From e8823f1ca8d5a0c5d69a8862682ee8bde26990ca Mon Sep 17 00:00:00 2001 From: Jun Chen Date: Wed, 7 Nov 2012 12:04:04 -0500 Subject: [PATCH] serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty This patch check whether the fifo lenth is empty before writing new data to fifo.If condition is true,ifx_spi_write need to trigger one mrdy_assert. If condition is false,the mrdy_assert will be trigger by the next ifx_spi_io. Cc: Bi Chao Signed-off-by: Chen Jun Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/ifx6x60.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c index 21eb70b..1754c14 100644 --- a/drivers/tty/serial/ifx6x60.c +++ b/drivers/tty/serial/ifx6x60.c @@ -508,9 +508,16 @@ static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf, { struct ifx_spi_device *ifx_dev = tty->driver_data; unsigned char *tmp_buf = (unsigned char *)buf; - int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count, - &ifx_dev->fifo_lock); - mrdy_assert(ifx_dev); + unsigned long flags; + bool is_fifo_empty; + + spin_lock_irqsave(&ifx_dev->fifo_lock, flags); + is_fifo_empty = kfifo_is_empty(&ifx_dev->tx_fifo); + int tx_count = kfifo_in(&ifx_dev->tx_fifo, tmp_buf, count); + spin_unlock_irqrestore(&ifx_dev->fifo_lock, flags); + if (is_fifo_empty) + mrdy_assert(ifx_dev); + return tx_count; } -- 2.7.4