USB: serial: handle Data Carrier Detect changes

commit d14fc1a74e846d7851f24fc9519fe87dc12a1231 upstream.

Alan's commit 335f8514f200e63d689113d29cb7253a5c282967 introduced
.carrier_raised function in several drivers.  That also means
tty_port_block_til_ready can now suspend the process trying to open the serial
port when Carrier Detect is low and put it into tty_port.open_wait queue.  We
need to wake up the process when Carrier Detect goes high and trigger TTY
hangup when CD goes low.

Some of the devices do not report modem status line changes, or at least we
don't understand the status message, so for those we remove .carrier_raised
again.

Signed-off-by: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 7e8e398184145f3d36e14a4632c9984378c44469..c46785025d52685d651c0cf9d8f36764df706a21 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -489,12 +489,22 @@ static void ch341_read_int_callback(struct urb *urb)
        if (actual_length >= 4) {
                struct ch341_private *priv = usb_get_serial_port_data(port);
                unsigned long flags;
+               u8 prev_line_status = priv->line_status;
 
                spin_lock_irqsave(&priv->lock, flags);
                priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
                if ((data[1] & CH341_MULT_STAT))
                        priv->multi_status_change = 1;
                spin_unlock_irqrestore(&priv->lock, flags);
+
+               if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
+                       struct tty_struct *tty = tty_port_tty_get(&port->port);
+                       if (tty)
+                               usb_serial_handle_dcd_change(port, tty,
+                                           priv->line_status & CH341_BIT_DCD);
+                       tty_kref_put(tty);
+               }
+
                wake_up_interruptible(&priv->delta_msr_wait);
        }
 

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index e85e325f2cd835476d0c4c5277193d2a7cc4eedb..8f462850b49031fb5aa6728cfce6936e4b7ed0e4 100644 (file)
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -51,7 +51,6 @@ static void cp210x_break_ctl(struct tty_struct *, int);
 static int cp210x_startup(struct usb_serial *);
 static void cp210x_disconnect(struct usb_serial *);
 static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
-static int cp210x_carrier_raised(struct usb_serial_port *p);
 
 static int debug;
 
@@ -165,8 +164,7 @@ static struct usb_serial_driver cp210x_device = {
        .tiocmset               = cp210x_tiocmset,
        .attach                 = cp210x_startup,
        .disconnect             = cp210x_disconnect,
-       .dtr_rts                = cp210x_dtr_rts,
-       .carrier_raised         = cp210x_carrier_raised
+       .dtr_rts                = cp210x_dtr_rts
 };
 
 /* Config request types */
@@ -795,15 +793,6 @@ static int cp210x_tiocmget (struct tty_struct *tty, struct file *file)
        return result;
 }
 
-static int cp210x_carrier_raised(struct usb_serial_port *p)
-{
-       unsigned int control;
-       cp210x_get_config(p, CP210X_GET_MDMSTS, &control, 1);
-       if (control & CONTROL_DCD)
-               return 1;
-       return 0;
-}
-
 static void cp210x_break_ctl (struct tty_struct *tty, int break_state)
 {
        struct usb_serial_port *port = tty->driver_data;

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 3edda3ed822a5326e1072e3f49bc163af2878dae..1832255b85aa260ea17522c45468cf3b33d9e12c 100644 (file)
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -455,7 +455,6 @@ static int digi_write_room(struct tty_struct *tty);
 static int digi_chars_in_buffer(struct tty_struct *tty);
 static int digi_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void digi_close(struct usb_serial_port *port);
-static int digi_carrier_raised(struct usb_serial_port *port);
 static void digi_dtr_rts(struct usb_serial_port *port, int on);
 static int digi_startup_device(struct usb_serial *serial);
 static int digi_startup(struct usb_serial *serial);
@@ -511,7 +510,6 @@ static struct usb_serial_driver digi_acceleport_2_device = {
        .open =                         digi_open,
        .close =                        digi_close,
        .dtr_rts =                      digi_dtr_rts,
-       .carrier_raised =               digi_carrier_raised,
        .write =                        digi_write,
        .write_room =                   digi_write_room,
        .write_bulk_callback =          digi_write_bulk_callback,
@@ -1338,14 +1336,6 @@ static void digi_dtr_rts(struct usb_serial_port *port, int on)
        digi_set_modem_signals(port, on * (TIOCM_DTR|TIOCM_RTS), 1);
 }
 
-static int digi_carrier_raised(struct usb_serial_port *port)
-{
-       struct digi_port *priv = usb_get_serial_port_data(port);
-       if (priv->dp_modem_signals & TIOCM_CD)
-               return 1;
-       return 0;
-}
-
 static int digi_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
        int ret;

