serial: pch: decomission pch_uart_hal_write()

It's horrid and if we inline it into callers, we can get rid of a lot of
sugar around.

So:
* x_char handling becomes a single iowrite8.
* xmit->buf handling is a single loop simply writing characters one by
  one directly from the buf instead of complex cnt_to_end computations.
  Until the buf is empty or fifo size is reached.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220503080808.28332-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 6cb63148738327d0f14288a5c791a8f1447be50f..4fcb6c144b548d170d06467c4235e04596758b4b 100644 (file)
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -550,18 +550,6 @@ static u8 pch_uart_hal_get_modem(struct eg20t_port *priv)
        return (u8)msr;
 }
 
-static void pch_uart_hal_write(struct eg20t_port *priv,
-                             const unsigned char *buf, int tx_size)
-{
-       int i;
-       unsigned int thr;
-
-       for (i = 0; i < tx_size;) {
-               thr = buf[i++];
-               iowrite8(thr, priv->membase + PCH_UART_THR);
-       }
-}
-
 static int pch_uart_hal_read(struct eg20t_port *priv, unsigned char *buf,
                             int rx_size)
 {
@@ -769,23 +757,21 @@ static void pch_dma_tx_complete(void *arg)
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT);
 }
 
-static int pop_tx(struct eg20t_port *priv, int size)
+static bool pop_tx(struct eg20t_port *priv, unsigned int size)
 {
-       int count = 0;
+       unsigned int count = 0;
        struct uart_port *port = &priv->port;
        struct circ_buf *xmit = &port->state->xmit;
 
-       if (uart_tx_stopped(port) || uart_circ_empty(xmit))
+       if (uart_tx_stopped(port))
                goto pop_tx_end;
 
-       do {
-               int cnt_to_end =
-                   CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
-               int sz = min(size - count, cnt_to_end);
-               pch_uart_hal_write(priv, &xmit->buf[xmit->tail], sz);
-               xmit->tail = (xmit->tail + sz) & (UART_XMIT_SIZE - 1);
-               count += sz;
-       } while (!uart_circ_empty(xmit) && count < size);
+       while (!uart_circ_empty(xmit) && count < size) {
+               iowrite8(xmit->buf[xmit->tail], priv->membase + PCH_UART_THR);
+               xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+               port->icount.tx++;
+               count++;
+       }
 
 pop_tx_end:
        dev_dbg(priv->port.dev, "%d characters. Remained %d characters.(%lu)\n",
@@ -859,7 +845,6 @@ static unsigned int handle_tx(struct eg20t_port *priv)
        struct uart_port *port = &priv->port;
        struct circ_buf *xmit = &port->state->xmit;
        int fifo_size;
-       int tx_size;
        int size;
        int tx_empty;
 
@@ -874,7 +859,7 @@ static unsigned int handle_tx(struct eg20t_port *priv)
        fifo_size = max(priv->fifo_size, 1);
        tx_empty = 1;
        if (port->x_char) {
-               pch_uart_hal_write(priv, &port->x_char, 1);
+               iowrite8(port->x_char, priv->membase + PCH_UART_THR);
                port->icount.tx++;
                port->x_char = 0;
                tx_empty = 0;
@@ -884,13 +869,8 @@ static unsigned int handle_tx(struct eg20t_port *priv)
        size = min(xmit->head - xmit->tail, fifo_size);
        if (size < 0)
                size = fifo_size;
-       if (size) {
-               tx_size = pop_tx(priv, size);
-               if (tx_size > 0) {
-                       port->icount.tx += tx_size;
-                       tx_empty = 0;
-               }
-       }
+       if (size && pop_tx(priv, size))
+               tx_empty = 0;
 
        priv->tx_empty = tx_empty;
 
@@ -935,7 +915,7 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
        fifo_size = max(priv->fifo_size, 1);
 
        if (port->x_char) {
-               pch_uart_hal_write(priv, &port->x_char, 1);
+               iowrite8(port->x_char, priv->membase + PCH_UART_THR);
                port->icount.tx++;
                port->x_char = 0;
                fifo_size--;