USB: safe_serial: reimplement write using generic framework

Kill custom single-urb write implementation.

Note that this driver still depended on the write callback from the old
generic framework.

Tested against original read processing using a cp210x device in a
loopback setup.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 32 insertions, 111 deletions

diff --git a/drivers/usb/serial/safe_serial.c b/drivers/usb/serial/safe_serial.c
index 43a0cadd5782..915c094ef92c 100644
--- a/drivers/usb/serial/safe_serial.c
+++ b/drivers/usb/serial/safe_serial.c
@@ -1,6 +1,7 @@
 /*
  * Safe Encapsulated USB Serial Driver
  *
+ *      Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
  *      Copyright (C) 2001 Lineo
  *      Copyright (C) 2001 Hewlett-Packard
  *
@@ -84,8 +85,8 @@ static int debug;
 static int safe = 1;
 static int padded = CONFIG_USB_SERIAL_SAFE_PADDED;
 
-#define DRIVER_VERSION "v0.0b"
-#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com"
+#define DRIVER_VERSION "v0.1"
+#define DRIVER_AUTHOR "sl@lineo.com, tbr@lineo.com, Johan Hovold <jhovold@gmail.com>"
 #define DRIVER_DESC "USB Safe Encapsulated Serial"
 
 MODULE_AUTHOR(DRIVER_AUTHOR);
@@ -284,119 +285,40 @@ static void safe_read_bulk_callback(struct urb *urb)
                 /* FIXME: Need a mechanism to retry later if this happens */
 }
 
-static int safe_write(struct tty_struct *tty, struct usb_serial_port *port,
-                                        const unsigned char *buf, int count)
+static int safe_prepare_write_buffer(struct usb_serial_port *port,
+                                                void *dest, size_t size)
 {
-        unsigned char *data;
-        int result;
-        int i;
-        int packet_length;
-
-        dbg("safe_write port: %p %d urb: %p count: %d",
-                                port, port->number, port->write_urb, count);
-
-        if (!port->write_urb) {
-                dbg("%s - write urb NULL", __func__);
-                return 0;
-        }
-
-        dbg("safe_write write_urb: %d transfer_buffer_length",
-             port->write_urb->transfer_buffer_length);
-
-        if (!port->write_urb->transfer_buffer_length) {
-                dbg("%s - write urb transfer_buffer_length zero", __func__);
-                return 0;
-        }
-        if (count == 0) {
-                dbg("%s - write request of 0 bytes", __func__);
-                return 0;
-        }
-        spin_lock_bh(&port->lock);
-        if (port->write_urb_busy) {
-                spin_unlock_bh(&port->lock);
-                dbg("%s - already writing", __func__);
-                return 0;
-        }
-        port->write_urb_busy = 1;
-        spin_unlock_bh(&port->lock);
-
-        packet_length = port->bulk_out_size;    /* get max packetsize */
-
-        i = packet_length - (safe ? 2 : 0);     /* get bytes to send */
-        count = (count > i) ? i : count;
-
-
-        /* get the data into the transfer buffer */
-        data = port->write_urb->transfer_buffer;
-        memset(data, '0', packet_length);
-
-        memcpy(data, buf, count);
-
-        if (safe) {
-                __u16 fcs;
-
-                /* pad if necessary */
-                if (!padded)
-                        packet_length = count + 2;
-                /* set count */
-                data[packet_length - 2] = count << 2;
-                data[packet_length - 1] = 0;
-
-                /* compute fcs and insert into trailer */
-                fcs = fcs_compute10(data, packet_length, CRC10_INITFCS);
-                data[packet_length - 2] |= fcs >> 8;
-                data[packet_length - 1] |= fcs & 0xff;
-
-                /* set length to send */
-                port->write_urb->transfer_buffer_length = packet_length;
+        unsigned char *buf = dest;
+        int count;
+        int trailer_len;
+        int pkt_len;
+        __u16 fcs;
+
+        trailer_len = safe ? 2 : 0;
+
+        count = kfifo_out_locked(&port->write_fifo, buf, size - trailer_len,
+                                                                &port->lock);
+        if (!safe)
+                return count;
+
+        /* pad if necessary */
+        if (padded) {
+                pkt_len = size;
+                memset(buf + count, '0', pkt_len - count - trailer_len);
         } else {
-                port->write_urb->transfer_buffer_length = count;
-        }
-
-        usb_serial_debug_data(debug, &port->dev, __func__, count,
-                                        port->write_urb->transfer_buffer);
-#ifdef ECHO_TX
-        {
-                int i;
-                unsigned char *cp = port->write_urb->transfer_buffer;
-                for (i = 0; i < port->write_urb->transfer_buffer_length; i++) {
-                        if ((i % 32) == 0)
-                                printk("\nsu[%02x] ", i);
-                        printk("%02x ", *cp++);
-                }
-                printk("\n");
+                pkt_len = count + trailer_len;
         }
-#endif
-        port->write_urb->dev = port->serial->dev;
-        result = usb_submit_urb(port->write_urb, GFP_KERNEL);
-        if (result) {
-                port->write_urb_busy = 0;
-                dev_err(&port->dev,
-                        "%s - failed submitting write urb, error %d\n",
-                        __func__, result);
-                return 0;
-        }
-        dbg("%s urb: %p submitted", __func__, port->write_urb);
 
-        return count;
-}
-
-static int safe_write_room(struct tty_struct *tty)
-{
-        struct usb_serial_port *port = tty->driver_data;
-        int room = 0;           /* Default: no room */
-        unsigned long flags;
-
-        dbg("%s", __func__);
+        /* set count */
+        buf[pkt_len - 2] = count << 2;
+        buf[pkt_len - 1] = 0;
 
-        spin_lock_irqsave(&port->lock, flags);
-        if (port->write_urb_busy)
-                room = port->bulk_out_size - (safe ? 2 : 0);
-        spin_unlock_irqrestore(&port->lock, flags);
+        /* compute fcs and insert into trailer */
+        fcs = fcs_compute10(buf, pkt_len, CRC10_INITFCS);
+        buf[pkt_len - 2] |= fcs >> 8;
+        buf[pkt_len - 1] |= fcs & 0xff;
 
-        if (room)
-                dbg("safe_write_room returns %d", room);
-        return room;
+        return pkt_len;
 }
 
 static int safe_startup(struct usb_serial *serial)
@@ -421,9 +343,8 @@ static struct usb_serial_driver safe_device = {
         .id_table =             id_table,
         .usb_driver =           &safe_driver,
         .num_ports =            1,
-        .write =                safe_write,
-        .write_room =           safe_write_room,
         .read_bulk_callback =   safe_read_bulk_callback,
+        .prepare_write_buffer = safe_prepare_write_buffer,
         .attach =               safe_startup,
 };