sc16is7xx: Handle modem status lines
The uart_handle_cts_change() and uart_handle_dcd_change() must be called with port lock being held. Acquire the lock after reading MSR register. Do not acquire spin lock when reading MSR register because I2C/SPI port functions cannot be called with spinlocks held. Update rng and dsr counters. Wake up delta_msr_wait to allow tty notice modem status change. Co-developed-by: Lech Perczak <l.perczak@camlintechnologies.com> Co-developed-by: Tomasz Moń <tomasz.mon@camlingroup.com> Signed-off-by: Lech Perczak <l.perczak@camlintechnologies.com> Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com> Link: https://lore.kernel.org/r/20220301060332.2561851-3-tomasz.mon@camlingroup.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -324,8 +324,10 @@ struct sc16is7xx_one {
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u8 line;
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struct kthread_work tx_work;
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struct kthread_work reg_work;
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struct kthread_delayed_work ms_work;
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struct sc16is7xx_one_config config;
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bool irda_mode;
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unsigned int old_mctrl;
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};
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struct sc16is7xx_port {
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@ -705,12 +707,56 @@ static void sc16is7xx_handle_tx(struct uart_port *port)
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port)
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{
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u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
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unsigned int mctrl = 0;
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mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
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mctrl |= (msr & SC16IS7XX_MSR_DSR_BIT) ? TIOCM_DSR : 0;
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mctrl |= (msr & SC16IS7XX_MSR_CD_BIT) ? TIOCM_CAR : 0;
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mctrl |= (msr & SC16IS7XX_MSR_RI_BIT) ? TIOCM_RNG : 0;
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return mctrl;
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}
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static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
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{
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struct uart_port *port = &one->port;
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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unsigned long flags;
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unsigned int status, changed;
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lockdep_assert_held_once(&s->efr_lock);
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status = sc16is7xx_get_hwmctrl(port);
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changed = status ^ one->old_mctrl;
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if (changed == 0)
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return;
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one->old_mctrl = status;
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spin_lock_irqsave(&port->lock, flags);
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if ((changed & TIOCM_RNG) && (status & TIOCM_RNG))
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port->icount.rng++;
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if (changed & TIOCM_DSR)
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port->icount.dsr++;
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if (changed & TIOCM_CAR)
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uart_handle_dcd_change(port, status & TIOCM_CAR);
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if (changed & TIOCM_CTS)
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uart_handle_cts_change(port, status & TIOCM_CTS);
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wake_up_interruptible(&port->state->port.delta_msr_wait);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
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{
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struct uart_port *port = &s->p[portno].port;
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do {
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unsigned int iir, rxlen;
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
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if (iir & SC16IS7XX_IIR_NO_INT_BIT)
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@ -727,6 +773,11 @@ static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
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if (rxlen)
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sc16is7xx_handle_rx(port, rxlen, iir);
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break;
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/* CTSRTS interrupt comes only when CTS goes inactive */
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case SC16IS7XX_IIR_CTSRTS_SRC:
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case SC16IS7XX_IIR_MSI_SRC:
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sc16is7xx_update_mlines(one);
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break;
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case SC16IS7XX_IIR_THRI_SRC:
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sc16is7xx_handle_tx(port);
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break;
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@ -874,6 +925,30 @@ static void sc16is7xx_stop_rx(struct uart_port *port)
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sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
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}
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static void sc16is7xx_ms_proc(struct kthread_work *ws)
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{
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struct sc16is7xx_one *one = to_sc16is7xx_one(ws, ms_work.work);
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struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
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if (one->port.state) {
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mutex_lock(&s->efr_lock);
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sc16is7xx_update_mlines(one);
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mutex_unlock(&s->efr_lock);
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kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
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}
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}
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static void sc16is7xx_enable_ms(struct uart_port *port)
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{
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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lockdep_assert_held_once(&port->lock);
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kthread_queue_delayed_work(&s->kworker, &one->ms_work, 0);
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}
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static void sc16is7xx_start_tx(struct uart_port *port)
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{
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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@ -893,10 +968,10 @@ static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
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static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
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{
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/* DCD and DSR are not wired and CTS/RTS is handled automatically
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* so just indicate DSR and CAR asserted
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*/
