USB: serial: handle Data Carrier Detect changes

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>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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 c3bea46e87fb4b7a952f953598e353e234d900f3..735ea03157abad3e9692978767a9d0e61d92eabd 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;
 
@@ -166,8 +165,7 @@ static struct usb_serial_driver cp210x_device = {
        .tiocmget               = cp210x_tiocmget,
        .tiocmset               = cp210x_tiocmset,
        .attach                 = cp210x_startup,
-       .dtr_rts                = cp210x_dtr_rts,
-       .carrier_raised         = cp210x_carrier_raised
+       .dtr_rts                = cp210x_dtr_rts
 };
 
 /* Config request types */
@@ -766,15 +764,6 @@ 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 b92070c103cd4b4854ccee1aad7bc807b829b874..666e5a6edd827edcf9e7e3a2e65532104dc55ec9 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,
@@ -1339,14 +1337,6 @@ 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 e6833e216fc9fa4e3628813d57f14891835caf6a..e4db5ad2bc55f1c37f2da2b15c086534e98248c7 100644 (file)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -479,6 +479,26 @@ 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 a10dd5676ccc0e70a930e0c7048daa675adc6f76..554a8693a463aabda0f4b514cad5574ab623b0be 100644 (file)
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -679,22 +679,6 @@ 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)
@@ -881,7 +865,6 @@ 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 45c40e6e9737fc411fa03815c70d5738c2e438e8..08c9181b8e4823192ec880181bcccdb1fe3b4fd2 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -678,9 +678,11 @@ 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);
@@ -702,11 +704,20 @@ 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 c7665d39d192bb5cde5284a830b4093787d1f6ee..cbfb70bffdd05e842a9e9479297ffb95edb2a6e0 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
@@ -525,6 +525,10 @@ static void spcp8x5_process_read_urb(struct urb *urb)
                /* overrun is special, not associated with a char */
                if (status & UART_OVERRUN_ERROR)
                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+               if (status & UART_DCD)
+                       usb_serial_handle_dcd_change(port, tty,
+                                  priv->line_status & MSR_STATUS_LINE_DCD);
        }
 
        tty_insert_flip_string_fixed_flag(tty, data, tty_flag,

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 16d682f4f7c3572fd946d736af644cd4ef9c0b27..c9049139a7a5a42f3a8f4d82d727355aeca9bce1 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -347,6 +347,9 @@ extern int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 extern int usb_serial_handle_sysrq_char(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);