Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2048 insertions, 0 deletions

diff --git a/drivers/serial/pmac_zilog.c b/drivers/serial/pmac_zilog.c
new file mode 100644
index 00000000000..0a6b9f0ed23
--- /dev/null
+++ b/drivers/serial/pmac_zilog.c
@@ -0,0 +1,2048 @@
+/*
+ * linux/drivers/serial/pmac_zilog.c
+ * 
+ * Driver for PowerMac Z85c30 based ESCC cell found in the
+ * "macio" ASICs of various PowerMac models
+ * 
+ * Copyright (C) 2003 Ben. Herrenschmidt (benh@kernel.crashing.org)
+ *
+ * Derived from drivers/macintosh/macserial.c by Paul Mackerras
+ * and drivers/serial/sunzilog.c by David S. Miller
+ *
+ * Hrm... actually, I ripped most of sunzilog (Thanks David !) and
+ * adapted special tweaks needed for us. I don't think it's worth
+ * merging back those though. The DMA code still has to get in
+ * and once done, I expect that driver to remain fairly stable in
+ * the long term, unless we change the driver model again...
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * 2004-08-06 Harald Welte <laforge@gnumonks.org>
+ *	- Enable BREAK interrupt
+ *	- Add support for sysreq
+ *
+ * TODO:   - Add DMA support
+ *         - Defer port shutdown to a few seconds after close
+ *         - maybe put something right into uap->clk_divisor
+ */
+
+#undef DEBUG
+#undef DEBUG_HARD
+#undef USE_CTRL_O_SYSRQ
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/tty.h>
+
+#include <linux/tty_flip.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/slab.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <linux/bitops.h>
+#include <linux/sysrq.h>
+#include <asm/sections.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/pmac_feature.h>
+#include <asm/dbdma.h>
+#include <asm/macio.h>
+#include <asm/semaphore.h>
+
+#if defined (CONFIG_SERIAL_PMACZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+
+#include "pmac_zilog.h"
+
+/* Not yet implemented */
+#undef HAS_DBDMA
+
+static char version[] __initdata = "pmac_zilog: 0.6 (Benjamin Herrenschmidt <benh@kernel.crashing.org>)";
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Driver for the PowerMac serial ports.");
+MODULE_LICENSE("GPL");
+
+#define PWRDBG(fmt, arg...)	printk(KERN_DEBUG fmt , ## arg)
+
+
+/*
+ * For the sake of early serial console, we can do a pre-probe
+ * (optional) of the ports at rather early boot time.
+ */
+static struct uart_pmac_port	pmz_ports[MAX_ZS_PORTS];
+static int			pmz_ports_count;
+static DECLARE_MUTEX(pmz_irq_sem);
+
+static struct uart_driver pmz_uart_reg = {
+	.owner		=	THIS_MODULE,
+	.driver_name	=	"ttyS",
+	.devfs_name	=	"tts/",
+	.dev_name	=	"ttyS",
+	.major		=	TTY_MAJOR,
+};
+
+
+/* 
+ * Load all registers to reprogram the port
+ * This function must only be called when the TX is not busy.  The UART
+ * port lock must be held and local interrupts disabled.
+ */
+static void pmz_load_zsregs(struct uart_pmac_port *uap, u8 *regs)
+{
+	int i;
+
+	if (ZS_IS_ASLEEP(uap))
+		return;
+
+	/* Let pending transmits finish.  */
+	for (i = 0; i < 1000; i++) {
+		unsigned char stat = read_zsreg(uap, R1);
+		if (stat & ALL_SNT)
+			break;
+		udelay(100);
+	}
+
+	ZS_CLEARERR(uap);
+	zssync(uap);
+	ZS_CLEARFIFO(uap);
+	zssync(uap);
+	ZS_CLEARERR(uap);
+
+	/* Disable all interrupts.  */
+	write_zsreg(uap, R1,
+		    regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
+
+	/* Set parity, sync config, stop bits, and clock divisor.  */
+	write_zsreg(uap, R4, regs[R4]);
+
+	/* Set misc. TX/RX control bits.  */
+	write_zsreg(uap, R10, regs[R10]);
+
+	/* Set TX/RX controls sans the enable bits.  */
+       	write_zsreg(uap, R3, regs[R3] & ~RxENABLE);
+       	write_zsreg(uap, R5, regs[R5] & ~TxENABLE);
+
+	/* now set R7 "prime" on ESCC */
+	write_zsreg(uap, R15, regs[R15] | EN85C30);
+	write_zsreg(uap, R7, regs[R7P]);
+
+	/* make sure we use R7 "non-prime" on ESCC */
+	write_zsreg(uap, R15, regs[R15] & ~EN85C30);
+
+	/* Synchronous mode config.  */
+	write_zsreg(uap, R6, regs[R6]);
+	write_zsreg(uap, R7, regs[R7]);
+
+	/* Disable baud generator.  */
+	write_zsreg(uap, R14, regs[R14] & ~BRENAB);
+
+	/* Clock mode control.  */
+	write_zsreg(uap, R11, regs[R11]);
+
+	/* Lower and upper byte of baud rate generator divisor.  */
+	write_zsreg(uap, R12, regs[R12]);
+	write_zsreg(uap, R13, regs[R13]);
+	
+	/* Now rewrite R14, with BRENAB (if set).  */
+	write_zsreg(uap, R14, regs[R14]);
+
+	/* Reset external status interrupts.  */
+	write_zsreg(uap, R0, RES_EXT_INT);
+	write_zsreg(uap, R0, RES_EXT_INT);
+
+	/* Rewrite R3/R5, this time without enables masked.  */
+	write_zsreg(uap, R3, regs[R3]);
+	write_zsreg(uap, R5, regs[R5]);
+
+	/* Rewrite R1, this time without IRQ enabled masked.  */
+	write_zsreg(uap, R1, regs[R1]);
+
+	/* Enable interrupts */
+	write_zsreg(uap, R9, regs[R9]);
+}
+
+/* 
+ * We do like sunzilog to avoid disrupting pending Tx
+ * Reprogram the Zilog channel HW registers with the copies found in the
+ * software state struct.  If the transmitter is busy, we defer this update
+ * until the next TX complete interrupt.  Else, we do it right now.
