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USB: cypress_m8: use kfifo to implement write buffering
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Kill custom fifo implementation.

Note that cypress_m8 has no port write fifo as it has no bulk-out
endpoint.

Compile-only tested.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Johan Hovold authored and Greg Kroah-Hartman committed May 20, 2010
1 parent c4f4736 commit 117fb8d
Showing 1 changed file with 17 additions and 222 deletions.
239 changes: 17 additions & 222 deletions drivers/usb/serial/cypress_m8.c
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,7 @@
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <linux/kfifo.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <asm/unaligned.h>
Expand All @@ -79,7 +80,7 @@ static int unstable_bauds;
/*
* Version Information
*/
#define DRIVER_VERSION "v1.09"
#define DRIVER_VERSION "v1.10"
#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
#define DRIVER_DESC "Cypress USB to Serial Driver"

Expand Down Expand Up @@ -134,7 +135,7 @@ struct cypress_private {
int bytes_out; /* used for statistics */
int cmd_count; /* used for statistics */
int cmd_ctrl; /* always set this to 1 before issuing a command */
struct cypress_buf *buf; /* write buffer */
struct kfifo write_fifo; /* write fifo */
int write_urb_in_use; /* write urb in use indicator */
int write_urb_interval; /* interval to use for write urb */
int read_urb_interval; /* interval to use for read urb */
Expand All @@ -156,14 +157,6 @@ struct cypress_private {
struct ktermios tmp_termios; /* stores the old termios settings */
};

/* write buffer structure */
struct cypress_buf {
unsigned int buf_size;
char *buf_buf;
char *buf_get;
char *buf_put;
};

/* function prototypes for the Cypress USB to serial device */
static int cypress_earthmate_startup(struct usb_serial *serial);
static int cypress_hidcom_startup(struct usb_serial *serial);
Expand All @@ -189,17 +182,6 @@ static void cypress_unthrottle(struct tty_struct *tty);
static void cypress_set_dead(struct usb_serial_port *port);
static void cypress_read_int_callback(struct urb *urb);
static void cypress_write_int_callback(struct urb *urb);
/* write buffer functions */
static struct cypress_buf *cypress_buf_alloc(unsigned int size);
static void cypress_buf_free(struct cypress_buf *cb);
static void cypress_buf_clear(struct cypress_buf *cb);
static unsigned int cypress_buf_data_avail(struct cypress_buf *cb);
static unsigned int cypress_buf_space_avail(struct cypress_buf *cb);
static unsigned int cypress_buf_put(struct cypress_buf *cb,
const char *buf, unsigned int count);
static unsigned int cypress_buf_get(struct cypress_buf *cb,
char *buf, unsigned int count);


static struct usb_serial_driver cypress_earthmate_device = {
.driver = {
Expand Down Expand Up @@ -502,8 +484,7 @@ static int generic_startup(struct usb_serial *serial)

priv->comm_is_ok = !0;
spin_lock_init(&priv->lock);
priv->buf = cypress_buf_alloc(CYPRESS_BUF_SIZE);
if (priv->buf == NULL) {
if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
kfree(priv);
return -ENOMEM;
}
Expand Down Expand Up @@ -626,7 +607,7 @@ static void cypress_release(struct usb_serial *serial)
priv = usb_get_serial_port_data(serial->port[0]);

if (priv) {
cypress_buf_free(priv->buf);
kfifo_free(&priv->write_fifo);
kfree(priv);
}
}
Expand Down Expand Up @@ -703,6 +684,7 @@ static void cypress_dtr_rts(struct usb_serial_port *port, int on)
static void cypress_close(struct usb_serial_port *port)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;

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

Expand All @@ -712,12 +694,14 @@ static void cypress_close(struct usb_serial_port *port)
mutex_unlock(&port->serial->disc_mutex);
return;
}
cypress_buf_clear(priv->buf);
spin_lock_irqsave(&priv->lock, flags);
kfifo_reset_out(&priv->write_fifo);
spin_unlock_irqrestore(&priv->lock, flags);

dbg("%s - stopping urbs", __func__);
usb_kill_urb(port->interrupt_in_urb);
usb_kill_urb(port->interrupt_out_urb);


if (stats)
dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
priv->bytes_in, priv->bytes_out, priv->cmd_count);
Expand All @@ -729,7 +713,6 @@ static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
const unsigned char *buf, int count)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;

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

Expand All @@ -744,9 +727,7 @@ static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
if (!count)
return count;

spin_lock_irqsave(&priv->lock, flags);
count = cypress_buf_put(priv->buf, buf, count);
spin_unlock_irqrestore(&priv->lock, flags);
count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);

finish:
cypress_send(port);
Expand Down Expand Up @@ -806,9 +787,10 @@ static void cypress_send(struct usb_serial_port *port)
} else
spin_unlock_irqrestore(&priv->lock, flags);

count = cypress_buf_get(priv->buf, &port->interrupt_out_buffer[offset],
port->interrupt_out_size-offset);

count = kfifo_out_locked(&priv->write_fifo,
&port->interrupt_out_buffer[offset],
port->interrupt_out_size - offset,
&priv->lock);
if (count == 0)
return;

