serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle

commit 211565b100993c90b53bf40851eacaefc830cfe0 upstream.

The driver must provide throttle and unthrottle in uart_ops when it
sets UPSTAT_AUTORTS. Add them using existing stop_rx &
enable_interrupts functions.

Fixes: 2a76fa283098 (serial: pl011: Adopt generic flag to store auto RTS status)
Cc: stable <stable@kernel.org>
Cc: Lukas Wunner <lukas@wunner.de>
Reported-by: Nuno Gonçalves <nunojpg@gmail.com>
Tested-by: Nuno Gonçalves <nunojpg@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220614075637.8558-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 0e90806..300a8bb 100644 (file)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1372,6 +1372,15 @@ static void pl011_stop_rx(struct uart_port *port)
        pl011_dma_rx_stop(uap);
 }
 
+static void pl011_throttle_rx(struct uart_port *port)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&port->lock, flags);
+       pl011_stop_rx(port);
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+
 static void pl011_enable_ms(struct uart_port *port)
 {
        struct uart_amba_port *uap =
@@ -1793,9 +1802,10 @@ static int pl011_allocate_irq(struct uart_amba_port *uap)
  */
 static void pl011_enable_interrupts(struct uart_amba_port *uap)
 {
+       unsigned long flags;
        unsigned int i;
 
-       spin_lock_irq(&uap->port.lock);
+       spin_lock_irqsave(&uap->port.lock, flags);
 
        /* Clear out any spuriously appearing RX interrupts */
        pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR);
@@ -1817,7 +1827,14 @@ static void pl011_enable_interrupts(struct uart_amba_port *uap)
        if (!pl011_dma_rx_running(uap))
                uap->im |= UART011_RXIM;
        pl011_write(uap->im, uap, REG_IMSC);
-       spin_unlock_irq(&uap->port.lock);
+       spin_unlock_irqrestore(&uap->port.lock, flags);
+}
+
+static void pl011_unthrottle_rx(struct uart_port *port)
+{
+       struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port);
+
+       pl011_enable_interrupts(uap);
 }
 
 static int pl011_startup(struct uart_port *port)
@@ -2245,6 +2262,8 @@ static const struct uart_ops amba_pl011_pops = {
        .stop_tx        = pl011_stop_tx,
        .start_tx       = pl011_start_tx,
        .stop_rx        = pl011_stop_rx,
+       .throttle       = pl011_throttle_rx,
+       .unthrottle     = pl011_unthrottle_rx,
        .enable_ms      = pl011_enable_ms,
        .break_ctl      = pl011_break_ctl,
        .startup        = pl011_startup,