+ *
+ * The UART port lock must be held and local interrupts disabled.
+ */
+static void pmz_maybe_update_regs(struct uart_pmac_port *uap)
+{
+       	if (!ZS_REGS_HELD(uap)) {
+		if (ZS_TX_ACTIVE(uap)) {
+			uap->flags |= PMACZILOG_FLAG_REGS_HELD;
+		} else {
+			pmz_debug("pmz: maybe_update_regs: updating\n");
+			pmz_load_zsregs(uap, uap->curregs);
+		}
+	}
+}
+
+static struct tty_struct *pmz_receive_chars(struct uart_pmac_port *uap,
+					    struct pt_regs *regs)
+{
+	struct tty_struct *tty = NULL;
+	unsigned char ch, r1, drop, error;
+	int loops = 0;
+
+ retry:
+	/* The interrupt can be enabled when the port isn't open, typically
+	 * that happens when using one port is open and the other closed (stale
+	 * interrupt) or when one port is used as a console.
+	 */
+	if (!ZS_IS_OPEN(uap)) {
+		pmz_debug("pmz: draining input\n");
+		/* Port is closed, drain input data */
+		for (;;) {
+			if ((++loops) > 1000)
+				goto flood;
+			(void)read_zsreg(uap, R1);
+			write_zsreg(uap, R0, ERR_RES);
+			(void)read_zsdata(uap);
+			ch = read_zsreg(uap, R0);
+			if (!(ch & Rx_CH_AV))
+				break;
+		}
+		return NULL;
+	}
+
+	/* Sanity check, make sure the old bug is no longer happening */
+	if (uap->port.info == NULL || uap->port.info->tty == NULL) {
+		WARN_ON(1);
+		(void)read_zsdata(uap);
+		return NULL;
+	}
+	tty = uap->port.info->tty;
+
+	while (1) {
+		error = 0;
+		drop = 0;
+
+		if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
+			/* Have to drop the lock here */
+			pmz_debug("pmz: flip overflow\n");
+			spin_unlock(&uap->port.lock);
+			tty->flip.work.func((void *)tty);
+			spin_lock(&uap->port.lock);
+			if (tty->flip.count >= TTY_FLIPBUF_SIZE)
+				drop = 1;
+			if (ZS_IS_ASLEEP(uap))
+				return NULL;
+			if (!ZS_IS_OPEN(uap))
+				goto retry;
+		}
+
+		r1 = read_zsreg(uap, R1);
+		ch = read_zsdata(uap);
+
+		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
+			write_zsreg(uap, R0, ERR_RES);
+			zssync(uap);
+		}
+
+		ch &= uap->parity_mask;
+		if (ch == 0 && uap->flags & PMACZILOG_FLAG_BREAK) {
+			uap->flags &= ~PMACZILOG_FLAG_BREAK;
+		}
+
+#if defined(CONFIG_MAGIC_SYSRQ) && defined(CONFIG_SERIAL_CORE_CONSOLE)
+#ifdef USE_CTRL_O_SYSRQ
+		/* Handle the SysRq ^O Hack */
+		if (ch == '\x0f') {
+			uap->port.sysrq = jiffies + HZ*5;
+			goto next_char;
+		}
+#endif /* USE_CTRL_O_SYSRQ */
+		if (uap->port.sysrq) {
+			int swallow;
+			spin_unlock(&uap->port.lock);
+			swallow = uart_handle_sysrq_char(&uap->port, ch, regs);
+			spin_lock(&uap->port.lock);
+			if (swallow)
+				goto next_char;
+ 		}
+#endif /* CONFIG_MAGIC_SYSRQ && CONFIG_SERIAL_CORE_CONSOLE */
+
+		/* A real serial line, record the character and status.  */
+		if (drop)
+			goto next_char;
+
+		*tty->flip.char_buf_ptr = ch;
+		*tty->flip.flag_buf_ptr = TTY_NORMAL;
+		uap->port.icount.rx++;
+
+		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | BRK_ABRT)) {
+			error = 1;
