Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1996 insertions, 0 deletions

diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
new file mode 100644
index 000000000..fe2e4ec42
--- /dev/null
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -0,0 +1,1996 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * 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...
+ *
+ * 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 USE_CTRL_O_SYSRQ
+
+#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/adb.h>
+#include <linux/pmu.h>
+#include <linux/bitops.h>
+#include <linux/sysrq.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <asm/sections.h>
+#include <linux/io.h>
+#include <asm/irq.h>
+
+#ifdef CONFIG_PPC_PMAC
+#include <asm/machdep.h>
+#include <asm/pmac_feature.h>
+#include <asm/macio.h>
+#else
+#include <linux/platform_device.h>
+#define of_machine_is_compatible(x) (0)
+#endif
+
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+
+#include "pmac_zilog.h"
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Driver for the Mac and PowerMac serial ports.");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_SERIAL_PMACZILOG_TTYS
+#define PMACZILOG_MAJOR		TTY_MAJOR
+#define PMACZILOG_MINOR		64
+#define PMACZILOG_NAME		"ttyS"
+#else
+#define PMACZILOG_MAJOR		204
+#define PMACZILOG_MINOR		192
+#define PMACZILOG_NAME		"ttyPZ"
+#endif
+
+#define pmz_debug(fmt, arg...)	pr_debug("ttyPZ%d: " fmt, uap->port.line, ## arg)
+#define pmz_error(fmt, arg...)	pr_err("ttyPZ%d: " fmt, uap->port.line, ## arg)
+#define pmz_info(fmt, arg...)	pr_info("ttyPZ%d: " fmt, uap->port.line, ## 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 struct uart_driver pmz_uart_reg = {
+	.owner		=	THIS_MODULE,
+	.driver_name	=	PMACZILOG_NAME,
+	.dev_name	=	PMACZILOG_NAME,
+	.major		=	PMACZILOG_MAJOR,
+	.minor		=	PMACZILOG_MINOR,
+};
+
+
+/* 
+ * 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;
+
+	/* 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 void pmz_interrupt_control(struct uart_pmac_port *uap, int enable)
+{
+	if (enable) {
+		uap->curregs[1] |= INT_ALL_Rx | TxINT_ENAB;
+		if (!ZS_IS_EXTCLK(uap))
+			uap->curregs[1] |= EXT_INT_ENAB;
+	} else {
+		uap->curregs[1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
+	}
+	write_zsreg(uap, R1, uap->curregs[1]);
+}
+
+static bool pmz_receive_chars(struct uart_pmac_port *uap)
+	__must_hold(&uap->port.lock)
+{
+	struct tty_port *port;
+	unsigned char ch, r1, drop, flag;
+	int loops = 0;
+
+	/* Sanity check, make sure the old bug is no longer happening */
+	if (uap->port.state == NULL) {
+		WARN_ON(1);
+		(void)read_zsdata(uap);
+		return false;
+	}
+	port = &uap->port.state->port;
+
+	while (1) {
+		drop = 0;
+
+		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);
+			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;
+
+		flag = TTY_NORMAL;
+		uap->port.icount.rx++;
+
+		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | BRK_ABRT)) {
+			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)
+				flag = TTY_BREAK;
+			else if (r1 & PAR_ERR)
+				flag = TTY_PARITY;
+			else if (r1 & CRC_ERR)
+				flag = TTY_FRAME;
+		}
+
+		if (uap->port.ignore_status_mask == 0xff ||
+		    (r1 & uap->port.ignore_status_mask) == 0) {
+			tty_insert_flip_char(port, ch, flag);
+		}
+		if (r1 & Rx_OVR)
+			tty_insert_flip_char(port, 0, TTY_OVERRUN);
+	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 strange is going on with the HW
+		 */
+		if ((++loops) > 1000)
+			goto flood;
+		ch = read_zsreg(uap, R0);
+		if (!(ch & Rx_CH_AV))
+			break;
+	}
+
+	return true;
+ flood:
+	pmz_interrupt_control(uap, 0);
+	pmz_error("pmz: rx irq flood !\n");
+	return true;
+}
+
+static void pmz_status_handle(struct uart_pmac_port *uap)
+{
+	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.state->port.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_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 becoming 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;
+	}
+
+	/* Under some circumstances, we see interrupts reported for
+	 * a closed channel. The interrupt mask in R1 is clear, but
+	 * R3 still signals the interrupts and we see them when taking
+	 * an interrupt for the other channel (this could be a qemu
+	 * bug but since the ESCC doc doesn't specify precsiely whether
+	 * R3 interrup status bits are masked by R1 interrupt enable
+	 * bits, better safe than sorry). --BenH.
