serial.c

In the ffuart.tar.gz it has one file. The serial.c is the source codes of the FFUART as a console

		info->last_active = jiffies;

		status = serial_inp(info, UART_LSR);
#ifdef SERIAL_DEBUG_INTR
		printk("status = %x...", status);
#endif
		if (status & UART_LSR_DR)
			receive_chars(info, &status, regs);
		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];
		/*
		 * The user was a bonehead, and misconfigured their
		 * multiport info.  Rather than lock up the kernel
		 * in an infinite loop, if we loop too many times,
		 * print a message and break out of the loop.
		 */
		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
			printk("Misconfigured multiport serial info "
			       "for irq %d.  Breaking out irq loop\n", irq);
			break; 
		}
		if (multi->port_monitor)
			printk("rs port monitor irq %d: 0x%x, 0x%x\n",
			       info->state->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
}
#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 (test_and_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);
#ifdef SERIAL_HAVE_POLL_WAIT
		wake_up_interruptible(&tty->poll_wait);
#endif
	}
}

/*
 * 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(unsigned long dummy)
{
	static unsigned long last_strobe;
	struct async_struct *info;
	unsigned int	i;
	unsigned long flags;

	if ((jiffies - last_strobe) >= RS_STROBE_TIME) {
		for (i=0; i < NR_IRQS; i++) {
			info = IRQ_ports[i];
			if (!info)
				continue;
			save_flags(flags); cli();
#ifdef CONFIG_SERIAL_SHARE_IRQ
			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);
#ifdef CONFIG_SERIAL_MULTIPORT
				if (rs_multiport[i].port1)
					rs_interrupt_multi(i, NULL, NULL);
				else
#endif
					rs_interrupt(i, NULL, NULL);
			} else
#endif /* CONFIG_SERIAL_SHARE_IRQ */
				rs_interrupt_single(i, NULL, NULL);
			restore_flags(flags);
		}
	}
	last_strobe = jiffies;
	mod_timer(&serial_timer, jiffies + RS_STROBE_TIME);

	if (IRQ_ports[0]) {
		save_flags(flags); cli();
#ifdef CONFIG_SERIAL_SHARE_IRQ
		rs_interrupt(0, NULL, NULL);
#else
		rs_interrupt_single(0, NULL, NULL);
#endif
		restore_flags(flags);

		mod_timer(&serial_timer, jiffies + IRQ_timeout[0]);
	}
}

/*
 * ---------------------------------------------------------------
 * 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.
 * ---------------------------------------------------------------
 */

/*
 * 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 > 3) ? timeout-2 : 1;
}

#ifdef CONFIG_SERIAL_RSA
/* Attempts to turn on the RSA FIFO.  Returns zero on failure */
static int enable_rsa(struct async_struct *info)
{
	unsigned char mode;
	int result;
	unsigned long flags;

	save_flags(flags); cli();
	mode = serial_inp(info, UART_RSA_MSR);
	result = mode & UART_RSA_MSR_FIFO;

	if (!result) {
		serial_outp(info, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
		mode = serial_inp(info, UART_RSA_MSR);
		result = mode & UART_RSA_MSR_FIFO;
	}

	restore_flags(flags);
	return result;
}

/* Attempts to turn off the RSA FIFO.  Returns zero on failure */
static int disable_rsa(struct async_struct *info)
{
	unsigned char mode;
	int result;
	unsigned long flags;

	save_flags(flags); cli();
	mode = serial_inp(info, UART_RSA_MSR);
	result = !(mode & UART_RSA_MSR_FIFO);

	if (!result) {
		serial_outp(info, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
		mode = serial_inp(info, UART_RSA_MSR);
		result = !(mode & UART_RSA_MSR_FIFO);
	}

	restore_flags(flags);
	return result;
}
#endif /* CONFIG_SERIAL_RSA */

static int startup(struct async_struct * info)
{
	unsigned long flags;
	int	retval=0;
	void (*handler)(int, void *, struct pt_regs *);
	struct serial_state *state= info->state;
	unsigned long page;
#ifdef CONFIG_SERIAL_MANY_PORTS
	unsigned short ICP;
#endif

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

	save_flags(flags); cli();

	if (info->flags & ASYNC_INITIALIZED) {
		free_page(page);
		goto errout;
	}

	if (!CONFIGURED_SERIAL_PORT(state) || !state->type) {
		if (info->tty)
			set_bit(TTY_IO_ERROR, &info->tty->flags);
		free_page(page);
		goto errout;
	}
	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, state->irq);
#endif

	if (uart_config[state->type].flags & UART_STARTECH) {
		/* Wake up UART */
		serial_outp(info, UART_LCR, 0xBF);
		serial_outp(info, UART_EFR, UART_EFR_ECB);
		/*
		 * Turn off LCR == 0xBF so we actually set the IER
		 * register on the XR16C850
		 */
		serial_outp(info, UART_LCR, 0);
		serial_outp(info, UART_IER, 0);
		/*
		 * Now reset LCR so we can turn off the ECB bit
		 */
		serial_outp(info, UART_LCR, 0xBF);
		serial_outp(info, UART_EFR, 0);
		/*
		 * For a XR16C850, we need to set the trigger levels
		 */
		if (state->type == PORT_16850) {
			serial_outp(info, UART_FCTR, UART_FCTR_TRGD |
					UART_FCTR_RX);
			serial_outp(info, UART_TRG, UART_TRG_96);
			serial_outp(info, UART_FCTR, UART_FCTR_TRGD |
					UART_FCTR_TX);
			serial_outp(info, UART_TRG, UART_TRG_96);
		}
		serial_outp(info, UART_LCR, 0);
	}

	if (state->type == PORT_16750) {
		/* Wake up UART */
		serial_outp(info, UART_IER, 0);
	}

	if (state->type == PORT_16C950) {
		/* Wake up and initialize UART */
		info->ACR = 0;
		serial_outp(info, UART_LCR, 0xBF);
		serial_outp(info, UART_EFR, UART_EFR_ECB);
		serial_outp(info, UART_IER, 0);
		serial_outp(info, UART_LCR, 0);
		serial_icr_write(info, UART_CSR, 0); /* Reset the UART */
		serial_outp(info, UART_LCR, 0xBF);
		serial_outp(info, UART_EFR, UART_EFR_ECB);
		serial_outp(info, UART_LCR, 0);
	}

