ps3-vuart.c

linux 内核源代码

 * Used to clear pending rx interrupt source.  Will not block.
 */

void ps3_vuart_clear_rx_bytes(struct ps3_system_bus_device *dev,
	unsigned int bytes)
{
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	u64 bytes_waiting;
	void* tmp;

	result = ps3_vuart_get_rx_bytes_waiting(dev, &bytes_waiting);

	BUG_ON(result);

	bytes = bytes ? min(bytes, (unsigned int)bytes_waiting) : bytes_waiting;

	dev_dbg(&dev->core, "%s:%d: %u\n", __func__, __LINE__, bytes);

	if (!bytes)
		return;

	/* Add some extra space for recently arrived data. */

	bytes += 128;

	tmp = kmalloc(bytes, GFP_KERNEL);

	if (!tmp)
		return;

	ps3_vuart_raw_read(dev, tmp, bytes, &bytes_waiting);

	kfree(tmp);

	/* Don't include these bytes in the stats. */

	priv->stats.bytes_read -= bytes_waiting;
}
EXPORT_SYMBOL_GPL(ps3_vuart_clear_rx_bytes);

/**
 * struct list_buffer - An element for a port device fifo buffer list.
 */

struct list_buffer {
	struct list_head link;
	const unsigned char *head;
	const unsigned char *tail;
	unsigned long dbg_number;
	unsigned char data[];
};

/**
 * ps3_vuart_write - the entry point for writing data to a port
 * @dev: The struct ps3_system_bus_device instance.
 *
 * If the port is idle on entry as much of the incoming data is written to
 * the port as the port will accept.  Otherwise a list buffer is created
 * and any remaning incoming data is copied to that buffer.  The buffer is
 * then enqueued for transmision via the transmit interrupt.
 */

int ps3_vuart_write(struct ps3_system_bus_device *dev, const void *buf,
	unsigned int bytes)
{
	static unsigned long dbg_number;
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long flags;
	struct list_buffer *lb;

	dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
		bytes, bytes);

	spin_lock_irqsave(&priv->tx_list.lock, flags);

	if (list_empty(&priv->tx_list.head)) {
		unsigned long bytes_written;

		result = ps3_vuart_raw_write(dev, buf, bytes, &bytes_written);

		spin_unlock_irqrestore(&priv->tx_list.lock, flags);

		if (result) {
			dev_dbg(&dev->core,
				"%s:%d: ps3_vuart_raw_write failed\n",
				__func__, __LINE__);
			return result;
		}

		if (bytes_written == bytes) {
			dev_dbg(&dev->core, "%s:%d: wrote %xh bytes\n",
				__func__, __LINE__, bytes);
			return 0;
		}

		bytes -= bytes_written;
		buf += bytes_written;
	} else
		spin_unlock_irqrestore(&priv->tx_list.lock, flags);

	lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_KERNEL);

	if (!lb) {
		return -ENOMEM;
	}

	memcpy(lb->data, buf, bytes);
	lb->head = lb->data;
	lb->tail = lb->data + bytes;
	lb->dbg_number = ++dbg_number;

	spin_lock_irqsave(&priv->tx_list.lock, flags);
	list_add_tail(&lb->link, &priv->tx_list.head);
	ps3_vuart_enable_interrupt_tx(dev);
	spin_unlock_irqrestore(&priv->tx_list.lock, flags);

	dev_dbg(&dev->core, "%s:%d: queued buf_%lu, %xh bytes\n",
		__func__, __LINE__, lb->dbg_number, bytes);

	return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_write);

/**
 * ps3_vuart_queue_rx_bytes - Queue waiting bytes into the buffer list.
 * @dev: The struct ps3_system_bus_device instance.
 * @bytes_queued: Number of bytes queued to the buffer list.
 *
 * Must be called with priv->rx_list.lock held.
 */

static int ps3_vuart_queue_rx_bytes(struct ps3_system_bus_device *dev,
	u64 *bytes_queued)
{
	static unsigned long dbg_number;
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	struct list_buffer *lb;
	u64 bytes;

	*bytes_queued = 0;

	result = ps3_vuart_get_rx_bytes_waiting(dev, &bytes);
	BUG_ON(result);

	if (result)
		return -EIO;

	if (!bytes)
		return 0;

