// SPDX-License-Identifier: GPL-2.0-only/* * Input Multitouch Library * * Copyright (c) 2008-2010 Henrik Rydberg */ #include <linux/input/mt.h>#include <linux/export.h>#include <linux/slab.h>#include "input-core-private.h" #define TRKID_SGN	((TRKID_MAX + 1) >> 1) static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src){	if (dev->absinfo && test_bit(src, dev->absbit)) {		dev->absinfo[dst] = dev->absinfo[src];		dev->absinfo[dst].fuzz = 0;		__set_bit(dst, dev->absbit);	}} /** * input_mt_init_slots() - initialize MT input slots * @dev: input device supporting MT events and finger tracking * @num_slots: number of slots used by the device * @flags: mt tasks to handle in core * * This function allocates all necessary memory for MT slot handling * in the input device, prepares the ABS_MT_SLOT and * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers. * Depending on the flags set, it also performs pointer emulation and * frame synchronization. * * May be called repeatedly. Returns -EINVAL if attempting to * reinitialize with a different number of slots. */int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,			unsigned int flags){	if (!num_slots)		return 0; 	if (dev->mt)		return dev->mt->num_slots != num_slots ? -EINVAL : 0; 	/* Arbitrary limit for avoiding too large memory allocation. */	if (num_slots > 1024)		return -EINVAL; 	struct input_mt *mt __free(kfree) =			kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);	if (!mt)		return -ENOMEM; 	mt->num_slots = num_slots;	mt->flags = flags;	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0); 	if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {		__set_bit(EV_KEY, dev->evbit);		__set_bit(BTN_TOUCH, dev->keybit); 		copy_abs(dev, ABS_X, ABS_MT_POSITION_X);		copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);		copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);	}	if (flags & INPUT_MT_POINTER) {		__set_bit(BTN_TOOL_FINGER, dev->keybit);		__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);		if (num_slots >= 3)			__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);		if (num_slots >= 4)			__set_bit(BTN_TOOL_QUADTAP, dev->keybit);		if (num_slots >= 5)			__set_bit(BTN_TOOL_QUINTTAP, dev->keybit);		__set_bit(INPUT_PROP_POINTER, dev->propbit);	}	if (flags & INPUT_MT_DIRECT)		__set_bit(INPUT_PROP_DIRECT, dev->propbit);	if (flags & INPUT_MT_SEMI_MT)		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);	if (flags & INPUT_MT_TRACK) {		unsigned int n2 = num_slots * num_slots;		mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);		if (!mt->red)			return -ENOMEM;	} 	/* Mark slots as 'inactive' */	for (unsigned int i = 0; i < num_slots; i++)		input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1); 	/* Mark slots as 'unused' */	mt->frame = 1; 	dev->mt = no_free_ptr(mt);	return 0;}EXPORT_SYMBOL(input_mt_init_slots); /** * input_mt_destroy_slots() - frees the MT slots of the input device * @dev: input device with allocated MT slots * * This function is only needed in error path as the input core will * automatically free the MT slots when the device is destroyed. */void input_mt_destroy_slots(struct input_dev *dev){	if (dev->mt) {		kfree(dev->mt->red);		kfree(dev->mt);	}	dev->mt = NULL;}EXPORT_SYMBOL(input_mt_destroy_slots); /** * input_mt_report_slot_state() - report contact state * @dev: input device with allocated MT slots * @tool_type: the tool type to use in this slot * @active: true if contact is active, false otherwise * * Reports a contact via ABS_MT_TRACKING_ID, and optionally * ABS_MT_TOOL_TYPE. If active is true and the slot is currently * inactive, or if the tool type is changed, a new tracking id is * assigned to the slot. The tool type is only reported if the * corresponding absbit field is set. * * Returns true if contact is active. */bool input_mt_report_slot_state(struct input_dev *dev,				unsigned int tool_type, bool active){	struct input_mt *mt = dev->mt;	struct input_mt_slot *slot;	int id; 	if (!mt)		return false; 	slot = &mt->slots[mt->slot];	slot->frame = mt->frame; 	if (!active) {		input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);		