ski.c

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/*
 * Copyright (c) 2005 Jakub Jermar
 * Copyright (c) 2009 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <unistd.h>
#include <kbd.h>
#include <kbd_port.h>
#include <sys/types.h>
#include <thread.h>
#include <bool.h>

#define SKI_GETCHAR             21

#define POLL_INTERVAL           10000

static void ski_thread_impl(void *arg);
static int32_t ski_getchar(void);

static volatile bool polling_disabled = false;

int kbd_port_init(void)
{
        thread_id_t tid;
        int rc;

        rc = thread_create(ski_thread_impl, NULL, "kbd_poll", &tid);
        if (rc != 0) {
                return rc;
        }

        return 0;
}

void kbd_port_yield(void)
{
        polling_disabled = true;
}

void kbd_port_reclaim(void)
{
        polling_disabled = false;
}

void kbd_port_write(uint8_t data)
{
        (void) data;
}

static void ski_thread_impl(void *arg)
{
        int32_t c;
        (void) arg;

        while (1) {
                while (polling_disabled == false) {
                        c = ski_getchar();
                        if (c == 0)
                                break;
                        kbd_push_scancode(c);
                }

                usleep(POLL_INTERVAL);
        }
}

static int32_t ski_getchar(void)
{
        uint64_t ch;
        
        asm volatile (
                "mov r15 = %1\n"
                "break 0x80000;;\n"     /* modifies r8 */
                "mov %0 = r8;;\n"               

                : "=r" (ch)
                : "i" (SKI_GETCHAR)
                : "r15", "r8"
        );

        return (int32_t) ch;
}

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