+	 */
+	if (!ZS_IS_OPEN(uap))
+		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.state == NULL)
+		goto ack_tx_int;
+	xmit = &uap->port.state->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 uart_pmac_port *uap = dev_id;
+	struct uart_pmac_port *uap_a;
+	struct uart_pmac_port *uap_b;
+	int rc = IRQ_NONE;
+	bool push;
+	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);
+
+	/* Channel A */
+	push = false;
+	if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
+		if (!ZS_IS_OPEN(uap_a)) {
+			pmz_debug("ChanA interrupt while not open !\n");
+			goto skip_a;
+		}
+		write_zsreg(uap_a, R0, RES_H_IUS);
+		zssync(uap_a);		
+		if (r3 & CHAEXT)
+			pmz_status_handle(uap_a);
+		if (r3 & CHARxIP)
+			push = pmz_receive_chars(uap_a);
+		if (r3 & CHATxIP)
+			pmz_transmit_chars(uap_a);
+		rc = IRQ_HANDLED;
+	}
+ skip_a:
+	spin_unlock(&uap_a->port.lock);
+	if (push)
+		tty_flip_buffer_push(&uap->port.state->port);
+
+	if (!uap_b)
+		goto out;
+
+	spin_lock(&uap_b->port.lock);
+	push = false;
+	if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
+		if (!ZS_IS_OPEN(uap_b)) {
+			pmz_debug("ChanB interrupt while not open !\n");
+			goto skip_b;
+		}
+		write_zsreg(uap_b, R0, RES_H_IUS);
+		zssync(uap_b);
+		if (r3 & CHBEXT)
+			pmz_status_handle(uap_b);
+		if (r3 & CHBRxIP)
+			push = pmz_receive_chars(uap_b);
+		if (r3 & CHBTxIP)
+			pmz_transmit_chars(uap_b);
+		rc = IRQ_HANDLED;
+	}
+ skip_b:
+	spin_unlock(&uap_b->port.lock);
+	if (push)
+		tty_flip_buffer_push(&uap->port.state->port);
+
+ out:
+	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)
+{
+	unsigned char status;
+
+	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_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;
+
+	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 held and interrupts are disabled.
+ */
+static unsigned int pmz_get_mctrl(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char status;
+	unsigned int ret;
+
+	status = read_zsreg(uap, R0);
+
+	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.
+ * The port lock is held and interrupts are disabled.
+ */
+static void pmz_stop_tx(struct uart_port *port)
+{
+	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)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned char status;
+
+	uap->flags |= PMACZILOG_FLAG_TX_ACTIVE;
+	uap->flags &= ~PMACZILOG_FLAG_TX_STOPPED;
+
+	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->state->xmit;
+
+		if (uart_circ_empty(xmit))
+			return;
+		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);
+	}
+}
+
+/* 
+ * 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);
+
+	/* Disable all RX interrupts.  */
+	uap->curregs[R1] &= ~RxINT_MASK;
+	pmz_maybe_update_regs(uap);
+}
+
+/* 
+ * 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))
+		return;
+	new_reg = uap->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
+	if (new_reg != uap->curregs[R15]) {
+		uap->curregs[R15] = new_reg;
+
+		/* 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;
+
+	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;
+		write_zsreg(uap, R5, uap->curregs[R5]);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+#ifdef CONFIG_PPC_PMAC
+
+/*
+ * 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;
+}
+
+#else
+
+static int pmz_set_scc_power(struct uart_pmac_port *uap, int state)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_PPC_PMAC */
+
+/*
+ * FixZeroBug....Works around a bug in the SCC receiving 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)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&uap->port.lock, flags);
+	uap->curregs[R5] |= DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+	spin_unlock_irqrestore(&uap->port.lock, flags);
+	msleep(110);
+
+	spin_lock_irqsave(&uap->port.lock, flags);
+	uap->curregs[R5] &= ~DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+	spin_unlock_irqrestore(&uap->port.lock, flags);
+	msleep(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;
+
+	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);
+	}	
+	sprintf(uap->irq_name, PMACZILOG_NAME"%d", uap->port.line);
+	if (request_irq(uap->port.irq, pmz_interrupt, IRQF_SHARED,
+			uap->irq_name, uap)) {
+		pmz_error("Unable to register zs interrupt handler.\n");
+		pmz_set_scc_power(uap, 0);
+		return -ENXIO;
+	}
+
+	/* 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 interrupt requests for the channel */
+	spin_lock_irqsave(&port->lock, flags);
+	pmz_interrupt_control(uap, 1);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return 0;
+}
+
+static void pmz_shutdown(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* Disable interrupt requests for the channel */
+	pmz_interrupt_control(uap, 0);
+
+	if (!ZS_IS_CONS(uap)) {
+		/* Disable receiver and transmitter */
+		uap->curregs[R3] &= ~RxENABLE;
+		uap->curregs[R5] &= ~TxENABLE;
+
+		/* Disable break assertion */
+		uap->curregs[R5] &= ~SND_BRK;
+		pmz_maybe_update_regs(uap);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	/* Release interrupt handler */
+	free_irq(uap->port.irq, uap);
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	uap->flags &= ~PMACZILOG_FLAG_IS_OPEN;
+
+	if (!ZS_IS_CONS(uap))
+		pmz_set_scc_power(uap, 0);	/* Shut the chip down */
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* 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 & (IGNBRK | 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:
+		cmdbyte = 0x52;
+		break;
+	case 9600:
+		cmdbyte = 0x51;
+		break;
+	case 19200:
+		cmdbyte = 0x50;
+		break;
+	case 38400:
+		cmdbyte = 0x4f;
+		break;
+	case 57600:
+		cmdbyte = 0x4e;
+		break;
+	case 115200:
+		cmdbyte = 0x4d;
+		break;
+	/* The FIR modes aren't really supported at this point, how
+	 * do we select the speed ? via the FCR on KeyLargo ?
