USB: g_serial: don't set low_latency flag
[linux-3.10.git] / drivers / usb / gadget / u_serial.c
index 6641efa..a0f79df 100644 (file)
@@ -23,6 +23,7 @@
 #include <linux/delay.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
+#include <linux/slab.h>
 
 #include "u_serial.h"
 
@@ -60,7 +61,8 @@
  * tty_struct links to the tty/filesystem framework
  *
  * gserial <---> gs_port ... links will be null when the USB link is
- * inactive; managed by gserial_{connect,disconnect}().
+ * inactive; managed by gserial_{connect,disconnect}().  each gserial
+ * instance can wrap its own USB control protocol.
  *     gserial->ioport == usb_ep->driver_data ... gs_port
  *     gs_port->port_usb ... gserial
  *
@@ -181,7 +183,7 @@ static void gs_buf_clear(struct gs_buf *gb)
 /*
  * gs_buf_data_avail
  *
- * Return the number of bytes of data available in the circular
+ * Return the number of bytes of data written into the circular
  * buffer.
  */
 static unsigned gs_buf_data_avail(struct gs_buf *gb)
@@ -282,7 +284,7 @@ gs_buf_get(struct gs_buf *gb, char *buf, unsigned count)
  * Allocate a usb_request and its buffer.  Returns a pointer to the
  * usb_request or NULL if there is an error.
  */
-static struct usb_request *
+struct usb_request *
 gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
 {
        struct usb_request *req;
@@ -306,7 +308,7 @@ gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
  *
  * Free a usb_request and its buffer.
  */
-static void gs_free_req(struct usb_ep *ep, struct usb_request *req)
+void gs_free_req(struct usb_ep *ep, struct usb_request *req)
 {
        kfree(req->buf);
        usb_ep_free_request(ep, req);
@@ -370,6 +372,7 @@ __acquires(&port->port_lock)
 
                req->length = len;
                list_del(&req->list);
+               req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0);
 
                pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
                                port->port_num, len, *((u8 *)req->buf),
@@ -533,17 +536,11 @@ recycle:
                list_move(&req->list, &port->read_pool);
        }
 
-       /* Push from tty to ldisc; this is immediate with low_latency, and
-        * may trigger callbacks to this driver ... so drop the spinlock.
+       /* Push from tty to ldisc; without low_latency set this is handled by
+        * a workqueue, so we won't get callbacks and can hold port_lock
         */
        if (tty && do_push) {
-               spin_unlock_irq(&port->port_lock);
                tty_flip_buffer_push(tty);
-               wake_up_interruptible(&tty->read_wait);
-               spin_lock_irq(&port->port_lock);
-
-               /* tty may have been closed */
-               tty = port->port_tty;
        }
 
 
@@ -781,17 +778,15 @@ static int gs_open(struct tty_struct *tty, struct file *file)
        port->open_count = 1;
        port->openclose = false;
 
-       /* low_latency means ldiscs work in tasklet context, without
-        * needing a workqueue schedule ... easier to keep up.
-        */
-       tty->low_latency = 1;
-
        /* if connected, start the I/O stream */
        if (port->port_usb) {
+               struct gserial  *gser = port->port_usb;
+
                pr_debug("gs_open: start ttyGS%d\n", port->port_num);
                gs_start_io(port);
 
-               /* REVISIT for ACM, issue "network connected" event */
+               if (gser->connect)
+                       gser->connect(gser);
        }
 
        pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file);
@@ -818,6 +813,7 @@ static int gs_writes_finished(struct gs_port *p)
 static void gs_close(struct tty_struct *tty, struct file *file)
 {
        struct gs_port *port = tty->driver_data;
+       struct gserial  *gser;
 
        spin_lock_irq(&port->port_lock);
 
@@ -837,26 +833,27 @@ static void gs_close(struct tty_struct *tty, struct file *file)
        port->openclose = true;
        port->open_count = 0;
 
