lkml.org 
[lkml]   [2016]   [Jan]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH LINUX 6/6] tty: xuartps: Consolidate TX handling
Date
start_tx and the ISR used largely identical code to transmit data.
Consolidate that in one place.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
drivers/tty/serial/xilinx_uartps.c | 97 ++++++++++++++++----------------------
1 file changed, 40 insertions(+), 57 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 3ff6e3c2347c..131a3117fbbb 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -239,6 +239,41 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
tty_flip_buffer_push(&port->state->port);
}

+static void cdns_uart_handle_tx(struct uart_port *port)
+{
+ unsigned int numbytes;
+
+ if (uart_circ_empty(&port->state->xmit)) {
+ writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
+ return;
+ }
+
+ numbytes = port->fifosize;
+ while (numbytes && !uart_circ_empty(&port->state->xmit) &&
+ !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
+ /*
+ * Get the data from the UART circular buffer
+ * and write it to the cdns_uart's TX_FIFO
+ * register.
+ */
+ writel(port->state->xmit.buf[port->state->xmit.tail],
+ port->membase + CDNS_UART_FIFO);
+ port->icount.tx++;
+
+ /*
+ * Adjust the tail of the UART buffer and wrap
+ * the buffer if it reaches limit.
+ */
+ port->state->xmit.tail =
+ (port->state->xmit.tail + 1) & (UART_XMIT_SIZE - 1);
+
+ numbytes--;
+ }
+
+ if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+}
+
/**
* cdns_uart_isr - Interrupt handler
* @irq: Irq number
@@ -250,7 +285,7 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
unsigned long flags;
- unsigned int isrstatus, numbytes;
+ unsigned int isrstatus;

spin_lock_irqsave(&port->lock, flags);

@@ -262,40 +297,8 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
if (isrstatus & CDNS_UART_RX_IRQS)
cdns_uart_handle_rx(port, isrstatus);

- /* Dispatch an appropriate handler */
- if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
- if (uart_circ_empty(&port->state->xmit)) {
- writel(CDNS_UART_IXR_TXEMPTY,
- port->membase + CDNS_UART_IDR);
- } else {
- numbytes = port->fifosize;
- /* Break if no more data available in the UART buffer */
- while (numbytes--) {
- if (uart_circ_empty(&port->state->xmit))
- break;
- /* Get the data from the UART circular buffer
- * and write it to the cdns_uart's TX_FIFO
- * register.
- */
- writel(port->state->xmit.buf[
- port->state->xmit.tail],
- port->membase + CDNS_UART_FIFO);
-
- port->icount.tx++;
-
- /* Adjust the tail of the UART buffer and wrap
- * the buffer if it reaches limit.
- */
- port->state->xmit.tail =
- (port->state->xmit.tail + 1) &
- (UART_XMIT_SIZE - 1);
- }
-
- if (uart_circ_chars_pending(
- &port->state->xmit) < WAKEUP_CHARS)
- uart_write_wakeup(port);
- }
- }
+ if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY)
+ cdns_uart_handle_tx(port);

writel(isrstatus, port->membase + CDNS_UART_ISR);

@@ -502,7 +505,7 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
*/
static void cdns_uart_start_tx(struct uart_port *port)
{
- unsigned int status, numbytes = port->fifosize;
+ unsigned int status;

if (uart_tx_stopped(port))
return;
@@ -519,31 +522,11 @@ static void cdns_uart_start_tx(struct uart_port *port)
if (uart_circ_empty(&port->state->xmit))
return;

- while (numbytes-- && ((readl(port->membase + CDNS_UART_SR) &
- CDNS_UART_SR_TXFULL)) != CDNS_UART_SR_TXFULL) {
- /* Break if no more data available in the UART buffer */
- if (uart_circ_empty(&port->state->xmit))
- break;
-
- /* Get the data from the UART circular buffer and
- * write it to the cdns_uart's TX_FIFO register.
- */
- writel(port->state->xmit.buf[port->state->xmit.tail],
- port->membase + CDNS_UART_FIFO);
- port->icount.tx++;
+ cdns_uart_handle_tx(port);

- /* Adjust the tail of the UART buffer and wrap
- * the buffer if it reaches limit.
- */
- port->state->xmit.tail = (port->state->xmit.tail + 1) &
- (UART_XMIT_SIZE - 1);
- }
writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
/* Enable the TX Empty interrupt */
writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER);
-
- if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
- uart_write_wakeup(port);
}

/**
--
2.7.0.3.g497ea1e
\
 
 \ /
  Last update: 2016-01-12 03:01    [W:0.057 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site