+	 */
+	case 1152000:
+		cmdbyte = 0;
+		break;
+	case 4000000:
+		cmdbyte = 0;
+		break;
+	default: /* 9600 */
+		cmdbyte = 0x51;
+		*baud = 9600;
+		break;
+	}
+
+	/* Wait for transmitter to drain */
+	t = 10000;
+	while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0
+	       || (read_zsreg(uap, R1) & ALL_SNT) == 0) {
+		if (--t <= 0) {
+			pmz_error("transmitter didn't drain\n");
+			return;
+		}
+		udelay(10);
+	}
+
+	/* Drain the receiver too */
+	t = 100;
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+	mdelay(10);
+	while (read_zsreg(uap, R0) & Rx_CH_AV) {
+		read_zsdata(uap);
+		mdelay(10);
+		if (--t <= 0) {
+			pmz_error("receiver didn't drain\n");
+			return;
+		}
+	}
+
+	/* Switch to command mode */
+	uap->curregs[R5] |= DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+	mdelay(1);
+
+	/* Switch SCC to 19200 */
+	pmz_convert_to_zs(uap, CS8, 0, 19200);		
+	pmz_load_zsregs(uap, uap->curregs);
+	mdelay(1);
+
+	/* Write get_version command byte */
+	write_zsdata(uap, 1);
+	t = 5000;
+	while ((read_zsreg(uap, R0) & Rx_CH_AV) == 0) {
+		if (--t <= 0) {
+			pmz_error("irda_setup timed out on get_version byte\n");
+			goto out;
+		}
+		udelay(10);
+	}
+	version = read_zsdata(uap);
+
+	if (version < 4) {
+		pmz_info("IrDA: dongle version %d not supported\n", version);
+		goto out;
+	}
+
+	/* Send speed mode */
+	write_zsdata(uap, cmdbyte);
+	t = 5000;
+	while ((read_zsreg(uap, R0) & Rx_CH_AV) == 0) {
+		if (--t <= 0) {
+			pmz_error("irda_setup timed out on speed mode byte\n");
+			goto out;
+		}
+		udelay(10);
+	}
+	t = read_zsdata(uap);
+	if (t != cmdbyte)
+		pmz_error("irda_setup speed mode byte = %x (%x)\n", t, cmdbyte);
+
+	pmz_info("IrDA setup for %ld bps, dongle version: %d\n",
+		 *baud, version);
+
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+
+ out:
+	/* Switch back to data mode */
+	uap->curregs[R5] &= ~DTR;
+	write_zsreg(uap, R5, uap->curregs[R5]);
+	zssync(uap);
+
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+	(void)read_zsdata(uap);
+}
+
+
+static void __pmz_set_termios(struct uart_port *port, struct ktermios *termios,
+			      const struct ktermios *old)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned long baud;
+
+	/* XXX Check which revs of machines actually allow 1 and 4Mb speeds
+	 * on the IR dongle. Note that the IRTTY driver currently doesn't know
+	 * about the FIR mode and high speed modes. So these are unused. For
+	 * implementing proper support for these, we should probably add some
+	 * DMA as well, at least on the Rx side, which isn't a simple thing
+	 * at this point.
