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| author | Wolfgang Denk <wd@pollux.(none)> | 2005-09-25 16:50:33 +0200 |
|---|---|---|
| committer | Wolfgang Denk <wd@pollux.(none)> | 2005-09-25 16:50:33 +0200 |
| commit | 7a22cd535b67e89af88190cd5143ba53f502f064 (patch) | |
| tree | aea616c948ead33b913a3fd774334d8ff63705b0 /cpu/mips | |
| parent | 875c78934ee252744be1e5b2a9ad7ec5df239239 (diff) | |
| download | u-boot-imx-7a22cd535b67e89af88190cd5143ba53f502f064.zip u-boot-imx-7a22cd535b67e89af88190cd5143ba53f502f064.tar.gz u-boot-imx-7a22cd535b67e89af88190cd5143ba53f502f064.tar.bz2 | |
Fix au1x00_serial baud rate calculation:
remove hardcoded cpu clock divisor and use register instead;
round up instead of truncate
Patch by Andrew Dyer, 15 Feb 2005
Diffstat (limited to 'cpu/mips')
| -rw-r--r-- | cpu/mips/au1x00_serial.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/cpu/mips/au1x00_serial.c b/cpu/mips/au1x00_serial.c index ac75da5..42c668e 100644 --- a/cpu/mips/au1x00_serial.c +++ b/cpu/mips/au1x00_serial.c @@ -70,9 +70,21 @@ void serial_setbrg (void) { volatile u32 *uart_clk = (volatile u32*)(UART0_ADDR+UART_CLK); volatile u32 *uart_lcr = (volatile u32*)(UART0_ADDR+UART_LCR); + volatile u32 *sys_powerctrl = (u32 *)SYS_POWERCTRL; + int sd; + int divisorx2; - /* Set baudrate - FIXME for bus speeds != CPU/2 */ - *uart_clk = ((CFG_HZ/(CONFIG_BAUDRATE * 64))); + /* sd is system clock divisor */ + /* see section 10.4.5 in au1550 datasheet */ + sd = (*sys_powerctrl & 0x03) + 2; + + /* calulate 2x baudrate and round */ + divisorx2 = ((CFG_HZ/(sd * 16 * CONFIG_BAUDRATE))); + + if (divisorx2 & 0x01) + divisorx2 = divisorx2 + 1; + + *uart_clk = divisorx2 / 2; /* Set parity, stop bits and word length to 8N1 */ *uart_lcr = UART_LCR_WLEN8; |