serial.c

arm平台上的uclinux系统全部源代码

			}
			continue;
		}
	} while (end_mark != info);
	if (multi->port_monitor)
		printk("rs port monitor (normal) irq %d: 0x%x, 0x%x\n",
		       info->irq, first_multi, inb(multi->port_monitor));
#ifdef SERIAL_DEBUG_INTR
	printk("end.\n");
#endif
}

/*
 * This is the serial driver's interrupt routine for a single port
 */
static void rs_interrupt_single(int irq, void *dev_id, struct pt_regs * regs)
{
	int status;
	int pass_counter = 0;
	int first_multi = 0;
	struct async_struct * info;
	struct rs_multiport_struct *multi;
	
#ifdef SERIAL_DEBUG_INTR
	printk("rs_interrupt_single(%d)...", irq);
#endif
	
	info = IRQ_ports[irq];
	if (!info || !info->tty)
		return;

	multi = &rs_multiport[irq];
	if (multi->port_monitor)
		first_multi = inb(multi->port_monitor);

	do {
		status = serial_inp(info, UART_LSR) & info->read_status_mask;
#ifdef SERIAL_DEBUG_INTR
		printk("status = %x...", status);
#endif
		if (status & UART_LSR_DR)
			receive_chars(info, &status);
		check_modem_status(info);
		if (status & UART_LSR_THRE)
			transmit_chars(info, 0);
		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
#if 0
			printk("rs_single loop break.\n");
#endif
			break;
		}
	} while (!(serial_in(info, UART_IIR) & UART_IIR_NO_INT));
	info->last_active = jiffies;
	if (multi->port_monitor)
		printk("rs port monitor (single) irq %d: 0x%x, 0x%x\n",
		       info->irq, first_multi, inb(multi->port_monitor));
#ifdef SERIAL_DEBUG_INTR
	printk("end.\n");
#endif
}

/*
 * This is the serial driver's for multiport boards
 */
static void rs_interrupt_multi(int irq, void *dev_id, struct pt_regs * regs)
{
	int status;
	struct async_struct * info;
	int pass_counter = 0;
	int first_multi= 0;
	struct rs_multiport_struct *multi;

#ifdef SERIAL_DEBUG_INTR
	printk("rs_interrupt_multi(%d)...", irq);
#endif
	
	info = IRQ_ports[irq];
	if (!info)
		return;
	multi = &rs_multiport[irq];
	if (!multi->port1) {
		/* Should never happen */
		printk("rs_interrupt_multi: NULL port1!\n");
		return;
	}
	if (multi->port_monitor)
		first_multi = inb(multi->port_monitor);
	
	while (1) {
		if (!info->tty ||
		    (serial_in(info, UART_IIR) & UART_IIR_NO_INT))
			goto next;

		info->last_active = jiffies;

		status = serial_inp(info, UART_LSR) & info->read_status_mask;
#ifdef SERIAL_DEBUG_INTR
		printk("status = %x...", status);
#endif
		if (status & UART_LSR_DR)
			receive_chars(info, &status);
		check_modem_status(info);
		if (status & UART_LSR_THRE)
			transmit_chars(info, 0);

	next:
		info = info->next_port;
		if (info)
			continue;

		info = IRQ_ports[irq];
		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
#if 1
			printk("rs_multi loop break\n");
#endif
			break; 	/* Prevent infinite loops */
		}
		if (multi->port_monitor)
			printk("rs port monitor irq %d: 0x%x, 0x%x\n",
			       info->irq, first_multi,
			       inb(multi->port_monitor));
		if ((inb(multi->port1) & multi->mask1) != multi->match1)
			continue;
		if (!multi->port2)
			break;
		if ((inb(multi->port2) & multi->mask2) != multi->match2)
			continue;
		if (!multi->port3)
			break;
		if ((inb(multi->port3) & multi->mask3) != multi->match3)
			continue;
		if (!multi->port4)
			break;
		if ((inb(multi->port4) & multi->mask4) == multi->match4)
			continue;
		break;
	} 
#ifdef SERIAL_DEBUG_INTR
	printk("end.\n");
#endif
}


/*
 * -------------------------------------------------------------------
 * Here ends the serial interrupt routines.
 * -------------------------------------------------------------------
 */