+	 */
+	if (ZS_IS_IRDA(uap)) {
+		/* Calc baud rate */
+		baud = uart_get_baud_rate(port, termios, old, 1200, 4000000);
+		pmz_debug("pmz: switch IRDA to %ld bauds\n", baud);
+		/* Cet the irda codec to the right rate */
+		pmz_irda_setup(uap, &baud);
+		/* Set final baud rate */
+		pmz_convert_to_zs(uap, termios->c_cflag, termios->c_iflag, baud);
+		pmz_load_zsregs(uap, uap->curregs);
+		zssync(uap);
+	} else {
+		baud = uart_get_baud_rate(port, termios, old, 1200, 230400);
+		pmz_convert_to_zs(uap, termios->c_cflag, termios->c_iflag, baud);
+		/* Make sure modem status interrupts are correctly configured */
+		if (UART_ENABLE_MS(&uap->port, termios->c_cflag)) {
+			uap->curregs[R15] |= DCDIE | SYNCIE | CTSIE;
+			uap->flags |= PMACZILOG_FLAG_MODEM_STATUS;
+		} else {
+			uap->curregs[R15] &= ~(DCDIE | SYNCIE | CTSIE);
+			uap->flags &= ~PMACZILOG_FLAG_MODEM_STATUS;
+		}
+
+		/* Load registers to the chip */
+		pmz_maybe_update_regs(uap);
+	}
+	uart_update_timeout(port, termios->c_cflag, baud);
+}
+
+/* The port lock is not held.  */
+static void pmz_set_termios(struct uart_port *port, struct ktermios *termios,
+			    const struct ktermios *old)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);	
+
+	/* Disable IRQs on the port */
+	pmz_interrupt_control(uap, 0);
+
+	/* Setup new port configuration */
+	__pmz_set_termios(port, termios, old);
+
+	/* Re-enable IRQs on the port */
+	if (ZS_IS_OPEN(uap))
+		pmz_interrupt_control(uap, 1);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *pmz_type(struct uart_port *port)
+{
+	struct uart_pmac_port *uap = to_pmz(port);
+
+	if (ZS_IS_IRDA(uap))
+		return "Z85c30 ESCC - Infrared port";
+	else if (ZS_IS_INTMODEM(uap))
+		return "Z85c30 ESCC - Internal modem";
+	return "Z85c30 ESCC - Serial port";
+}
+
+/* We do not request/release mappings of the registers here, this
+ * happens at early serial probe time.
+ */
+static void pmz_release_port(struct uart_port *port)
+{
+}
+
+static int pmz_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+/* These do not need to do anything interesting either.  */
+static void pmz_config_port(struct uart_port *port, int flags)
+{
+}
+
+/* We do not support letting the user mess with the divisor, IRQ, etc. */
+static int pmz_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	return -EINVAL;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+
+static int pmz_poll_get_char(struct uart_port *port)
+{
+	struct uart_pmac_port *uap =
+		container_of(port, struct uart_pmac_port, port);
+	int tries = 2;
+
+	while (tries) {
+		if ((read_zsreg(uap, R0) & Rx_CH_AV) != 0)
+			return read_zsdata(uap);
+		if (tries--)
+			udelay(5);
+	}
+
+	return NO_POLL_CHAR;
+}
+
+static void pmz_poll_put_char(struct uart_port *port, unsigned char c)
+{
+	struct uart_pmac_port *uap =
+		container_of(port, struct uart_pmac_port, port);
+
+	/* Wait for the transmit buffer to empty. */
+	while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0)
+		udelay(5);
+	write_zsdata(uap, c);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
+static const struct uart_ops pmz_pops = {
+	.tx_empty	=	pmz_tx_empty,
+	.set_mctrl	=	pmz_set_mctrl,
+	.get_mctrl	=	pmz_get_mctrl,
+	.stop_tx	=	pmz_stop_tx,
+	.start_tx	=	pmz_start_tx,
+	.stop_rx	=	pmz_stop_rx,
+	.enable_ms	=	pmz_enable_ms,
+	.break_ctl	=	pmz_break_ctl,
+	.startup	=	pmz_startup,
+	.shutdown	=	pmz_shutdown,
+	.set_termios	=	pmz_set_termios,
+	.type		=	pmz_type,
+	.release_port	=	pmz_release_port,
+	.request_port	=	pmz_request_port,
+	.config_port	=	pmz_config_port,
+	.verify_port	=	pmz_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	=	pmz_poll_get_char,
+	.poll_put_char	=	pmz_poll_put_char,
+#endif
+};
+
+#ifdef CONFIG_PPC_PMAC
+
+/*
+ * Setup one port structure after probing, HW is down at this point,
+ * Unlike sunzilog, we don't need to pre-init the spinlock as we don't
+ * register our console before uart_add_one_port() is called
+ */
+static int __init pmz_init_port(struct uart_pmac_port *uap)
+{
+	struct device_node *np = uap->node;
