[PATCH linux-next 3/8] pch_uart : Reduce memcpy

From: Tomoya MORINAGA
Date: Tue Feb 22 2011 - 20:06:08 EST


Reduce memcpy for performance improvement.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/pch_uart.c | 13 +++++--------
1 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 9c631ab..d4bcbce 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -389,7 +389,7 @@ static u8 pch_uart_hal_get_modem(struct eg20t_port *priv)
return get_msr(priv, priv->membase);
}

-static int pch_uart_hal_write(struct eg20t_port *priv,
+static void pch_uart_hal_write(struct eg20t_port *priv,
const unsigned char *buf, int tx_size)
{
int i;
@@ -399,7 +399,6 @@ static int pch_uart_hal_write(struct eg20t_port *priv,
thr = buf[i++];
iowrite8(thr, priv->membase + PCH_UART_THR);
}
- return i;
}

static int pch_uart_hal_read(struct eg20t_port *priv, unsigned char *buf,
@@ -633,7 +632,7 @@ 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, unsigned char *buf, int size)
+static int pop_tx(struct eg20t_port *priv, int size)
{
int count = 0;
struct uart_port *port = &priv->port;
@@ -646,7 +645,7 @@ static int pop_tx(struct eg20t_port *priv, unsigned char *buf, int size)
int cnt_to_end =
CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
int sz = min(size - count, cnt_to_end);
- memcpy(&buf[count], &xmit->buf[xmit->tail], sz);
+ 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);
@@ -722,7 +721,6 @@ static unsigned int handle_tx(struct eg20t_port *priv)
{
struct uart_port *port = &priv->port;
struct circ_buf *xmit = &port->state->xmit;
- int ret;
int fifo_size;
int tx_size;
int size;
@@ -747,10 +745,9 @@ static unsigned int handle_tx(struct eg20t_port *priv)
if (size < 0)
size = fifo_size;

- tx_size = pop_tx(priv, xmit->buf, size);
+ tx_size = pop_tx(priv, size);
if (tx_size > 0) {
- ret = pch_uart_hal_write(priv, xmit->buf, tx_size);
- port->icount.tx += ret;
+ port->icount.tx += tx_size;
tx_empty = 0;
}

--
1.7.3.4

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