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return TIOCM_DSR | TIOCM_CAR;
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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/* Called with port lock taken so we can only return cached value */
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return one->old_mctrl;
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}
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static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
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@ -920,8 +995,12 @@ static void sc16is7xx_set_termios(struct uart_port *port,
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struct ktermios *old)
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{
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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unsigned int lcr, flow = 0;
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int baud;
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unsigned long flags;
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kthread_cancel_delayed_work_sync(&one->ms_work);
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/* Mask termios capabilities we don't support */
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termios->c_cflag &= ~CMSPAR;
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@ -1010,8 +1089,15 @@ static void sc16is7xx_set_termios(struct uart_port *port,
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/* Setup baudrate generator */
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baud = sc16is7xx_set_baud(port, baud);
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spin_lock_irqsave(&port->lock, flags);
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/* Update timeout according to new baud rate */
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uart_update_timeout(port, termios->c_cflag, baud);
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if (UART_ENABLE_MS(port, termios->c_cflag))
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sc16is7xx_enable_ms(port);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static int sc16is7xx_config_rs485(struct uart_port *port,
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@ -1052,6 +1138,7 @@ static int sc16is7xx_startup(struct uart_port *port)
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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unsigned int val;
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unsigned long flags;
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sc16is7xx_power(port, 1);
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@ -1102,16 +1189,25 @@ static int sc16is7xx_startup(struct uart_port *port)
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SC16IS7XX_EFCR_TXDISABLE_BIT,
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0);
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/* Enable RX interrupt */
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val = SC16IS7XX_IER_RDI_BIT;
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/* Enable RX, CTS change and modem lines interrupts */
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val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_CTSI_BIT |
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SC16IS7XX_IER_MSI_BIT;
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sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
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/* Enable modem status polling */
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spin_lock_irqsave(&port->lock, flags);
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sc16is7xx_enable_ms(port);
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spin_unlock_irqrestore(&port->lock, flags);
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return 0;
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}
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static void sc16is7xx_shutdown(struct uart_port *port)
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{
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struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
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struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
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kthread_cancel_delayed_work_sync(&one->ms_work);
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/* Disable all interrupts */
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sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
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@ -1175,6 +1271,7 @@ static const struct uart_ops sc16is7xx_ops = {
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.stop_tx = sc16is7xx_stop_tx,
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.start_tx = sc16is7xx_start_tx,
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.stop_rx = sc16is7xx_stop_rx,
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.enable_ms = sc16is7xx_enable_ms,
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.break_ctl = sc16is7xx_break_ctl,
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.startup = sc16is7xx_startup,
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.shutdown = sc16is7xx_shutdown,
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@ -1341,7 +1438,9 @@ static int sc16is7xx_probe(struct device *dev,
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s->p[i].port.uartclk = freq;
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s->p[i].port.rs485_config = sc16is7xx_config_rs485;
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s->p[i].port.ops = &sc16is7xx_ops;
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s->p[i].old_mctrl = 0;
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s->p[i].port.line = sc16is7xx_alloc_line();
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if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
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ret = -ENOMEM;
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goto out_ports;
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@ -1353,9 +1452,17 @@ static int sc16is7xx_probe(struct device *dev,
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sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
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SC16IS7XX_EFCR_RXDISABLE_BIT |
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SC16IS7XX_EFCR_TXDISABLE_BIT);
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/* Use GPIO lines as modem status registers */
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if (devtype->has_mctrl)
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sc16is7xx_port_write(&s->p[i].port,
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SC16IS7XX_IOCONTROL_REG,
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SC16IS7XX_IOCONTROL_MODEM_BIT);
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/* Initialize kthread work structs */
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kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
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kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
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kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc);
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/* Register port */
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uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
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@ -1439,6 +1546,7 @@ static void sc16is7xx_remove(struct device *dev)
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#endif
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for (i = 0; i < s->devtype->nr_uart; i++) {
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kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
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uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
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clear_bit(s->p[i].port.line, &sc16is7xx_lines);
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sc16is7xx_power(&s->p[i].port, 0);
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