+	const char *conn;
+	const struct slot_names_prop {
+		int	count;
+		char	name[1];
+	} *slots;
+	int len;
+	struct resource r_ports;
+
+	/*
+	 * Request & map chip registers
+	 */
+	if (of_address_to_resource(np, 0, &r_ports))
+		return -ENODEV;
+	uap->port.mapbase = r_ports.start;
+	uap->port.membase = ioremap(uap->port.mapbase, 0x1000);
+
+	uap->control_reg = uap->port.membase;
+	uap->data_reg = uap->control_reg + 0x10;
+
+	/*
+	 * Detect port type
+	 */
+	if (of_device_is_compatible(np, "cobalt"))
+		uap->flags |= PMACZILOG_FLAG_IS_INTMODEM;
+	conn = of_get_property(np, "AAPL,connector", &len);
+	if (conn && (strcmp(conn, "infrared") == 0))
+		uap->flags |= PMACZILOG_FLAG_IS_IRDA;
+	uap->port_type = PMAC_SCC_ASYNC;
+	/* 1999 Powerbook G3 has slot-names property instead */
+	slots = of_get_property(np, "slot-names", &len);
+	if (slots && slots->count > 0) {
+		if (strcmp(slots->name, "IrDA") == 0)
+			uap->flags |= PMACZILOG_FLAG_IS_IRDA;
+		else if (strcmp(slots->name, "Modem") == 0)
+			uap->flags |= PMACZILOG_FLAG_IS_INTMODEM;
+	}
+	if (ZS_IS_IRDA(uap))
+		uap->port_type = PMAC_SCC_IRDA;
+	if (ZS_IS_INTMODEM(uap)) {
+		struct device_node* i2c_modem =
+			of_find_node_by_name(NULL, "i2c-modem");
+		if (i2c_modem) {
+			const char* mid =
+				of_get_property(i2c_modem, "modem-id", NULL);
+			if (mid) switch(*mid) {
+			case 0x04 :
+			case 0x05 :
+			case 0x07 :
+			case 0x08 :
+			case 0x0b :
+			case 0x0c :
+				uap->port_type = PMAC_SCC_I2S1;
+			}
+			printk(KERN_INFO "pmac_zilog: i2c-modem detected, id: %d\n",
+				mid ? (*mid) : 0);
+			of_node_put(i2c_modem);
+		} else {
+			printk(KERN_INFO "pmac_zilog: serial modem detected\n");
+		}
+	}
+
+	/*
+	 * Init remaining bits of "port" structure
+	 */
+	uap->port.iotype = UPIO_MEM;
+	uap->port.irq = irq_of_parse_and_map(np, 0);
+	uap->port.uartclk = ZS_CLOCK;
+	uap->port.fifosize = 1;
+	uap->port.ops = &pmz_pops;
+	uap->port.type = PORT_PMAC_ZILOG;
+	uap->port.flags = 0;
+
+	/*
+	 * Fixup for the port on Gatwick for which the device-tree has
+	 * missing interrupts. Normally, the macio_dev would contain
+	 * fixed up interrupt info, but we use the device-tree directly
+	 * here due to early probing so we need the fixup too.
+	 */
+	if (uap->port.irq == 0 &&
+	    np->parent && np->parent->parent &&
+	    of_device_is_compatible(np->parent->parent, "gatwick")) {
+		/* IRQs on gatwick are offset by 64 */
+		uap->port.irq = irq_create_mapping(NULL, 64 + 15);
+	}
+
+	/* Setup some valid baud rate information in the register
+	 * shadows so we don't write crap there before baud rate is
+	 * first initialized.
+	 */
+	pmz_convert_to_zs(uap, CS8, 0, 9600);
+
+	return 0;
+}
+
+/*
+ * Get rid of a port on module removal
+ */
+static void pmz_dispose_port(struct uart_pmac_port *uap)
+{
+	struct device_node *np;
+
+	np = uap->node;
+	iounmap(uap->control_reg);
+	uap->node = NULL;
+	of_node_put(np);
+	memset(uap, 0, sizeof(struct uart_pmac_port));
+}
+
+/*
+ * Called upon match with an escc node in the device-tree.
+ */
+static int pmz_attach(struct macio_dev *mdev, const struct of_device_id *match)
+{
+	struct uart_pmac_port *uap;
+	int i;
+	
+	/* Iterate the pmz_ports array to find a matching entry
+	 */
+	for (i = 0; i < MAX_ZS_PORTS; i++)
+		if (pmz_ports[i].node == mdev->ofdev.dev.of_node)
+			break;
+	if (i >= MAX_ZS_PORTS)
+		return -ENODEV;
+
+
+	uap = &pmz_ports[i];
+	uap->dev = mdev;
+	uap->port.dev = &mdev->ofdev.dev;
+	dev_set_drvdata(&mdev->ofdev.dev, uap);
+
+	/* We still activate the port even when failing to request resources
+	 * to work around bugs in ancient Apple device-trees
+	 */
+	if (macio_request_resources(uap->dev, "pmac_zilog"))
+		printk(KERN_WARNING "%pOFn: Failed to request resource"
+		       ", port still active\n",
+		       uap->node);
+	else
+		uap->flags |= PMACZILOG_FLAG_RSRC_REQUESTED;
+
+	return uart_add_one_port(&pmz_uart_reg, &uap->port);
+}
+
+/*
+ * That one should not be called, macio isn't really a hotswap device,
+ * we don't expect one of those serial ports to go away...
