Loading...
/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1999 by Ralf Baechle * Copyright (C) 1999, 2000 Silicon Graphics, Inc. */ #ifndef _ASM_SERIAL_H #define _ASM_SERIAL_H /* * This assumes you have a 1.8432 MHz clock for your UART. * * It'd be nice if someone built a serial card with a 24.576 MHz * clock, since the 16550A is capable of handling a top speed of 1.5 * megabits/second; but this requires the faster clock. */ #define BASE_BAUD (1843200 / 16) /* * Note about serial ports and consoles: * For console output, everyone uses the IOC3 UARTA (offset 0x178) * connected to the master node (look in ip27_setup_console() and * ip27prom_console_write()). * * For serial (/dev/ttyS0 etc), we can not have hardcoded serial port * addresses on a partitioned machine. Since we currently use the ioc3 * serial ports, we use dynamic serial port discovery that the serial.c * driver uses for pci/pnp ports (there is an entry for the SGI ioc3 * boards in pci_boards[]). Unfortunately, UARTA's pio address is greater * than UARTB's, although UARTA on o200s has traditionally been known as * port 0. So, we just use one serial port from each ioc3 (since the * serial driver adds addresses to get to higher ports). * * The first one to do a register_console becomes the preferred console * (if there is no kernel command line console= directive). /dev/console * (ie 5, 1) is then "aliased" into the device number returned by the * "device" routine referred to in this console structure * (ip27prom_console_dev). * * Also look in ip27-pci.c:pci_fixuop_ioc3() for some comments on working * around ioc3 oddities in this respect. * * The IOC3 serials use a 22MHz clock rate with an additional divider by 3. * (IOC3_BAUD = (22000000 / (3*16))) */ #define RS_TABLE_SIZE 64 #define SERIAL_PORT_DFNS #endif /* _ASM_SERIAL_H */ |