// SPDX-License-Identifier: GPL-2.0+
/* fakekey.c
 * Functions for simulating key presses.
 *
 * Copyright (C) 2010 the Speakup Team
 */
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/percpu.h>
#include <linux/input.h>

#include "speakup.h"

#define PRESSED 1
#define RELEASED 0

static DEFINE_PER_CPU(int, reporting_keystroke);

static struct input_dev *virt_keyboard;

int speakup_add_virtual_keyboard(void)
{
        int err;

        virt_keyboard = input_allocate_device();

        if (!virt_keyboard)
                return -ENOMEM;

        virt_keyboard->name = "Speakup";
        virt_keyboard->id.bustype = BUS_VIRTUAL;
        virt_keyboard->phys = "speakup/input0";
        virt_keyboard->dev.parent = NULL;

        __set_bit(EV_KEY, virt_keyboard->evbit);
        __set_bit(KEY_DOWN, virt_keyboard->keybit);

        err = input_register_device(virt_keyboard);
        if (err) {
                input_free_device(virt_keyboard);
                virt_keyboard = NULL;
        }

        return err;
}

void speakup_remove_virtual_keyboard(void)
{
        if (virt_keyboard) {
                input_unregister_device(virt_keyboard);
                virt_keyboard = NULL;
        }
}

/*
 * Send a simulated down-arrow to the application.
 */
void speakup_fake_down_arrow(void)
{
        unsigned long flags;

        /* disable keyboard interrupts */
        local_irq_save(flags);
        /* don't change CPU */
        preempt_disable();

        __this_cpu_write(reporting_keystroke, true);
        input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
        input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
        input_sync(virt_keyboard);
        __this_cpu_write(reporting_keystroke, false);

        /* reenable preemption */
        preempt_enable();
        /* reenable keyboard interrupts */
        local_irq_restore(flags);
}

/*
 * Are we handling a simulated key press on the current CPU?
 * Returns a boolean.
 */
bool speakup_fake_key_pressed(void)
{
        return this_cpu_read(reporting_keystroke);
}