+ */
+static int pmz_detach(struct macio_dev *mdev)
+{
+	struct uart_pmac_port	*uap = dev_get_drvdata(&mdev->ofdev.dev);
+	
+	if (!uap)
+		return -ENODEV;
+
+	uart_remove_one_port(&pmz_uart_reg, &uap->port);
+
+	if (uap->flags & PMACZILOG_FLAG_RSRC_REQUESTED) {
+		macio_release_resources(uap->dev);
+		uap->flags &= ~PMACZILOG_FLAG_RSRC_REQUESTED;
+	}
+	dev_set_drvdata(&mdev->ofdev.dev, NULL);
+	uap->dev = NULL;
+	uap->port.dev = NULL;
+	
+	return 0;
+}
+
+
+static int pmz_suspend(struct macio_dev *mdev, pm_message_t pm_state)
+{
+	struct uart_pmac_port *uap = dev_get_drvdata(&mdev->ofdev.dev);
+
+	if (uap == NULL) {
+		printk("HRM... pmz_suspend with NULL uap\n");
+		return 0;
+	}
+
+	uart_suspend_port(&pmz_uart_reg, &uap->port);
+
+	return 0;
+}
+
+
+static int pmz_resume(struct macio_dev *mdev)
+{
+	struct uart_pmac_port *uap = dev_get_drvdata(&mdev->ofdev.dev);
+
+	if (uap == NULL)
+		return 0;
+
+	uart_resume_port(&pmz_uart_reg, &uap->port);
+
+	return 0;
+}
+
+/*
+ * Probe all ports in the system and build the ports array, we register
+ * with the serial layer later, so we get a proper struct device which
+ * allows the tty to attach properly. This is later than it used to be
+ * but the tty layer really wants it that way.
+ */
+static int __init pmz_probe(void)
+{
+	struct device_node	*node_p, *node_a, *node_b, *np;
+	int			count = 0;
+	int			rc;
+
+	/*
+	 * Find all escc chips in the system
+	 */
+	for_each_node_by_name(node_p, "escc") {
+		/*
+		 * First get channel A/B node pointers
+		 * 
+		 * TODO: Add routines with proper locking to do that...
+		 */
+		node_a = node_b = NULL;
+		for_each_child_of_node(node_p, np) {
+			if (of_node_name_prefix(np, "ch-a"))
+				node_a = of_node_get(np);
+			else if (of_node_name_prefix(np, "ch-b"))
+				node_b = of_node_get(np);
+		}
+		if (!node_a && !node_b) {
+			of_node_put(node_a);
+			of_node_put(node_b);
+			printk(KERN_ERR "pmac_zilog: missing node %c for escc %pOF\n",
+				(!node_a) ? 'a' : 'b', node_p);
+			continue;
+		}
+
+		/*
+		 * Fill basic fields in the port structures
+		 */
+		if (node_b != NULL) {
+			pmz_ports[count].mate		= &pmz_ports[count+1];
+			pmz_ports[count+1].mate		= &pmz_ports[count];
+		}
+		pmz_ports[count].flags		= PMACZILOG_FLAG_IS_CHANNEL_A;
+		pmz_ports[count].node		= node_a;
+		pmz_ports[count+1].node		= node_b;
+		pmz_ports[count].port.line	= count;
+		pmz_ports[count+1].port.line	= count+1;
+
+		/*
+		 * Setup the ports for real
+		 */
+		rc = pmz_init_port(&pmz_ports[count]);
+		if (rc == 0 && node_b != NULL)
+			rc = pmz_init_port(&pmz_ports[count+1]);
+		if (rc != 0) {
+			of_node_put(node_a);
+			of_node_put(node_b);
+			memset(&pmz_ports[count], 0, sizeof(struct uart_pmac_port));
+			memset(&pmz_ports[count+1], 0, sizeof(struct uart_pmac_port));
+			continue;
+		}
+		count += 2;
+	}
+	pmz_ports_count = count;
+
+	return 0;
+}
+
+#else
+
+/* On PCI PowerMacs, pmz_probe() does an explicit search of the OpenFirmware
+ * tree to obtain the device_nodes needed to start the console before the
+ * macio driver. On Macs without OpenFirmware, global platform_devices take
+ * the place of those device_nodes.
