sclp_tty.c

linux-2.6.15.6

/*
 * This routine is called by the kernel to write a single character to the tty
 * device. If the kernel uses this routine, it must call the flush_chars()
 * routine (if defined) when it is done stuffing characters into the driver.
 *
 * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.
 * If the given character is a '\n' the contents of the SCLP write buffer
 * - including previous characters from sclp_tty_put_char() and strings from
 * sclp_write() without final '\n' - will be written.
 */
static void
sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
	sclp_tty_chars[sclp_tty_chars_count++] = ch;
	if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * This routine is called by the kernel after it has written a series of
 * characters to the tty device using put_char().
 */
static void
sclp_tty_flush_chars(struct tty_struct *tty)
{
	if (sclp_tty_chars_count > 0) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * This routine returns the number of characters in the write buffer of the
 * SCLP driver. The provided number includes all characters that are stored
 * in the SCCB (will be written next time the SCLP is not busy) as well as
 * characters in the write buffer (will not be written as long as there is a
 * final line feed missing).
 */
static int
sclp_tty_chars_in_buffer(struct tty_struct *tty)
{
	unsigned long flags;
	struct list_head *l;
	struct sclp_buffer *t;
	int count;

	spin_lock_irqsave(&sclp_tty_lock, flags);
	count = 0;
	if (sclp_ttybuf != NULL)
		count = sclp_chars_in_buffer(sclp_ttybuf);
	list_for_each(l, &sclp_tty_outqueue) {
		t = list_entry(l, struct sclp_buffer, list);
		count += sclp_chars_in_buffer(t);
	}
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
	return count;
}

/*
 * removes all content from buffers of low level driver
 */
static void
sclp_tty_flush_buffer(struct tty_struct *tty)
{
	if (sclp_tty_chars_count > 0) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * push input to tty
 */
static void
sclp_tty_input(unsigned char* buf, unsigned int count)
{
	unsigned int cchar;

	/*
	 * If this tty driver is currently closed
	 * then throw the received input away.
	 */
	if (sclp_tty == NULL)
		return;
	cchar = ctrlchar_handle(buf, count, sclp_tty);
	switch (cchar & CTRLCHAR_MASK) {
	case CTRLCHAR_SYSRQ:
		break;
	case CTRLCHAR_CTRL:
		sclp_tty->flip.count++;
		*sclp_tty->flip.flag_buf_ptr++ = TTY_NORMAL;
		*sclp_tty->flip.char_buf_ptr++ = cchar;
		tty_flip_buffer_push(sclp_tty);
		break;
	case CTRLCHAR_NONE:
		/* send (normal) input to line discipline */
		memcpy(sclp_tty->flip.char_buf_ptr, buf, count);
		if (count < 2 ||
		    (strncmp ((const char *) buf + count - 2, "^n", 2) &&
		     strncmp ((const char *) buf + count - 2, "\0252n", 2))) {
			sclp_tty->flip.char_buf_ptr[count] = '\n';
			count++;
		} else
			count -= 2;
		memset(sclp_tty->flip.flag_buf_ptr, TTY_NORMAL, count);
		sclp_tty->flip.char_buf_ptr += count;
		sclp_tty->flip.flag_buf_ptr += count;
		sclp_tty->flip.count += count;
		tty_flip_buffer_push(sclp_tty);
		break;
	}
}

/*
 * get a EBCDIC string in upper/lower case,
 * find out characters in lower/upper case separated by a special character,
 * modifiy original string,
 * returns length of resulting string
 */
static int
sclp_switch_cases(unsigned char *buf, int count,
		  unsigned char delim, int tolower)
{
	unsigned char *ip, *op;
	int toggle;

