Commit 01a305a3 authored by Gabriel Somlo's avatar Gabriel Somlo Committed by Greg Kroah-Hartman
Browse files

serial: liteuart: add IRQ support for the TX path 



Switch the TX path to IRQ-driven operation, while maintaining support
for polling mode via the poll timer.

Signed-off-by: default avatarGabriel Somlo <gsomlo@gmail.com>
Reviewed-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: default avatarJiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221123130500.1030189-14-gsomlo@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5602cf99

drivers/tty/serial/liteuart.c

+13 −17
Original line number Original line Diff line number Diff line
@@ -93,27 +93,12 @@ static void liteuart_update_irq_reg(struct uart_port *port, bool set, u8 mask) 




static void liteuart_stop_tx(struct uart_port *port)

static void liteuart_stop_tx(struct uart_port *port)

{

{

	liteuart_update_irq_reg(port, false, EV_TX);

}

}





static void liteuart_start_tx(struct uart_port *port)

static void liteuart_start_tx(struct uart_port *port)

{

{

	struct circ_buf *xmit = &port->state->xmit;

	liteuart_update_irq_reg(port, true, EV_TX);

	unsigned char ch;



	if (unlikely(port->x_char)) {

		litex_write8(port->membase + OFF_RXTX, port->x_char);

		port->icount.tx++;

		port->x_char = 0;

	} else if (!uart_circ_empty(xmit)) {

		while (xmit->head != xmit->tail) {

			ch = xmit->buf[xmit->tail];

			uart_xmit_advance(port, 1);

			liteuart_putchar(port, ch);

		}

	}



	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)

		uart_write_wakeup(port);

}

}





static void liteuart_stop_rx(struct uart_port *port)

static void liteuart_stop_rx(struct uart_port *port)
@@ -144,6 +129,15 @@ static void liteuart_rx_chars(struct uart_port *port) 
	tty_flip_buffer_push(&port->state->port);

	tty_flip_buffer_push(&port->state->port);

}

}





static void liteuart_tx_chars(struct uart_port *port)

{

	u8 ch;



	uart_port_tx(port, ch,

		!litex_read8(port->membase + OFF_TXFULL),

		litex_write8(port->membase + OFF_RXTX, ch));

}



static irqreturn_t liteuart_interrupt(int irq, void *data)

static irqreturn_t liteuart_interrupt(int irq, void *data)

{

{

	struct liteuart_port *uart = data;

	struct liteuart_port *uart = data;
@@ -159,6 +153,8 @@ static irqreturn_t liteuart_interrupt(int irq, void *data) 
	isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;

	isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;

	if (isr & EV_RX)

	if (isr & EV_RX)

		liteuart_rx_chars(port);

		liteuart_rx_chars(port);

	if (isr & EV_TX)

		liteuart_tx_chars(port);

	spin_unlock_irqrestore(&port->lock, flags);

	spin_unlock_irqrestore(&port->lock, flags);





	return IRQ_RETVAL(isr);

	return IRQ_RETVAL(isr);