Re: [PATCH] Altix console driver

Re: [PATCH] Altix console driver

[Andrew Morton]

jbarnes@sgi.com (Jesse Barnes) wrote:
>
> Just a simple addition to drivers/char for the Altix serial console.
> 
>  MAINTAINERS              |    6 
>  drivers/char/Kconfig     |   16 
>  drivers/char/Makefile    |    1 
>  drivers/char/sn_serial.c | 1189 +++++++++++++++++++++++++++++++++++++++++++++++

Would it be more appropriate to place this under arch/ia64?

[PATCH] Altix console driver

[Jesse Barnes]

Just a simple addition to drivers/char for the Altix serial console.

 MAINTAINERS              |    6 
 drivers/char/Kconfig     |   16 
 drivers/char/Makefile    |    1 
 drivers/char/sn_serial.c | 1189 +++++++++++++++++++++++++++++++++++++++++++++++

Thanks,
Jesse

diff -Nru a/MAINTAINERS b/MAINTAINERS
--- a/MAINTAINERS	Wed Sep 17 15:22:32 2003
+++ b/MAINTAINERS	Wed Sep 17 15:22:32 2003
@@ -1727,6 +1727,12 @@
 W:	http://www.nsa.gov/selinux
 S:	Supported
 
+SGI SN-IA64 (Altix) SERIAL CONSOLE DRIVER
+P:	Pat Gefre
+M:	pfg@sgi.com
+L:	linux-ia64@vger.kernel.org
+S:	Supported
+
 SGI VISUAL WORKSTATION 320 AND 540
 P:	Andrey Panin
 M:	pazke@donpac.ru
diff -Nru a/drivers/char/Kconfig b/drivers/char/Kconfig
--- a/drivers/char/Kconfig	Wed Sep 17 15:22:32 2003
+++ b/drivers/char/Kconfig	Wed Sep 17 15:22:32 2003
@@ -393,6 +393,22 @@
 	  If you have an Alchemy AU1000 processor (MIPS based) and you want
 	  to use a console on a serial port, say Y.  Otherwise, say N.
 
+config SGI_L1_SERIAL
+	bool "SGI Altix L1 serial support"
+	depends on SERIAL_NONSTANDARD && IA64
+	help
+	  If you have an SGI Altix and you want to use the serial port
+	  connected to the system controller (you want this!), say Y.
+	  Otherwise, say N.
+
+config SGI_L1_SERIAL_CONSOLE
+	bool "SGI Altix L1 serial console support"
+	depends on SGI_L1_SERIAL
+	help
+	  If you have an SGI Altix and you would like to use the system
+	  controller serial port as your console (you want this!), 
+	  say Y.  Otherwise, say N.
+
 config QTRONIX_KEYBOARD
 	bool "Enable Qtronix 990P Keyboard Support"
 	depends on IT8712
diff -Nru a/drivers/char/Makefile b/drivers/char/Makefile
--- a/drivers/char/Makefile	Wed Sep 17 15:22:32 2003
+++ b/drivers/char/Makefile	Wed Sep 17 15:22:32 2003
@@ -41,6 +41,7 @@
 obj-$(CONFIG_SERIAL_TX3912) += generic_serial.o serial_tx3912.o
 obj-$(CONFIG_HVC_CONSOLE) += hvc_console.o
 obj-$(CONFIG_RAW_DRIVER) += raw.o
+obj-$(CONFIG_SGI_L1_SERIAL) += sn_serial.o
 
