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serial: liteuart: add IRQ support for the TX path

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

Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221123130500.1030189-14-gsomlo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gabriel Somlo 2022-11-23 08:04:59 -05:00 committed by Greg Kroah-Hartman
parent 5602cf99dc
commit 01a305a366
1 changed files with 13 additions and 17 deletions
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30
drivers/tty/serial/liteuart.c
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@ -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)
{
liteuart_update_irq_reg(port, false, EV_TX);
}
static void liteuart_start_tx(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
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);
liteuart_update_irq_reg(port, true, EV_TX);
}
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);
}
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)
{
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;
if (isr & EV_RX)
liteuart_rx_chars(port);
if (isr & EV_TX)
liteuart_tx_chars(port);
spin_unlock_irqrestore(&port->lock, flags);
return IRQ_RETVAL(isr);