-       if (port->port_usb)
-               /* REVISIT for ACM, issue "network disconnected" event */;
+       gser = port->port_usb;
+       if (gser && gser->disconnect)
+               gser->disconnect(gser);
 
        /* wait for circular write buffer to drain, disconnect, or at
         * most GS_CLOSE_TIMEOUT seconds; then discard the rest
         */
-       if (gs_buf_data_avail(&port->port_write_buf) > 0
-                       && port->port_usb) {
+       if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) {
                spin_unlock_irq(&port->port_lock);
                wait_event_interruptible_timeout(port->drain_wait,
                                        gs_writes_finished(port),
                                        GS_CLOSE_TIMEOUT * HZ);
                spin_lock_irq(&port->port_lock);
+               gser = port->port_usb;
        }
 
        /* Iff we're disconnected, there can be no I/O in flight so it's
         * ok to free the circular buffer; else just scrub it.  And don't
         * let the push tasklet fire again until we're re-opened.
         */
-       if (port->port_usb == NULL)
+       if (gser == NULL)
                gs_buf_free(&port->port_write_buf);
        else
                gs_buf_clear(&port->port_write_buf);
@@ -974,6 +971,24 @@ static void gs_unthrottle(struct tty_struct *tty)
        spin_unlock_irqrestore(&port->port_lock, flags);
 }
 
+static int gs_break_ctl(struct tty_struct *tty, int duration)
+{
+       struct gs_port  *port = tty->driver_data;
+       int             status = 0;
+       struct gserial  *gser;
+
+       pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n",
+                       port->port_num, duration);
+
+       spin_lock_irq(&port->port_lock);
+       gser = port->port_usb;
+       if (gser && gser->send_break)
+               status = gser->send_break(gser, duration);
+       spin_unlock_irq(&port->port_lock);
+
+       return status;
+}
+
 static const struct tty_operations gs_tty_ops = {
        .open =                 gs_open,
        .close =                gs_close,
@@ -983,6 +998,7 @@ static const struct tty_operations gs_tty_ops = {
        .write_room =           gs_write_room,
        .chars_in_buffer =      gs_chars_in_buffer,
        .unthrottle =           gs_unthrottle,
+       .break_ctl =            gs_break_ctl,
 };
 
 /*-------------------------------------------------------------------------*/
@@ -1067,7 +1083,7 @@ int __init gserial_setup(struct usb_gadget *g, unsigned count)
        gs_tty_driver->init_termios.c_ispeed = 9600;
        gs_tty_driver->init_termios.c_ospeed = 9600;
 
-       coding.dwDTERate = __constant_cpu_to_le32(9600);
+       coding.dwDTERate = cpu_to_le32(9600);
        coding.bCharFormat = 8;
        coding.bParityType = USB_CDC_NO_PARITY;
        coding.bDataBits = USB_CDC_1_STOP_BITS;
@@ -1088,7 +1104,6 @@ int __init gserial_setup(struct usb_gadget *g, unsigned count)
        /* export the driver ... */
        status = tty_register_driver(gs_tty_driver);
        if (status) {
-               put_tty_driver(gs_tty_driver);
                pr_err("%s: cannot register, err %d\n",
                                __func__, status);
                goto fail;
@@ -1230,14 +1245,17 @@ int gserial_connect(struct gserial *gser, u8 port_num)
 
        /* REVISIT if waiting on "carrier detect", signal. */
 
-       /* REVISIT for ACM, issue "network connection" status notification:
-        * connected if open_count, else disconnected.
+       /* if it's already open, start I/O ... and notify the serial
+        * protocol about open/close status (connect/disconnect).
         */
-
-       /* if it's already open, start I/O */
        if (port->open_count) {
                pr_debug("gserial_connect: start ttyGS%d\n", port->port_num);
                gs_start_io(port);
+               if (gser->connect)
+                       gser->connect(gser);
+       } else {
+               if (gser->disconnect)
+                       gser->disconnect(gser);
        }
 
        spin_unlock_irqrestore(&port->port_lock, flags);