USB: cypress_m8: use kfifo to implement write buffering

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>

diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index d963748..f5d0674 100644 (file)
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -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>
@@ -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"
 
@@ -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 */
@@ -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);
@@ -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 = {
@@ -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;
        }
@@ -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);
        }
 }
@@ -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);
 
@@ -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);
@@ -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);
 
@@ -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);
@@ -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;
 
@@ -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);
@@ -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);
@@ -1396,193 +1378,6 @@ 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
  *****************************************************************************/