+ */
+extern struct platform_device scc_a_pdev, scc_b_pdev;
+
+static int __init pmz_init_port(struct uart_pmac_port *uap)
+{
+	struct resource *r_ports;
+	int irq;
+
+	r_ports = platform_get_resource(uap->pdev, IORESOURCE_MEM, 0);
+	if (!r_ports)
+		return -ENODEV;
+
+	irq = platform_get_irq(uap->pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	uap->port.mapbase  = r_ports->start;
+	uap->port.membase  = (unsigned char __iomem *) r_ports->start;
+	uap->port.iotype   = UPIO_MEM;
+	uap->port.irq      = irq;
+	uap->port.uartclk  = ZS_CLOCK;
+	uap->port.fifosize = 1;
+	uap->port.ops      = &pmz_pops;
+	uap->port.type     = PORT_PMAC_ZILOG;
+	uap->port.flags    = 0;
+
+	uap->control_reg   = uap->port.membase;
+	uap->data_reg      = uap->control_reg + 4;
+	uap->port_type     = 0;
+	uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_PMACZILOG_CONSOLE);
+
+	pmz_convert_to_zs(uap, CS8, 0, 9600);
+
+	return 0;
+}
+
+static int __init pmz_probe(void)
+{
+	int err;
+
+	pmz_ports_count = 0;
+
+	pmz_ports[0].port.line = 0;
+	pmz_ports[0].flags     = PMACZILOG_FLAG_IS_CHANNEL_A;
+	pmz_ports[0].pdev      = &scc_a_pdev;
+	err = pmz_init_port(&pmz_ports[0]);
+	if (err)
+		return err;
+	pmz_ports_count++;
+
+	pmz_ports[0].mate      = &pmz_ports[1];
+	pmz_ports[1].mate      = &pmz_ports[0];
+	pmz_ports[1].port.line = 1;
+	pmz_ports[1].flags     = 0;
+	pmz_ports[1].pdev      = &scc_b_pdev;
+	err = pmz_init_port(&pmz_ports[1]);
+	if (err)
+		return err;
+	pmz_ports_count++;
+
+	return 0;
+}
+
+static void pmz_dispose_port(struct uart_pmac_port *uap)
+{
+	memset(uap, 0, sizeof(struct uart_pmac_port));
+}
+
+static int __init pmz_attach(struct platform_device *pdev)
+{
+	struct uart_pmac_port *uap;
+	int i;
+
+	/* Iterate the pmz_ports array to find a matching entry */
+	for (i = 0; i < pmz_ports_count; i++)
+		if (pmz_ports[i].pdev == pdev)
+			break;
+	if (i >= pmz_ports_count)
+		return -ENODEV;
+
+	uap = &pmz_ports[i];
+	uap->port.dev = &pdev->dev;
+	platform_set_drvdata(pdev, uap);
+
+	return uart_add_one_port(&pmz_uart_reg, &uap->port);
+}
+
+static int __exit pmz_detach(struct platform_device *pdev)
+{
+	struct uart_pmac_port *uap = platform_get_drvdata(pdev);
+
+	if (!uap)
+		return -ENODEV;
+
+	uart_remove_one_port(&pmz_uart_reg, &uap->port);
+
+	uap->port.dev = NULL;
+
+	return 0;
+}
+
+#endif /* !CONFIG_PPC_PMAC */
+
+#ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
+
+static void pmz_console_write(struct console *con, const char *s, unsigned int count);
+static int __init pmz_console_setup(struct console *co, char *options);
+
+static struct console pmz_console = {
+	.name	=	PMACZILOG_NAME,
+	.write	=	pmz_console_write,
+	.device	=	uart_console_device,
+	.setup	=	pmz_console_setup,
+	.flags	=	CON_PRINTBUFFER,
+	.index	=	-1,
+	.data   =	&pmz_uart_reg,
+};
+
+#define PMACZILOG_CONSOLE	&pmz_console
+#else /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
+#define PMACZILOG_CONSOLE	(NULL)
+#endif /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
+
+/*
+ * Register the driver, console driver and ports with the serial
+ * core
+ */
+static int __init pmz_register(void)
+{
+	pmz_uart_reg.nr = pmz_ports_count;
+	pmz_uart_reg.cons = PMACZILOG_CONSOLE;
+
+	/*
+	 * Register this driver with the serial core
+	 */
+	return uart_register_driver(&pmz_uart_reg);
+}
+
+#ifdef CONFIG_PPC_PMAC
+
+static const struct of_device_id pmz_match[] =
+{
+	{
+	.name		= "ch-a",
+	},
+	{
+	.name		= "ch-b",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE (of, pmz_match);
+
+static struct macio_driver pmz_driver = {
+	.driver = {
+		.name 		= "pmac_zilog",
+		.owner		= THIS_MODULE,
+		.of_match_table	= pmz_match,
+	},
+	.probe		= pmz_attach,
+	.remove		= pmz_detach,
+	.suspend	= pmz_suspend,
+	.resume		= pmz_resume,
+};
+
+#else
+
+static struct platform_driver pmz_driver = {
+	.remove		= __exit_p(pmz_detach),
+	.driver		= {
+		.name		= "scc",
+	},
+};
+
+#endif /* !CONFIG_PPC_PMAC */
+
+static int __init init_pmz(void)
+{
+	int rc, i;
+
+	/* 
+	 * First, we need to do a direct OF-based probe pass. We
+	 * do that because we want serial console up before the
