epca.c

powerpc内核mpc8241linux系统下char驱动程序

	if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) 
	{ /* A cud device has been opened */
		if (ch->asyncflags & ASYNC_NORMAL_ACTIVE)
			return -EBUSY;

		if ((ch->asyncflags & ASYNC_CALLOUT_ACTIVE) &&
		    (ch->asyncflags & ASYNC_SESSION_LOCKOUT) &&
		    (ch->session != current->session))
		    return -EBUSY;

		if ((ch->asyncflags & ASYNC_CALLOUT_ACTIVE) &&
		    (ch->asyncflags & ASYNC_PGRP_LOCKOUT) &&
		    (ch->pgrp != current->pgrp))
		    return -EBUSY;
 
		ch->asyncflags |= ASYNC_CALLOUT_ACTIVE;

		return 0;
	} /* End a cud device has been opened */

	if (filp->f_flags & O_NONBLOCK) 
	{
		/* ----------------------------------------------------------------- 
	  	 If non-blocking mode is set, then make the check up front
	  	 and then exit.
		-------------------------------------------------------------------- */

		if (ch->asyncflags & ASYNC_CALLOUT_ACTIVE)
			return -EBUSY;

		ch->asyncflags |= ASYNC_NORMAL_ACTIVE;

		return 0;
	}


	if (ch->asyncflags & ASYNC_CALLOUT_ACTIVE) 
	{
		if (ch->normal_termios.c_cflag & CLOCAL)
			do_clocal = 1;
	}
	else 
	{
		if (tty->termios->c_cflag & CLOCAL)
			do_clocal = 1;
	}
	
   /* Block waiting for the carrier detect and the line to become free */
	
	retval = 0;
	add_wait_queue(&ch->open_wait, &wait);
	save_flags(flags);
	cli();


	/* We dec count so that pc_close will know when to free things */
	if (!tty_hung_up_p(filp))
		ch->count--;

	restore_flags(flags);

	ch->blocked_open++;

	while(1) 
	{ /* Begin forever while  */

		current->state = TASK_INTERRUPTIBLE;

		if (tty_hung_up_p(filp) ||
		    !(ch->asyncflags & ASYNC_INITIALIZED)) 
		{
			if (ch->asyncflags & ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;	
			break;
		}

		if (!(ch->asyncflags & ASYNC_CLOSING) && 
		    !(ch->asyncflags & ASYNC_CALLOUT_ACTIVE) &&
			  (do_clocal || (ch->imodem & ch->dcd)))
			break;

		if (signal_pending(current)) 
		{
			retval = -ERESTARTSYS;
			break;
		}

		/* ---------------------------------------------------------------
			Allow someone else to be scheduled.  We will occasionaly go
			through this loop until one of the above conditions change.
			The below schedule call will allow other processes to enter and
			prevent this loop from hogging the cpu.
		------------------------------------------------------------------ */
		schedule();

	} /* End forever while  */

	current->state = TASK_RUNNING;
	remove_wait_queue(&ch->open_wait, &wait);
	cli();
	if (!tty_hung_up_p(filp))
		ch->count++;
	restore_flags(flags);

	ch->blocked_open--;

	if (retval)
		return retval;

	ch->asyncflags |= ASYNC_NORMAL_ACTIVE;

	return 0;

} /* End block_til_ready */	

/* ------------------ Begin pc_open  ---------------------- */

static int pc_open(struct tty_struct *tty, struct file * filp)
{ /* Begin pc_open */

	struct channel *ch;
	unsigned long flags;
	int line, retval, boardnum;
	volatile struct board_chan *bc;
	volatile unsigned int head;

	/* Nothing "real" happens in open of control device */

	if (tty->driver.subtype == SERIAL_TYPE_INFO) 
	{
		return (0) ;
	}

	line = MINOR(tty->device) - tty->driver.minor_start;
	if (line < 0 || line >= nbdevs) 
	{
		printk(KERN_ERR "<Error> - pc_open : line out of range in pc_open\n");
		tty->driver_data = NULL;
		return(-ENODEV);
	}

#ifdef MODULE

	MOD_INC_USE_COUNT;

#endif

	ch = &digi_channels[line];
	boardnum = ch->boardnum;

