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 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 8d7731dbf478f9592d8dff350374dc6375649c44..d82cd7a2438bffe559164aa76ec92f566e9a6c2b 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;
 
@@ -165,8 +164,7 @@ 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 */
@@ -765,15 +763,6 @@ 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 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 8ae4c6cbc38a04ea250d43aad68aa43081098245..e3a9e2e0ec57868b4231e1d3238468ae61290e69 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..1dea329009f305f20415aa3b0777ba4f9761fd11 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
@@ -526,6 +526,10 @@ 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 55675b1efb28659b37ff7b165fc6aa6ab0835fd7..e02848c55bd6a8e5bb98a91bff37222444a367ca 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -345,6 +345,9 @@ 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);