From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerry Van Baren Date: Thu, 10 Jul 2008 21:25:40 -0400 Subject: [U-Boot-Users] [PATCH] Round the serial port clock divisor value returned by calc_divisor() Message-ID: <20080711012540.GA29444@cideas.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de This formula is better at avoiding integer overflow. Signed-off-by: Gerald Van Baren --- (try 2) The formula I proposed previously in this thread compiles OK. I cannot verify it is correct on real hardware, however. Best regards, gvb drivers/serial/serial.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c index 182ca2d..48579ae 100644 --- a/drivers/serial/serial.c +++ b/drivers/serial/serial.c @@ -150,7 +150,9 @@ static int calc_divisor (NS16550_t port) * but we need to round that value by adding 0.5 or 8/16. * Rounding is especially important at high baud rates. */ - return (((16 * CFG_NS16550_CLK) / MODE_X_DIV / gd->baudrate) + 8) / 16; + return (CFG_NS16550_CLK + (gd->baudrate / 2)) / + (MODE_X_DIV * gd->baudrate); + } #if !defined(CONFIG_SERIAL_MULTI) -- 1.5.6