	/* Add some extra space for recently arrived data. */

	bytes += 128;

	lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_ATOMIC);

	if (!lb)
		return -ENOMEM;

	ps3_vuart_raw_read(dev, lb->data, bytes, &bytes);

	lb->head = lb->data;
	lb->tail = lb->data + bytes;
	lb->dbg_number = ++dbg_number;

	list_add_tail(&lb->link, &priv->rx_list.head);
	priv->rx_list.bytes_held += bytes;

	dev_dbg(&dev->core, "%s:%d: buf_%lu: queued %lxh bytes\n",
		__func__, __LINE__, lb->dbg_number, bytes);

	*bytes_queued = bytes;

	return 0;
}

/**
 * ps3_vuart_read - The entry point for reading data from a port.
 *
 * Queue data waiting at the port, and if enough bytes to satisfy the request
 * are held in the buffer list those bytes are dequeued and copied to the
 * caller's buffer.  Emptied list buffers are retiered.  If the request cannot
 * be statified by bytes held in the list buffers -EAGAIN is returned.
 */

int ps3_vuart_read(struct ps3_system_bus_device *dev, void *buf,
	unsigned int bytes)
{
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long flags;
	struct list_buffer *lb, *n;
	unsigned long bytes_read;

	dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
		bytes, bytes);

	spin_lock_irqsave(&priv->rx_list.lock, flags);

	/* Queue rx bytes here for polled reads. */

	while (priv->rx_list.bytes_held < bytes) {
		u64 tmp;

		result = ps3_vuart_queue_rx_bytes(dev, &tmp);
		if (result || !tmp) {
			dev_dbg(&dev->core, "%s:%d: starved for %lxh bytes\n",
				__func__, __LINE__,
				bytes - priv->rx_list.bytes_held);
			spin_unlock_irqrestore(&priv->rx_list.lock, flags);
			return -EAGAIN;
		}
	}

	list_for_each_entry_safe(lb, n, &priv->rx_list.head, link) {
		bytes_read = min((unsigned int)(lb->tail - lb->head), bytes);

		memcpy(buf, lb->head, bytes_read);
		buf += bytes_read;
		bytes -= bytes_read;
		priv->rx_list.bytes_held -= bytes_read;

		if (bytes_read < lb->tail - lb->head) {
			lb->head += bytes_read;
			dev_dbg(&dev->core, "%s:%d: buf_%lu: dequeued %lxh "
				"bytes\n", __func__, __LINE__, lb->dbg_number,
				bytes_read);
			spin_unlock_irqrestore(&priv->rx_list.lock, flags);
			return 0;
		}

		dev_dbg(&dev->core, "%s:%d: buf_%lu: free, dequeued %lxh "
			"bytes\n", __func__, __LINE__, lb->dbg_number,
			bytes_read);

		list_del(&lb->link);
		kfree(lb);
	}

	spin_unlock_irqrestore(&priv->rx_list.lock, flags);
	return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_read);

/**
 * ps3_vuart_work - Asynchronous read handler.
 */

static void ps3_vuart_work(struct work_struct *work)
{
	struct ps3_system_bus_device *dev =
		ps3_vuart_work_to_system_bus_dev(work);
	struct ps3_vuart_port_driver *drv =
		ps3_system_bus_dev_to_vuart_drv(dev);

	BUG_ON(!drv);
	drv->work(dev);
}

int ps3_vuart_read_async(struct ps3_system_bus_device *dev, unsigned int bytes)
{
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long flags;

	if (priv->rx_list.work.trigger) {
		dev_dbg(&dev->core, "%s:%d: warning, multiple calls\n",
			__func__, __LINE__);
		return -EAGAIN;
	}

	BUG_ON(!bytes);