 obj-$(CONFIG_PRINTER) += lp.o
 obj-$(CONFIG_TIPAR) += tipar.o
diff -Nru a/drivers/char/sn_serial.c b/drivers/char/sn_serial.c
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/drivers/char/sn_serial.c	Wed Sep 17 15:22:32 2003
@@ -0,0 +1,1189 @@
+/*
+ * C-Brick Serial Port (and console) driver for SGI Altix machines.
+ *
+ * This driver is NOT suitable for talking to the l1-controller for
+ * anything other than 'console activities' --- please use the l1
+ * driver for that.
+ *
+ *
+ * Copyright (c) 2003 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/NoticeExplan
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/module.h>
+#ifdef CONFIG_MAGIC_SYSRQ
+#include <linux/sysrq.h>
+#endif
+#include <linux/string.h>
+#include <linux/circ_buf.h>
+#include <linux/serial_reg.h>
+#include <asm/irq.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/sn/sn_sal.h>
+#include <asm/sn/pci/pciio.h>		/* this is needed for snia_get_console_nasid */
+#include <asm/sn/nodepda.h>
+#include <asm/sn/simulator.h>
+#include <asm/sn/sn2/intr.h>
+#include <asm/sn/sn2/sn_private.h>
+#include <asm/sn/clksupport.h>
+
+#ifdef CONFIG_KDB
+#include <linux/kdb.h>
+#include <linux/serial_reg.h>
+
+/*
+ * The following KDB configuration info is borrowed from
+ * linux/drivers/char/serial.c:
+ */
+
+/*
+ * "kdb_serial_str[] is the sequence that the user must enter on the serial
+ * console to invoke kdb.  It can be a single character such as "\001"
+ * (control-A) or multiple characters such as "\eKdB".  NOTE: All except the
+ * last character are passed through to the application reading from the serial
+ * console.
+ *
+ * I tried to make the sequence a CONFIG_ option but most of CML1 cannot cope
+ * with '\' in strings, CML2 should be able to do it.  KAO."
+ */
+
+static int  kdb_serial_line = -1;
+static const char kdb_serial_str[] = "\eKDB";
+static char *kdb_serial_ptr = (char *)kdb_serial_str;
+#endif /* CONFIG_KDB */
+
+#if defined(CONFIG_SGI_L1_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+static char sysrq_serial_str[] = "\eSYS";
+static char *sysrq_serial_ptr = sysrq_serial_str;
+static unsigned long sysrq_requested;
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE && CONFIG_MAGIC_SYSRQ */
+
+static char *serial_revdate = "2003-09-10";
+
+#define snia_get_console_nasid	get_console_nasid
+
+/* minor device number */
+#define SN_SAL_MINOR 64
+
+/* number of characters left in xmit buffer before we ask for more */
+#define WAKEUP_CHARS 128
+
+/* number of characters we can transmit to the SAL console at a time */
+#define SN_SAL_MAX_CHARS 120
+
+/* event types for our task queue -- so far just one */
+#define SN_SAL_EVENT_WRITE_WAKEUP 0
+
+#define CONSOLE_RESTART 0
+
+/* 64K, when we're asynch, it must be at least printk's LOG_BUF_LEN to
+ * avoid losing chars, (always has to be a power of 2) */
+#if 1
+#define SN_SAL_BUFFER_SIZE (64 * (1 << 10))
+#else
+#define SN_SAL_BUFFER_SIZE (64)
+#endif
+
+#define SN_SAL_UART_FIFO_DEPTH 16
+#define SN_SAL_UART_FIFO_SPEED_CPS 9600/10
+
+/* we don't kmalloc/get_free_page these as we want them available
+ * before either of those are initialized */
+static volatile char sn_xmit_buff_mem[SN_SAL_BUFFER_SIZE];
+
+struct volatile_circ_buf {
+	volatile char *cb_buf;
+	int cb_head;
+	int cb_tail;
+};
+
+static volatile struct volatile_circ_buf xmit = { .cb_buf = sn_xmit_buff_mem };
+static char sn_tmp_buffer[SN_SAL_BUFFER_SIZE];
+
+static volatile struct tty_struct *sn_sal_tty;
+
+static struct timer_list sn_sal_timer;
+static int sn_sal_event; /* event type for task queue */
+
+static volatile int sn_sal_is_asynch;
+static volatile int sn_sal_irq;
+static spinlock_t sn_sal_lock = SPIN_LOCK_UNLOCKED;
+static volatile int sn_total_tx_count;
+static volatile int sn_total_rx_count;
+
+static void sn_sal_tasklet_action(unsigned long data);
+static DECLARE_TASKLET(sn_sal_tasklet, sn_sal_tasklet_action, 0);
+
+static volatile unsigned long sn_interrupt_timeout;
+
+extern u64 master_node_bedrock_address;
+
+static int sn_debug_printf(const char *fmt, ...);
+
+#undef DEBUG
+#ifdef DEBUG
+#define DPRINTF(x...) sn_debug_printf(x)
+#else
+#define DPRINTF(x...) do { } while (0)
+#endif
+
+struct sn_sal_ops {
+	int (*sal_puts)(const char *s, int len);
+	int (*sal_getc)(void);
+	int (*sal_input_pending)(void);
+	void (*sal_wakeup_transmit)(void);
+};
+
+/* This is the pointer used. It is assigned to point to one of
+ * the tables below.
+ */
+static volatile struct sn_sal_ops *sn_func;
+
+/* Prototypes */
+static int snt_hw_puts(const char *, int);
+static int snt_poll_getc(void);
+static int snt_poll_input_pending(void);
+static int snt_sim_puts(const char *, int);
+static int snt_sim_getc(void);
+static int snt_sim_input_pending(void);
+static int snt_intr_getc(void);
+static int snt_intr_input_pending(void);
+static void sn_intr_transmit_chars(void);
+
+/* A table for polling */
+static struct sn_sal_ops poll_ops = {
+	.sal_puts = snt_hw_puts,
+	.sal_getc = snt_poll_getc,
+	.sal_input_pending = snt_poll_input_pending
+};
+
+/* A table for the simulator */
+static struct sn_sal_ops sim_ops = {
+	.sal_puts = snt_sim_puts,
+	.sal_getc = snt_sim_getc,
+	.sal_input_pending = snt_sim_input_pending
+};
+
+/* A table for interrupts enabled */
+static struct sn_sal_ops intr_ops = {
+	.sal_puts = snt_hw_puts,
+	.sal_getc = snt_intr_getc,
+	.sal_input_pending = snt_intr_input_pending,
+	.sal_wakeup_transmit = sn_intr_transmit_chars
+};
+
+
+/* the console does output in two distinctly different ways:
+ * synchronous and asynchronous (buffered).  initally, early_printk
+ * does synchronous output.  any data written goes directly to the SAL
+ * to be output (incidentally, it is internally buffered by the SAL)
+ * after interrupts and timers are initialized and available for use,
+ * the console init code switches to asynchronous output.  this is
+ * also the earliest opportunity to begin polling for console input.
+ * after console initialization, console output and tty (serial port)
