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: Andi Kleen <ak@linux.intel.com>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 63f7cc45bcaca15b34691ce081fdd30b7b0007d8..7b8815ddf3688e725a1cbde438d1b74ea6120999 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -486,12 +486,22 @@ 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 9927bca29b3ab22c318fc5e3d02b186a33d7741f..9fa3cde25641e8cb961b61c823633be5ff74dacf 100644 (file)
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -49,7 +49,6 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port, struct file *,
 static void cp210x_break_ctl(struct tty_struct *, int);
 static int cp210x_startup(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;
 
@@ -165,7 +164,6 @@ static struct usb_serial_driver cp210x_device = {
        .tiocmset               = cp210x_tiocmset,
        .attach                 = cp210x_startup,
        .dtr_rts                = cp210x_dtr_rts,
-       .carrier_raised         = cp210x_carrier_raised
 };
 
 /* Config request types */
@@ -764,15 +762,6 @@ 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 fd35f73b572154b33b60d6415cf59ea4edde054f..0c366952f98cfac6563fa32bc92cc02b97114d45 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,
@@ -1337,14 +1335,6 @@ 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 ca92f67747cc2f2c4b1f5a411bc3763be9a0b009..d2d5505490384d1241a97f9aa4e0cbd7a61ba582 100644 (file)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -481,6 +481,26 @@ 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 c98f0fb675bac35d25f29c636b83e81af1d2a2af..3d619e4086df49a4b9725df0e78bbe676b16e8fe 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -677,9 +677,11 @@ 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);
@@ -701,11 +703,20 @@ 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 329d311a35d9b1ef9d10e3ac96924c450fd1c4bb..b9575c805108ec192e6760320ffaf4d9d826a857 100644 (file)
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -133,7 +133,7 @@ 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
@@ -531,6 +531,9 @@ static void spcp8x5_process_read_urb(struct urb *urb)
        tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
                                                        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);
 }
 

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 84a4c44c208b78a7eb9602091bc5a1401afdab8d..8ab6142be3f72c253a405c20707fa42aad525046 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -346,6 +346,9 @@ 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);