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index f804acb138ec508f85fe63481b9b6622e084ace1..bad7045ccace1147f1b3eb54f6dbd8483b65a823 100644 (file)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -584,6 +584,26 @@ int usb_serial_handle_break(struct usb_serial_port *port)
 }
 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 
+/**
+ *     usb_serial_handle_dcd_change - handle a change of carrier detect state
+ *     @port: usb_serial_port structure for the open port
+ *     @tty: tty_struct structure for the port
+ *     @status: new carrier detect status, nonzero if active
+ */
+void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+                               struct tty_struct *tty, unsigned int status)
+{
+       struct tty_port *port = &usb_port->port;
+
+       dbg("%s - port %d, status %d", __func__, usb_port->number, status);
+
+       if (status)
+               wake_up_interruptible(&port->open_wait);
+       else if (tty && !C_CLOCAL(tty))
+               tty_hangup(tty);
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
+
 int usb_serial_generic_resume(struct usb_serial *serial)
 {
        struct usb_serial_port *port;

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 185fe9a7d4e05f277bd1293343aa0f80394d8835..2cbd661a92f7109bb1e1976dbc5ace3f6074e450 100644 (file)
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -680,22 +680,6 @@ static void keyspan_pda_dtr_rts(struct usb_serial_port *port, int on)
        }
 }
 
-static int keyspan_pda_carrier_raised(struct usb_serial_port *port)
-{
-       struct usb_serial *serial = port->serial;
-       unsigned char modembits;
-
-       /* If we can read the modem status and the DCD is low then
-          carrier is not raised yet */
-       if (keyspan_pda_get_modem_info(serial, &modembits) >= 0) {
-               if (!(modembits & (1>>6)))
-                       return 0;
-       }
-       /* Carrier raised, or we failed (eg disconnected) so
-          progress accordingly */
-       return 1;
-}
-
 
 static int keyspan_pda_open(struct tty_struct *tty,
                                        struct usb_serial_port *port)
@@ -882,7 +866,6 @@ static struct usb_serial_driver keyspan_pda_device = {
        .id_table =             id_table_std,
        .num_ports =            1,
        .dtr_rts =              keyspan_pda_dtr_rts,
-       .carrier_raised =       keyspan_pda_carrier_raised,
        .open =                 keyspan_pda_open,
        .close =                keyspan_pda_close,
        .write =                keyspan_pda_write,

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 89609e1af7490380d3de87cb7a661ac0d605c2de..f6e4703d458846e945db53dcb846df9db11a7414 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -967,9 +967,11 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
 {
 
        struct pl2303_private *priv = usb_get_serial_port_data(port);
+       struct tty_struct *tty;
        unsigned long flags;
        u8 status_idx = UART_STATE;
        u8 length = UART_STATE + 1;
+       u8 prev_line_status;
        u16 idv, idp;
 
        idv = le16_to_cpu(port->serial->dev->descriptor.idVendor);
@@ -991,11 +993,20 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
 
        /* Save off the uart status for others to look at */
        spin_lock_irqsave(&priv->lock, flags);
+       prev_line_status = priv->line_status;
        priv->line_status = data[status_idx];
        spin_unlock_irqrestore(&priv->lock, flags);
        if (priv->line_status & UART_BREAK_ERROR)
                usb_serial_handle_break(port);
        wake_up_interruptible(&priv->delta_msr_wait);
+
+       tty = tty_port_tty_get(&port->port);
+       if (!tty)
+               return;
+       if ((priv->line_status ^ prev_line_status) & UART_DCD)
+               usb_serial_handle_dcd_change(port, tty,
+                               priv->line_status & UART_DCD);
+       tty_kref_put(tty);
 }
 
 static void pl2303_read_int_callback(struct urb *urb)

diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c
index 2ea32c561d02ef933ae47658ba7780c52918c80e..706f46f755e233910799d1c69b9c557e8a2fe2d0 100644 (file)
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -137,7 +137,7 @@ struct spcp8x5_usb_ctrl_arg {
 
 /* how come ??? */
 #define UART_STATE                     0x08
-#define UART_STATE_TRANSIENT_MASK      0x74
+#define UART_STATE_TRANSIENT_MASK      0x75
 #define UART_DCD                       0x01
 #define UART_DSR                       0x02
 #define UART_BREAK_ERROR               0x04
@@ -730,6 +730,10 @@ static void spcp8x5_read_bulk_callback(struct urb *urb)
                                                        urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+
+       if (status & UART_DCD)
+               usb_serial_handle_dcd_change(port, tty,
+                          priv->line_status & MSR_STATUS_LINE_DCD);
        tty_kref_put(tty);
 
        /* Schedule the next read */

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 0a458b86193365d9113f49abc360faf00b2b2519..453ab9517edd9fa5744c10979dce31808f8e5a60 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -324,6 +324,9 @@ extern int usb_serial_handle_sysrq_char(struct tty_struct *tty,
                                        struct usb_serial_port *port,
                                        unsigned int ch);
 extern int usb_serial_handle_break(struct usb_serial_port *port);
+extern void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+                                        struct tty_struct *tty,
+                                        unsigned int status);
 
 
 extern int usb_serial_bus_register(struct usb_serial_driver *device);