+ * output is buffered and sent to the SAL asynchronously (either by
+ * timer callback or by UART interrupt) */
+
+
+/* routines for running the console in polling mode */
+
+static int
+snt_hw_puts(const char *s, int len)
+{
+	/* looking at the PROM source code, putb calls the flush
+	 * routine, so if we send characters in FIFO sized chunks, it
+	 * should go out by the next time the timer gets called */
+	return ia64_sn_console_putb(s, len);
+}
+
+static int
+snt_poll_getc(void)
+{
+	int ch;
+	ia64_sn_console_getc(&ch);
+	return ch;
+}
+
+static int
+snt_poll_input_pending(void)
+{
+	int status, input;
+
+	status = ia64_sn_console_check(&input);
+	return !status && input;
+}
+
+
+/* routines for running the console on the simulator */
+
+static int
+snt_sim_puts(const char *str, int count)
+{
+	int counter = count;
+
+#ifdef FLAG_DIRECT_CONSOLE_WRITES
+	/* This is an easy way to pre-pend the output to know whether the output
+	 * was done via sal or directly */
+	writeb('[', master_node_bedrock_address + (UART_TX << 3));
+	writeb('+', master_node_bedrock_address + (UART_TX << 3));
+	writeb(']', master_node_bedrock_address + (UART_TX << 3));
+	writeb(' ', master_node_bedrock_address + (UART_TX << 3));
+#endif /* FLAG_DIRECT_CONSOLE_WRITES */
+	while (counter > 0) {
+		writeb(*str, master_node_bedrock_address + (UART_TX << 3));
+		counter--;
+		str++;
+	}
+
+	return count;
+}
+
+static int
+snt_sim_getc(void)
+{
+	return readb(master_node_bedrock_address + (UART_RX << 3));
+}
+
+static int
+snt_sim_input_pending(void)
+{
+	return readb(master_node_bedrock_address + (UART_LSR << 3)) & UART_LSR_DR;
+}
+
+
+/* routines for an interrupt driven console (normal) */
+
+static int
+snt_intr_getc(void)
+{
+	return ia64_sn_console_readc();
+}
+
+static int
+snt_intr_input_pending(void)
+{
+	return ia64_sn_console_intr_status() & SAL_CONSOLE_INTR_RECV;
+}
+
+/* The early printk (possible setup) and function call */
+
+void
+early_printk_sn_sal(const char *s, unsigned count)
+{
+	extern void early_sn_setup(void);
+
+	if (!sn_func) {
+		if (IS_RUNNING_ON_SIMULATOR())
+			sn_func = &sim_ops;
+		else
+			sn_func = &poll_ops;
+
+		early_sn_setup();
+	}
+	sn_func->sal_puts(s, count);
+}
+
+/* this is as "close to the metal" as we can get, used when the driver
+ * itself may be broken */
+static int
+sn_debug_printf(const char *fmt, ...)
+{
+	static char printk_buf[1024];
+	int printed_len;
+	va_list args;
+
+	va_start(args, fmt);
+	printed_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
+	early_printk_sn_sal(printk_buf, printed_len);
+	va_end(args);
+	return printed_len;
+}
+
+/*********************************************************************
+ * Interrupt handling routines.
+ */
+
+static void
+sn_sal_sched_event(int event)
+{
+	sn_sal_event |= (1 << event);
+	tasklet_schedule(&sn_sal_tasklet);
+}
+
+/* sn_receive_chars can be called before sn_sal_tty is initialized.  in
+ * that case, its only use is to trigger sysrq and kdb */
+static void
+sn_receive_chars(struct pt_regs *regs)
+{
+	int ch;
+
+	while (sn_func->sal_input_pending()) {
+		ch = sn_func->sal_getc();
+		if (ch < 0) {
+			printk(KERN_ERR "sn_serial: An error occured while "
+			       "obtaining data from the console (0x%0x)\n", ch);
+			break;
+		}
+#ifdef CONFIG_KDB
+		if (kdb_on) {
+			if (ch == *kdb_serial_ptr) {
+				if (!(*++kdb_serial_ptr)) {
+					if (!regs)
+						KDB_ENTER();	/* to get some registers */
+					else
+						kdb(KDB_REASON_KEYBOARD, 0, regs);
+					kdb_serial_ptr = (char *)kdb_serial_str;
+					break;
+				}
+			}
+			else
+				kdb_serial_ptr = (char *)kdb_serial_str;
+		}
+#endif /* CONFIG_KDB */
+
+#if defined(CONFIG_SGI_L1_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+		if (sysrq_requested) {
+			unsigned long sysrq_timeout = sysrq_requested + HZ*5;
+			sysrq_requested = 0;
+			if (ch && time_before(jiffies, sysrq_timeout)) {
+				spin_unlock(&sn_sal_lock);
+				handle_sysrq(ch, regs, NULL);
+				spin_lock(&sn_sal_lock);
+				/* don't record this char */
+				continue;
+			}
+		}
+		if (ch == *sysrq_serial_ptr) {
+			if (!(*++sysrq_serial_ptr)) {
+				sysrq_requested = jiffies;
+				sysrq_serial_ptr = sysrq_serial_str;
+			}
+		}
+		else
+			sysrq_serial_ptr = sysrq_serial_str;
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE && CONFIG_MAGIC_SYSRQ */
+
+		/* record the character to pass up to the tty layer */
+		if (sn_sal_tty) {
+			*sn_sal_tty->flip.char_buf_ptr = ch;
+			sn_sal_tty->flip.char_buf_ptr++;
+			sn_sal_tty->flip.count++;
+			if (sn_sal_tty->flip.count == TTY_FLIPBUF_SIZE)
+				break;
+		}
+		sn_total_rx_count++;
+	}
+
+	if (sn_sal_tty)
+		tty_flip_buffer_push((struct tty_struct *)sn_sal_tty);
+}
+
+
+/* synch_flush_xmit must be called with sn_sal_lock */
+static void
+synch_flush_xmit(void)
+{
+	int xmit_count, tail, head, loops, ii;
+	int result;
+	volatile char *start;
+
+	if (xmit.cb_head == xmit.cb_tail)
+		return; /* Nothing to do. */
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	/* twice around gets the tail to the end of the buffer and
+	 * then to the head, if needed */
+	loops = (head < tail) ? 2 : 1;
+
+	for (ii = 0; ii < loops; ii++) {
+		xmit_count = (head < tail) ?  (SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+		if (xmit_count > 0) {
+			result = sn_func->sal_puts((char *)start, xmit_count);
+			if (!result)
+				sn_debug_printf("\n*** synch_flush_xmit failed to flush\n");
+			if (result > 0) {
+				xmit_count -= result;
+				sn_total_tx_count += result;
+				tail += result;
+				tail &= SN_SAL_BUFFER_SIZE - 1;
+				xmit.cb_tail = tail;
+				start = (char *)&xmit.cb_buf[tail];
+			}
+		}
+	}
+}
+
+/* must be called with a lock protecting the circular buffer and
+ * sn_sal_tty */
+static void
+sn_poll_transmit_chars(void)
+{
+	int xmit_count, tail, head;
+	int result;
+	volatile char *start;
+
+	BUG_ON(!sn_sal_is_asynch);
+
+	if (xmit.cb_head == xmit.cb_tail ||
+	    (sn_sal_tty && (sn_sal_tty->stopped || sn_sal_tty->hw_stopped))) {
