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Subject[PATCH v2 08/23] tty: serial: fls_lpuart: Split shared TX IRQ handler into two
Date
While sharing code for Tx interrupt handler between 8 and 32 bit
variant of the peripheral saves a bit of code duplication it also adds
quite a number of lpuart_is_32() checks which makes it harder to
understand. Move shared bits back into corresponding
lpuart*_transmit_buffer functions, split lpuart_txint into
lpuart_txint and lpuart32_txint so we can drop all extra
lpuart_is_32() check and make the code flow more linear.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
drivers/tty/serial/fsl_lpuart.c | 61 +++++++++++++++++++--------------
1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 8657addbfd1c..ed6d3f836c93 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -663,6 +663,18 @@ static inline void lpuart_transmit_buffer(struct lpuart_port *sport)
{
struct circ_buf *xmit = &sport->port.state->xmit;

+ if (sport->port.x_char) {
+ writeb(sport->port.x_char, sport->port.membase + UARTDR);
+ sport->port.icount.tx++;
+ sport->port.x_char = 0;
+ return;
+ }
+
+ if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
+ lpuart_stop_tx(&sport->port);
+ return;
+ }
+
while (!uart_circ_empty(xmit) &&
(readb(sport->port.membase + UARTTCFIFO) < sport->txfifo_size)) {
writeb(xmit->buf[xmit->tail], sport->port.membase + UARTDR);
@@ -682,6 +694,18 @@ static inline void lpuart32_transmit_buffer(struct lpuart_port *sport)
struct circ_buf *xmit = &sport->port.state->xmit;
unsigned long txcnt;

+ if (sport->port.x_char) {
+ lpuart32_write(&sport->port, sport->port.x_char, UARTDATA);
+ sport->port.icount.tx++;
+ sport->port.x_char = 0;
+ return;
+ }
+
+ if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
+ lpuart32_stop_tx(&sport->port);
+ return;
+ }
+
txcnt = lpuart32_read(&sport->port, UARTWATER);
txcnt = txcnt >> UARTWATER_TXCNT_OFF;
txcnt &= UARTWATER_COUNT_MASK;
@@ -773,34 +797,10 @@ static unsigned int lpuart32_tx_empty(struct uart_port *port)

static void lpuart_txint(struct lpuart_port *sport)
{
- struct circ_buf *xmit = &sport->port.state->xmit;
unsigned long flags;

spin_lock_irqsave(&sport->port.lock, flags);
- if (sport->port.x_char) {
- if (lpuart_is_32(sport))
- lpuart32_write(&sport->port, sport->port.x_char, UARTDATA);
- else
- writeb(sport->port.x_char, sport->port.membase + UARTDR);
- sport->port.icount.tx++;
- sport->port.x_char = 0;
- goto out;
- }
-
- if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
- if (lpuart_is_32(sport))
- lpuart32_stop_tx(&sport->port);
- else
- lpuart_stop_tx(&sport->port);
- goto out;
- }
-
- if (lpuart_is_32(sport))
- lpuart32_transmit_buffer(sport);
- else
- lpuart_transmit_buffer(sport);
-
-out:
+ lpuart_transmit_buffer(sport);
spin_unlock_irqrestore(&sport->port.lock, flags);
}

@@ -876,6 +876,15 @@ static void lpuart_rxint(struct lpuart_port *sport)
tty_flip_buffer_push(port);
}

+static void lpuart32_txint(struct lpuart_port *sport)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+ lpuart32_transmit_buffer(sport);
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+}
+
static void lpuart32_rxint(struct lpuart_port *sport)
{
unsigned int flg, ignored = 0;
@@ -967,7 +976,7 @@ static irqreturn_t lpuart32_int(int irq, void *dev_id)
lpuart32_rxint(sport);

if ((sts & UARTSTAT_TDRE) && !sport->lpuart_dma_tx_use)
- lpuart_txint(sport);
+ lpuart32_txint(sport);

lpuart32_write(&sport->port, sts, UARTSTAT);
return IRQ_HANDLED;
--
2.21.0
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