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| author | Xu, Hong <Hong.Xu@atmel.com> | 2011-08-02 01:05:04 +0000 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2012-09-01 17:06:13 +0200 |
| commit | 1f4faedd51ee72a57afb9edba2d71ba01a2ec20e (patch) | |
| tree | efe5bab5df41095ccbd183db051e9de26c6cfa45 | |
| parent | 88461f164ed751b582998b28b93d5668d4afec56 (diff) | |
| download | u-boot-imx-1f4faedd51ee72a57afb9edba2d71ba01a2ec20e.zip u-boot-imx-1f4faedd51ee72a57afb9edba2d71ba01a2ec20e.tar.gz u-boot-imx-1f4faedd51ee72a57afb9edba2d71ba01a2ec20e.tar.bz2 | |
AT91: Small fix on AT91 USART initialization code
Before reset dbgu transmitter, we just wait TXEMPTY to drain the
transmitter register(Just in case). If not doing this, we may sometimes
see several weird characters from DBGU.
A short delay is also added to make sure the new serial settings are
settled.
Signed-off-by: Hong Xu <hong.xu@atmel.com>
[cherry-picked from u-boot-atmel/old-next]
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
| -rw-r--r-- | drivers/serial/atmel_usart.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c index e326b2b..943ef70 100644 --- a/drivers/serial/atmel_usart.c +++ b/drivers/serial/atmel_usart.c @@ -49,17 +49,26 @@ int serial_init(void) { atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; + /* + * Just in case: drain transmitter register + * 1000us is enough for baudrate >= 9600 + */ + if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY))) + __udelay(1000); + writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr); serial_setbrg(); - writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr); writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) | USART3_BF(USCLKS, USART3_USCLKS_MCK) | USART3_BF(CHRL, USART3_CHRL_8) | USART3_BF(PAR, USART3_PAR_NONE) | USART3_BF(NBSTOP, USART3_NBSTOP_1)), &usart->mr); + writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr); + /* 100us is enough for the new settings to be settled */ + __udelay(100); return 0; } |