return false;	} 	id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);	if (id < 0)		id = input_mt_new_trkid(mt); 	input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);	input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type); 	return true;}EXPORT_SYMBOL(input_mt_report_slot_state); /** * input_mt_report_finger_count() - report contact count * @dev: input device with allocated MT slots * @count: the number of contacts * * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP, * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP. * * The input core ensures only the KEY events already setup for * this device will produce output. */void input_mt_report_finger_count(struct input_dev *dev, int count){	input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);	input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);	input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);	input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);	input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);}EXPORT_SYMBOL(input_mt_report_finger_count); /** * input_mt_report_pointer_emulation() - common pointer emulation * @dev: input device with allocated MT slots * @use_count: report number of active contacts as finger count * * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true. * * The input core ensures only the KEY and ABS axes already setup for * this device will produce output. */void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count){	struct input_mt *mt = dev->mt;	struct input_mt_slot *oldest;	int oldid, count, i; 	if (!mt)		return; 	oldest = NULL;	oldid = mt->trkid;	count = 0; 	for (i = 0; i < mt->num_slots; ++i) {		struct input_mt_slot *ps = &mt->slots[i];		int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID); 		if (id < 0)			continue;		if ((id - oldid) & TRKID_SGN) {			oldest = ps;			oldid = id;		}		count++;	} 	input_event(dev, EV_KEY, BTN_TOUCH, count > 0); 	if (use_count) {		if (count == 0 &&		    !test_bit(ABS_MT_DISTANCE, dev->absbit) &&		    test_bit(ABS_DISTANCE, dev->absbit) &&		    input_abs_get_val(dev, ABS_DISTANCE) != 0) {			/*			 * Force reporting BTN_TOOL_FINGER for devices that			 * only report general hover (and not per-contact			 * distance) when contact is in proximity but not			 * on the surface.			 */			count = 1;		} 		input_mt_report_finger_count(dev, count);	} 	if (oldest) {		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);		int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y); 		input_event(dev, EV_ABS, ABS_X, x);		input_event(dev, EV_ABS, ABS_Y, y); 		if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {			int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);			input_event(dev, EV_ABS, ABS_PRESSURE, p);		}	} else {		if (test_bit(ABS_MT_PRESSURE, dev->absbit))			input_event(dev, EV_ABS, ABS_PRESSURE, 0);	}}EXPORT_SYMBOL(input_mt_report_pointer_emulation); static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt){	int i; 	lockdep_assert_held(&dev->event_lock); 	for (i = 0; i < mt->num_slots; i++) {		if (input_mt_is_active(&mt->slots[i]) &&		    !input_mt_is_used(mt, &mt->slots[i])) {			input_handle_event(dev, EV_ABS, ABS_MT_SLOT, i);			input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);		}	}} /** * input_mt_drop_unused() - Inactivate slots not seen in this frame * @dev: input device with allocated MT slots * * Lift all slots not seen since the last call to this function. */void input_mt_drop_unused(struct input_dev *dev){	struct input_mt *mt = dev->mt; 	if (mt) {		guard(spinlock_irqsave)(&dev->event_lock); 		__input_mt_drop_unused(dev, mt);		mt->frame++;	}}EXPORT_SYMBOL(input_mt_drop_unused); /** * input_mt_release_slots() - Deactivate all slots * @dev: input device with allocated MT slots * * Lift all active slots. */void input_mt_release_slots(struct input_dev *dev){	struct input_mt *mt = dev->mt; 	lockdep_assert_held(&dev->event_lock); 	if (mt) {		/* This will effectively mark all slots unused. */		mt->frame++; 		__input_mt_drop_unused(dev, mt); 		if (test_bit(ABS_PRESSURE, dev->absbit))			input_handle_event(dev, EV_ABS, ABS_PRESSURE, 