diff options
| author | David Woodhouse <dwmw2@org.rmk.(none)> | 2005-05-21 15:52:23 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2005-05-21 15:52:23 +0100 |
| commit | 857dde2e79082d2954ede7f10783addaae956777 (patch) | |
| tree | 5a7ba015eb22985d69e03e315b249c4c89750ee2 /drivers/serial/8250.c | |
| parent | 9636273dae265b9354b861b373cd43cd76a6d0fe (diff) | |
| download | lwn-857dde2e79082d2954ede7f10783addaae956777.tar.gz lwn-857dde2e79082d2954ede7f10783addaae956777.zip | |
When we detect that a 16550 was in fact part of a NatSemi SuperIO chip
with high-speed mode enabled, we switch it to high-speed mode so that
baud_base becomes 921600. However, we also need to multiply the baud
divisor by 8 at the same time, in case it's already in use as a console.
Signed-off-by: David Woodhouse
Acked-by: Tom Rini
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/serial/8250.c')
| -rw-r--r-- | drivers/serial/8250.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 3bbf0cc6e53f..30e8beb71430 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -682,8 +682,6 @@ static void autoconfig_16550a(struct uart_8250_port *up) * from EXCR1. Switch back to bank 0, change it in MCR. Then * switch back to bank 2, read it from EXCR1 again and check * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2 - * On PowerPC we don't want to change baud_base, as we have - * a number of different divisors. -- Tom Rini */ serial_outp(up, UART_LCR, 0); status1 = serial_in(up, UART_MCR); @@ -699,16 +697,25 @@ static void autoconfig_16550a(struct uart_8250_port *up) serial_outp(up, UART_MCR, status1); if ((status2 ^ status1) & UART_MCR_LOOP) { -#ifndef CONFIG_PPC + unsigned short quot; + serial_outp(up, UART_LCR, 0xE0); + + quot = serial_inp(up, UART_DLM) << 8; + quot += serial_inp(up, UART_DLL); + quot <<= 3; + status1 = serial_in(up, 0x04); /* EXCR1 */ status1 &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */ status1 |= 0x10; /* 1.625 divisor for baud_base --> 921600 */ serial_outp(up, 0x04, status1); + + serial_outp(up, UART_DLL, quot & 0xff); + serial_outp(up, UART_DLM, quot >> 8); + serial_outp(up, UART_LCR, 0); - up->port.uartclk = 921600*16; -#endif + up->port.uartclk = 921600*16; up->port.type = PORT_NS16550A; up->capabilities |= UART_NATSEMI; return; |