diff options
| author | Kevin O'Connor <kevin@koconnor.net> | 2011-07-09 20:22:21 -0400 |
|---|---|---|
| committer | Patrick Georgi <patrick@georgi-clan.de> | 2011-07-12 11:36:20 +0200 |
| commit | a68555f48d06b4c8d55f7e4ca208805bec3d5512 (patch) | |
| tree | 132a21ab3f20d2ca5ce967705d4d92c3c0dbe476 /src/console | |
| parent | 537cacfa04c9dc56cd608012a73d95ab342d2f81 (diff) | |
Do full flush on uart8250 only at end of printk.
The previous code does a full flush of the uart after every character.
Unfortunately, this can cause transmission delays on some serial
ports.
This patch changes the code so that it does a flush at the end of
every printk instead of at the end of every character. This reduces
the time it takes to transmit serial messages (up to 9% on my Asrock
e350m1 board). It also makes the transmission time more consistent
which is important when performing timing tests via serial
transmissions.
Change-Id: I6b28488b905da68c6d68d7c517cc743cde567d70
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Reviewed-on: http://review.coreboot.org/90
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Rudolf Marek <r.marek@assembler.cz>
Reviewed-by: Sven Schnelle <svens@stackframe.org>
Diffstat (limited to 'src/console')
| -rw-r--r-- | src/console/uart8250_console.c | 6 | ||||
| -rw-r--r-- | src/console/uart8250mem_console.c | 6 |
2 files changed, 12 insertions, 0 deletions
diff --git a/src/console/uart8250_console.c b/src/console/uart8250_console.c index 4799ca66e5..330ed684f7 100644 --- a/src/console/uart8250_console.c +++ b/src/console/uart8250_console.c @@ -31,6 +31,11 @@ static void ttyS0_tx_byte(unsigned char data) uart8250_tx_byte(CONFIG_TTYS0_BASE, data); } +static void ttyS0_tx_flush(void) +{ + uart8250_tx_flush(CONFIG_TTYS0_BASE); +} + static unsigned char ttyS0_rx_byte(void) { return uart8250_rx_byte(CONFIG_TTYS0_BASE); @@ -44,6 +49,7 @@ static int ttyS0_tst_byte(void) static const struct console_driver uart8250_console __console = { .init = ttyS0_init, .tx_byte = ttyS0_tx_byte, + .tx_flush = ttyS0_tx_flush, .rx_byte = ttyS0_rx_byte, .tst_byte = ttyS0_tst_byte, }; diff --git a/src/console/uart8250mem_console.c b/src/console/uart8250mem_console.c index a6968ddc4b..e622ad090c 100644 --- a/src/console/uart8250mem_console.c +++ b/src/console/uart8250mem_console.c @@ -36,6 +36,11 @@ static void uartmem_tx_byte(unsigned char data) uart8250_mem_tx_byte(uart_bar, data); } +static void uartmem_tx_flush(void) +{ + uart8250_mem_tx_flush(uart_bar); +} + static unsigned char uartmem_rx_byte(void) { if (!uart_bar) @@ -55,6 +60,7 @@ static int uartmem_tst_byte(void) static const struct console_driver uart8250mem_console __console = { .init = uartmem_init, .tx_byte = uartmem_tx_byte, + .tx_flush = uartmem_tx_flush, .rx_byte = uartmem_rx_byte, .tst_byte = uartmem_tst_byte, }; |