+		/* Nothing to do. */
+		return;
+	}
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	xmit_count = (head < tail) ?  (SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+	if (xmit_count == 0)
+		sn_debug_printf("\n*** empty xmit_count\n");
+
+	/* use the ops, as we could be on the simulator */
+	result = sn_func->sal_puts((char *)start, xmit_count);
+	if (!result)
+		sn_debug_printf("\n*** error in synchronous sal_puts\n");
+	/* XXX chadt clean this up */
+	if (result > 0) {
+		xmit_count -= result;
+		sn_total_tx_count += result;
+		tail += result;
+		tail &= SN_SAL_BUFFER_SIZE - 1;
+		xmit.cb_tail = tail;
+		start = &xmit.cb_buf[tail];
+	}
+
+	/* if there's few enough characters left in the xmit buffer
+	 * that we could stand for the upper layer to send us some
+	 * more, ask for it. */
+	if (sn_sal_tty)
+		if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) < WAKEUP_CHARS)
+			sn_sal_sched_event(SN_SAL_EVENT_WRITE_WAKEUP);
+}
+
+
+/* must be called with a lock protecting the circular buffer and
+ * sn_sal_tty */
+static void
+sn_intr_transmit_chars(void)
+{
+	int xmit_count, tail, head, loops, ii;
+	int result;
+	volatile char *start;
+
+	BUG_ON(!sn_sal_is_asynch);
+
+	if (xmit.cb_head == xmit.cb_tail ||
+	    (sn_sal_tty && (sn_sal_tty->stopped || sn_sal_tty->hw_stopped))) {
+		/* Nothing to do. */
+		return;
+	}
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	/* twice around gets the tail to the end of the buffer and
+	 * then to the head, if needed */
+	loops = (head < tail) ? 2 : 1;
+
+	for (ii = 0; ii < loops; ii++) {
+		xmit_count = (head < tail) ?
+			(SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+		if (xmit_count > 0) {
+			result = ia64_sn_console_xmit_chars((char *)start, xmit_count);
+#ifdef DEBUG
+			if (!result)
+				sn_debug_printf("`");
+#endif
+			if (result > 0) {
+				xmit_count -= result;
+				sn_total_tx_count += result;
+				tail += result;
+				tail &= SN_SAL_BUFFER_SIZE - 1;
+				xmit.cb_tail = tail;
+				start = &xmit.cb_buf[tail];
+			}
+		}
+	}
+
+	/* if there's few enough characters left in the xmit buffer
+	 * that we could stand for the upper layer to send us some
+	 * more, ask for it. */
+	if (sn_sal_tty)
+		if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) < WAKEUP_CHARS)
+			sn_sal_sched_event(SN_SAL_EVENT_WRITE_WAKEUP);
+}
+
+
+static irqreturn_t
+sn_sal_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	/* this call is necessary to pass the interrupt back to the
+	 * SAL, since it doesn't intercept the UART interrupts
+	 * itself */
+	int status = ia64_sn_console_intr_status();
+
+	spin_lock(&sn_sal_lock);
+	if (status & SAL_CONSOLE_INTR_RECV)
+		sn_receive_chars(regs);
+	if (status & SAL_CONSOLE_INTR_XMIT)
+		sn_intr_transmit_chars();
+	spin_unlock(&sn_sal_lock);
+	return IRQ_HANDLED;
+}
+
+
+/* returns the console irq if interrupt is successfully registered,
+ * else 0 */
+static int
+sn_sal_connect_interrupt(void)
+{
+	cpuid_t intr_cpuid;
+	unsigned int intr_cpuloc;
+	nasid_t console_nasid;
+	unsigned int console_irq;
+	int result;
+
+	console_nasid = ia64_sn_get_console_nasid();
+	intr_cpuid = NODEPDA(NASID_TO_COMPACT_NODEID(console_nasid))->node_first_cpu;
+	intr_cpuloc = cpu_physical_id(intr_cpuid);
+	console_irq = CPU_VECTOR_TO_IRQ(intr_cpuloc, SGI_UART_VECTOR);
+
+	result = intr_connect_level(intr_cpuid, SGI_UART_VECTOR, 0 /*not used*/, 0 /*not used*/);
+	BUG_ON(result != SGI_UART_VECTOR);
+
+	result = request_irq(console_irq, sn_sal_interrupt, SA_INTERRUPT,  "SAL console driver", &sn_sal_tty);
+	if (result >= 0)
+		return console_irq;
+
+	printk(KERN_INFO "sn_serial: console proceeding in polled mode\n");
+	return 0;
+}
+
+/*
+ * End of the interrupt routines.
+ *********************************************************************/
+
+
+static void
+sn_sal_tasklet_action(unsigned long data)
+{
+	unsigned long flags;
+
+	if (sn_sal_tty) {
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		if (sn_sal_tty) {
+			if (test_and_clear_bit(SN_SAL_EVENT_WRITE_WAKEUP, &sn_sal_event)) {
+				if ((sn_sal_tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && sn_sal_tty->ldisc.write_wakeup)
+					(sn_sal_tty->ldisc.write_wakeup)((struct tty_struct *)sn_sal_tty);
+				wake_up_interruptible((wait_queue_head_t *)&sn_sal_tty->write_wait);
+			}
+		}
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+
+/*
+ * This function handles polled mode.
+ */
+static void
+sn_sal_timer_poll(unsigned long dummy)
+{
+	if (!sn_sal_irq) {
+		spin_lock(&sn_sal_lock);
+		sn_receive_chars(NULL);
+		sn_poll_transmit_chars();
+		spin_unlock(&sn_sal_lock);
+		mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+	}
+}
+
+static void
+sn_sal_timer_restart(unsigned long dummy)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	sn_sal_interrupt(0, NULL, NULL);
+	local_irq_restore(flags);
+	mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+}
+
+/*
+ * End of "sofware interrupt" routines.
+ *********************************************************************/
+
+
+/*********************************************************************
+ * User-level console routines
+ */
+
+static int
+sn_sal_open(struct tty_struct *tty, struct file *filp)
+{
+	unsigned long flags;
+
+	DPRINTF("sn_sal_open: sn_sal_tty = %p, tty = %p, filp = %p\n",
+		sn_sal_tty, tty, filp);
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (!sn_sal_tty)
+		sn_sal_tty = tty;
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	return 0;
+}
+
+
+/* We're keeping all our resources.  We're keeping interrupts turned
+ * on.  Maybe just let the tty layer finish its stuff...? GMSH
+ */
+static void
+sn_sal_close(struct tty_struct *tty, struct file * filp)
+{
+	if (tty->count == 1) {
+		unsigned long flags;
+		tty->closing = 1;
+		if (tty->driver->flush_buffer)
+			tty->driver->flush_buffer(tty);
+		if (tty->ldisc.flush_buffer)
+			tty->ldisc.flush_buffer(tty);
+		tty->closing = 0;
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		sn_sal_tty = NULL;
