[PATCH v2 08/23] tty: serial: fls_lpuart: Split shared TX IRQ handler into two

[Andrey Smirnov]

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.smir...@gmail.com>
Cc: Stefan Agner <ste...@agner.ch>
Cc: Chris Healy <cphe...@gmail.com>
Cc: Cory Tusar <cory.tu...@zii.aero>
Cc: Lucas Stach <l.st...@pengutronix.de>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Jiri Slaby <jsl...@suse.com>
Cc: linux-...@nxp.com
Cc: linux-ser...@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