+			if (r1 & BRK_ABRT) {
+				pmz_debug("pmz: got break !\n");
+				r1 &= ~(PAR_ERR | CRC_ERR);
+				uap->port.icount.brk++;
+				if (uart_handle_break(&uap->port))
+					goto next_char;
+			}
+			else if (r1 & PAR_ERR)
+				uap->port.icount.parity++;
+			else if (r1 & CRC_ERR)
+				uap->port.icount.frame++;
+			if (r1 & Rx_OVR)
+				uap->port.icount.overrun++;
+			r1 &= uap->port.read_status_mask;
+			if (r1 & BRK_ABRT)
+				*tty->flip.flag_buf_ptr = TTY_BREAK;
+			else if (r1 & PAR_ERR)
+				*tty->flip.flag_buf_ptr = TTY_PARITY;
+			else if (r1 & CRC_ERR)
+				*tty->flip.flag_buf_ptr = TTY_FRAME;
+		}
+
+		if (uap->port.ignore_status_mask == 0xff ||
+		    (r1 & uap->port.ignore_status_mask) == 0) {
+			tty->flip.flag_buf_ptr++;
+			tty->flip.char_buf_ptr++;
+			tty->flip.count++;
+		}
+		if ((r1 & Rx_OVR) &&
+		    tty->flip.count < TTY_FLIPBUF_SIZE) {
+			*tty->flip.flag_buf_ptr = TTY_OVERRUN;
+			tty->flip.flag_buf_ptr++;
+			tty->flip.char_buf_ptr++;
+			tty->flip.count++;
+		}
+	next_char:
+		/* We can get stuck in an infinite loop getting char 0 when the
+		 * line is in a wrong HW state, we break that here.
+		 * When that happens, I disable the receive side of the driver.
+		 * Note that what I've been experiencing is a real irq loop where
+		 * I'm getting flooded regardless of the actual port speed.
+		 * Something stange is going on with the HW
+		 */
+		if ((++loops) > 1000)
+			goto flood;
+		ch = read_zsreg(uap, R0);
+		if (!(ch & Rx_CH_AV))
+			break;
+	}
+
+	return tty;
+ flood:
+	uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
+	write_zsreg(uap, R1, uap->curregs[R1]);
+	zssync(uap);
+	dev_err(&uap->dev->ofdev.dev, "pmz: rx irq flood !\n");
+	return tty;
+}
+
+static void pmz_status_handle(struct uart_pmac_port *uap, struct pt_regs *regs)
+{
+	unsigned char status;
+
+	status = read_zsreg(uap, R0);
+	write_zsreg(uap, R0, RES_EXT_INT);
+	zssync(uap);
+
+	if (ZS_IS_OPEN(uap) && ZS_WANTS_MODEM_STATUS(uap)) {
+		if (status & SYNC_HUNT)
+			uap->port.icount.dsr++;
+
+		/* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
+		 * But it does not tell us which bit has changed, we have to keep
+		 * track of this ourselves.
+		 * The CTS input is inverted for some reason.  -- paulus
+		 */
+		if ((status ^ uap->prev_status) & DCD)
+			uart_handle_dcd_change(&uap->port,
+					       (status & DCD));
+		if ((status ^ uap->prev_status) & CTS)
+			uart_handle_cts_change(&uap->port,
+					       !(status & CTS));
+
+		wake_up_interruptible(&uap->port.info->delta_msr_wait);
+	}
+
+	if (status & BRK_ABRT)
+		uap->flags |= PMACZILOG_FLAG_BREAK;
+
+	uap->prev_status = status;
+}
+
+static void pmz_transmit_chars(struct uart_pmac_port *uap)
+{
+	struct circ_buf *xmit;
+
+	if (ZS_IS_ASLEEP(uap))
+		return;
+	if (ZS_IS_CONS(uap)) {
+		unsigned char status = read_zsreg(uap, R0);
+
+		/* TX still busy?  Just wait for the next TX done interrupt.