0); 		mt->frame++;	}} /** * input_mt_sync_frame() - synchronize mt frame * @dev: input device with allocated MT slots * * Close the frame and prepare the internal state for a new one. * Depending on the flags, marks unused slots as inactive and performs * pointer emulation. */void input_mt_sync_frame(struct input_dev *dev){	struct input_mt *mt = dev->mt;	bool use_count = false; 	if (!mt)		return; 	if (mt->flags & INPUT_MT_DROP_UNUSED) {		guard(spinlock_irqsave)(&dev->event_lock);		__input_mt_drop_unused(dev, mt);	} 	if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))		use_count = true; 	input_mt_report_pointer_emulation(dev, use_count); 	mt->frame++;}EXPORT_SYMBOL(input_mt_sync_frame); static int adjust_dual(int *begin, int step, int *end, int eq, int mu){	int f, *p, s, c; 	if (begin == end)		return 0; 	f = *begin;	p = begin + step;	s = p == end ? f + 1 : *p; 	for (; p != end; p += step) {		if (*p < f) {			s = f;			f = *p;		} else if (*p < s) {			s = *p;		}	} 	c = (f + s + 1) / 2;	if (c == 0 || (c > mu && (!eq || mu > 0)))		return 0;	/* Improve convergence for positive matrices by penalizing overcovers */	if (s < 0 && mu <= 0)		c *= 2; 	for (p = begin; p != end; p += step)		*p -= c; 	return (c < s && s <= 0) || (f >= 0 && f < c);} static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu){	int i, k, sum; 	for (k = 0; k < nrc; k++) {		for (i = 0; i < nr; i++)			adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);		sum = 0;		for (i = 0; i < nrc; i += nr)			sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);		if (!sum)			break;	}} static int input_mt_set_matrix(struct input_mt *mt,			       const struct input_mt_pos *pos, int num_pos,			       int mu){	const struct input_mt_pos *p;	struct input_mt_slot *s;	int *w = mt->red;	int x, y; 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {		if (!input_mt_is_active(s))			continue;		x = input_mt_get_value(s, ABS_MT_POSITION_X);		y = input_mt_get_value(s, ABS_MT_POSITION_Y);		for (p = pos; p != pos + num_pos; p++) {			int dx = x - p->x, dy = y - p->y;			*w++ = dx * dx + dy * dy - mu;		}	} 	return w - mt->red;} static void input_mt_set_slots(struct input_mt *mt,			       int *slots, int num_pos){	struct input_mt_slot *s;	int *w = mt->red, j; 	for (j = 0; j != num_pos; j++)		slots[j] = -1; 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {		if (!input_mt_is_active(s))			continue; 		for (j = 0; j != num_pos; j++) {			if (w[j] < 0) {				slots[j] = s - mt->slots;				break;			}		} 		w += num_pos;	} 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {		if (input_mt_is_active(s))			continue; 		for (j = 0; j != num_pos; j++) {			if (slots[j] < 0) {				slots[j] = s - mt->slots;				break;			}		}	}} /** * input_mt_assign_slots() - perform a best-match assignment * @dev: input device with allocated MT slots * @slots: the slot assignment to be filled * @pos: the position array to match * @num_pos: number of positions * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite) * * Performs a best match against the current contacts and returns * the slot assignment list. New contacts are assigned to unused * slots. * * The assignments are balanced so that all coordinate displacements are * below the euclidian distance dmax. If no such assignment can be found, * some contacts are assigned to unused slots. * * Returns zero on success, or negative error in case of failure. */int input_mt_assign_slots(struct input_dev *dev, int *slots,			  const struct input_mt_pos *pos, int num_pos,			  int dmax){	struct input_mt *mt = dev->mt;	int mu = 2 * dmax * dmax;	int nrc; 	if (!mt || !mt->red)		return -ENXIO;	if (num_pos > mt->num_slots)		return -EINVAL;	if (num_pos < 1)		return 0; 	nrc = input_mt_set_matrix(mt, pos, num_pos, mu);	find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);	input_mt_set_slots(mt, slots, num_pos); 	return 0;}EXPORT_SYMBOL(input_mt_assign_slots); /** * input_mt_get_slot_by_key() - return slot matching key * @dev: input device with allocated MT slots * @key: the key of the sought slot *

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