From 857dde2e79082d2954ede7f10783addaae956777 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Sat, 21 May 2005 15:52:23 +0100 Subject: [PATCH] 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 --- drivers/serial/8250.c | 17 ++++++++++++----- 1 file 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; -- 2.20.1