+		 *
+		 * It can occur because of how we do serial console writes.  It would
+		 * be nice to transmit console writes just like we normally would for
+		 * a TTY line. (ie. buffered and TX interrupt driven).  That is not
+		 * easy because console writes cannot sleep.  One solution might be
+		 * to poll on enough port->xmit space becomming free.  -DaveM
+		 */
+		if (!(status & Tx_BUF_EMP))
+			return;
+	}
+
+	uap->flags &= ~PMACZILOG_FLAG_TX_ACTIVE;
+
+	if (ZS_REGS_HELD(uap)) {
+		pmz_load_zsregs(uap, uap->curregs);
+		uap->flags &= ~PMACZILOG_FLAG_REGS_HELD;
+	}
+
+	if (ZS_TX_STOPPED(uap)) {
+		uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
+		goto ack_tx_int;
+	}
+
+	if (uap->port.x_char) {
+		uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
+		write_zsdata(uap, uap->port.x_char);
+		zssync(uap);
+		uap->port.icount.tx++;
+		uap->port.x_char = 0;
+		return;
+	}
+
+	if (uap->port.info == NULL)
+		goto ack_tx_int;
+	xmit = &uap->port.info->xmit;
+	if (uart_circ_empty(xmit)) {
+		uart_write_wakeup(&uap->port);
+		goto ack_tx_int;
+	}
+	if (uart_tx_stopped(&uap->port))
+		goto ack_tx_int;
+
+	uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
+	write_zsdata(uap, xmit->buf[xmit->tail]);
+	zssync(uap);
+
+	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+	uap->port.icount.tx++;
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&uap->port);
+
+	return;
+
+ack_tx_int:
+	write_zsreg(uap, R0, RES_Tx_P);
+	zssync(uap);
+}
+
+/* Hrm... we register that twice, fixme later.... */
+static irqreturn_t pmz_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct uart_pmac_port *uap = dev_id;
+	struct uart_pmac_port *uap_a;
+	struct uart_pmac_port *uap_b;
+	int rc = IRQ_NONE;
+	struct tty_struct *tty;
+	u8 r3;
+
+	uap_a = pmz_get_port_A(uap);
+	uap_b = uap_a->mate;
+       
+       	spin_lock(&uap_a->port.lock);
+	r3 = read_zsreg(uap_a, R3);
+
+#ifdef DEBUG_HARD
+	pmz_debug("irq, r3: %x\n", r3);
+#endif
+       	/* Channel A */
+	tty = NULL;
+       	if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
+		write_zsreg(uap_a, R0, RES_H_IUS);
+		zssync(uap_a);		
+       		if (r3 & CHAEXT)
+       			pmz_status_handle(uap_a, regs);
+		if (r3 & CHARxIP)
+			tty = pmz_receive_chars(uap_a, regs);
+       		if (r3 & CHATxIP)
+       			pmz_transmit_chars(uap_a);
+	        rc = IRQ_HANDLED;
+       	}
+       	spin_unlock(&uap_a->port.lock);
+	if (tty != NULL)
+		tty_flip_buffer_push(tty);
+
+	if (uap_b->node == NULL)
+		goto out;
+
+       	spin_lock(&uap_b->port.lock);
+	tty = NULL;
+	if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
+		write_zsreg(uap_b, R0, RES_H_IUS);
+		zssync(uap_b);
+       		if (r3 & CHBEXT)
+       			pmz_status_handle(uap_b, regs);
+       	       	if (r3 & CHBRxIP)
+       			tty = pmz_receive_chars(uap_b, regs);
+       		if (r3 & CHBTxIP)
+       			pmz_transmit_chars(uap_b);
+	       	rc = IRQ_HANDLED;
+       	}
+       	spin_unlock(&uap_b->port.lock);
+	if (tty != NULL)
+		tty_flip_buffer_push(tty);
+
+ out:
+#ifdef DEBUG_HARD
+	pmz_debug("irq done.\n");
+#endif
+	return rc;
+}
+
+/*
+ * Peek the status register, lock not held by caller
+ */
+static inline u8 pmz_peek_status(struct uart_pmac_port *uap)
+{
+	unsigned long flags;
+	u8 status;
+	
+	spin_lock_irqsave(&uap->port.lock, flags);
+	status = read_zsreg(uap, R0);
+	spin_unlock_irqrestore(&uap->port.lock, flags);
+
+	return status;
+}
+
+/* 
+ * Check if transmitter is empty
+ * The port lock is not held.
+ */
+static unsigned int pmz_tx_empty(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char status;
+
+	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
+		return TIOCSER_TEMT;
+
+	status = pmz_peek_status(to_pmz(port));
+	if (status & Tx_BUF_EMP)
+		return TIOCSER_TEMT;
+	return 0;
+}
+
+/* 
+ * Set Modem Control (RTS & DTR) bits
+ * The port lock is held and interrupts are disabled.
+ * Note: Shall we really filter out RTS on external ports or
+ * should that be dealt at higher level only ?
+ */
+static void pmz_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char set_bits, clear_bits;
+
+        /* Do nothing for irda for now... */
+	if (ZS_IS_IRDA(uap))
+		return;
+	/* We get called during boot with a port not up yet */
+	if (ZS_IS_ASLEEP(uap) ||
+	    !(ZS_IS_OPEN(uap) || ZS_IS_CONS(uap)))
+		return;
+
+	set_bits = clear_bits = 0;
+
+	if (ZS_IS_INTMODEM(uap)) {
+		if (mctrl & TIOCM_RTS)
+			set_bits |= RTS;
+		else
+			clear_bits |= RTS;
+	}
+	if (mctrl & TIOCM_DTR)
+		set_bits |= DTR;
+	else
+		clear_bits |= DTR;
+
+	/* NOTE: Not subject to 'transmitter active' rule.  */ 
+	uap->curregs[R5] |= set_bits;
+	uap->curregs[R5] &= ~clear_bits;
+	if (ZS_IS_ASLEEP(uap))
+		return;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	pmz_debug("pmz_set_mctrl: set bits: %x, clear bits: %x -> %x\n",
+		  set_bits, clear_bits, uap->curregs[R5]);
+	zssync(uap);
+}
+
+/* 
+ * Get Modem Control bits (only the input ones, the core will
+ * or that with a cached value of the control ones)
+ * The port lock is not held.