/*
 * This routine is used to handle the "bottom half" processing for the
 * serial driver, known also the "software interrupt" processing.
 * This processing is done at the kernel interrupt level, after the
 * rs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
 * is where time-consuming activities which can not be done in the
 * interrupt driver proper are done; the interrupt driver schedules
 * them using rs_sched_event(), and they get done here.
 */
static void do_serial_bh(void)
{
	run_task_queue(&tq_serial);
}

static void do_softint(void *private_)
{
	struct async_struct	*info = (struct async_struct *) private_;
	struct tty_struct	*tty;
	
	tty = info->tty;
	if (!tty)
		return;

	if (clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
		if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
		    tty->ldisc.write_wakeup)
			(tty->ldisc.write_wakeup)(tty);
		wake_up_interruptible(&tty->write_wait);
	}
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 * 	serial interrupt routine -> (scheduler tqueue) ->
 * 	do_serial_hangup() -> tty->hangup() -> rs_hangup()
 * 
 */
static void do_serial_hangup(void *private_)
{
	struct async_struct	*info = (struct async_struct *) private_;
	struct tty_struct	*tty;
	
	tty = info->tty;
	if (!tty)
		return;

	tty_hangup(tty);
}


/*
 * This subroutine is called when the RS_TIMER goes off.  It is used
 * by the serial driver to handle ports that do not have an interrupt
 * (irq=0).  This doesn't work very well for 16450's, but gives barely
 * passable results for a 16550A.  (Although at the expense of much
 * CPU overhead).
 */
static void rs_timer(void)
{
	static unsigned long last_strobe = 0;
	struct async_struct *info;
	unsigned int	i;

	if ((jiffies - last_strobe) >= RS_STROBE_TIME) {
		for (i=0; i < 32; i++) {
			info = IRQ_ports[i];
			if (!info)
				continue;
			cli();
			if (info->next_port) {
				do {
					serial_out(info, UART_IER, 0);
					info->IER |= UART_IER_THRI;
					serial_out(info, UART_IER, info->IER);
					info = info->next_port;
				} while (info);
				if (rs_multiport[i].port1)
					rs_interrupt_multi(i, NULL, NULL);
				else
					rs_interrupt(i, NULL, NULL);
			} else
				rs_interrupt_single(i, NULL, NULL);
			sti();
		}
	}
	last_strobe = jiffies;
	timer_table[RS_TIMER].expires = jiffies + RS_STROBE_TIME;
	timer_active |= 1 << RS_TIMER;

	if (IRQ_ports[0]) {
		cli();
		rs_interrupt(0, NULL, NULL);
		sti();

		timer_table[RS_TIMER].expires = jiffies + IRQ_timeout[0] - 2;
	}
}

/*
 * ---------------------------------------------------------------
 * Low level utility subroutines for the serial driver:  routines to
 * figure out the appropriate timeout for an interrupt chain, routines
 * to initialize and startup a serial port, and routines to shutdown a
 * serial port.  Useful stuff like that.
 * ---------------------------------------------------------------
 */

/*
 * Grab all interrupts in preparation for doing an automatic irq
 * detection.  dontgrab is a mask of irq's _not_ to grab.  Returns a
 * mask of irq's which were grabbed and should therefore be freed
 * using free_all_interrupts().
 */
static int grab_all_interrupts(int dontgrab)
{
	int 			irq_lines = 0;
	int			i, mask;
	
	for (i = 0, mask = 1; i < 16; i++, mask <<= 1) {
		if (!(mask & dontgrab) && !request_irq(i, rs_probe, SA_INTERRUPT, "serial probe", NULL)) {
			irq_lines |= mask;
		}
	}
	return irq_lines;
}

/*
 * Release all interrupts grabbed by grab_all_interrupts
 */
static void free_all_interrupts(int irq_lines)
{
	int	i;
	
	for (i = 0; i < 16; i++) {
		if (irq_lines & (1 << i))
			free_irq(i, NULL);
	}
}

/*
 * This routine figures out the correct timeout for a particular IRQ.
 * It uses the smallest timeout of all of the serial ports in a
 * particular interrupt chain.  Now only used for IRQ 0....
 */
static void figure_IRQ_timeout(int irq)
{
	struct	async_struct	*info;
	int	timeout = 60*HZ;	/* 60 seconds === a long time :-) */

	info = IRQ_ports[irq];
	if (!info) {
		IRQ_timeout[irq] = 60*HZ;
		return;
	}
	while (info) {
		if (info->timeout < timeout)
			timeout = info->timeout;
		info = info->next_port;
	}
	if (!irq)
		timeout = timeout / 2;
	IRQ_timeout[irq] = timeout ? timeout : 1;
}

static int startup(struct async_struct * info)
{
	unsigned short ICP;
	unsigned long flags;
	int	retval;
	void (*handler)(int, void *, struct pt_regs *);
	unsigned long page;

	page = get_free_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;

		
	save_flags_cli(flags);

	if (info->flags & ASYNC_INITIALIZED) {
		free_page(page);
		restore_flags(flags);
		return 0;
	}

	if (!info->port || !info->type) {
		if (info->tty)
			set_bit(TTY_IO_ERROR, &info->tty->flags);
		free_page(page);
		restore_flags(flags);
		return 0;
	}
	if (info->xmit_buf)
		free_page(page);
	else
		info->xmit_buf = (unsigned char *) page;

