From: Jun Chen Date: Wed, 7 Nov 2012 17:04:04 +0000 (-0500) Subject: serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty X-Git-Tag: firefly_0821_release~3680^2~1518^2~73 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e8823f1ca8d5a0c5d69a8862682ee8bde26990ca;p=firefly-linux-kernel-4.4.55.git 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 --- diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c index 21eb70bcb6a0..1754c147a94c 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; }