zs.c

自己根据lkd和情境分析

		ZSLOG(REGDATA, ch, 0);
		ch &= info->parity_mask;
		ZSDELAY();

		/* If this is the console keyboard, we need to handle
		 * L1-A's here.
		 */
		if (info->cons_keyb) {
			if (ch == SUNKBD_RESET) {
				l1a_state.kbd_id = 1;
				l1a_state.l1_down = 0;
			} else if (l1a_state.kbd_id) {
				l1a_state.kbd_id = 0;
			} else if (ch == SUNKBD_L1) {
				l1a_state.l1_down = 1;
			} else if (ch == (SUNKBD_L1|SUNKBD_UP)) {
				l1a_state.l1_down = 0;
			} else if (ch == SUNKBD_A && l1a_state.l1_down) {
				/* whee... */
				batten_down_hatches();
				/* Continue execution... */
				l1a_state.l1_down = 0;
				l1a_state.kbd_id = 0;
				return;
			}
			sunkbd_inchar(ch, regs);
			goto next_char;
		}
		if (info->cons_mouse) {
			sun_mouse_inbyte(ch, 0);
			goto next_char;
		}
		if (info->is_cons) {
			if (ch == 0) {
				/* whee, break received */
				batten_down_hatches();
				/* Continue execution... */
				return;
			}
			/* It is a 'keyboard interrupt' ;-) */
			wake_up(&keypress_wait);
		}
#ifndef __sparc_v9__
		/* Look for kgdb 'stop' character, consult the gdb
		 * documentation for remote target debugging and
		 * arch/sparc/kernel/sparc-stub.c to see how all this works.
		 */
		if (info->kgdb_channel && (ch =='\003')) {
			breakpoint();
			return;
		}
#endif
		if (!tty)
			return;

		do_queue_task++;

		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			break;

		tty->flip.count++;
		if (r1 & PAR_ERR)
			*tty->flip.flag_buf_ptr++ = TTY_PARITY;
		else if (r1 & Rx_OVR)
			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
		else if (r1 & CRC_ERR)
			*tty->flip.flag_buf_ptr++ = TTY_FRAME;
		else
			*tty->flip.flag_buf_ptr++ = 0;
		*tty->flip.char_buf_ptr++ = ch;

	next_char:
		{
			unsigned char stat;

			/* Check if we have another character... */
			stat = sbus_readb(&info->zs_channel->control);
			ZSDELAY();
			ZSLOG(REGCTRL, stat, 0);
			if (!(stat & Rx_CH_AV))
				break;
		}
	}

	if (do_queue_task != 0)
		queue_task(&tty->flip.tqueue, &tq_timer);
}

static void transmit_chars(struct sun_serial *info)
{
	struct tty_struct *tty = info->tty;

	if (info->x_char) {
		/* Send next char */
		zs_put_char(info->zs_channel, info->x_char);
		info->x_char = 0;
		return;
	}

	if ((info->xmit_cnt <= 0) || (tty != 0 && tty->stopped)) {
		/* That's peculiar... */
		sbus_writeb(RES_Tx_P, &info->zs_channel->control);
		ZSDELAY();
		ZS_WSYNC(info->zs_channel);
		ZSLOG(REGCTRL, RES_Tx_P, 1);
		return;
	}

	/* Send char */
	zs_put_char(info->zs_channel, info->xmit_buf[info->xmit_tail++]);
	info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
	info->xmit_cnt--;

	if (info->xmit_cnt < WAKEUP_CHARS)
		zs_sched_event(info, RS_EVENT_WRITE_WAKEUP);

	if (info->xmit_cnt <= 0) {
		sbus_writeb(RES_Tx_P, &info->zs_channel->control);
		ZSDELAY();
		ZS_WSYNC(info->zs_channel);
		ZSLOG(REGCTRL, RES_Tx_P, 1);
	}
}

static void status_handle(struct sun_serial *info)
{
	unsigned char status;

	/* Get status from Read Register 0 */
	status = sbus_readb(&info->zs_channel->control);
	ZSDELAY();
	ZSLOG(REGCTRL, status, 0);
	/* Clear status condition... */
	sbus_writeb(RES_EXT_INT, &info->zs_channel->control);
	ZSDELAY();
	ZS_WSYNC(info->zs_channel);
	ZSLOG(REGCTRL, RES_EXT_INT, 1);
#if 0
	if (status & DCD) {
		if ((info->tty->termios->c_cflag & CRTSCTS) &&
		    ((info->curregs[3] & AUTO_ENAB)==0)) {
			info->curregs[3] |= AUTO_ENAB;
			write_zsreg(info->zs_channel, 3, info->curregs[3]);
		}
	} else {
		if ((info->curregs[3] & AUTO_ENAB)) {
			info->curregs[3] &= ~AUTO_ENAB;
			write_zsreg(info->zs_channel, 3, info->curregs[3]);
		}
	}
#endif
	/* Whee, if this is console input and this is a
	 * 'break asserted' status change interrupt, call
	 * the boot prom.
	 */
	if (status & BRK_ABRT) {
		if (info->break_abort)
			batten_down_hatches();
		if (info->cons_mouse)
			sun_mouse_inbyte(0, 1);
	}

