diff options
| author | Loic Poulain <loic.poulain@linaro.org> | 2023-01-12 20:19:51 +0300 |
|---|---|---|
| committer | Stefano Babic <sbabic@denx.de> | 2023-01-31 01:23:02 +0300 |
| commit | ad725073d1666d94a96fbf9cba03777c3d58de24 (patch) | |
| tree | 0521c3d7fe69748fc989894d037d1689b68231ba /drivers/serial/serial_mxc.c | |
| parent | 7150f56a85fd8d3b8ad162621026b0ba7bb6a367 (diff) | |
| download | u-boot-ad725073d1666d94a96fbf9cba03777c3d58de24.tar.xz | |
serial: mxc: Speed-up character transmission
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.poulain@linaro.org>
Tested-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Fabio Estevam <festevam@denx.de>
Tested-by: Fabio Estevam <festevam@denx.de>
Diffstat (limited to 'drivers/serial/serial_mxc.c')
| -rw-r--r-- | drivers/serial/serial_mxc.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/serial/serial_mxc.c b/drivers/serial/serial_mxc.c index e4ffa9c3f6..cc85a50272 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); |