+ */
+static unsigned int pmz_get_mctrl(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char status;
+	unsigned int ret;
+
+	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
+		return 0;
+
+	status = pmz_peek_status(to_pmz(port));
+
+	ret = 0;
+	if (status & DCD)
+		ret |= TIOCM_CAR;
+	if (status & SYNC_HUNT)
+		ret |= TIOCM_DSR;
+	if (!(status & CTS))
+		ret |= TIOCM_CTS;
+
+	return ret;
+}
+
+/* 
+ * Stop TX side. Dealt like sunzilog at next Tx interrupt,
+ * though for DMA, we will have to do a bit more. What is
+ * the meaning of the tty_stop bit ? XXX
+ * The port lock is held and interrupts are disabled.
+ */
+static void pmz_stop_tx(struct uart_port *port, unsigned int tty_stop)
+{
+	to_pmz(port)->flags |= PMACZILOG_FLAG_TX_STOPPED;
+}
+
+/* 
+ * Kick the Tx side.
+ * The port lock is held and interrupts are disabled.
+ */
+static void pmz_start_tx(struct uart_port *port, unsigned int tty_start)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char status;
+
+	pmz_debug("pmz: start_tx()\n");
+
+	uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
+	uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
+
+	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
+		return;
+
+	status = read_zsreg(uap, R0);
+
+	/* TX busy?  Just wait for the TX done interrupt.  */
+	if (!(status & Tx_BUF_EMP))
+		return;
+
+	/* Send the first character to jump-start the TX done
+	 * IRQ sending engine.
+	 */
+	if (port->x_char) {
+		write_zsdata(uap, port->x_char);
+		zssync(uap);
+		port->icount.tx++;
+		port->x_char = 0;
+	} else {
+		struct circ_buf *xmit = &port->info->xmit;
+
+		write_zsdata(uap, xmit->buf[xmit->tail]);
+		zssync(uap);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+
+		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+			uart_write_wakeup(&uap->port);
+	}
+	pmz_debug("pmz: start_tx() done.\n");
+}
+
+/* 
+ * Stop Rx side, basically disable emitting of
+ * Rx interrupts on the port. We don't disable the rx
+ * side of the chip proper though
+ * The port lock is held.
+ */
+static void pmz_stop_rx(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+
+	if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
+		return;
+
+	pmz_debug("pmz: stop_rx()()\n");
+
+	/* Disable all RX interrupts.  */
+	uap->curregs[R1] &= ~RxINT_MASK;
+	pmz_maybe_update_regs(uap);
+
+	pmz_debug("pmz: stop_rx() done.\n");
+}
+
+/* 
+ * Enable modem status change interrupts
+ * The port lock is held.
+ */
+static void pmz_enable_ms(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char new_reg;
+
+	if (ZS_IS_IRDA(uap) || uap->node == NULL)
+		return;
+	new_reg = uap->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
+	if (new_reg != uap->curregs[R15]) {
+		uap->curregs[R15] = new_reg;
+
+		if (ZS_IS_ASLEEP(uap))
+			return;
+		/* NOTE: Not subject to 'transmitter active' rule.  */ 
+		write_zsreg(uap, R15, uap->curregs[R15]);
+	}
+}
+
+/* 
+ * Control break state emission
+ * The port lock is not held.
+ */
+static void pmz_break_ctl(struct uart_port *port, int break_state)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char set_bits, clear_bits, new_reg;
+	unsigned long flags;
+
+	if (uap->node == NULL)
+		return;
+	set_bits = clear_bits = 0;
+
+	if (break_state)
+		set_bits |= SND_BRK;
+	else
+		clear_bits |= SND_BRK;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	new_reg = (uap->curregs[R5] | set_bits) & ~clear_bits;
+	if (new_reg != uap->curregs[R5]) {
+		uap->curregs[R5] = new_reg;
+
+		/* NOTE: Not subject to 'transmitter active' rule.  */ 
+		if (ZS_IS_ASLEEP(uap))
+			return;
+		write_zsreg(uap, R5, uap->curregs[R5]);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/*
+ * Turn power on or off to the SCC and associated stuff
+ * (port drivers, modem, IR port, etc.)
+ * Returns the number of milliseconds we should wait before
+ * trying to use the port.