	/* Check status of board configured in system.  */

	/* -----------------------------------------------------------------
		I check to see if the epca_setup routine detected an user error.  
		It might be better to put this in pc_init, but for the moment it
		goes here.
	---------------------------------------------------------------------- */

	if (invalid_lilo_config)
	{
		if (setup_error_code & INVALID_BOARD_TYPE)
			printk(KERN_ERR "<Error> - pc_open: Invalid board type specified in LILO command\n");

		if (setup_error_code & INVALID_NUM_PORTS)
			printk(KERN_ERR "<Error> - pc_open: Invalid number of ports specified in LILO command\n");

		if (setup_error_code & INVALID_MEM_BASE)
			printk(KERN_ERR "<Error> - pc_open: Invalid board memory address specified in LILO command\n");

		if (setup_error_code & INVALID_PORT_BASE)
			printk(KERN_ERR "<Error> - pc_open: Invalid board port address specified in LILO command\n");

		if (setup_error_code & INVALID_BOARD_STATUS)
			printk(KERN_ERR "<Error> - pc_open: Invalid board status specified in LILO command\n");

		if (setup_error_code & INVALID_ALTPIN)
			printk(KERN_ERR "<Error> - pc_open: Invalid board altpin specified in LILO command\n");

		tty->driver_data = NULL;   /* Mark this device as 'down' */
		return(-ENODEV);
	}

	if ((boardnum >= num_cards) || (boards[boardnum].status == DISABLED)) 
	{
		tty->driver_data = NULL;   /* Mark this device as 'down' */
		return(-ENODEV);
	}
	
	if (( bc = ch->brdchan) == 0) 
	{
		tty->driver_data = NULL;
		return(-ENODEV);
	}

	/* ------------------------------------------------------------------
		Every time a channel is opened, increment a counter.  This is 
		necessary because we do not wish to flush and shutdown the channel
		until the last app holding the channel open, closes it.	 	
	--------------------------------------------------------------------- */

	ch->count++;

	/* ----------------------------------------------------------------
		Set a kernel structures pointer to our local channel 
		structure.  This way we can get to it when passed only
		a tty struct.
	------------------------------------------------------------------ */

	tty->driver_data = ch;
	
	/* ----------------------------------------------------------------
		If this is the first time the channel has been opened, initialize
		the tty->termios struct otherwise let pc_close handle it.
	-------------------------------------------------------------------- */

	/* Should this be here except for SPLIT termios ? */
	if (ch->count == 1) 
	{
		if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
			*tty->termios = ch->normal_termios;
		else 
			*tty->termios = ch->callout_termios;
	}

	ch->session = current->session;
	ch->pgrp = current->pgrp;

	save_flags(flags);
	cli();

	globalwinon(ch);
	ch->statusflags = 0;

	/* Save boards current modem status */
	ch->imodem = bc->mstat;

	/* ----------------------------------------------------------------
	   Set receive head and tail ptrs to each other.  This indicates
	   no data available to read.
	----------------------------------------------------------------- */
	head = bc->rin;
	bc->rout = head;

	/* Set the channels associated tty structure */
	ch->tty = tty;

	/* -----------------------------------------------------------------
		The below routine generally sets up parity, baud, flow control 
		issues, etc.... It effect both control flags and input flags.
	-------------------------------------------------------------------- */
	epcaparam(tty,ch);

	ch->asyncflags |= ASYNC_INITIALIZED;
	memoff(ch);

	restore_flags(flags);

	retval = block_til_ready(tty, filp, ch);
	if (retval)
	{
		return retval;
	}

	/* -------------------------------------------------------------
		Set this again in case a hangup set it to zero while this 
		open() was waiting for the line...
	--------------------------------------------------------------- */
	ch->tty = tty;

	save_flags(flags);
	cli();
	globalwinon(ch);

	/* Enable Digi Data events */
	bc->idata = 1;

	memoff(ch);
	restore_flags(flags);

	return 0;