+	 * macio stuffs calls us back, and since that makes it
+	 * easier to pass the proper number of channels to
+	 * uart_register_driver()
+	 */
+	if (pmz_ports_count == 0)
+		pmz_probe();
+
+	/*
+	 * Bail early if no port found
+	 */
+	if (pmz_ports_count == 0)
+		return -ENODEV;
+
+	/*
+	 * Now we register with the serial layer
+	 */
+	rc = pmz_register();
+	if (rc) {
+		printk(KERN_ERR 
+			"pmac_zilog: Error registering serial device, disabling pmac_zilog.\n"
+		 	"pmac_zilog: Did another serial driver already claim the minors?\n"); 
+		/* effectively "pmz_unprobe()" */
+		for (i=0; i < pmz_ports_count; i++)
+			pmz_dispose_port(&pmz_ports[i]);
+		return rc;
+	}
+
+	/*
+	 * Then we register the macio driver itself
+	 */
+#ifdef CONFIG_PPC_PMAC
+	return macio_register_driver(&pmz_driver);
+#else
+	return platform_driver_probe(&pmz_driver, pmz_attach);
+#endif
+}
+
+static void __exit exit_pmz(void)
+{
+	int i;
+
+#ifdef CONFIG_PPC_PMAC
+	/* Get rid of macio-driver (detach from macio) */
+	macio_unregister_driver(&pmz_driver);
+#else
+	platform_driver_unregister(&pmz_driver);
+#endif
+
+	for (i = 0; i < pmz_ports_count; i++) {
+		struct uart_pmac_port *uport = &pmz_ports[i];
+#ifdef CONFIG_PPC_PMAC
+		if (uport->node != NULL)
+			pmz_dispose_port(uport);
+#else
+		if (uport->pdev != NULL)
+			pmz_dispose_port(uport);
+#endif
+	}
+	/* Unregister UART driver */
+	uart_unregister_driver(&pmz_uart_reg);
+}
+
+#ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
+
+static void pmz_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	struct uart_pmac_port *uap =
+		container_of(port, struct uart_pmac_port, port);
+
+	/* Wait for the transmit buffer to empty. */
+	while ((read_zsreg(uap, R0) & Tx_BUF_EMP) == 0)
+		udelay(5);
+	write_zsdata(uap, ch);
+}
+
+/*
+ * Print a string to the serial port trying not to disturb
+ * any possible real use of the port...
+ */
+static void pmz_console_write(struct console *con, const char *s, unsigned int count)
+{
+	struct uart_pmac_port *uap = &pmz_ports[con->index];
+	unsigned long flags;
+
+	spin_lock_irqsave(&uap->port.lock, flags);
+
+	/* Turn of interrupts and enable the transmitter. */
+	write_zsreg(uap, R1, uap->curregs[1] & ~TxINT_ENAB);
+	write_zsreg(uap, R5, uap->curregs[5] | TxENABLE | RTS | DTR);
+
+	uart_console_write(&uap->port, s, count, pmz_console_putchar);
+
+	/* Restore the values in the registers. */
+	write_zsreg(uap, R1, uap->curregs[1]);
+	/* Don't disable the transmitter. */
+
+	spin_unlock_irqrestore(&uap->port.lock, flags);
+}
+
+/*
+ * Setup the serial console
+ */
+static int __init pmz_console_setup(struct console *co, char *options)
+{
+	struct uart_pmac_port *uap;
+	struct uart_port *port;
+	int baud = 38400;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	unsigned long pwr_delay;
+
+	/*
+	 * XServe's default to 57600 bps
+	 */
+	if (of_machine_is_compatible("RackMac1,1")
+	    || of_machine_is_compatible("RackMac1,2")
+	    || of_machine_is_compatible("MacRISC4"))
+		baud = 57600;
+
+	/*
+	 * Check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index >= pmz_ports_count)
+		co->index = 0;
+	uap = &pmz_ports[co->index];
+#ifdef CONFIG_PPC_PMAC
+	if (uap->node == NULL)
+		return -ENODEV;
+#else
+	if (uap->pdev == NULL)
+		return -ENODEV;
+#endif
+	port = &uap->port;
+
+	/*
+	 * Mark port as beeing a console
+	 */
+	uap->flags |= PMACZILOG_FLAG_IS_CONS;
+
+	/*
+	 * Temporary fix for uart layer who didn't setup the spinlock yet
+	 */
+	spin_lock_init(&port->lock);
+
+	/*
+	 * Enable the hardware
+	 */
+	pwr_delay = __pmz_startup(uap);
+	if (pwr_delay)
+		mdelay(pwr_delay);
+	
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static int __init pmz_console_init(void)
+{
+	/* Probe ports */
+	pmz_probe();
+
+	if (pmz_ports_count == 0)
+		return -ENODEV;
+
+	/* TODO: Autoprobe console based on OF */
+	/* pmz_console.index = i; */
+	register_console(&pmz_console);
+
+	return 0;
+
+}
+console_initcall(pmz_console_init);
+#endif /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
+
+module_init(init_pmz);
+module_exit(exit_pmz);