	/* initially changing case is off */
	toggle = 0;
	ip = op = buf;
	while (count-- > 0) {
		/* compare with special character */
		if (*ip == delim) {
			/* followed by another special character? */
			if (count && ip[1] == delim) {
				/*
				 * ... then put a single copy of the special
				 * character to the output string
				 */
				*op++ = *ip++;
				count--;
			} else
				/*
				 * ... special character follower by a normal
				 * character toggles the case change behaviour
				 */
				toggle = ~toggle;
			/* skip special character */
			ip++;
		} else
			/* not the special character */
			if (toggle)
				/* but case switching is on */
				if (tolower)
					/* switch to uppercase */
					*op++ = _ebc_toupper[(int) *ip++];
				else
					/* switch to lowercase */
					*op++ = _ebc_tolower[(int) *ip++];
			else
				/* no case switching, copy the character */
				*op++ = *ip++;
	}
	/* return length of reformatted string. */
	return op - buf;
}

static void
sclp_get_input(unsigned char *start, unsigned char *end)
{
	int count;

	count = end - start;
	/*
	 * if set in ioctl convert EBCDIC to lower case
	 * (modify original input in SCCB)
	 */
	if (sclp_ioctls.tolower)
		EBC_TOLOWER(start, count);

	/*
	 * if set in ioctl find out characters in lower or upper case
	 * (depends on current case) separated by a special character,
	 * works on EBCDIC
	 */
	if (sclp_ioctls.delim)
		count = sclp_switch_cases(start, count,
					  sclp_ioctls.delim,
					  sclp_ioctls.tolower);

	/* convert EBCDIC to ASCII (modify original input in SCCB) */
	sclp_ebcasc_str(start, count);

	/* if set in ioctl write operators input to console  */
	if (sclp_ioctls.echo)
		sclp_tty_write(sclp_tty, start, count);

	/* transfer input to high level driver */
	sclp_tty_input(start, count);
}

static inline struct gds_vector *
find_gds_vector(struct gds_vector *start, struct gds_vector *end, u16 id)
{
	struct gds_vector *vec;

	for (vec = start; vec < end; vec = (void *) vec + vec->length)
		if (vec->gds_id == id)
			return vec;
	return NULL;
}

static inline struct gds_subvector *
find_gds_subvector(struct gds_subvector *start,
		   struct gds_subvector *end, u8 key)
{
	struct gds_subvector *subvec;

	for (subvec = start; subvec < end;
	     subvec = (void *) subvec + subvec->length)
		if (subvec->key == key)
			return subvec;
	return NULL;
}

static inline void
sclp_eval_selfdeftextmsg(struct gds_subvector *start,
			 struct gds_subvector *end)
{
	struct gds_subvector *subvec;

	subvec = start;
	while (subvec < end) {
		subvec = find_gds_subvector(subvec, end, 0x30);
		if (!subvec)
			break;
		sclp_get_input((unsigned char *)(subvec + 1),
			       (unsigned char *) subvec + subvec->length);
		subvec = (void *) subvec + subvec->length;
	}
}

static inline void
sclp_eval_textcmd(struct gds_subvector *start,
		  struct gds_subvector *end)
{
	struct gds_subvector *subvec;

	subvec = start;
	while (subvec < end) {
		subvec = find_gds_subvector(subvec, end,
					    GDS_KEY_SelfDefTextMsg);
		if (!subvec)
			break;
		sclp_eval_selfdeftextmsg((struct gds_subvector *)(subvec + 1),
					 (void *)subvec + subvec->length);
		subvec = (void *) subvec + subvec->length;
	}
}

static inline void
sclp_eval_cpmsu(struct gds_vector *start, struct gds_vector *end)
{
	struct gds_vector *vec;

	vec = start;
	while (vec < end) {
		vec = find_gds_vector(vec, end, GDS_ID_TextCmd);
		if (!vec)
			break;
		sclp_eval_textcmd((struct gds_subvector *)(vec + 1),
				  (void *) vec + vec->length);
		vec = (void *) vec + vec->length;
	}
}


static inline void
sclp_eval_mdsmu(struct gds_vector *start, void *end)
{
	struct gds_vector *vec;

	vec = find_gds_vector(start, end, GDS_ID_CPMSU);
	if (vec)
		sclp_eval_cpmsu(vec + 1, (void *) vec + vec->length);
}