Expand Down Expand Up @@ -874,7 +856,7 @@ static int cypress_write_room(struct tty_struct *tty)
dbg("%s - port %d", __func__, port->number);

spin_lock_irqsave(&priv->lock, flags);
room = cypress_buf_space_avail(priv->buf);
room = kfifo_avail(&priv->write_fifo);
spin_unlock_irqrestore(&priv->lock, flags);

dbg("%s - returns %d", __func__, room);
Expand Down Expand Up @@ -1142,7 +1124,7 @@ static int cypress_chars_in_buffer(struct tty_struct *tty)
dbg("%s - port %d", __func__, port->number);

spin_lock_irqsave(&priv->lock, flags);
chars = cypress_buf_data_avail(priv->buf);
chars = kfifo_len(&priv->write_fifo);
spin_unlock_irqrestore(&priv->lock, flags);

dbg("%s - returns %d", __func__, chars);
Expand Down Expand Up @@ -1395,193 +1377,6 @@ static void cypress_write_int_callback(struct urb *urb)
}


/*****************************************************************************
* Write buffer functions - buffering code from pl2303 used
*****************************************************************************/

/*
* cypress_buf_alloc
*
* Allocate a circular buffer and all associated memory.
*/

static struct cypress_buf *cypress_buf_alloc(unsigned int size)
{

struct cypress_buf *cb;


if (size == 0)
return NULL;

cb = kmalloc(sizeof(struct cypress_buf), GFP_KERNEL);
if (cb == NULL)
return NULL;

cb->buf_buf = kmalloc(size, GFP_KERNEL);
if (cb->buf_buf == NULL) {
kfree(cb);
return NULL;
}

cb->buf_size = size;
cb->buf_get = cb->buf_put = cb->buf_buf;

return cb;

}


/*
* cypress_buf_free
*
* Free the buffer and all associated memory.
*/

static void cypress_buf_free(struct cypress_buf *cb)
{
if (cb) {
kfree(cb->buf_buf);
kfree(cb);
}
}


/*
* cypress_buf_clear
*
* Clear out all data in the circular buffer.
*/

static void cypress_buf_clear(struct cypress_buf *cb)
{
if (cb != NULL)
cb->buf_get = cb->buf_put;
/* equivalent to a get of all data available */
}


/*
* cypress_buf_data_avail
*
* Return the number of bytes of data available in the circular
* buffer.
*/

static unsigned int cypress_buf_data_avail(struct cypress_buf *cb)
{
if (cb != NULL)
return (cb->buf_size + cb->buf_put - cb->buf_get)
% cb->buf_size;
else
return 0;
}


/*
* cypress_buf_space_avail
*
* Return the number of bytes of space available in the circular
* buffer.
*/

static unsigned int cypress_buf_space_avail(struct cypress_buf *cb)
{
if (cb != NULL)
return (cb->buf_size + cb->buf_get - cb->buf_put - 1)
% cb->buf_size;
else
return 0;
}


/*
* cypress_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 cypress_buf_put(struct cypress_buf *cb, const char *buf,
unsigned int count)
{

unsigned int len;


if (cb == NULL)
return 0;

len = cypress_buf_space_avail(cb);
if (count > len)
count = len;

if (count == 0)
return 0;

len = cb->buf_buf + cb->buf_size - cb->buf_put;
if (count > len) {
memcpy(cb->buf_put, buf, len);
memcpy(cb->buf_buf, buf+len, count - len);
cb->buf_put = cb->buf_buf + count - len;
} else {
memcpy(cb->buf_put, buf, count);
if (count < len)
cb->buf_put += count;
else /* count == len */
cb->buf_put = cb->buf_buf;
}

return count;

}


/*
* cypress_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 cypress_buf_get(struct cypress_buf *cb, char *buf,
unsigned int count)
{

unsigned int len;


if (cb == NULL)
return 0;

len = cypress_buf_data_avail(cb);
if (count > len)
count = len;

if (count == 0)
return 0;

len = cb->buf_buf + cb->buf_size - cb->buf_get;
if (count > len) {
memcpy(buf, cb->buf_get, len);
memcpy(buf+len, cb->buf_buf, count - len);
cb->buf_get = cb->buf_buf + count - len;
} else {
memcpy(buf, cb->buf_get, count);
if (count < len)
cb->buf_get += count;
else /* count == len */
cb->buf_get = cb->buf_buf;
}

return count;

}

/*****************************************************************************
* Module functions
*****************************************************************************/
Expand Down

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