+ */
+static int pmz_set_scc_power(struct uart_pmac_port *uap, int state)
+{
+	int delay = 0;
+	int rc;
+
+	if (state) {
+		rc = pmac_call_feature(
+			PMAC_FTR_SCC_ENABLE, uap->node, uap->port_type, 1);
+		pmz_debug("port power on result: %d\n", rc);
+		if (ZS_IS_INTMODEM(uap)) {
+			rc = pmac_call_feature(
+				PMAC_FTR_MODEM_ENABLE, uap->node, 0, 1);
+			delay = 2500;	/* wait for 2.5s before using */
+			pmz_debug("modem power result: %d\n", rc);
+		}
+	} else {
+		/* TODO: Make that depend on a timer, don't power down
+		 * immediately
+		 */
+		if (ZS_IS_INTMODEM(uap)) {
+			rc = pmac_call_feature(
+				PMAC_FTR_MODEM_ENABLE, uap->node, 0, 0);
+			pmz_debug("port power off result: %d\n", rc);
+		}
+		pmac_call_feature(PMAC_FTR_SCC_ENABLE, uap->node, uap->port_type, 0);
+	}
+	return delay;
+}
+
+/*
+ * FixZeroBug....Works around a bug in the SCC receving channel.
+ * Inspired from Darwin code, 15 Sept. 2000  -DanM
+ *
+ * The following sequence prevents a problem that is seen with O'Hare ASICs
+ * (most versions -- also with some Heathrow and Hydra ASICs) where a zero
+ * at the input to the receiver becomes 'stuck' and locks up the receiver.
+ * This problem can occur as a result of a zero bit at the receiver input
+ * coincident with any of the following events:
+ *
+ *	The SCC is initialized (hardware or software).
+ *	A framing error is detected.
+ *	The clocking option changes from synchronous or X1 asynchronous
+ *		clocking to X16, X32, or X64 asynchronous clocking.
+ *	The decoding mode is changed among NRZ, NRZI, FM0, or FM1.
+ *
+ * This workaround attempts to recover from the lockup condition by placing
+ * the SCC in synchronous loopback mode with a fast clock before programming
+ * any of the asynchronous modes.
+ */
+static void pmz_fix_zero_bug_scc(struct uart_pmac_port *uap)
+{
+	write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
+	zssync(uap);
+	udelay(10);
+	write_zsreg(uap, 9, (ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB) | NV);
+	zssync(uap);
+
+	write_zsreg(uap, 4, X1CLK | MONSYNC);
+	write_zsreg(uap, 3, Rx8);
+	write_zsreg(uap, 5, Tx8 | RTS);
+	write_zsreg(uap, 9, NV);	/* Didn't we already do this? */
+	write_zsreg(uap, 11, RCBR | TCBR);
+	write_zsreg(uap, 12, 0);
+	write_zsreg(uap, 13, 0);
+	write_zsreg(uap, 14, (LOOPBAK | BRSRC));
+	write_zsreg(uap, 14, (LOOPBAK | BRSRC | BRENAB));
+	write_zsreg(uap, 3, Rx8 | RxENABLE);
+	write_zsreg(uap, 0, RES_EXT_INT);
+	write_zsreg(uap, 0, RES_EXT_INT);
+	write_zsreg(uap, 0, RES_EXT_INT);	/* to kill some time */
+
+	/* The channel should be OK now, but it is probably receiving
+	 * loopback garbage.
+	 * Switch to asynchronous mode, disable the receiver,
+	 * and discard everything in the receive buffer.
+	 */
+	write_zsreg(uap, 9, NV);
+	write_zsreg(uap, 4, X16CLK | SB_MASK);
+	write_zsreg(uap, 3, Rx8);
+
+	while (read_zsreg(uap, 0) & Rx_CH_AV) {
+		(void)read_zsreg(uap, 8);
+		write_zsreg(uap, 0, RES_EXT_INT);
+		write_zsreg(uap, 0, ERR_RES);
+	}
+}
+
+/*
+ * Real startup routine, powers up the hardware and sets up
+ * the SCC. Returns a delay in ms where you need to wait before
+ * actually using the port, this is typically the internal modem
+ * powerup delay. This routine expect the lock to be taken.