static void
sclp_tty_receiver(struct evbuf_header *evbuf)
{
	struct gds_vector *start, *end, *vec;

	start = (struct gds_vector *)(evbuf + 1);
	end = (void *) evbuf + evbuf->length;
	vec = find_gds_vector(start, end, GDS_ID_MDSMU);
	if (vec)
		sclp_eval_mdsmu(vec + 1, (void *) vec + vec->length);
}

static void
sclp_tty_state_change(struct sclp_register *reg)
{
}

static struct sclp_register sclp_input_event =
{
	.receive_mask = EvTyp_OpCmd_Mask | EvTyp_PMsgCmd_Mask,
	.state_change_fn = sclp_tty_state_change,
	.receiver_fn = sclp_tty_receiver
};

static struct tty_operations sclp_ops = {
	.open = sclp_tty_open,
	.close = sclp_tty_close,
	.write = sclp_tty_write,
	.put_char = sclp_tty_put_char,
	.flush_chars = sclp_tty_flush_chars,
	.write_room = sclp_tty_write_room,
	.chars_in_buffer = sclp_tty_chars_in_buffer,
	.flush_buffer = sclp_tty_flush_buffer,
	.ioctl = sclp_tty_ioctl,
};

int __init
sclp_tty_init(void)
{
	struct tty_driver *driver;
	void *page;
	int i;
	int rc;

	if (!CONSOLE_IS_SCLP)
		return 0;
	driver = alloc_tty_driver(1);
	if (!driver)
		return -ENOMEM;

	rc = sclp_rw_init();
	if (rc) {
		printk(KERN_ERR SCLP_TTY_PRINT_HEADER
		       "could not register tty - "
		       "sclp_rw_init returned %d\n", rc);
		put_tty_driver(driver);
		return rc;
	}
	/* Allocate pages for output buffering */
	INIT_LIST_HEAD(&sclp_tty_pages);
	for (i = 0; i < MAX_KMEM_PAGES; i++) {
		page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
		if (page == NULL) {
			put_tty_driver(driver);
			return -ENOMEM;
		}
		list_add_tail((struct list_head *) page, &sclp_tty_pages);
	}
	INIT_LIST_HEAD(&sclp_tty_outqueue);
	spin_lock_init(&sclp_tty_lock);
	init_waitqueue_head(&sclp_tty_waitq);
	init_timer(&sclp_tty_timer);
	sclp_ttybuf = NULL;
	sclp_tty_buffer_count = 0;
	if (MACHINE_IS_VM) {
		/*
		 * save 4 characters for the CPU number
		 * written at start of each line by VM/CP
		 */
		sclp_ioctls_init.columns = 76;
		/* case input lines to lowercase */
		sclp_ioctls_init.tolower = 1;
	}
	sclp_ioctls = sclp_ioctls_init;
	sclp_tty_chars_count = 0;
	sclp_tty = NULL;

	rc = sclp_register(&sclp_input_event);
	if (rc) {
		put_tty_driver(driver);
		return rc;
	}

	driver->owner = THIS_MODULE;
	driver->driver_name = "sclp_line";
	driver->name = "sclp_line";
	driver->major = TTY_MAJOR;
	driver->minor_start = 64;
	driver->type = TTY_DRIVER_TYPE_SYSTEM;
	driver->subtype = SYSTEM_TYPE_TTY;
	driver->init_termios = tty_std_termios;
	driver->init_termios.c_iflag = IGNBRK | IGNPAR;
	driver->init_termios.c_oflag = ONLCR | XTABS;
	driver->init_termios.c_lflag = ISIG | ECHO;
	driver->flags = TTY_DRIVER_REAL_RAW;
	tty_set_operations(driver, &sclp_ops);
	rc = tty_register_driver(driver);
	if (rc) {
		printk(KERN_ERR SCLP_TTY_PRINT_HEADER
		       "could not register tty - "
		       "tty_register_driver returned %d\n", rc);
		put_tty_driver(driver);
		return rc;
	}
	sclp_tty_driver = driver;
	return 0;
}
module_init(sclp_tty_init);