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authorKevin O'Connor <kevin@koconnor.net>2011-07-09 20:22:21 -0400
committerPatrick Georgi <patrick@georgi-clan.de>2011-07-12 11:36:20 +0200
commita68555f48d06b4c8d55f7e4ca208805bec3d5512 (patch)
tree132a21ab3f20d2ca5ce967705d4d92c3c0dbe476 /src
parent537cacfa04c9dc56cd608012a73d95ab342d2f81 (diff)
downloadcoreboot-a68555f48d06b4c8d55f7e4ca208805bec3d5512.tar.xz
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')
-rw-r--r--src/arch/x86/lib/romstage_console.c19
-rw-r--r--src/console/uart8250_console.c6
-rw-r--r--src/console/uart8250mem_console.c6
-rw-r--r--src/include/uart8250.h2
-rw-r--r--src/lib/uart8250.c5
-rw-r--r--src/lib/uart8250mem.c5
6 files changed, 38 insertions, 5 deletions
diff --git a/src/arch/x86/lib/romstage_console.c b/src/arch/x86/lib/romstage_console.c
index a5f2e2b074..8adb3ba93d 100644
--- a/src/arch/x86/lib/romstage_console.c
+++ b/src/arch/x86/lib/romstage_console.c
@@ -48,6 +48,19 @@ static void console_tx_byte(unsigned char byte)
#endif
}
+static void console_tx_flush(void)
+{
+#if CONFIG_CONSOLE_SERIAL8250MEM
+ uart8250_mem_tx_flush(CONFIG_OXFORD_OXPCIE_BASE_ADDRESS + 0x1000);
+#endif
+#if CONFIG_CONSOLE_SERIAL8250
+ uart8250_tx_flush(CONFIG_TTYS0_BASE);
+#endif
+#if CONFIG_CONSOLE_NE2K
+ ne2k_transmit(CONFIG_CONSOLE_NE2K_IO_PORT);
+#endif
+}
+
int do_printk(int msg_level, const char *fmt, ...)
{
va_list args;
@@ -60,8 +73,8 @@ int do_printk(int msg_level, const char *fmt, ...)
va_start(args, fmt);
i = vtxprintf(console_tx_byte, fmt, args);
va_end(args);
-#if CONFIG_CONSOLE_NE2K
- ne2k_transmit(CONFIG_CONSOLE_NE2K_IO_PORT);
-#endif
+
+ console_tx_flush();
+
return i;
}
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,
};
diff --git a/src/include/uart8250.h b/src/include/uart8250.h
index bbf2d8c8a9..4a02179210 100644
--- a/src/include/uart8250.h
+++ b/src/include/uart8250.h
@@ -131,6 +131,7 @@
unsigned char uart8250_rx_byte(unsigned base_port);
int uart8250_can_rx_byte(unsigned base_port);
void uart8250_tx_byte(unsigned base_port, unsigned char data);
+void uart8250_tx_flush(unsigned base_port);
/* Yes it is silly to have three different uart init functions. But we used to
* have three different sets of uart code, so it's an improvement.
@@ -142,6 +143,7 @@ void uart_init(void);
unsigned char uart8250_mem_rx_byte(unsigned base_port);
int uart8250_mem_can_rx_byte(unsigned base_port);
void uart8250_mem_tx_byte(unsigned base_port, unsigned char data);
+void uart8250_mem_tx_flush(unsigned base_port);
void uart8250_mem_init(unsigned base_port, unsigned divisor);
u32 uart_mem_init(void);
diff --git a/src/lib/uart8250.c b/src/lib/uart8250.c
index 64e8854ef5..e7ddd0bfd5 100644
--- a/src/lib/uart8250.c
+++ b/src/lib/uart8250.c
@@ -48,7 +48,10 @@ void uart8250_tx_byte(unsigned base_port, unsigned char data)
{
uart8250_wait_to_tx_byte(base_port);
outb(data, base_port + UART_TBR);
- /* Make certain the data clears the fifos */
+}
+
+void uart8250_tx_flush(unsigned base_port)
+{
uart8250_wait_until_sent(base_port);
}
diff --git a/src/lib/uart8250mem.c b/src/lib/uart8250mem.c
index 918308ecdf..e79cb63346 100644
--- a/src/lib/uart8250mem.c
+++ b/src/lib/uart8250mem.c
@@ -51,7 +51,10 @@ void uart8250_mem_tx_byte(unsigned base_port, unsigned char data)
{
uart8250_mem_wait_to_tx_byte(base_port);
write8(base_port + UART_TBR, data);
- /* Make certain the data clears the FIFOs */
+}
+
+void uart8250_mem_tx_flush(unsigned base_port)
+{
uart8250_mem_wait_until_sent(base_port);
}