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>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 59eff721fcc5bb1e3374b1bfd098b0a67b558ddc..e50823a089672ceac9a8b4b7fd222d861e159317 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -479,12 +479,22 @@ 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 9f8f0d0443c73001bf4397fcfb19046415e0c136..1cedc4c21750d20ef91f77fe15ab218b5d39a028 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 */
@@ -800,15 +798,6 @@ 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 68e80be6b9e1888dbc82b7c8cc6584a9f7abddb7..2acfb38271caedaca04fcb0eba81f031a11f33ad 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 e0fb294291e3d696bbb2eff3c8641753191af49c..a7b8a55a7ef768e067ab1630c50e0fb16db97fe1 100644 (file)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -578,6 +578,26 @@ 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 1296a097f5c354285efdad53d7e10388cbaa6a7b..0761b5a2227dc07036848f03ca930e4490739c42 100644 (file)
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -663,22 +663,6 @@ 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)
@@ -854,7 +838,6 @@ 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 ecb17081e003e3bebab25e1eeb5bf9810b3f0964..362dad2621deb2ce5e88c3898269032e8adc1ed2 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -955,9 +955,11 @@ 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);
@@ -979,11 +981,20 @@ 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 1e58220403d1f7f466425d77c1d3ccf124fa993a..f863d2d404341cfcc4c04f94b258a91519d08850 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
@@ -734,6 +734,10 @@ static void spcp8x5_read_bulk_callback(struct urb *urb)
                        tty_insert_flip_char(tty, data[i], tty_flag);
                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 _if_ we are still open */

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index ce911ebf91e82c54c65cc2f46d428ed4c1bcab6a..bb911e3c636c4adcdf889f5d33ec6395862f1297 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -326,6 +326,9 @@ 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);