#ifdef SERIAL_DEBUG_OPEN
	printk("starting up ttys%d (irq %d)...", info->line, info->irq);
#endif

	/*
	 * Clear the FIFO buffers and disable them
	 * (they will be reenabled in change_speed())
	 */
	if (info->type == PORT_16650) {
		serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
					     UART_FCR_CLEAR_XMIT));
		info->xmit_fifo_size = 1; /* disabled for now */
	} else if (info->type == PORT_16550A) {
		serial_outp(info, UART_FCR, (UART_FCR_CLEAR_RCVR |
					     UART_FCR_CLEAR_XMIT));
		info->xmit_fifo_size = 16;
	} else
		info->xmit_fifo_size = 1;

	/*
	 * At this point there's no way the LSR could still be 0xFF;
	 * if it is, then bail out, because there's likely no UART
	 * here.
	 */
	if (serial_inp(info, UART_LSR) == 0xff) {
		restore_flags(flags);
		if (suser()) {
			if (info->tty)
				set_bit(TTY_IO_ERROR, &info->tty->flags);
			return 0;
		} else
			return -ENODEV;
	}
	
	/*
	 * Allocate the IRQ if necessary
	 */
	if (info->irq && (!IRQ_ports[info->irq] ||
			  !IRQ_ports[info->irq]->next_port)) {
		if (IRQ_ports[info->irq]) {
			free_irq(info->irq, NULL);
			if (rs_multiport[info->irq].port1)
				handler = rs_interrupt_multi;
			else
				handler = rs_interrupt;
		} else 
			handler = rs_interrupt_single;

		retval = request_irq(info->irq, handler, IRQ_T(info),
				     "serial", NULL);
		if (retval) {
			restore_flags(flags);
			if (suser()) {
				if (info->tty)
					set_bit(TTY_IO_ERROR,
						&info->tty->flags);
				return 0;
			} else
				return retval;
		}
	}

	/*
	 * Clear the interrupt registers.
	 */
     /* (void) serial_inp(info, UART_LSR); */   /* (see above) */
	(void) serial_inp(info, UART_RX);
	(void) serial_inp(info, UART_IIR);
	(void) serial_inp(info, UART_MSR);

	/*
	 * Now, initialize the UART 
	 */
	serial_outp(info, UART_LCR, UART_LCR_WLEN8);	/* reset DLAB */
	if (info->flags & ASYNC_FOURPORT) {
		info->MCR = UART_MCR_DTR | UART_MCR_RTS;
		info->MCR_noint = UART_MCR_DTR | UART_MCR_OUT1;
	} else {
		info->MCR = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
		info->MCR_noint = UART_MCR_DTR | UART_MCR_RTS;
	}
#if defined(__alpha__) && !defined(CONFIG_PCI)
	info->MCR |= UART_MCR_OUT1 | UART_MCR_OUT2;
	info->MCR_noint |= UART_MCR_OUT1 | UART_MCR_OUT2;
#endif
	if (info->irq == 0)
		info->MCR = info->MCR_noint;
	serial_outp(info, UART_MCR, info->MCR);
	
	/*
	 * Finally, enable interrupts
	 */
	info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
	serial_outp(info, UART_IER, info->IER);	/* enable interrupts */
	
	if (info->flags & ASYNC_FOURPORT) {
		/* Enable interrupts on the AST Fourport board */
		ICP = (info->port & 0xFE0) | 0x01F;
		outb_p(0x80, ICP);
		(void) inb_p(ICP);
	}

	/*
	 * And clear the interrupt registers again for luck.
	 */
	(void)serial_inp(info, UART_LSR);
	(void)serial_inp(info, UART_RX);
	(void)serial_inp(info, UART_IIR);
	(void)serial_inp(info, UART_MSR);

	if (info->tty)
		clear_bit(TTY_IO_ERROR, &info->tty->flags);
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

	/*
	 * Insert serial port into IRQ chain.
	 */
	info->prev_port = 0;
	info->next_port = IRQ_ports[info->irq];
	if (info->next_port)
		info->next_port->prev_port = info;
	IRQ_ports[info->irq] = info;
	figure_IRQ_timeout(info->irq);

	/*
	 * Set up serial timers...
	 */
	timer_table[RS_TIMER].expires = jiffies + 2*HZ/100;
	timer_active |= 1 << RS_TIMER;

	/*
	 * and set the speed of the serial port
	 */
	change_speed(info);

	info->flags |= ASYNC_INITIALIZED;
	restore_flags(flags);
	return 0;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void shutdown(struct async_struct * info)
{
	unsigned long	flags;
	int		retval;

	if (!(info->flags & ASYNC_INITIALIZED))
		return;

#ifdef SERIAL_DEBUG_OPEN
	printk("Shutting down serial port %d (irq %d)....", info->line,
	       info->irq);
#endif