners[effect_id] != file)
+ return -EACCES;
+
+ return 0;
+}
+
+/*
+ * Checks whether 2 effects can be combined together
+ */
+static inline int check_effects_compatible(struct ff_effect *e1,
+ struct ff_effect *e2)
+{
+ return e1->type == e2->type &&
+ (e1->type != FF_PERIODIC ||
+ e1->u.periodic.waveform == e2->u.periodic.waveform);
+}
+
+/*
+ * Convert an effect into compatible one
+ */
+static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
+{
+ int magnitude;
+
+ switch (effect->type) {
+ case FF_RUMBLE:
+ if (!test_bit(FF_PERIODIC, ff->ffbit))
+ return -EINVAL;
+
+ /*
+ * calculate manginude of sine wave as average of rumble's
+ * 2/3 of strong magnitude and 1/3 of weak magnitude
+ */
+ magnitude = effect->u.rumble.strong_magnitude / 3 +
+ effect->u.rumble.weak_magnitude / 6;
+
+ effect->type = FF_PERIODIC;
+ effect->u.periodic.waveform = FF_SINE;
+ effect->u.periodic.period = 50;
+ effect->u.periodic.magnitude = max(magnitude, 0x7fff);
+ effect->u.periodic.offset = 0;
+ effect->u.periodic.phase = 0;
+ effect->u.periodic.envelope.attack_length = 0;
+ effect->u.periodic.envelope.attack_level = 0;
+ effect->u.periodic.envelope.fade_length = 0;
+ effect->u.periodic.envelope.fade_level = 0;
+
+ return 0;
+
+ default:
+ /* Let driver handle conversion */
+ return 0;
+ }
+}
+
+/**
+ * input_ff_upload() - upload effect into force-feedback device
+ * @dev: input device
+ * @effect: effect to be uploaded
+ * @file: owner of the effect
+ */
+int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
+ struct file *file)
+{
+ struct ff_device *ff = dev->ff;
+ struct ff_effect *old;
+ int ret = 0;
+ int id;
+
+ if (!test_bit(EV_FF, dev->evbit))
+ return -ENOSYS;
+
+ if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
+ !test_bit(effect->type, dev->ffbit)) {
+ debug("invalid or not supported effect type in upload");
+ return -EINVAL;
+ }
+
+ if (effect->type == FF_PERIODIC &&
+ (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
+ effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
+ !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
+ debug("invalid or not supported wave form in upload");
+ return -EINVAL;
+ }
+
+ if (!test_bit(effect->type, ff->ffbit)) {
+ ret = compat_effect(ff, effect);
+ if (ret)
+ return ret;
+ }
+
+ mutex_lock(&ff->mutex);
+
+ if (effect->id == -1) {
+ for (id = 0; id < ff->max_effects; id++)
+ if (!ff->effect_owners[id])
+ break;
+
+ if (id >= ff->max_effects) {
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ effect->id = id;
+ old = NULL;
+
+ } else {
+ id = effect->id;
+
+ ret = check_effect_access(ff, id, file);
+ if (ret)
+ goto out;
+
+ old = &ff->effects[id];
+
+ if (!check_effects_compatible(effect, old)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ ret = ff->upload(dev, effect, old);
+ if (ret)
+ goto out;
+
+ ff->effects[id] = *effect;
+ ff->effect_owners[id] = file;
+
+ out:
+ mutex_unlock(&ff->mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(input_ff_upload);
+
+/*
+ * Erases the effect if the requester is also the effect owner. The mutex
+ * should already be locked before calling this function.
+ */
+static int erase_effect(struct input_dev *dev, int effect_id,
+ struct file *file)
+{
+ struct ff_device *ff = dev->ff;
+ int error;
+
+ error = check_effect_access(ff, effect_id, file);
+ if (error)
+ return error;
+
+ ff->playback(dev, effect_id, 0);
+
+ if (ff->erase) {
+ error = ff->erase(dev, effect_id);
+ if (error)
+ return error;
+ }
+
+ ff->effect_owners[effect_id] = NULL;
+
+ return 0;
+}
+
+/**
+ * input_ff_erase - erase an effect from device
+ * @dev: input device to erase effect from
+ * @effect_id: id of the ffect to be erased
+ * @file: purported owner of the request
+ *
+ * This function erases a force-feedback effect from specified device.
