[PATCH 09/16] serial: mvebu-uart: add TX interrupt trigger for pulse interrupts
From: Gregory CLEMENT <hidden>
Date: 2017-10-06 20:22:09
Also in:
linux-devicetree, linux-gpio, linux-serial
Hi Miquel, On ven., oct. 06 2017, Miquel Raynal [off-list ref] wrote:
From: Allen Yan <redacted> Pulse interrupts (extended UART only) needs a change of state to trigger the TX interrupt. In addition to enabling the TX_READY_INT_EN flag, produce a FIFO state change from 'empty' to 'not full'. For this, write only one data byte in TX start, making the TX FIFO not empty, and wait for the TX interrupt to continue the transfer. Signed-off-by: Allen Yan <redacted> Signed-off-by: Miquel Raynal <redacted>
Reviewed-by: Gregory CLEMENT <redacted> Thanks, Gregory
quoted hunk
--- drivers/tty/serial/mvebu-uart.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 67f302748b78..46d10209637a 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c@@ -165,8 +165,16 @@ static void mvebu_uart_stop_tx(struct uart_port *port) static void mvebu_uart_start_tx(struct uart_port *port) { - unsigned int ctl = readl(port->membase + UART_INTR(port)); + unsigned int ctl; + struct circ_buf *xmit = &port->state->xmit; + if (IS_EXTENDED(port) && !uart_circ_empty(xmit)) { + writel(xmit->buf[xmit->tail], port->membase + UART_TSH(port)); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + } + + ctl = readl(port->membase + UART_INTR(port)); ctl |= CTRL_TX_RDY_INT(port); writel(ctl, port->membase + UART_INTR(port)); }-- 2.11.0
-- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com