hvsi.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,320 行 · 第 1/3 页

		return NULL;

	if (overflow > 0) {
		pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
		datalen = TTY_THRESHOLD_THROTTLE;
	}

	hvsi_insert_chars(hp, data, datalen);

	if (overflow > 0) {
		/*
		 * we still have more data to deliver, so we need to save off the
		 * overflow and send it later
		 */
		pr_debug("%s: deferring overflow\n", __FUNCTION__);
		memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
		hp->n_throttle = overflow;
	}

	return hp->tty;
}

/*
 * Returns true/false indicating data successfully read from hypervisor.
 * Used both to get packets for tty connections and to advance the state
 * machine during console handshaking (in which case tty = NULL and we ignore
 * incoming data).
 */
static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
		struct tty_struct **hangup)
{
	uint8_t *packet = hp->inbuf;
	int chunklen;

	*flip = NULL;
	*hangup = NULL;

	chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
	if (chunklen == 0)
		return 0;

	pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
	dbg_dump_hex(hp->inbuf_end, chunklen);

	hp->inbuf_end += chunklen;

	/* handle all completed packets */
	while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
		struct hvsi_header *header = (struct hvsi_header *)packet;

		if (!is_header(packet)) {
			printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
			/* skip bytes until we find a header or run out of data */
			while ((packet < hp->inbuf_end) && (!is_header(packet)))
				packet++;
			continue;
		}

		pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
				len_packet(packet));
		dbg_dump_packet(packet);

		switch (header->type) {
			case VS_DATA_PACKET_HEADER:
				if (!is_open(hp))
					break;
				if (hp->tty == NULL)
					break; /* no tty buffer to put data in */
				*flip = hvsi_recv_data(hp, packet);
				break;
			case VS_CONTROL_PACKET_HEADER:
				*hangup = hvsi_recv_control(hp, packet);
				break;
			case VS_QUERY_RESPONSE_PACKET_HEADER:
				hvsi_recv_response(hp, packet);
				break;
			case VS_QUERY_PACKET_HEADER:
				hvsi_recv_query(hp, packet);
				break;
			default:
				printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
						hp->index, header->type);
				dump_packet(packet);
				break;
		}

		packet += len_packet(packet);

		if (*hangup) {
			pr_debug("%s: hangup\n", __FUNCTION__);
			/*
			 * we need to send the hangup now before receiving any more data.
			 * If we get "data, hangup, data", we can't deliver the second
			 * data before the hangup.
			 */
			break;
		}
	}

	compact_inbuf(hp, packet);

	return 1;
}

static void hvsi_send_overflow(struct hvsi_struct *hp)
{
	pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
			hp->n_throttle);

	hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
	hp->n_throttle = 0;
}

/*
 * must get all pending data because we only get an irq on empty->non-empty
 * transition
 */
static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
{
	struct hvsi_struct *hp = (struct hvsi_struct *)arg;
	struct tty_struct *flip;
	struct tty_struct *hangup;
	unsigned long flags;
	irqreturn_t handled = IRQ_NONE;
	int again = 1;

	pr_debug("%s\n", __FUNCTION__);

	while (again) {
		spin_lock_irqsave(&hp->lock, flags);
		again = hvsi_load_chunk(hp, &flip, &hangup);
		handled = IRQ_HANDLED;
		spin_unlock_irqrestore(&hp->lock, flags);

		/*
		 * we have to call tty_flip_buffer_push() and tty_hangup() outside our
		 * spinlock. But we also have to keep going until we've read all the
		 * available data.
		 */

		if (flip) {
			/* there was data put in the tty flip buffer */
			tty_flip_buffer_push(flip);
			flip = NULL;
		}

		if (hangup) {
			tty_hangup(hangup);
		}
	}

	spin_lock_irqsave(&hp->lock, flags);
	if (hp->tty && hp->n_throttle
			&& (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
		/* we weren't hung up and we weren't throttled, so we can deliver the
		 * rest now */
		flip = hp->tty;
		hvsi_send_overflow(hp);
	}
	spin_unlock_irqrestore(&hp->lock, flags);

	if (flip) {
		tty_flip_buffer_push(flip);
	}

	return handled;
}

/* for boot console, before the irq handler is running */
static int __init poll_for_state(struct hvsi_struct *hp, int state)
{
	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;

	for (;;) {
		hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */

		if (hp->state == state)
			return 0;

		mdelay(5);
		if (time_after(jiffies, end_jiffies))
			return -EIO;
	}
}

/* wait for irq handler to change our state */
static int wait_for_state(struct hvsi_struct *hp, int state)
{
	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
	unsigned long timeout;
	int ret = 0;

	DECLARE_WAITQUEUE(myself, current);
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&hp->stateq, &myself);

