xinu: Desktop/xinu_mips-1.0.2.tar/xinu_mips-1.0.2/tty/ttyOpen.c Source File

00001 
00007 /* Embedded XINU, Copyright (C) 2007.  All rights reserved. */
00008 
00009 #include <kernel.h>
00010 #include <device.h>
00011 #include <tty.h>
00012 #include <vararg.h>
00013 
00020 devcall ttyOpen(device *pdev, va_list ap)
00021 {
00022         struct tty *ptty = NULL;
00023         int dvnum = 0;
00024 
00025         /* Check if TTY is already open */
00026         if (pdev->controlblk)
00027     {   return OK;   }
00028 
00029         /* Allocate a tty */
00030         ptty = (struct tty *)ttyAlloc();
00031 
00032         ASSERT(NULL != ptty);
00033 
00034         /* Mutually link tty record with device table entry */
00035         pdev->controlblk = (char *)ptty;
00036         ptty->tty_dev = pdev;
00037 
00038         /* Initialize input buffer */
00039         ptty->iflags = 0;
00040         ptty->istart = 0;
00041         ptty->icount = 0;
00042 
00043         /* Initialize output flags */
00044         ptty->oflags = 0;
00045 
00046         /* Second arg should be device index for physical hardware */
00047         dvnum = va_arg(ap, int); 
00048         ASSERT(!isbaddev(dvnum));
00049 
00050         ptty->tty_phw  = &devtab[dvnum];
00051 
00052         return OK;
00053 }