Commit e3c1803f authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: oti6858: use kfifo to implement write buffering 



Kill custom fifo implementation.

Use private write fifo to minimise changes to lock handling.

Compile-only tested.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 117fb8d0

drivers/usb/serial/oti6858.c

+17 −201
Original line number Diff line number Diff line
@@ -51,12 +51,13 @@ 
#include <linux/usb.h>

#include <linux/usb/serial.h>

#include <linux/uaccess.h>

#include <linux/kfifo.h>

#include "oti6858.h"



#define OTI6858_DESCRIPTION \

	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"

#define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"

#define OTI6858_VERSION "0.1"

#define OTI6858_VERSION "0.2"



static const struct usb_device_id id_table[] = {

	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
@@ -75,17 +76,7 @@ static struct usb_driver oti6858_driver = { 


static int debug;





/* buffering code, copied from pl2303 driver */

#define PL2303_BUF_SIZE		1024

#define PL2303_TMP_BUF_SIZE	1024



struct oti6858_buf {

	unsigned int	buf_size;

	char		*buf_buf;

	char		*buf_get;

	char		*buf_put;

};

#define OTI6858_FIFO_SIZE		1024



/* requests */

#define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
@@ -161,18 +152,6 @@ static int oti6858_tiocmset(struct tty_struct *tty, struct file *file, 
static int oti6858_startup(struct usb_serial *serial);

static void oti6858_release(struct usb_serial *serial);



/* functions operating on buffers */

static struct oti6858_buf *oti6858_buf_alloc(unsigned int size);

static void oti6858_buf_free(struct oti6858_buf *pb);

static void oti6858_buf_clear(struct oti6858_buf *pb);

static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);

static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);

static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,

					unsigned int count);

static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,

					unsigned int count);





/* device info */

static struct usb_serial_driver oti6858_device = {

	.driver = {
@@ -201,7 +180,7 @@ static struct usb_serial_driver oti6858_device = { 
struct oti6858_private {

	spinlock_t lock;



	struct oti6858_buf *buf;

	struct kfifo write_fifo;

	struct oti6858_control_pkt status;



	struct {
@@ -315,7 +294,7 @@ static void send_data(struct work_struct *work) 
	}

	priv->flags.write_urb_in_use = 1;



	count = oti6858_buf_data_avail(priv->buf);

	count = kfifo_len(&priv->write_fifo);

	spin_unlock_irqrestore(&priv->lock, flags);

	if (count > port->bulk_out_size)

		count = port->bulk_out_size;
@@ -350,10 +329,9 @@ static void send_data(struct work_struct *work) 
		return;

	}



	spin_lock_irqsave(&priv->lock, flags);

	oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);

	spin_unlock_irqrestore(&priv->lock, flags);



	count = kfifo_out_locked(&priv->write_fifo,

					port->write_urb->transfer_buffer,

					count, &priv->lock);

	port->write_urb->transfer_buffer_length = count;

	port->write_urb->dev = port->serial->dev;

	result = usb_submit_urb(port->write_urb, GFP_NOIO);
@@ -376,8 +354,8 @@ static int oti6858_startup(struct usb_serial *serial) 
		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);

		if (!priv)

			break;

		priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);

		if (priv->buf == NULL) {

		if (kfifo_alloc(&priv->write_fifo, OTI6858_FIFO_SIZE,

								GFP_KERNEL)) {

			kfree(priv);

			break;

		}
@@ -397,7 +375,7 @@ static int oti6858_startup(struct usb_serial *serial) 


	for (--i; i >= 0; --i) {

		priv = usb_get_serial_port_data(serial->port[i]);

		oti6858_buf_free(priv->buf);

		kfifo_free(&priv->write_fifo);

		kfree(priv);

		usb_set_serial_port_data(serial->port[i], NULL);

	}
@@ -408,16 +386,13 @@ static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port, 
			const unsigned char *buf, int count)

{

	struct oti6858_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;



	dbg("%s(port = %d, count = %d)", __func__, port->number, count);



	if (!count)

		return count;



	spin_lock_irqsave(&priv->lock, flags);

	count = oti6858_buf_put(priv->buf, buf, count);

	spin_unlock_irqrestore(&priv->lock, flags);

	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);



	return count;

}
@@ -432,7 +407,7 @@ static int oti6858_write_room(struct tty_struct *tty) 
	dbg("%s(port = %d)", __func__, port->number);



	spin_lock_irqsave(&priv->lock, flags);

	room = oti6858_buf_space_avail(priv->buf);

	room = kfifo_avail(&priv->write_fifo);

	spin_unlock_irqrestore(&priv->lock, flags);



	return room;
@@ -448,7 +423,7 @@ static int oti6858_chars_in_buffer(struct tty_struct *tty) 
	dbg("%s(port = %d)", __func__, port->number);



	spin_lock_irqsave(&priv->lock, flags);

	chars = oti6858_buf_data_avail(priv->buf);

	chars = kfifo_len(&priv->write_fifo);

	spin_unlock_irqrestore(&priv->lock, flags);



	return chars;
@@ -642,7 +617,7 @@ static void oti6858_close(struct usb_serial_port *port) 


	spin_lock_irqsave(&priv->lock, flags);