	/* XXX Whee, put in a buffer somewhere, the status information
	 * XXX whee whee whee... Where does the information go...
	 */
	return;
}

/*
 * This is the serial driver's generic interrupt routine
 */
void zs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	struct sun_serial *info;
	int i;

	info = (struct sun_serial *)dev_id;
	ZSLOG(REGIRQ, 0, 0);
	for (i = 0; i < NUM_SERIAL; i++) {
		unsigned char r3 = read_zsreg(info->zs_channel, 3);

		/* Channel A -- /dev/ttya or /dev/kbd, could be the console */
		if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
			sbus_writeb(RES_H_IUS, &info->zs_channel->control);
			ZSDELAY();
			ZS_WSYNC(info->zs_channel);
			ZSLOG(REGCTRL, RES_H_IUS, 1);
			if (r3 & CHARxIP)
				receive_chars(info, regs);
			if (r3 & CHAEXT)
				status_handle(info);
			if (r3 & CHATxIP)
				transmit_chars(info);
		}

		/* Channel B -- /dev/ttyb or /dev/mouse, could be the console */
		info = info->zs_next;
		if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
			sbus_writeb(RES_H_IUS, &info->zs_channel->control);
			ZSDELAY();
			ZS_WSYNC(info->zs_channel);
			ZSLOG(REGCTRL, RES_H_IUS, 1);
			if (r3 & CHBRxIP)
				receive_chars(info, regs);
			if (r3 & CHBEXT)
				status_handle(info);
			if (r3 & CHBTxIP)
				transmit_chars(info);
		}

		info = info->zs_next;
	}
}

/*
 * -------------------------------------------------------------------
 * 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
 * zs_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 zs_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 sun_serial	*info = (struct sun_serial *) 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);
	}
}

/*
 * 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() -> zs_hangup()
 * 
 */
static void do_serial_hangup(void *private_)
{
	struct sun_serial	*info = (struct sun_serial *) private_;
	struct tty_struct	*tty;
	
	tty = info->tty;
	if (!tty)
		return;
#ifdef SERIAL_DEBUG_OPEN
	printk("do_serial_hangup<%p: tty-%d\n",
		__builtin_return_address(0), info->line);
#endif

	tty_hangup(tty);
}

static int startup(struct sun_serial * info)
{
	unsigned long flags;

	if (info->flags & ZILOG_INITIALIZED)
		return 0;

	if (!info->xmit_buf) {
		info->xmit_buf = (unsigned char *) get_free_page(GFP_KERNEL);
		if (!info->xmit_buf)
			return -ENOMEM;
	}

	save_flags(flags); cli();

#ifdef SERIAL_DEBUG_OPEN
	printk("Starting up tty-%d (irq %d)...\n", info->line, info->irq);
#endif

	/*
	 * Clear the FIFO buffers and disable them
	 * (they will be reenabled in change_speed())
	 */
	ZS_CLEARFIFO(info->zs_channel);
	info->xmit_fifo_size = 1;

	/*
	 * Clear the interrupt registers.
	 */
	sbus_writeb(ERR_RES, &info->zs_channel->control);
	ZSDELAY();
	ZS_WSYNC(info->zs_channel);
	ZSLOG(REGCTRL, ERR_RES, 1);

	sbus_writeb(RES_H_IUS, &info->zs_channel->control);
	ZSDELAY();
	ZS_WSYNC(info->zs_channel);
	ZSLOG(REGCTRL, RES_H_IUS, 1);

	/*
	 * Now, initialize the Zilog
	 */
	zs_rtsdtr(info, 1);

	/*
	 * Finally, enable sequencing and interrupts
	 */
	info->curregs[1] |= (info->curregs[1] & ~(RxINT_MASK)) |
				(EXT_INT_ENAB | INT_ALL_Rx);
	info->curregs[3] |= (RxENAB | Rx8);
	/* We enable Tx interrupts as needed. */
	info->curregs[5] |= (TxENAB | Tx8);
	info->curregs[9] |= (NV | MIE);
	write_zsreg(info->zs_channel, 3, info->curregs[3]);
	write_zsreg(info->zs_channel, 5, info->curregs[5]);
	write_zsreg(info->zs_channel, 9, info->curregs[9]);
	