	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (hp->state == state)
			break;
		timeout = end_jiffies - jiffies;
		if (time_after(jiffies, end_jiffies)) {
			ret = -EIO;
			break;
		}
		schedule_timeout(timeout);
	}
	remove_wait_queue(&hp->stateq, &myself);
	set_current_state(TASK_RUNNING);

	return ret;
}

static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
{
	struct hvsi_query packet __ALIGNED__;
	int wrote;

	packet.type = VS_QUERY_PACKET_HEADER;
	packet.len = sizeof(struct hvsi_query);
	packet.seqno = atomic_inc_return(&hp->seqno);
	packet.verb = verb;

	pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
	dbg_dump_hex((uint8_t*)&packet, packet.len);

	wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
	if (wrote != packet.len) {
		printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
			wrote);
		return -EIO;
	}

	return 0;
}

static int hvsi_get_mctrl(struct hvsi_struct *hp)
{
	int ret;

	set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
	hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);

	ret = hvsi_wait(hp, HVSI_OPEN);
	if (ret < 0) {
		printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
		set_state(hp, HVSI_OPEN);
		return ret;
	}

	pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);

	return 0;
}

/* note that we can only set DTR */
static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
{
	struct hvsi_control packet __ALIGNED__;
	int wrote;

	packet.type = VS_CONTROL_PACKET_HEADER,
	packet.seqno = atomic_inc_return(&hp->seqno);
	packet.len = sizeof(struct hvsi_control);
	packet.verb = VSV_SET_MODEM_CTL;
	packet.mask = HVSI_TSDTR;

	if (mctrl & TIOCM_DTR)
		packet.word = HVSI_TSDTR;

	pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
	dbg_dump_hex((uint8_t*)&packet, packet.len);

	wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
	if (wrote != packet.len) {
		printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
		return -EIO;
	}

	return 0;
}

static void hvsi_drain_input(struct hvsi_struct *hp)
{
	uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;

	while (time_before(end_jiffies, jiffies))
		if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
			break;
}

static int hvsi_handshake(struct hvsi_struct *hp)
{
	int ret;

	/*
	 * We could have a CLOSE or other data waiting for us before we even try
	 * to open; try to throw it all away so we don't get confused. (CLOSE
	 * is the first message sent up the pipe when the FSP comes online. We
	 * need to distinguish between "it came up a while ago and we're the first
	 * user" and "it was just reset before it saw our handshake packet".)
	 */
	hvsi_drain_input(hp);

	set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
	ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
	if (ret < 0) {
		printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
		return ret;
	}

	ret = hvsi_wait(hp, HVSI_OPEN);
	if (ret < 0)
		return ret;

	return 0;
}

static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
{
	struct hvsi_data packet __ALIGNED__;
	int ret;

	BUG_ON(count > HVSI_MAX_OUTGOING_DATA);

	packet.type = VS_DATA_PACKET_HEADER;
	packet.seqno = atomic_inc_return(&hp->seqno);
	packet.len = count + sizeof(struct hvsi_header);
	memcpy(&packet.data, buf, count);

	ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
	if (ret == packet.len) {
		/* return the number of chars written, not the packet length */
		return count;
	}
	return ret; /* return any errors */
}

static void hvsi_close_protocol(struct hvsi_struct *hp)
{
	struct hvsi_control packet __ALIGNED__;

	packet.type = VS_CONTROL_PACKET_HEADER;
	packet.seqno = atomic_inc_return(&hp->seqno);
	packet.len = 6;
	packet.verb = VSV_CLOSE_PROTOCOL;

	pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
	dbg_dump_hex((uint8_t*)&packet, packet.len);

	hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
}

static int hvsi_open(struct tty_struct *tty, struct file *filp)
{
	struct hvsi_struct *hp;
	unsigned long flags;
	int line = tty->index;
	int ret;

	pr_debug("%s\n", __FUNCTION__);

	if (line < 0 || line >= hvsi_count)
		return -ENODEV;
	hp = &hvsi_ports[line];

	tty->driver_data = hp;
	tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */

	spin_lock_irqsave(&hp->lock, flags);
	hp->tty = tty;
	hp->count++;
	atomic_set(&hp->seqno, 0);
	h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
	spin_unlock_irqrestore(&hp->lock, flags);

	if (hp->flags & HVSI_CONSOLE)
		return 0; /* this has already been handshaked as the console */

	ret = hvsi_handshake(hp);
	if (ret < 0) {
		printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
		return ret;
	}

	ret = hvsi_get_mctrl(hp);
	if (ret < 0) {
		printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
		return ret;
	}

	ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
	if (ret < 0) {
		printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
		return ret;
	}

	return 0;
}

/* wait for hvsi_write_worker to empty hp->outbuf */
static void hvsi_flush_output(struct hvsi_struct *hp)
{
	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
	unsigned long timeout;

	DECLARE_WAITQUEUE(myself, current);
	set_current_state(TASK_UNINTERRUPTIBLE);
	add_wait_queue(&hp->emptyq, &myself);

	for (;;) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (hp->n_outbuf <= 0)
			break;
		timeout = end_jiffies - jiffies;
		if (time_after(jiffies, end_jiffies))
			break;
		schedule_timeout(timeout);
	}
	remove_wait_queue(&hp->emptyq, &myself);
	set_current_state(TASK_RUNNING);

	/* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
	cancel_delayed_work(&hp->writer);
	flush_scheduled_work();

	/*
	 * it's also possible that our timeout expired and hvsi_write_worker
	 * didn't manage to push outbuf. poof.
	 */
	hp->n_outbuf = 0;
}

static void hvsi_close(struct tty_struct *tty, struct file *filp)
{
	struct hvsi_struct *hp = tty->driver_data;
	unsigned long flags;

	pr_debug("%s\n", __FUNCTION__);