	/* clear out any remaining data in the buffer */

	oti6858_buf_clear(priv->buf);

	kfifo_reset_out(&priv->write_fifo);

	spin_unlock_irqrestore(&priv->lock, flags);



	dbg("%s(): after buf_clear()", __func__);
@@ -793,7 +768,7 @@ static void oti6858_release(struct usb_serial *serial) 
	for (i = 0; i < serial->num_ports; ++i) {

		priv = usb_get_serial_port_data(serial->port[i]);

		if (priv) {

			oti6858_buf_free(priv->buf);

			kfifo_free(&priv->write_fifo);

			kfree(priv);

		}

	}
@@ -892,7 +867,7 @@ static void oti6858_read_int_callback(struct urb *urb) 


		spin_lock_irqsave(&priv->lock, flags);

		if (priv->flags.write_urb_in_use == 0

				&& oti6858_buf_data_avail(priv->buf) != 0) {

				&& kfifo_len(&priv->write_fifo) != 0) {

			schedule_delayed_work(&priv->delayed_write_work, 0);

			resubmit = 0;

		}
@@ -1014,165 +989,6 @@ static void oti6858_write_bulk_callback(struct urb *urb) 
	}

}





/*

 * oti6858_buf_alloc

 *

 * Allocate a circular buffer and all associated memory.

 */

static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)

{

	struct oti6858_buf *pb;



	if (size == 0)

		return NULL;



	pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);

	if (pb == NULL)

		return NULL;



	pb->buf_buf = kmalloc(size, GFP_KERNEL);

	if (pb->buf_buf == NULL) {

		kfree(pb);

		return NULL;

	}



	pb->buf_size = size;

	pb->buf_get = pb->buf_put = pb->buf_buf;



	return pb;

}



/*

 * oti6858_buf_free

 *

 * Free the buffer and all associated memory.

 */

static void oti6858_buf_free(struct oti6858_buf *pb)

{

	if (pb) {

		kfree(pb->buf_buf);

		kfree(pb);

	}

}



/*

 * oti6858_buf_clear

 *

 * Clear out all data in the circular buffer.

 */

static void oti6858_buf_clear(struct oti6858_buf *pb)

{

	if (pb != NULL) {

		/* equivalent to a get of all data available */

		pb->buf_get = pb->buf_put;

	}

}



/*

 * oti6858_buf_data_avail

 *

 * Return the number of bytes of data available in the circular

 * buffer.

 */

static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)

{

	if (pb == NULL)

		return 0;

	return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;

}



/*

 * oti6858_buf_space_avail

 *

 * Return the number of bytes of space available in the circular

 * buffer.

 */

static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)

{

	if (pb == NULL)

		return 0;

	return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;

}



/*

 * oti6858_buf_put

 *

 * Copy data data from a user buffer and put it into the circular buffer.

 * Restrict to the amount of space available.

 *

 * Return the number of bytes copied.

 */

static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,

					unsigned int count)

{

	unsigned int len;



	if (pb == NULL)

		return 0;



	len  = oti6858_buf_space_avail(pb);

	if (count > len)

		count = len;



	if (count == 0)

		return 0;



	len = pb->buf_buf + pb->buf_size - pb->buf_put;

	if (count > len) {

		memcpy(pb->buf_put, buf, len);

		memcpy(pb->buf_buf, buf+len, count - len);

		pb->buf_put = pb->buf_buf + count - len;

	} else {

		memcpy(pb->buf_put, buf, count);

		if (count < len)

			pb->buf_put += count;

		else /* count == len */

			pb->buf_put = pb->buf_buf;

	}



	return count;

}



/*

 * oti6858_buf_get

 *

 * Get data from the circular buffer and copy to the given buffer.

 * Restrict to the amount of data available.

 *

 * Return the number of bytes copied.

 */

static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,

					unsigned int count)

{

	unsigned int len;



	if (pb == NULL)

		return 0;



	len = oti6858_buf_data_avail(pb);

	if (count > len)

		count = len;



	if (count == 0)

		return 0;



	len = pb->buf_buf + pb->buf_size - pb->buf_get;

	if (count > len) {

		memcpy(buf, pb->buf_get, len);

		memcpy(buf+len, pb->buf_buf, count - len);

		pb->buf_get = pb->buf_buf + count - len;

	} else {

		memcpy(buf, pb->buf_get, count);

		if (count < len)

			pb->buf_get += count;

		else /* count == len */

			pb->buf_get = pb->buf_buf;

	}



	return count;

}



/* module description and (de)initialization */



static int __init oti6858_init(void)

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