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+
+static int
+sn_sal_write(struct tty_struct *tty, int from_user,
+	     const unsigned char *buf, int count)
+{
+	int c, ret = 0;
+	unsigned long flags;
+
+	if (from_user) {
+		while (1) {
+			int c1;
+			c = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail,
+					      SN_SAL_BUFFER_SIZE);
+
+			if (count < c)
+				c = count;
+			if (c <= 0)
+				break;
+
+			c -= copy_from_user(sn_tmp_buffer, buf, c);
+			if (!c) {
+				if (!ret)
+					ret = -EFAULT;
+				break;
+			}
+
+			/* Turn off interrupts and see if the xmit buffer has
+			 * moved since the last time we looked.
+			 */
+			spin_lock_irqsave(&sn_sal_lock, flags);
+			c1 = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+
+			if (c1 < c)
+				c = c1;
+
+			memcpy((char *)xmit.cb_buf + xmit.cb_head, sn_tmp_buffer, c);
+			xmit.cb_head = ((xmit.cb_head + c) & (SN_SAL_BUFFER_SIZE - 1));
+			spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+			buf += c;
+			count -= c;
+			ret += c;
+		}
+	}
+	else {
+		/* The buffer passed in isn't coming from userland,
+		 * so cut out the middleman (sn_tmp_buffer).
+		 */
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		while (1) {
+			c = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+
+			if (count < c)
+				c = count;
+			if (c <= 0) {
+				break;
+			}
+			memcpy((char *)xmit.cb_buf + xmit.cb_head, buf, c);
+			xmit.cb_head = ((xmit.cb_head + c) & (SN_SAL_BUFFER_SIZE - 1));
+			buf += c;
+			count -= c;
+			ret += c;
+		}
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (xmit.cb_head != xmit.cb_tail && !(tty && (tty->stopped || tty->hw_stopped)))
+		if (sn_func->sal_wakeup_transmit)
+			sn_func->sal_wakeup_transmit();
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	return ret;
+}
+
+
+static void
+sn_sal_put_char(struct tty_struct *tty, unsigned char ch)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (CIRC_SPACE(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) != 0) {
+		xmit.cb_buf[xmit.cb_head] = ch;
+		xmit.cb_head = (xmit.cb_head + 1) & (SN_SAL_BUFFER_SIZE-1);
+		if ( sn_func->sal_wakeup_transmit )
+			sn_func->sal_wakeup_transmit();
+	}
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+
+static void
+sn_sal_flush_chars(struct tty_struct *tty)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE))
+		if (sn_func->sal_wakeup_transmit)
+			sn_func->sal_wakeup_transmit();
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+
+static int
+sn_sal_write_room(struct tty_struct *tty)
+{
+	unsigned long flags;
+	int space;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	space = CIRC_SPACE(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+	return space;
+}
+
+
+static int
+sn_sal_chars_in_buffer(struct tty_struct *tty)
+{
+	unsigned long flags;
+	int space;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	space = CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+	DPRINTF("<%d>", space);
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+	return space;
+}
+
+
+static int
+sn_sal_ioctl(struct tty_struct *tty, struct file *file,
+	       unsigned int cmd, unsigned long arg)
+{
+	/* nothing supported */
+
+	return -ENOIOCTLCMD;
+}
+
+
+static void
+sn_sal_flush_buffer(struct tty_struct *tty)
+{
+	unsigned long flags;
+
+	/* drop everything */
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	xmit.cb_head = xmit.cb_tail = 0;
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	/* wake up tty level */
+	wake_up_interruptible(&tty->write_wait);
+	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup)
+		(tty->ldisc.write_wakeup)(tty);
+}
+
+
+static void
+sn_sal_hangup(struct tty_struct *tty)
+{
+	sn_sal_flush_buffer(tty);
+}
+
+
+static void
+sn_sal_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+	/* this is SAL's problem */
+	DPRINTF("<sn_serial: should wait until sent>");
+}
+
+
+/*
+ * sn_sal_read_proc
+ *
+ * Console /proc interface
+ */
+
+static int
+sn_sal_read_proc(char *page, char **start, off_t off, int count,
+		   int *eof, void *data)
+{
+	int len = 0;
+	off_t	begin = 0;
+
+	len += sprintf(page, "sn_serial: revision:%s nasid:%d irq:%d tx:%d rx:%d\n",
+		       serial_revdate, snia_get_console_nasid(), sn_sal_irq,
+		       sn_total_tx_count, sn_total_rx_count);
+	*eof = 1;
+
+	if (off >= len+begin)
+		return 0;
+	*start = page + (off-begin);
+
+	return count < begin+len-off ? count : begin+len-off;
+}
+
+
+static struct tty_operations sn_sal_driver_ops = {
+	.open = sn_sal_open,
+	.close = sn_sal_close,
+	.write = sn_sal_write,
+	.put_char = sn_sal_put_char,
+	.flush_chars = sn_sal_flush_chars,
+	.write_room = sn_sal_write_room,
+	.chars_in_buffer = sn_sal_chars_in_buffer,
+	.ioctl = sn_sal_ioctl,
+	.hangup = sn_sal_hangup,
+	.wait_until_sent = sn_sal_wait_until_sent,
+	.read_proc = sn_sal_read_proc,
+};
+static struct tty_driver *sn_sal_driver;
+
+/* sn_sal_init wishlist:
+ * - allocate sn_tmp_buffer
+ * - fix up the tty_driver struct
+ * - turn on receive interrupts
+ * - do any termios twiddling once and for all
+ */
+
+/*
+ * Boot-time initialization code
+ */
+
+static void __init
+sn_sal_switch_to_asynch(void)
+{
+	sn_debug_printf("sn_serial: about to switch to asynchronous console\n");
+
+	/* without early_printk, we may be invoked late enough to race
+	 * with other cpus doing console IO at this point, however
+	 * console interrupts will never be enabled */
+	spin_lock(&sn_sal_lock);
+
+	/* early_printk invocation may have done this for us */
+	if (!sn_func) {
+		if (IS_RUNNING_ON_SIMULATOR())
+			sn_func = &sim_ops;
+		else
+			sn_func = &poll_ops;
+	}
+
+	/* we can't turn on the console interrupt (as request_irq
+	 * calls kmalloc, which isn't set up yet), so we rely on a
+	 * timer to poll for input and push data from the console
+	 * buffer.
+	 */
+	init_timer(&sn_sal_timer);
+	sn_sal_timer.function = sn_sal_timer_poll;
+
+	if (IS_RUNNING_ON_SIMULATOR())
+		sn_interrupt_timeout = 6;
+	else {
+		/* 960cps / 16 char FIFO = 60HZ 