+ */
+static int __pmz_startup(struct uart_pmac_port *uap)
+{
+	int pwr_delay = 0;
+
+	memset(&uap->curregs, 0, sizeof(uap->curregs));
+
+	/* Power up the SCC & underlying hardware (modem/irda) */
+	pwr_delay = pmz_set_scc_power(uap, 1);
+
+	/* Nice buggy HW ... */
+	pmz_fix_zero_bug_scc(uap);
+
+	/* Reset the channel */
+	uap->curregs[R9] = 0;
+	write_zsreg(uap, 9, ZS_IS_CHANNEL_A(uap) ? CHRA : CHRB);
+	zssync(uap);
+	udelay(10);
+	write_zsreg(uap, 9, 0);
+	zssync(uap);
+
+	/* Clear the interrupt registers */
+	write_zsreg(uap, R1, 0);
+	write_zsreg(uap, R0, ERR_RES);
+	write_zsreg(uap, R0, ERR_RES);
+	write_zsreg(uap, R0, RES_H_IUS);
+	write_zsreg(uap, R0, RES_H_IUS);
+
+	/* Setup some valid baud rate */
+	uap->curregs[R4] = X16CLK | SB1;
+	uap->curregs[R3] = Rx8;
+	uap->curregs[R5] = Tx8 | RTS;
+	if (!ZS_IS_IRDA(uap))
+		uap->curregs[R5] |= DTR;
+	uap->curregs[R12] = 0;
+	uap->curregs[R13] = 0;
+	uap->curregs[R14] = BRENAB;
+
+	/* Clear handshaking, enable BREAK interrupts */
+	uap->curregs[R15] = BRKIE;
+
+	/* Master interrupt enable */
+	uap->curregs[R9] |= NV | MIE;
+
+	pmz_load_zsregs(uap, uap->curregs);
+
+	/* Enable receiver and transmitter.  */
+	write_zsreg(uap, R3, uap->curregs[R3] |= RxENABLE);
+	write_zsreg(uap, R5, uap->curregs[R5] |= TxENABLE);
+
+	/* Remember status for DCD/CTS changes */
+	uap->prev_status = read_zsreg(uap, R0);
+
+
+	return pwr_delay;
+}
+
+static void pmz_irda_reset(struct uart_pmac_port *uap)
+{
+	uap->curregs[R5] |= DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+	mdelay(110);
+	uap->curregs[R5] &= ~DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+	mdelay(10);
+}
+
+/*
+ * This is the "normal" startup routine, using the above one
+ * wrapped with the lock and doing a schedule delay
+ */
+static int pmz_startup(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned long flags;
+	int pwr_delay = 0;
+
+	pmz_debug("pmz: startup()\n");
+
+	if (ZS_IS_ASLEEP(uap))
+		return -EAGAIN;
+	if (uap->node == NULL)
+		return -ENODEV;
+
+	down(&pmz_irq_sem);
+
+	uap->flags |= PMACZILOG_FLAG_IS_OPEN;
+
+	/* A console is never powered down. Else, power up and
+	 * initialize the chip
+	 */
+	if (!ZS_IS_CONS(uap)) {
+		spin_lock_irqsave(&port->lock, flags);
+		pwr_delay = __pmz_startup(uap);
+		spin_unlock_irqrestore(&port->lock, flags);
+	}	
+
+	pmz_get_port_A(uap)->flags |= PMACZILOG_FLAG_IS_IRQ_ON;
+	if (request_irq(uap->port.irq, pmz_interrupt, SA_SHIRQ, "PowerMac Zilog", uap)) {
+		dev_err(&uap->dev->ofdev.dev,
+			"Unable to register zs interrupt handler.\n");
+		pmz_set_scc_power(uap, 0);
+		up(&pmz_irq_sem);
+		return -ENXIO;
+	}
+
+	up(&pmz_irq_sem);
+
+	/* Right now, we deal with delay by blocking here, I'll be
+	 * smarter later on
+	 */
+	if (pwr_delay != 0) {
+		pmz_debug("pmz: delaying %d ms\n", pwr_delay);
+		msleep(pwr_delay);
+	}
+
+	/* IrDA reset is done now */
+	if (ZS_IS_IRDA(uap))
+		pmz_irda_reset(uap);
+
+	/* Enable interrupts emission from the chip */
+	spin_lock_irqsave(&port->lock, flags);
+	uap->curregs[R1] |= INT_ALL_Rx | TxINT_ENAB;
+	if (!ZS_IS_EXTCLK(uap))
+		uap->curregs[R1] |= EXT_INT_ENAB;
+	write_zsreg(uap, R1, uap->curregs[R1]);
+       	spin_unlock_irqrestore(&port->lock, flags);
+
+	pmz_debug("pmz: startup() done.\n");
+
+	return 0;
+}
+
+static void pmz_shutdown(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned long flags;
+
+	pmz_debug("pmz: shutdown()\n");
+
+	if (uap->node == NULL)
+		return;
+
+	down(&pmz_irq_sem);
+
+	/* Release interrupt handler */
+       	free_irq(uap->port.irq, uap);
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	uap->flags &= ~PMACZILOG_FLAG_IS_OPEN;
+
+	if (!ZS_IS_OPEN(uap->mate))
+		pmz_get_port_A(uap)->flags &= ~PMACZILOG_FLAG_IS_IRQ_ON;
+
+	/* Disable interrupts */
+	if (!ZS_IS_ASLEEP(uap)) {
+		uap->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
+		write_zsreg(uap, R1, uap->curregs[R1]);
+		zssync(uap);
+	}
+
+	if (ZS_IS_CONS(uap) || ZS_IS_ASLEEP(uap)) {
+		spin_unlock_irqrestore(&port->lock, flags);
+		up(&pmz_irq_sem);
+		return;
+	}
+
+	/* Disable receiver and transmitter.  */
+	uap->curregs[R3] &= ~RxENABLE;
+	uap->curregs[R5] &= ~TxENABLE;
+
+	/* Disable all interrupts and BRK assertion.  */
+	uap->curregs[R5] &= ~SND_BRK;
+	pmz_maybe_update_regs(uap);
+
+	/* Shut the chip down */
+	pmz_set_scc_power(uap, 0);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	up(&pmz_irq_sem);
+
+	pmz_debug("pmz: shutdown() done.\n");
+}
+
+/* Shared by TTY driver and serial console setup.  The port lock is held
+ * and local interrupts are disabled.
