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serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty

PATCH In review Jun Chen 2 participants 2 messages Nov 7, 2012 TTY layer and serial drivers

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Jun Chen

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PATCH 1/1 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 <[email protected]>
Signed-off-by Chen Jun <[email protected]>
---
 drivers/tty/serial/ifx6x60.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)
drivers/tty/serial/ifx6x60.c +10 -3
index a688f8f..4a21f5e 100644
@@ -520,9 +520,16 @@ 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;
 }
Signature · 1 line
1.7.4.1