Instead of waiting for empty FIFO condition before writing a
character, wait for non-full FIFO condition.
This helps in saving several tens of milliseconds during boot
(depending verbosity).
Signed-off-by: Loic Poulain <loic.poul...@linaro.org>
Tested-by: Lothar Waßmann <l...@karo-electronics.de>
Acked-by: Pali Rohár <p...@kernel.org>
---
v2: fixing transfert abort & char corruption commit
v3: Reordering commits for good bisectability
v4: no code change
drivers/serial/serial_mxc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c
index 9e5b987994..cac1922354 100644
--- a/drivers/serial/serial_mxc.c
+++ b/drivers/serial/serial_mxc.c
@@ -240,11 +240,11 @@ static void mxc_serial_putc(const char c)
if (c == '\n')
serial_putc('\r');
- writel(c, &mxc_base->txd);
-
/* wait for transmitter to be ready */
- while (!(readl(&mxc_base->ts) & UTS_TXEMPTY))
+ while (readl(&mxc_base->ts) & UTS_TXFULL)
schedule();
+
+ writel(c, &mxc_base->txd);
}
/* Test whether a character is in the RX buffer */
@@ -335,7 +335,7 @@ static int mxc_serial_putc(struct udevice *dev, const char
ch)
struct mxc_serial_plat *plat = dev_get_plat(dev);
struct mxc_uart *const uart = plat->reg;
- if (!(readl(&uart->ts) & UTS_TXEMPTY))
+ if (readl(&uart->ts) & UTS_TXFULL)
return -EAGAIN;
writel(ch, &uart->txd);
--
2.34.1