	PREPARE_WORK(&priv->rx_list.work.work, ps3_vuart_work);

	spin_lock_irqsave(&priv->rx_list.lock, flags);
	if (priv->rx_list.bytes_held >= bytes) {
		dev_dbg(&dev->core, "%s:%d: schedule_work %xh bytes\n",
			__func__, __LINE__, bytes);
		schedule_work(&priv->rx_list.work.work);
		spin_unlock_irqrestore(&priv->rx_list.lock, flags);
		return 0;
	}

	priv->rx_list.work.trigger = bytes;
	spin_unlock_irqrestore(&priv->rx_list.lock, flags);

	dev_dbg(&dev->core, "%s:%d: waiting for %u(%xh) bytes\n", __func__,
		__LINE__, bytes, bytes);

	return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_read_async);

void ps3_vuart_cancel_async(struct ps3_system_bus_device *dev)
{
	to_port_priv(dev)->rx_list.work.trigger = 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_cancel_async);

/**
 * ps3_vuart_handle_interrupt_tx - third stage transmit interrupt handler
 *
 * Services the transmit interrupt for the port.  Writes as much data from the
 * buffer list as the port will accept.  Retires any emptied list buffers and
 * adjusts the final list buffer state for a partial write.
 */

static int ps3_vuart_handle_interrupt_tx(struct ps3_system_bus_device *dev)
{
	int result = 0;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long flags;
	struct list_buffer *lb, *n;
	unsigned long bytes_total = 0;

	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

	spin_lock_irqsave(&priv->tx_list.lock, flags);

	list_for_each_entry_safe(lb, n, &priv->tx_list.head, link) {

		unsigned long bytes_written;

		result = ps3_vuart_raw_write(dev, lb->head, lb->tail - lb->head,
			&bytes_written);

		if (result) {
			dev_dbg(&dev->core,
				"%s:%d: ps3_vuart_raw_write failed\n",
				__func__, __LINE__);
			break;
		}

		bytes_total += bytes_written;

		if (bytes_written < lb->tail - lb->head) {
			lb->head += bytes_written;
			dev_dbg(&dev->core,
				"%s:%d cleared buf_%lu, %lxh bytes\n",
				__func__, __LINE__, lb->dbg_number,
				bytes_written);
			goto port_full;
		}

		dev_dbg(&dev->core, "%s:%d free buf_%lu\n", __func__, __LINE__,
			lb->dbg_number);

		list_del(&lb->link);
		kfree(lb);
	}

	ps3_vuart_disable_interrupt_tx(dev);
port_full:
	spin_unlock_irqrestore(&priv->tx_list.lock, flags);
	dev_dbg(&dev->core, "%s:%d wrote %lxh bytes total\n",
		__func__, __LINE__, bytes_total);
	return result;
}

/**
 * ps3_vuart_handle_interrupt_rx - third stage receive interrupt handler
 *
 * Services the receive interrupt for the port.  Creates a list buffer and
 * copies all waiting port data to that buffer and enqueues the buffer in the
 * buffer list.  Buffer list data is dequeued via ps3_vuart_read.
 */

static int ps3_vuart_handle_interrupt_rx(struct ps3_system_bus_device *dev)
{
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long flags;
	u64 bytes;

	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

	spin_lock_irqsave(&priv->rx_list.lock, flags);
	result = ps3_vuart_queue_rx_bytes(dev, &bytes);

	if (result) {
		spin_unlock_irqrestore(&priv->rx_list.lock, flags);
		return result;
	}

	if (priv->rx_list.work.trigger && priv->rx_list.bytes_held
		>= priv->rx_list.work.trigger) {
		dev_dbg(&dev->core, "%s:%d: schedule_work %lxh bytes\n",
			__func__, __LINE__, priv->rx_list.work.trigger);
		priv->rx_list.work.trigger = 0;
		schedule_work(&priv->rx_list.work.work);
	}

	spin_unlock_irqrestore(&priv->rx_list.lock, flags);
	return result;
}

static int ps3_vuart_handle_interrupt_disconnect(
	struct ps3_system_bus_device *dev)
{
	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
	BUG_ON("no support");
	return -1;
}

/**
 * ps3_vuart_handle_port_interrupt - second stage interrupt handler
 *
 * Services any pending interrupt types for the port.  Passes control to the
 * third stage type specific interrupt handler.  Returns control to the first
 * stage handler after one iteration.
 */

static int ps3_vuart_handle_port_interrupt(struct ps3_system_bus_device *dev)
{
	int result;
	struct ps3_vuart_port_priv *priv = to_port_priv(dev);
	unsigned long status;

	result = ps3_vuart_get_interrupt_status(dev, &status);

	if (result)