+ */
+static void pmz_convert_to_zs(struct uart_pmac_port *uap, unsigned int cflag,
+			      unsigned int iflag, unsigned long baud)
+{
+	int brg;
+
+
+	/* Switch to external clocking for IrDA high clock rates. That
+	 * code could be re-used for Midi interfaces with different
+	 * multipliers
+	 */
+	if (baud >= 115200 && ZS_IS_IRDA(uap)) {
+		uap->curregs[R4] = X1CLK;
+		uap->curregs[R11] = RCTRxCP | TCTRxCP;
+		uap->curregs[R14] = 0; /* BRG off */
+		uap->curregs[R12] = 0;
+		uap->curregs[R13] = 0;
+		uap->flags |= PMACZILOG_FLAG_IS_EXTCLK;
+	} else {
+		switch (baud) {
+		case ZS_CLOCK/16:	/* 230400 */
+			uap->curregs[R4] = X16CLK;
+			uap->curregs[R11] = 0;
+			uap->curregs[R14] = 0;
+			break;
+		case ZS_CLOCK/32:	/* 115200 */
+			uap->curregs[R4] = X32CLK;
+			uap->curregs[R11] = 0;
+			uap->curregs[R14] = 0;
+			break;
+		default:
+			uap->curregs[R4] = X16CLK;
+			uap->curregs[R11] = TCBR | RCBR;
+			brg = BPS_TO_BRG(baud, ZS_CLOCK / 16);
+			uap->curregs[R12] = (brg & 255);
+			uap->curregs[R13] = ((brg >> 8) & 255);
+			uap->curregs[R14] = BRENAB;
+		}
+		uap->flags &= ~PMACZILOG_FLAG_IS_EXTCLK;
+	}
+
+	/* Character size, stop bits, and parity. */
+	uap->curregs[3] &= ~RxN_MASK;
+	uap->curregs[5] &= ~TxN_MASK;
+
+	switch (cflag & CSIZE) {
+	case CS5:
+		uap->curregs[3] |= Rx5;
+		uap->curregs[5] |= Tx5;
+		uap->parity_mask = 0x1f;
+		break;
+	case CS6:
+		uap->curregs[3] |= Rx6;
+		uap->curregs[5] |= Tx6;
+		uap->parity_mask = 0x3f;
+		break;
+	case CS7:
+		uap->curregs[3] |= Rx7;
+		uap->curregs[5] |= Tx7;
+		uap->parity_mask = 0x7f;
+		break;
+	case CS8:
+	default:
+		uap->curregs[3] |= Rx8;
+		uap->curregs[5] |= Tx8;
+		uap->parity_mask = 0xff;
+		break;
+	};
+	uap->curregs[4] &= ~(SB_MASK);
+	if (cflag & CSTOPB)
+		uap->curregs[4] |= SB2;
+	else
+		uap->curregs[4] |= SB1;
+	if (cflag & PARENB)
+		uap->curregs[4] |= PAR_ENAB;
+	else
+		uap->curregs[4] &= ~PAR_ENAB;
+	if (!(cflag & PARODD))
+		uap->curregs[4] |= PAR_EVEN;
+	else
+		uap->curregs[4] &= ~PAR_EVEN;
+
+	uap->port.read_status_mask = Rx_OVR;
+	if (iflag & INPCK)
+		uap->port.read_status_mask |= CRC_ERR | PAR_ERR;
+	if (iflag & (BRKINT | PARMRK))
+		uap->port.read_status_mask |= BRK_ABRT;
+
+	uap->port.ignore_status_mask = 0;
+	if (iflag & IGNPAR)
+		uap->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
+	if (iflag & IGNBRK) {
+		uap->port.ignore_status_mask |= BRK_ABRT;
+		if (iflag & IGNPAR)
+			uap->port.ignore_status_mask |= Rx_OVR;
+	}
+
+	if ((cflag & CREAD) == 0)
+		uap->port.ignore_status_mask = 0xff;
+}
+
+
+/*
+ * Set the irda codec on the imac to the specified baud rate.
+ */
+static void pmz_irda_setup(struct uart_pmac_port *uap, unsigned long *baud)
+{
+	u8 cmdbyte;
+	int t, version;
+
+	switch (*baud) {
+	/* SIR modes */
+	case 2400:
+		cmdbyte = 0x53;
+		break;
+	case 4800: