vizzini: add flow control patch and bump

2 files changed, 159 insertions, 1 deletions

diff --git a/multitech/recipes/vizzini/vizzini-0.76/vizzini-0.76-flow-control.patch b/multitech/recipes/vizzini/vizzini-0.76/vizzini-0.76-flow-control.patch
new file mode 100644
index 0000000..77adf53
--- /dev/null
+++ b/multitech/recipes/vizzini/vizzini-0.76/vizzini-0.76-flow-control.patch
@@ -0,0 +1,157 @@
+--- a/vizzini.c	2013-03-26 11:34:39.362546946 -0500
++++ b/vizzini.c	2013-03-27 10:43:03.123460275 -0500
+@@ -92,6 +92,9 @@
+ #define N_OUT_URB   4
+ #define IN_BUFLEN   4096
+ 
++#define READ_URB_RUNNING    0
++#define READ_URB_STOPPED    1
++
+ static int debug;
+ 
+ 
+@@ -169,6 +172,7 @@
+ 
+         struct urb   *in_urbs[N_IN_URB];
+         char         *in_buffer[N_IN_URB];
++        int           in_urb_flags[N_IN_URB];
+ 
+         int           ctrlin;
+         int           ctrlout;
+@@ -995,6 +999,8 @@
+         char                            *transfer_buffer = urb->transfer_buffer;
+         int                              length, room, have_extra_byte;
+         int                              err;
++        unsigned long                    flags;
++        int j;
+ 
+         if (debug) dev_dbg(&port->dev, "%s: %p\n", __func__, urb);
+ 
+@@ -1085,9 +1091,26 @@
+                 portdata->extra_byte = transfer_buffer[urb->actual_length - 1];
+         }
+ 
+-        err = usb_submit_urb(urb, GFP_ATOMIC);
+-        if (err)
+-                dev_err(&port->dev, "resubmit read urb failed. (%d)\n", err);
++        /* throttle device if requested */
++        spin_lock_irqsave(&port->lock, flags);
++        port->throttled = port->throttle_req;
++        if (! port->throttled) {
++                spin_unlock_irqrestore(&port->lock, flags);
++                err = usb_submit_urb(urb, GFP_ATOMIC);
++                if (err)
++                        dev_err(&port->dev, "resubmit read urb failed. (%d)\n", err);
++        } else {
++                spin_unlock_irqrestore(&port->lock, flags);
++                for (j = 0; j < N_IN_URB; j++) {
++                        if (portdata->in_urbs[j] == urb) {
++                                if (debug) dev_dbg(&port->dev, "throttling urb %d\n", j);
++                                spin_lock_irqsave(&port->lock, flags);
++                                portdata->in_urb_flags[j] = READ_URB_STOPPED;
++                                spin_unlock_irqrestore(&port->lock, flags);
++                                break;
++                        }
++                }
++        }
+ }
+ 
+ 
+@@ -1172,6 +1195,7 @@
+         int                              i;
+         struct urb                      *urb;
+         int                              result;
++        unsigned long                    flags;
+ 
+         portdata = usb_get_serial_port_data(port);
+ 
+@@ -1179,10 +1203,19 @@
+ 
+         acm_set_control(port, portdata->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS);
+ 
++        /* unthrottle device in case TTY was closed while throttled */
++        spin_lock_irqsave(&port->lock, flags);
++        port->throttled = 0;
++        port->throttle_req = 0;
++        spin_unlock_irqrestore(&port->lock, flags);
++
+         /* Reset low level data toggle and start reading from endpoints */
+         for (i = 0; i < N_IN_URB; i++) {
+                 if (debug) dev_dbg(&port->dev, "%s urb %d\n", __func__, i);
+ 
++                spin_lock_irqsave(&port->lock, flags);
++                portdata->in_urb_flags[i] = READ_URB_RUNNING;
++                spin_unlock_irqrestore(&port->lock, flags);
+                 urb = portdata->in_urbs[i];
+                 if (!urb)
+                         continue;
+@@ -1207,8 +1240,6 @@
+                 }
+         }
+ 
+-        tty->low_latency = 1;
+-
+         /* start up the interrupt endpoint if we have one */
+         if (port->interrupt_in_urb) {
+                 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+@@ -1592,6 +1623,51 @@
+         usb_serial_disconnect(interface);
+ }
+ 
++static void vizzini_throttle(struct tty_struct *tty)
++{ 
++        unsigned long flags;
++        struct usb_serial_port *port = tty->driver_data;
++
++        if (debug) dev_dbg(&port->dev, "TTY buffer approaching limit, stopping USB reads\n");
++
++        spin_lock_irqsave(&port->lock, flags);
++        port->throttle_req = 1;
++        spin_unlock_irqrestore(&port->lock, flags);
++}
++
++static void vizzini_unthrottle(struct tty_struct *tty)
++{ 
++        unsigned long flags;
++        unsigned int was_throttled;
++        struct usb_serial_port *port = tty->driver_data;
++        struct vizzini_port_private *portdata = usb_get_serial_port_data(port);
++        int err;
++        int i;
++
++        if (debug) dev_dbg(&port->dev, "Resuming USB reads\n");
++
++        spin_lock_irqsave(&port->lock, flags);
++        was_throttled = port->throttled;
++        port->throttled = 0;
++        port->throttle_req = 0;
++        spin_unlock_irqrestore(&port->lock, flags);
++
++        if (was_throttled) {
++                for (i = 0; i < N_IN_URB; i++) {
++                        spin_lock_irqsave(&port->lock, flags);
++                        if (portdata->in_urb_flags[i] == READ_URB_STOPPED) {
++                                if (debug) dev_dbg(&port->dev, "unthrottling urb %d\n", i);
++                                portdata->in_urb_flags[i] = READ_URB_RUNNING;
++                                spin_unlock_irqrestore(&port->lock, flags);
++                                err = usb_submit_urb(portdata->in_urbs[i], GFP_ATOMIC);
++                                if (err)
++                                        dev_err(&port->dev, "resubmit read urb failed. (%d)\n", err);
++                        } else {
++                                spin_unlock_irqrestore(&port->lock, flags);
++                        }
++                }
++        }
++}
+ 
+ 
+ static struct usb_serial_driver vizzini_device = {
+@@ -1606,6 +1682,8 @@
+         .probe              = vizzini_probe,
+         .open               = vizzini_open,
+         .close              = vizzini_close,
++        .throttle           = vizzini_throttle,
++        .unthrottle         = vizzini_unthrottle,
+         .write              = vizzini_write,
+         .write_room         = vizzini_write_room,
+         .ioctl              = vizzini_ioctl,
diff --git a/multitech/recipes/vizzini/vizzini_0.76.bb b/multitech/recipes/vizzini/vizzini_0.76.bb
index ff1f421..d1cc653 100644
--- a/multitech/recipes/vizzini/vizzini_0.76.bb
+++ b/multitech/recipes/vizzini/vizzini_0.76.bb
@@ -1,10 +1,11 @@
 require vizzini.inc
 
-LOCAL_PR = "${INC_PR}.0"
+LOCAL_PR = "${INC_PR}.1"
 MACHINE_KERNEL_PR_append = "${LOCAL_PR}"
 
 SRC_URI += "file://xr21v141x-lnx-3.0-pak.tar.gz \
 			file://vizzini-0.76-rs485.patch \
+			file://vizzini-0.76-flow-control.patch \
 			"
 S = "${WORKDIR}/xr21v141x-lnx-3.0-pak"