+ * The effect will only be erased if it was uploaded through the same
+ * file handle that is requesting erase.
+ */
+int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
+{
+ struct ff_device *ff = dev->ff;
+ int ret;
+
+ if (!test_bit(EV_FF, dev->evbit))
+ return -ENOSYS;
+
+ mutex_lock(&ff->mutex);
+ ret = erase_effect(dev, effect_id, file);
+ mutex_unlock(&ff->mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(input_ff_erase);
+
+/*
+ * flush_effects - erase all effects owned by a file handle
+ */
+static int flush_effects(struct input_dev *dev, struct file *file)
+{
+ struct ff_device *ff = dev->ff;
+ int i;
+
+ debug("flushing now");
+
+ mutex_lock(&ff->mutex);
+
+ for (i = 0; i < ff->max_effects; i++)
+ erase_effect(dev, i, file);
+
+ mutex_unlock(&ff->mutex);
+
+ return 0;
+}
+
+/**
+ * input_ff_event() - generic handler for force-feedback events
+ * @dev: input device to send the effect to
+ * @type: event type (anything but EV_FF is ignored)
+ * @code: event code
+ * @value: event value
+ */
+int input_ff_event(struct input_dev *dev, unsigned int type,
+ unsigned int code, int value)
+{
+ struct ff_device *ff = dev->ff;
+
+ if (type != EV_FF)
+ return 0;
+
+ mutex_lock(&ff->mutex);
+
+ switch (code) {
+ case FF_GAIN:
+ if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff)
+ break;
+
+ ff->set_gain(dev, value);
+ break;
+
+ case FF_AUTOCENTER:
+ if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffff)
+ break;
+
+ ff->set_autocenter(dev, value);
+ break;
+
+ default:
+ ff->playback(dev, code, value);
+ break;
+ }
+
+ mutex_unlock(&ff->mutex);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(input_ff_event);
+
+/**
+ * input_ff_create() - create force-feedback device
+ * @dev: input device supporting force-feedback
+ * @max_effects: maximum number of effects supported by the device
+ *
+ * This function allocates all necessary memory for a force feedback
+ * portion of an input device and installs all default handlers.
+ * @dev->ffbit should be already set up before calling this function.
+ * Once ff device is created you need to setup its upload, erase,
+ * playback and other handlers before registering input device
+ */
+int input_ff_create(struct input_dev *dev, int max_effects)
+{
+ struct ff_device *ff;
+ int i;
+
+ if (!max_effects) {
+ printk(KERN_ERR
+ "ff-core: cannot allocate device without any effects\n");
+ return -EINVAL;
+ }
+
+ ff = kzalloc(sizeof(struct ff_device) +
+ max_effects * sizeof(struct file *), GFP_KERNEL);
+ if (!ff)
+ return -ENOMEM;
+
+ ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
+ GFP_KERNEL);
+ if (!ff->effects) {
+ kfree(ff);
+ return -ENOMEM;
+ }
+
+ ff->max_effects = max_effects;
+ mutex_init(&ff->mutex);
+
+ dev->ff = ff;
+ dev->flush = flush_effects;
+ dev->event = input_ff_event;
+ set_bit(EV_FF, dev->evbit);
+
+ /* Copy "true" bits into ff device bitmap */
+ for (i = 0; i <= FF_MAX; i++)
+ if (test_bit(i, dev->ffbit))
+ set_bit(i, ff->ffbit);
+
+ /* we can emulate RUMBLE with periodic effects */
+ if (test_bit(FF_PERIODIC, ff->ffbit))
+ set_bit(FF_RUMBLE, dev->ffbit);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(input_ff_create);
+
+/**
+ * input_ff_free() - frees force feedback portion of input device
+ * @dev: input device supporintg force feedback
+ *
+ * This function is only needed in error path as input core will
+ * automatically free force feedback structures when device is
+ * destroyed.
+ */
+void input_ff_destroy(struct input_dev *dev)
+{
+ clear_bit(EV_FF, dev->evbit);
+ if (dev->ff) {
+ if (dev->ff->destroy)
+ dev->ff->destroy(dev->ff);
+ kfree(dev->ff->private);
+ kfree(dev->ff);
+ dev->ff = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(input_ff_destroy);