#ifdef CONFIG_SERIAL_RSA
	/*
	 * If this is an RSA port, see if we can kick it up to the
	 * higher speed clock.
	 */
	if (state->type == PORT_RSA) {
		if (state->baud_base != SERIAL_RSA_BAUD_BASE &&
		    enable_rsa(info))
			state->baud_base = SERIAL_RSA_BAUD_BASE;
		if (state->baud_base == SERIAL_RSA_BAUD_BASE)
			serial_outp(info, UART_RSA_FRR, 0);
	}
#endif

#ifdef CONFIG_ARCH_PXA
	if (state->type == PORT_PXA) {
		switch ((long)state->iomem_base) {
			case (long)&FFUART: CKEN |= CKEN6_FFUART; break;
			case (long)&BTUART: CKEN |= CKEN7_BTUART; break;
			case (long)&STUART: CKEN |= CKEN5_STUART; break;
		}
	}
#endif

	/*
	 * Clear the FIFO buffers and disable them
	 * (they will be reenabled in change_speed())
	 */
	if (uart_config[state->type].flags & UART_CLEAR_FIFO) {
		serial_outp(info, UART_FCR, UART_FCR_ENABLE_FIFO);
		serial_outp(info, UART_FCR, (UART_FCR_ENABLE_FIFO |
					     UART_FCR_CLEAR_RCVR |
					     UART_FCR_CLEAR_XMIT));
		serial_outp(info, UART_FCR, 0);
	}

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

	/*
	 * 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 (!(info->flags & ASYNC_BUGGY_UART) &&
	    (serial_inp(info, UART_LSR) == 0xff)) {
		printk("ttyS%d: LSR safety check engaged!\n", state->line);
		if (capable(CAP_SYS_ADMIN)) {
			if (info->tty)
				set_bit(TTY_IO_ERROR, &info->tty->flags);
		} else
			retval = -ENODEV;
		goto errout;
	}
	
	/*
	 * Allocate the IRQ if necessary
	 */
	if (state->irq && (!IRQ_ports[state->irq] ||
			  !IRQ_ports[state->irq]->next_port)) {
		if (IRQ_ports[state->irq]) {
#ifdef CONFIG_SERIAL_SHARE_IRQ
			free_irq(state->irq, &IRQ_ports[state->irq]);
#ifdef CONFIG_SERIAL_MULTIPORT				
			if (rs_multiport[state->irq].port1)
				handler = rs_interrupt_multi;
			else
#endif
				handler = rs_interrupt;
#else
			retval = -EBUSY;
			goto errout;
#endif /* CONFIG_SERIAL_SHARE_IRQ */
		} else 
			handler = rs_interrupt_single;

		retval = request_irq(state->irq, handler, SA_SHIRQ,
				     "serial", &IRQ_ports[state->irq]);
		if (retval) {
			if (capable(CAP_SYS_ADMIN)) {
				if (info->tty)
					set_bit(TTY_IO_ERROR,
						&info->tty->flags);
				retval = 0;
			}
			goto errout;
		}
	}

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

	/*
	 * Now, initialize the UART 
	 */
	serial_outp(info, UART_LCR, UART_LCR_WLEN8);	/* reset DLAB */

	info->MCR = 0;
	if (info->tty->termios->c_cflag & CBAUD)
		info->MCR = UART_MCR_DTR | UART_MCR_RTS;
#ifdef CONFIG_SERIAL_MANY_PORTS
	if (info->flags & ASYNC_FOURPORT) {
		if (state->irq == 0)
			info->MCR |= UART_MCR_OUT1;
	} else
#endif
	{
		if (state->irq != 0)
			info->MCR |= UART_MCR_OUT2;
		if (pxa_buggy_port(state->type) && state->irq != 0)
			info->MCR ^= UART_MCR_OUT2;
	}
	info->MCR |= ALPHA_KLUDGE_MCR; 		/* Don't ask */
	serial_outp(info, UART_MCR, info->MCR);
	
	/*
	 * Finally, enable interrupts
	 */
	info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI;
	if (pxa_port(state->type))
		info->IER |= UART_IER_UUE | UART_IER_RTOIE;
	serial_outp(info, UART_IER, info->IER);	/* enable interrupts */
	
#ifdef CONFIG_SERIAL_MANY_PORTS
	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);
	}
#endif

	/*
	 * 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.head = info->xmit.tail = 0;

	/*
	 * Set up serial timers...
	 */
	mod_timer(&serial_timer, jiffies + 2*HZ/100);

	/*
	 * Set up the tty->alt_speed kludge
	 */
#if (LINUX_VERSION_CODE >= 131394) /* Linux 2.1.66 */
	if (info->tty) {
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			info->tty->alt_speed = 57600;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			info->tty->alt_speed = 115200;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
			info->tty->alt_speed = 230400;
		if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
			info->tty->alt_speed = 460800;
	}
#endif
	
	/*
	 * and set the speed of the serial port
	 */