+		 * HZ / (SN_SAL_FIFO_SPEED_CPS / SN_SAL_FIFO_DEPTH) */
+		sn_interrupt_timeout = HZ * SN_SAL_UART_FIFO_DEPTH / SN_SAL_UART_FIFO_SPEED_CPS;
+	}
+	mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+
+	sn_sal_is_asynch = 1;
+	spin_unlock(&sn_sal_lock);
+}
+
+static void __init
+sn_sal_switch_to_interrupts(void)
+{
+	int irq;
+
+	sn_debug_printf("sn_serial: switching to interrupt driven console\n");
+
+	irq = sn_sal_connect_interrupt();
+	if (irq) {
+		unsigned long flags;
+		spin_lock_irqsave(&sn_sal_lock, flags);
+
+		/* sn_sal_irq is a global variable.  When it's set to
+		 * a non-zero value, we stop polling for input (since
+		 * interrupts should now be enabled). */
+		sn_sal_irq = irq;
+		sn_func = &intr_ops;
+
+		/* turn on receive interrupts */
+		ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);
+
+		/* the polling timer is already set up, we just change the
+		 * frequency.  if we've successfully enabled interrupts (and
+		 * CONSOLE_RESTART isn't defined) the next timer expiration
+		 * will be the last, otherwise we continue polling */
+		if (CONSOLE_RESTART) {
+			/* kick the console every once in a while in
+			 * case we miss an interrupt */
+			sn_interrupt_timeout = 20*HZ;
+			sn_sal_timer.function = sn_sal_timer_restart;
+			mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+		}
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+static int __init
+sn_sal_module_init(void)
+{
+	int retval;
+
+	printk("sn_serial: sn_sal_module_init\n");
+
+	if (!ia64_platform_is("sn2"))
+		return -ENODEV;
+
+	sn_sal_driver = alloc_tty_driver(1);
+	if ( !sn_sal_driver )
+		return -ENOMEM;
+
+	sn_sal_driver->owner = THIS_MODULE;
+	sn_sal_driver->driver_name = "sn_serial";
+	sn_sal_driver->name = "ttyS";
+	sn_sal_driver->major = TTY_MAJOR;
+	sn_sal_driver->minor_start = SN_SAL_MINOR;
+	sn_sal_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	sn_sal_driver->subtype = SERIAL_TYPE_NORMAL;
+	sn_sal_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+
+	tty_set_operations(sn_sal_driver, &sn_sal_driver_ops);
+
+	/* when this driver is compiled in, the console initialization
+	 * will have already switched us into asynchronous operation
+	 * before we get here through the module initcalls */
+	if (!sn_sal_is_asynch)
+		sn_sal_switch_to_asynch();
+
+	/* at this point (module_init) we can try to turn on interrupts */
+	if (!IS_RUNNING_ON_SIMULATOR())
+	    sn_sal_switch_to_interrupts();
+
+	sn_sal_driver->init_termios = tty_std_termios;
+	sn_sal_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+
+	if ((retval = tty_register_driver(sn_sal_driver))) {
+		printk(KERN_ERR "sn_serial: Unable to register tty driver\n");
+		return retval;
+	}
+#ifdef CONFIG_SGI_L1_SERIAL_CONSOLE
+	{
+		void __init sn_sal_serial_console_init(void);
+		sn_sal_serial_console_init();
+	}
+#endif	/* CONFIG_SGI_L1_SERIAL_CONSOLE */
+	return 0;
+}
+
+
+static void __exit
+sn_sal_module_exit(void)
+{
+	unsigned long flags;
+	int tmp;
+
+	del_timer_sync(&sn_sal_timer);
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if ((tmp = tty_unregister_driver(sn_sal_driver)))
+		printk(KERN_ERR "sn_serial: failed to unregister driver (%d)\n", tmp);
+
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+module_init(sn_sal_module_init);
+module_exit(sn_sal_module_exit);
+
+/*
+ * End of user-level console routines.
+ *********************************************************************/
+
+
+/*********************************************************************
+ * Kernel console definitions
+ */
+
+#ifdef CONFIG_SGI_L1_SERIAL_CONSOLE
+/*
+ * Print a string to the SAL console.  The console_lock must be held
+ * when we get here.
+ */
+static void
+sn_sal_console_write(struct console *co, const char *s, unsigned count)
+{
+	BUG_ON(!sn_sal_is_asynch);
+
+	/* somebody really wants this output, might be an
+	 * oops, kdb, panic, etc.  make sure they get it. */
+	if (spin_is_locked(&sn_sal_lock)) {
+		synch_flush_xmit();
+		sn_func->sal_puts(s, count);
+	}
+	else if (in_interrupt()) {
+		spin_lock(&sn_sal_lock);
+		synch_flush_xmit();
+		spin_unlock(&sn_sal_lock);
+		sn_func->sal_puts(s, count);
+	}
+	else
+		sn_sal_write(NULL, 0, s, count);
+}
+
+static struct tty_driver *
+sn_sal_console_device(struct console *c, int *index)
+{
+	*index = c->index;
+	return sn_sal_driver;
+}
+
+static int __init
+sn_sal_console_setup(struct console *co, char *options)
+{
+#ifdef CONFIG_KDB
+	/*
+	 * Remember the line number of the first serial
+	 * console.  We'll make this the kdb serial console too.
+	 */
+	if (kdb_serial_line == -1) {
+		kdb_serial_line = co->index;
+	}
+#endif /* CONFIG_KDB */
+	return 0;
+}
+
+
+static struct console sal_console = {
+	.name = "ttyS",
+	.write = sn_sal_console_write,
+	.device = sn_sal_console_device,
+	.setup = sn_sal_console_setup,
+	.index = -1
+};
+
+/*
+ * End of kernel console definitions.
+ *********************************************************************/
+
+
+void __init
+sn_sal_serial_console_init(void)
+{
+	if (ia64_platform_is("sn2")) {
+		sn_sal_switch_to_asynch();
+		sn_debug_printf("sn_sal_serial_console_init : register console\n");
+		register_console(&sal_console);
+	}
+}
+
+
+#ifdef	CONFIG_KDB
+int
+l1_control_in_polled(int offset)
+{
+	int sal_call_status = 0, input;
+	int ret = 0;
+
+	if (IS_RUNNING_ON_SIMULATOR()) {
+		ret = readb((unsigned long)master_node_bedrock_address + (offset<< 3));
+		return(ret);
+	}		
+	if (offset == UART_LSR) {
+		ret = (UART_LSR_THRE | UART_LSR_TEMT);	/* can send anytime */
+		sal_call_status = ia64_sn_console_check(&input);
+		if (!sal_call_status && input) {
+			/* input pending */
+			ret |= UART_LSR_DR;
+		}
+	}
+	return ret;
+}
+
+int
+l1_serial_in_polled(void)
+{
+	int ch;
+
+	if (IS_RUNNING_ON_SIMULATOR()) {
+		return readb((unsigned long)master_node_bedrock_address + (UART_RX<< 3));
+	}		
+
+	if (!ia64_sn_console_getc(&ch))
+		return ch;
+	else
+		return 0;
+}
+#endif /* CONFIG_KDB */
+
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE */

Re: [PATCH] Altix console driver

[Jesse Barnes]

On Wed, Sep 17, 2003 at 03:21:39PM -0700, Andrew Morton wrote:
> jbarnes@sgi.com (Jesse Barnes) wrote:
> >
> > Just a simple addition to drivers/char for the Altix serial console.
> > 
> >  MAINTAINERS              |    6 
> >  drivers/char/Kconfig     |   16 
> >  drivers/char/Makefile    |    1 
> >  drivers/char/sn_serial.c | 1189 +++++++++++++++++++++++++++++++++++++++++++++++
> 
> Would it be more appropriate to place this under arch/ia64?

I've always been told not to do that.  Christoph? ;)

Jesse

Re: [PATCH] Altix console driver

[Pete Zaitcev]

>> Just a simple addition to drivers/char for the Altix serial console.
>> 
>>  MAINTAINERS              |    6 
>>  drivers/char/Kconfig     |   16 
>>  drivers/char/Makefile    |    1 
>>  drivers/char/sn_serial.c | 1189 +++++++++++++++++++++++++++++++++++++++++++++++
> 
> Would it be more appropriate to place this under arch/ia64?

It was discussed on other occasions, and it "was decided"
(sprinkled with holy penguin pee) that such things go into
drivers/, e.g. drivers/serial/sunsu.c is Sun-specific,
but it helps to keep it near drivers/serial/8250.c, for
diffing. If an additional API is involved, e.g.
sbus_alloc_consistent, drivers get a subdir like
drivers/sbus or drivers/s390. Also, you never know
when sharing hits you across the head, e.g. sparc, sparc64,
and m68k (for sun3) share some drivers.

-- Pete

Re: [PATCH] Altix console driver

[Christoph Hellwig]

On Wed, Sep 17, 2003 at 03:21:39PM -0700, Andrew Morton wrote:
> Would it be more appropriate to place this under arch/ia64?

arch/ drivers are evil.  Also the driver could possibly used on mips
if someone does the port to this hardware..

Re: [PATCH] Altix console driver

[Christoph Hellwig]

On Wed, Sep 17, 2003 at 03:24:14PM -0700, Jesse Barnes wrote:
> + * Further, this software is distributed without any warranty that it is
> + * free of the rightful claim of any third person regarding infringement
> + * or the like.  Any license provided herein, whether implied or
> + * otherwise, applies only to this software file.  Patent licenses, if
> + * any, provided herein do not apply to combinations of this program with
> + * other software, or any other product whatsoever.

This seems to be a restriction not compatible with the GPL.  And it looks
like many SGI files in the tree have it aswell..

> +#include <linux/console.h>
> +#include <linux/module.h>
> +#ifdef CONFIG_MAGIC_SYSRQ
> +#include <linux/sysrq.h>
> +#endif

Please include it unconditionally.

> +#include <asm/sn/sn_sal.h>
> +#include <asm/sn/pci/pciio.h>		/* this is needed for snia_get_console_nasid */
> +#include <asm/sn/nodepda.h>
> +#include <asm/sn/simulator.h>
> +#include <asm/sn/sn2/intr.h>
> +#include <asm/sn/sn2/sn_private.h>
> +#include <asm/sn/clksupport.h>

Yuck.  Do you really need all these crufty includes?

> +#ifdef CONFIG_KDB
> +#include <linux/kdb.h>
> +#include <linux/serial_reg.h>

Keith doesn't like kdb code hitting mainline...

> +static char *serial_revdate = "2003-09-10";

This gets out of sync easily if someone external modifies the driver,
don't do it.

> +
> +#define snia_get_console_nasid	get_console_nasid

Another level of obsfuction?

> +/* event types for our task queue -- so far just one */
> +#define SN_SAL_EVENT_WRITE_WAKEUP 0

So kill this layher of indirection?

> +#define CONSOLE_RESTART 0

When will this be enabled?


> +
> +/* 64K, when we're asynch, it must be at least printk's LOG_BUF_LEN to
> + * avoid losing chars, (always has to be a power of 2) */
> +#if 1
> +#define SN_SAL_BUFFER_SIZE (64 * (1 << 10))
> +#else
> +#define SN_SAL_BUFFER_SIZE (64)
> +#endif

Why keep the #if 0?

> +
> +#define SN_SAL_UART_FIFO_DEPTH 16
> +#define SN_SAL_UART_FIFO_SPEED_CPS 9600/10
> +
> +/* we don't kmalloc/get_free_page these as we want them available
> + * before either of those are initialized */
> +static volatile char sn_xmit_buff_mem[SN_SAL_BUFFER_SIZE];
> +
> +struct volatile_circ_buf {
> +	volatile char *cb_buf;
> +	int cb_head;
> +	int cb_tail;
> +};
> +
> +static volatile struct volatile_circ_buf xmit = { .cb_buf = sn_xmit_buff_mem };
> +static char sn_tmp_buffer[SN_SAL_BUFFER_SIZE];
> +
> +static volatile struct tty_struct *sn_sal_tty;

Please do proper locking instread of volatile abuse.

> +
> +/* The early printk (possible setup) and function call */
> +
> +void
> +early_printk_sn_sal(const char *s, unsigned count)
> +{
> +	extern void early_sn_setup(void);
> +

there is not early printk in mainline, only in the ia64 tree, isn't it?

> +/*********************************************************************
> + * Interrupt handling routines.
> + */

Please fix the comment format.

> +
> +static irqreturn_t
> +sn_sal_interrupt(int irq, void *dev_id, struct pt_regs *regs)
> +{
> +	/* this call is necessary to pass the interrupt back to the
> +	 * SAL, since it doesn't intercept the UART interrupts
> +	 * itself */
> +	int status = ia64_sn_console_intr_status();
> +
> +	spin_lock(&sn_sal_lock);

This is registered with SA_INTERRUPT, so the plain spin_lock probably
is not enough.

> +/* returns the console irq if interrupt is successfully registered,
> + * else 0 */
> +static int
> +sn_sal_connect_interrupt(void)
> +{
> +	cpuid_t intr_cpuid;
> +	unsigned int intr_cpuloc;
> +	nasid_t console_nasid;
> +	unsigned int console_irq;
> +	int result;
> +
> +	console_nasid = ia64_sn_get_console_nasid();
> +	intr_cpuid = NODEPDA(NASID_TO_COMPACT_NODEID(console_nasid))->node_first_cpu;
> +	intr_cpuloc = cpu_physical_id(intr_cpuid);
> +	console_irq = CPU_VECTOR_TO_IRQ(intr_cpuloc, SGI_UART_VECTOR);
> +
> +	result = intr_connect_level(intr_cpuid, SGI_UART_VECTOR, 0 /*not used*/, 0 /*not used*/);
> +	BUG_ON(result != SGI_UART_VECTOR);
> +
> +	result = request_irq(console_irq, sn_sal_interrupt, SA_INTERRUPT,  "SAL console driver", &sn_sal_tty);
> +	if (result >= 0)
> +		return console_irq;
> +
> +	printk(KERN_INFO "sn_serial: console proceeding in polled mode\n");
> +	return 0;

Yikes!  WTF is this?  Okay, looking through arch/ia64/sn I see that
request_irq is basically a noop on SN2 and you must do intr_connect_level
instead.  Could you _please_fix this up by registering a
struct hw_interrupt_type for the hub-level interrupts and getting rid of
all this intr_connect_level madness?