} /* End pc_open */

#ifdef MODULE
/* -------------------- Begin init_module ---------------------- */
int init_module()
{ /* Begin init_module */

	unsigned long	flags;

	save_flags(flags);
	cli();

	pc_init();

	restore_flags(flags);

	return(0);
} /* End init_module */

#endif
#ifdef MODULE
/* -------------------- Begin cleanup_module  ---------------------- */
void cleanup_module()
{ /* Begin cleanup_module */

	int               count, crd;
	struct board_info *bd;
	struct channel    *ch;
	unsigned long     flags;


	save_flags(flags);
	cli();

	timer_table[DIGI_TIMER].fn = 0;

	if ((tty_unregister_driver(&pc_driver)) ||  
	    (tty_unregister_driver(&pc_callout)))
	{
		printk(KERN_WARNING "<Error> - DIGI : cleanup_module failed to un-register tty driver\n");
		restore_flags(flags);
		return;
	}

	for (crd = 0; crd < num_cards; crd++) 
	{ /* Begin for each card */

		bd = &boards[crd];

		if (!bd)
		{ /* Begin sanity check */
			printk(KERN_ERR "<Error> - Digi : cleanup_module failed\n");
			return;
		} /* End sanity check */

		ch = card_ptr[crd]; 

		for (count = 0; count < bd->numports; count++, ch++) 
		{ /* Begin for each port */

			if (ch) 
			{
				if (ch->tty)
					tty_hangup(ch->tty);
				kfree_s(ch->tmp_buf, ch->txbufsize);
			}

		} /* End for each port */
	} /* End for each card */


	restore_flags(flags);

} /* End cleanup_module */
#endif /* MODULE */

/* ------------------ Begin pc_init  ---------------------- */

int pc_init(void)
{ /* Begin pc_init */

	/* ----------------------------------------------------------------
		pc_init is called by the operating system during boot up prior to
		any open calls being made.  In the older versions of Linux (Prior
		to 2.0.0) an entry is made into tty_io.c.  A pointer to the last
		memory location (from kernel space) used (kmem_start) is passed
		to pc_init.  It is pc_inits responsibility to modify this value 
		for any memory that the Digi driver might need and then return
		this value to the operating system.  For example if the driver
		wishes to allocate 1K of kernel memory, pc_init would return 
		(kmem_start + 1024).  This memory (Between kmem_start and kmem_start
		+ 1024) would then be available for use exclusively by the driver.  
		In this case our driver does not allocate any of this kernel 
		memory.
	------------------------------------------------------------------*/

	ulong flags, save_loops_per_sec; 
	int crd;
	struct board_info *bd;
	unsigned char board_id = 0;
	

#ifdef ENABLE_PCI
	int pci_boards_found, pci_count;

	pci_count = 0;
#endif /* ENABLE_PCI */

	/* -----------------------------------------------------------------------
		If epca_setup has not been ran by LILO set num_cards to defaults; copy
		board structure defined by digiConfig into drivers board structure.
		Note : If LILO has ran epca_setup then epca_setup will handle defining
		num_cards as well as copying the data into the board structure.
	-------------------------------------------------------------------------- */
	if (!liloconfig)
	{ /* Begin driver has been configured via. epcaconfig */

		nbdevs = NBDEVS;
		num_cards = NUMCARDS;
		memcpy((void *)&boards, (void *)&static_boards,
		       (sizeof(struct board_info) * NUMCARDS));
	} /* End driver has been configured via. epcaconfig */

	/* -----------------------------------------------------------------
		Note : If lilo was used to configure the driver and the 
		ignore epcaconfig option was choosen (digiepca=2) then 
		nbdevs and num_cards will equal 0 at this point.  This is
		okay; PCI cards will still be picked up if detected.
	--------------------------------------------------------------------- */

	/*  -----------------------------------------------------------
		Set up interrupt, we will worry about memory allocation in
		post_fep_init. 
	--------------------------------------------------------------- */


	printk(KERN_INFO "DIGI epca driver version %s loaded.\n",VERSION);

#ifdef ENABLE_PCI

	/* ------------------------------------------------------------------
		NOTE : This code assumes that the number of ports found in 
		       the boards array is correct.  This could be wrong if
		       the card in question is PCI (And therefore has no ports 
		       entry in the boards structure.)  The rest of the 
		       information will be valid for PCI because the begining
		       of pc_init scans for PCI and determines i/o and base
		       memory addresses.  I am not sure if it is possible to 
		       read the number of ports supported by the card prior to
		       it being booted (Since that is the state it is in when