The interrupt endpoint will report current IIR. If we got IIR with MSR changed , We will do read MSR with interrupt_work worker to do f81232_read_msr() function.
We also confirmd MSR strange delta value is not locking-issue. The issue is set MCR & get MSR before IIR notice with MSR changed (Loopback only). When we use RS232 loopback, assume doing RTS change will cause CTS change, DTR change will cause DCD/DSR change too. Sometimes we got 7~4 bits of MSR changed but the 3~0 bits of MSR(delta) maybe not changed when set & get MCR rapidly. So we add more check not only UART_MSR_ANY_DELTA but also with comparing DCD/RI/DSR/CTS change with old value. Because of the state bit is always correct, we direct save msr when read. The following step to reproduce this problem with while loop step 1~4: 1. ioctl(fd, TIOCMSET, &data) to set RTS or DTR 2. ioctl(fd, TIOCMGET, &data) to read CTS or DCD/DSR state 3. ioctl(fd, TIOCMSET, &data) to unset RTS or DTR 4. ioctl(fd, TIOCMGET, &data) to read CTS or DCD/DSR state Signed-off-by: Peter Hung <hpeter+linux_ker...@gmail.com> --- drivers/usb/serial/f81232.c | 106 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 98 insertions(+), 8 deletions(-) diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c index bf072fe..339be30 100644 --- a/drivers/usb/serial/f81232.c +++ b/drivers/usb/serial/f81232.c @@ -36,6 +36,9 @@ MODULE_DEVICE_TABLE(usb, id_table); #define F81232_GET_REGISTER 0xc0 #define F81232_SET_REGISTER 0x40 +#define SERIAL_BASE_ADDRESS 0x0120 +#define MODEM_STATUS_REGISTER (0x06 + SERIAL_BASE_ADDRESS) + #define CONTROL_DTR 0x01 #define CONTROL_RTS 0x02 @@ -54,6 +57,8 @@ struct f81232_private { struct mutex lock; u8 line_control; u8 modem_status; + struct work_struct interrupt_work; + struct usb_serial_port *port; }; static int f81232_get_register(struct usb_serial_port *port, u16 reg, u8 *data) @@ -130,17 +135,92 @@ static int f81232_set_register(struct usb_serial_port *port, u16 reg, u8 data) kfree(tmp); return status; } + +static void f81232_read_msr(struct usb_serial_port *port) +{ + int status; + u8 current_msr, prev_msr; + u8 msr_mask = ~UART_MSR_ANY_DELTA; + u8 msr_changed_bit; + struct tty_struct *tty; + struct f81232_private *priv = usb_get_serial_port_data(port); + + status = f81232_get_register(port, MODEM_STATUS_REGISTER, + ¤t_msr); + if (status) { + dev_err(&port->dev, "%s fail, status: %d\n", __func__, status); + return; + } + + /* + * The 7~4 bits of MSR will change but the 3~0 bits of MSR(delta) + * maybe not change when set MCR & get MSR rapidly. + * + * So we add more check with comparing DCD/RI/DSR/CTS + * change. and direct save msr when read. + */ + + mutex_lock(&priv->lock); + prev_msr = priv->modem_status; + priv->modem_status = current_msr; + mutex_unlock(&priv->lock); + + if (!(current_msr & UART_MSR_ANY_DELTA) && + !((prev_msr ^ current_msr) & msr_mask)) + return; + + /* find checked delta bits set */ + msr_changed_bit = + (current_msr & UART_MSR_ANY_DELTA) << 4; + + /* append with not delta but changed bits */ + msr_changed_bit |= (prev_msr ^ current_msr) & msr_mask; + + if (msr_changed_bit & UART_MSR_CTS) + port->icount.cts++; + if (msr_changed_bit & UART_MSR_DSR) + port->icount.dsr++; + if (msr_changed_bit & UART_MSR_RI) + port->icount.rng++; + if (msr_changed_bit & UART_MSR_DCD) { + + port->icount.dcd++; + tty = tty_port_tty_get(&port->port); + if (tty) { + + usb_serial_handle_dcd_change(port, tty, + current_msr & UART_MSR_DCD); + + tty_kref_put(tty); + } + } + + wake_up_interruptible(&port->port.delta_msr_wait); +} + static void f81232_update_line_status(struct usb_serial_port *port, unsigned char *data, - unsigned int actual_length) + size_t actual_length) { - /* - * FIXME: Update port->icount, and call - * - * wake_up_interruptible(&port->port.delta_msr_wait); - * - * on MSR changes. - */ + struct f81232_private *priv = usb_get_serial_port_data(port); + + if (!actual_length) + return; + + switch (data[0] & 0x07) { + case 0x00: /* msr change */ + dev_dbg(&port->dev, "IIR: MSR Change: %02x\n", data[0]); + schedule_work(&priv->interrupt_work); + break; + case 0x02: /* tx-empty */ + break; + case 0x04: /* rx data available */ + break; + case 0x06: /* lsr change */ + /* we can forget it. the LSR will read from bulk-in */ + dev_dbg(&port->dev, "IIR: LSR Change: %02x\n", data[0]); + break; + } } static void f81232_read_int_callback(struct urb *urb) @@ -351,6 +431,14 @@ static int f81232_ioctl(struct tty_struct *tty, return -ENOIOCTLCMD; } +static void f81232_interrupt_work(struct work_struct *work) +{ + struct f81232_private *priv = + container_of(work, struct f81232_private, interrupt_work); + + f81232_read_msr(priv->port); +} + static int f81232_port_probe(struct usb_serial_port *port) { struct f81232_private *priv; @@ -360,10 +448,12 @@ static int f81232_port_probe(struct usb_serial_port *port) return -ENOMEM; mutex_init(&priv->lock); + INIT_WORK(&priv->interrupt_work, f81232_interrupt_work); usb_set_serial_port_data(port, priv); port->port.drain_delay = 256; + priv->port = port; return 0; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/