	/*
	 * And clear the interrupt registers again for luck.
	 */
	sbus_writeb(ERR_RES, &info->zs_channel->control);
	ZSDELAY();
	ZS_WSYNC(info->zs_channel);
	ZSLOG(REGCTRL, ERR_RES, 1);

	sbus_writeb(RES_H_IUS, &info->zs_channel->control);
	ZSDELAY();
	ZS_WSYNC(info->zs_channel);
	ZSLOG(REGCTRL, RES_H_IUS, 1);

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

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

	info->flags |= ZILOG_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 sun_serial * info)
{
	unsigned long	flags;

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

#ifdef SERIAL_DEBUG_OPEN
	printk("Shutting down serial port %d (irq %d)....", info->line,
	       info->irq);
#endif
	
	save_flags(flags); cli(); /* Disable interrupts */
	
	if (info->xmit_buf) {
		free_page((unsigned long) info->xmit_buf);
		info->xmit_buf = 0;
	}

	if (info->tty)
		set_bit(TTY_IO_ERROR, &info->tty->flags);
	
	info->flags &= ~ZILOG_INITIALIZED;
	restore_flags(flags);
}

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct sun_serial *info)
{
	unsigned cflag;
	int	baud, quot = 0;
	int	brg;

	if (!info->tty || !info->tty->termios)
		return;
	cflag = info->tty->termios->c_cflag;
	if (!info->port)
		return;
	baud = tty_get_baud_rate(info->tty);
	
	if ((baud == 38400) && 
	    ((info->flags & ZILOG_SPD_MASK) == ZILOG_SPD_CUST))
		quot = info->custom_divisor;

	if (quot) {
		info->zs_baud = info->baud_base / quot;
		info->clk_divisor = 16;

		info->curregs[4] = X16CLK;
		info->curregs[11] = TCBR | RCBR;
		brg = BPS_TO_BRG(info->zs_baud, ZS_CLOCK/info->clk_divisor);
		info->curregs[12] = (brg & 255);
		info->curregs[13] = ((brg >> 8) & 255);
		info->curregs[14] = BRSRC | BRENAB;
		zs_rtsdtr(info, 1);
	} else if (baud) {
		info->zs_baud = baud;
		info->clk_divisor = 16;

		info->curregs[4] = X16CLK;
		info->curregs[11] = TCBR | RCBR;
		brg = BPS_TO_BRG(info->zs_baud, ZS_CLOCK/info->clk_divisor);
		info->curregs[12] = (brg & 255);
		info->curregs[13] = ((brg >> 8) & 255);
		info->curregs[14] = BRSRC | BRENAB;
		zs_rtsdtr(info, 1);
	} else {
		zs_rtsdtr(info, 0);
		return;
	}

	/* byte size and parity */
	switch (cflag & CSIZE) {
	case CS5:
		info->curregs[3] &= ~(RxN_MASK);
		info->curregs[3] |= Rx5;
		info->curregs[5] &= ~(TxN_MASK);
		info->curregs[5] |= Tx5;
		info->parity_mask = 0x1f;
		break;
	case CS6:
		info->curregs[3] &= ~(RxN_MASK);
		info->curregs[3] |= Rx6;
		info->curregs[5] &= ~(TxN_MASK);
		info->curregs[5] |= Tx6;
		info->parity_mask = 0x3f;
		break;
	case CS7:
		info->curregs[3] &= ~(RxN_MASK);
		info->curregs[3] |= Rx7;
		info->curregs[5] &= ~(TxN_MASK);
		info->curregs[5] |= Tx7;
		info->parity_mask = 0x7f;
		break;
	case CS8:
	default: /* defaults to 8 bits */
		info->curregs[3] &= ~(RxN_MASK);
		info->curregs[3] |= Rx8;
		info->curregs[5] &= ~(TxN_MASK);
		info->curregs[5] |= Tx8;
		info->parity_mask = 0xff;
		break;
	}
	info->curregs[4] &= ~(0x0c);
	if (cflag & CSTOPB) {
		info->curregs[4] |= SB2;
	} else {
		info->curregs[4] |= SB1;
	}
	if (cflag & PARENB) {
		info->curregs[4] |= PAR_ENAB;
	} else {
		info->curregs[4] &= ~PAR_ENAB;
	}
	if (!(cflag & PARODD)) {
		info->curregs[4] |= PAR_EVEN;
	} else {
		info->curregs[4] &= ~PAR_EVEN;
	}

	/* Load up the new values */
	load_zsregs(info, info->curregs);

	return;
}

/* This is for mouse/keyboard output.
 * XXX mouse output??? can we send it commands??? XXX
 */
static void kbd_put_char(unsigned char ch)
{
	struct sun_zschannel *chan = zs_kbdchan;
	unsigned long flags;

	if(!chan)
		return;

	save_flags(flags); cli();
	zs_put_char(chan, ch);