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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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 <sys/tty.h>
#include <sys/cdefs.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <fs/devfs.h>
#include <string.h>
static dev_t tty_major = 0;
struct tty g_root_tty = {
.scr = &g_syslog_screen,
.ring = {
.enq_index = 0,
.deq_index = 0,
}
};
static inline dev_t
tty_alloc_id(void)
{
static dev_t id = 1;
return id++;
}
/*
* Flushes the TTY ring buffer.
*
* @tty: TTY to flush.
*
* Returns number of bytes flushed.
*/
static ssize_t
__tty_flush(struct tty *tty)
{
struct tty_ring *ring = &tty->ring;
size_t count = 0;
char tmp;
/* Do we have any data left? */
if (ring->deq_index >= ring->enq_index)
return -EAGAIN;
/* Flush the ring */
while (ring->deq_index < ring->enq_index) {
tmp = ring->data[ring->deq_index++];
vcons_putch(tty->scr, tmp);
++count;
}
ring->enq_index = 0;
ring->deq_index = 0;
return count;
}
/*
* Device structure routine for reading a
* TTY device file.
*/
static int
tty_dev_read(struct device *dev, struct sio_txn *sio)
{
struct tty_ring *ring = &g_root_tty.ring;
size_t len;
spinlock_acquire(&g_root_tty.rlock);
len = (ring->enq_index - ring->deq_index);
/*
* Transfer data from the TTY ring with SIO and
* flush it.
*
* TODO: As of now we are just reading the root
* TTY, add support for multiple TTYs.
*/
memcpy(sio->buf, ring->data, len);
__tty_flush(&g_root_tty);
spinlock_release(&g_root_tty.rlock);
return len;
}
/*
* Serialized wrapper over __tty_flush()
*/
ssize_t
tty_flush(struct tty *tty)
{
ssize_t ret;
spinlock_acquire(&tty->rlock);
ret = __tty_flush(tty);
spinlock_release(&tty->rlock);
return ret;
}
/*
* Write a character to a TTY
*
* @tty: TTY to write to.
* @c: Character to write.
*/
int
tty_putc(struct tty *tty, int c)
{
struct tty_ring *ring;
ring = &tty->ring;
spinlock_acquire(&tty->rlock);
if (ring->enq_index >= TTY_RING_SIZE) {
__tty_flush(tty);
}
ring->data[ring->enq_index++] = c;
spinlock_release(&tty->rlock);
return 0;
}
dev_t
tty_attach(struct tty *tty)
{
int tmp;
char devname[128];
struct device *dev = device_alloc();
if (dev == NULL)
return -ENOMEM;
/*
* Allocate a major for the driver if we don't
* have one yet.
*/
if (tty_major == 0)
tty_major = device_alloc_major();
/* Now try to create the device */
tty->id = tty_alloc_id();
if ((tmp = device_create(dev, tty_major, tty->id)) < 0)
return tmp;
dev->read = tty_dev_read;
dev->blocksize = 1;
snprintf(devname, sizeof(devname), "tty%d", tty->id);
return devfs_add_dev(devname, dev);
}
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