Re: [U-Boot] [PATCH 1/1 v3] omap3_beagle: Enabling UART3 first allows the Transmitter to be empty

On Fri, Mar 29, 2013 at 10:43:34AM +0100, Albert ARIBAUD wrote:

Hi Manfred,

On Fri, 29 Mar 2013 10:20:25 +0100, Manfred Huber man.huber@arcor.de wrote:

...

On some OMAP3 devices when UART3 is configured for boot mode before SPL starts only THRE bit is set. We have to empty the transmitter before initialization starts. This patch avoids the use of CONFIG_SYS_NS16550_BROKEN_TEMT.

Signed-off-by: Manfred Huber man.huber@arcor.de

Patch history is missing here.

That's largely because each iteration has been fairly different (we started with adding CONFIG_SYS_NS16550_BROKEN_TEMPT to omap3_beagle).

Also, I would like the commit summary (first commit message line, also subject of the patch mail) to clearly state what the patch *does* as opposed to what *happens*, because it is unclear right now if you're describing the solution or the issue. Something like :

"omap3_beagle: flush UART3 xmit on enable if TEMT is broken"

Agreed.

...

README | 8 -------- drivers/serial/ns16550.c | 16 ++++++++++++++-- include/configs/igep00x0.h | 3 --- 3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/README b/README index a336476..e6b3a50 100644 --- a/README +++ b/README @@ -616,14 +616,6 @@ 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 87a0917..2922a2c 100644 --- a/drivers/serial/ns16550.c +++ b/drivers/serial/ns16550.c @@ -36,10 +36,22 @@

void NS16550_init(NS16550_t com_port, int baud_divisor) { -#if (!defined(CONFIG_SYS_NS16550_BROKEN_TEMT)) +#if (defined(CONFIG_SPL_BUILD) && defined(CONFIG_OMAP34XX))

• /* On some OMAP3 devices when UART3 is configured for boot mode before

•   SPL starts only THRE bit is set. We have to empty the transmitter
  

•   before initialization starts. */
  

/* * Multiline comments * must be like this. */