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| author | Javier Martinez Canillas <javier@dowhile0.org> | 2013-01-07 01:35:20 +0000 |
|---|---|---|
| committer | Tom Rini <trini@ti.com> | 2013-01-10 15:09:24 -0700 |
| commit | 7de0fe1ac330399afc1873e11061668a93cf4fb9 (patch) | |
| tree | 1dbd487b9b511aec938cb52c1b4accf62b051f75 | |
| parent | 94bcfe524cab9574f799bd2b7df9c7de2b81465a (diff) | |
| download | u-boot-imx-7de0fe1ac330399afc1873e11061668a93cf4fb9.zip u-boot-imx-7de0fe1ac330399afc1873e11061668a93cf4fb9.tar.gz u-boot-imx-7de0fe1ac330399afc1873e11061668a93cf4fb9.tar.bz2 | |
serial/ns16550: add an option to avoid hanging on broken platforms
Some platforms (e.g. IGEPv2 board) has a broken ns16550 UART that
does not set the TEMT bit when the transmitter is empty in SPL.
This makes U-Boot to hang while waiting for TEMT to be set.
Add a new option to avoid this:
CONFIG_SYS_NS16550_BROKEN_TEMT
16550 UART set the Transmitter Empty (TEMT) Bit when all output
has finished and the transmitter is totally empty. U-Boot waits
for this bit to be set to initialize the serial console. On some
broken platforms this bit is not set in SPL making U-Boot to
hang while waiting for TEMT. Define this option to avoid it.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
| -rw-r--r-- | README | 8 | ||||
| -rw-r--r-- | drivers/serial/ns16550.c | 2 |
2 files changed, 10 insertions, 0 deletions
@@ -616,6 +616,14 @@ The following options need to be configured: boot loader that has already initialized the UART. Define this variable to flush the UART at init time. + CONFIG_SYS_NS16550_BROKEN_TEMT + + 16550 UART set the Transmitter Empty (TEMT) Bit when all output + has finished and the transmitter is totally empty. U-Boot waits + for this bit to be set to initialize the serial console. On some + broken platforms this bit is not set in SPL making U-Boot to + hang while waiting for TEMT. Define this option to avoid it. + - Console Interface: Depending on board, define exactly one serial port diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c index bbd91ca..87a0917 100644 --- a/drivers/serial/ns16550.c +++ b/drivers/serial/ns16550.c @@ -36,8 +36,10 @@ void NS16550_init(NS16550_t com_port, int baud_divisor) { +#if (!defined(CONFIG_SYS_NS16550_BROKEN_TEMT)) while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT)) ; +#endif serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier); #if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \ |