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>
diff --git a/README b/README
index 653ef6a..98dbe98 100644
--- a/README
+++ b/README
@@ -616,6 +616,14 @@
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