> +static void
> +sn_sal_tasklet_action(unsigned long data)
> +{
> +	unsigned long flags;
> +
> +	if (sn_sal_tty) {
> +		spin_lock_irqsave(&sn_sal_lock, flags);
> +		if (sn_sal_tty) {
> +			if (test_and_clear_bit(SN_SAL_EVENT_WRITE_WAKEUP, &sn_sal_event)) {
> +				if ((sn_sal_tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && sn_sal_tty->ldisc.write_wakeup)
> +					(sn_sal_tty->ldisc.write_wakeup)((struct tty_struct *)sn_sal_tty);
> +				wake_up_interruptible((wait_queue_head_t *)&sn_sal_tty->write_wait);
> +			}

Please linebreak after 80 chars.

> +static int
> +sn_sal_open(struct tty_struct *tty, struct file *filp)
> +{
> +	unsigned long flags;
> +
> +	DPRINTF("sn_sal_open: sn_sal_tty = %p, tty = %p, filp = %p\n",
> +		sn_sal_tty, tty, filp);
> +
> +	spin_lock_irqsave(&sn_sal_lock, flags);
> +	if (!sn_sal_tty)
> +		sn_sal_tty = tty;

Eeek.  Either you allow opening just one tty and you don't need this
lock or you fix up the driver to pass the tty_struct to where it is used
properly.

> +
> +			memcpy((char *)xmit.cb_buf + xmit.cb_head, sn_tmp_buffer, c);

No need to cast the first ar to memcpy.  And even if you did it it would
be void *..

> +static int
> +sn_sal_ioctl(struct tty_struct *tty, struct file *file,
> +	       unsigned int cmd, unsigned long arg)
> +{
> +	/* nothing supported */
> +
> +	return -ENOIOCTLCMD;
> +}

So don't implement this function at all.  The upper layers will deal
with this nicely.

> +static int
> +sn_sal_read_proc(char *page, char **start, off_t off, int count,
> +		   int *eof, void *data)
> +{
> +	int len = 0;
> +	off_t	begin = 0;
> +
> +	len += sprintf(page, "sn_serial: revision:%s nasid:%d irq:%d tx:%d rx:%d\n",
> +		       serial_revdate, snia_get_console_nasid(), sn_sal_irq,
> +		       sn_total_tx_count, sn_total_rx_count);
> +	*eof = 1;
> +
> +	if (off >= len+begin)
> +		return 0;
> +	*start = page + (off-begin);
> +
> +	return count < begin+len-off ? count : begin+len-off;
> +}

Either convert to seq_file or better kill it off completly.  I don't
look very useful.

> +static struct tty_operations sn_sal_driver_ops = {
> +	.open = sn_sal_open,
> +	.close = sn_sal_close,
> +	.write = sn_sal_write,

	.open			= sn_sal_open,
	.close			= sn_sal_close,

etc..

> +	sn_sal_driver->owner = THIS_MODULE;
> +	sn_sal_driver->driver_name = "sn_serial";
> +	sn_sal_driver->name = "ttyS";
> +	sn_sal_driver->major = TTY_MAJOR;
> +	sn_sal_driver->minor_start = SN_SAL_MINOR;
> +	sn_sal_driver->type = TTY_DRIVER_TYPE_SERIAL;
> +	sn_sal_driver->subtype = SERIAL_TYPE_NORMAL;
> +	sn_sal_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;

So you're using the normal TTY_MAJOR in this driver?  And use a different
name for 64 minors offsets.  So what happens if someone puts a multiport
pci serial card into an SN2?

Also you really want to use drivers/serial/serial_core.c for this driver
and move it to drivers/serial.  rmk has a 2.4 version of that file aswell
so the 2.4 altix driver can use it, too.

> +	if ((retval = tty_register_driver(sn_sal_driver))) {
> +		printk(KERN_ERR "sn_serial: Unable to register tty driver\n");
> +		return retval;
> +	}
> +#ifdef CONFIG_SGI_L1_SERIAL_CONSOLE
> +	{
> +		void __init sn_sal_serial_console_init(void);
> +		sn_sal_serial_console_init();
> +	}
> +#endif	/* CONFIG_SGI_L1_SERIAL_CONSOLE */

Eeek.  sn_sal_serial_console_init should be static, shouldn't it.  And
have a proper prototype.  Then you could also get rid of the ugly scoping
mess.

> +	del_timer_sync(&sn_sal_timer);
> +	spin_lock_irqsave(&sn_sal_lock, flags);
> +	if ((tmp = tty_unregister_driver(sn_sal_driver)))
> +		printk(KERN_ERR "sn_serial: failed to unregister driver (%d)\n", tmp);
> +
> +	spin_unlock_irqrestore(&sn_sal_lock, flags);

tty_unregister_driver under a look looks strange.  Also where's the
put_tty_driver?  And the retval from tty_unregister_driver is meaningless,
your module is gone now anyway.

> +static void
> +sn_sal_console_write(struct console *co, const char *s, unsigned count)
> +{
> +	BUG_ON(!sn_sal_is_asynch);
> +
> +	/* somebody really wants this output, might be an
> +	 * oops, kdb, panic, etc.  make sure they get it. */
> +	if (spin_is_locked(&sn_sal_lock)) {

spin_is_locked doesn't work on !SMP && !PREEMPT..

> +		synch_flush_xmit();
> +		sn_func->sal_puts(s, count);
> +	}
> +	else if (in_interrupt()) {

	} else if (in_interrupt()) {

> +		spin_lock(&sn_sal_lock);
> +		synch_flush_xmit();
> +		spin_unlock(&sn_sal_lock);
> +		sn_func->sal_puts(s, count);
> +	}
> +	else

	} else

Re: [PATCH] Altix console driver

[Alan Cox]

On Mer, 2003-09-17 at 23:21, Andrew Morton wrote:

> Would it be more appropriate to place this under arch/ia64?

Unless they clarify the GPL violating license clause I'd suggest
strongly it goes into /dev/null. The GPL states:


  6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions.  You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.

I am perfectly permitted by the GPL to modify Linux and add other code
to it, or to create a new product based on it that is GPL licensed. 


SGI need to fix their boilerplate. I can kind of guess what they are
trying to say but it needs tweaking.

Re: [PATCH] Altix console driver

[Jesse Barnes]

Well, according to the FSF our extra clauses are compatible with the GPL
and LGPL.  See http://oss.sgi.com/projects/GenInfo/NoticeExplan/.  If
you still disagree then we'll have to try to find another solution.

Thanks,
Jesse

On Thu, Sep 18, 2003 at 01:09:31PM +0100, Alan Cox wrote:
> On Mer, 2003-09-17 at 23:21, Andrew Morton wrote:
> 
> > Would it be more appropriate to place this under arch/ia64?
> 
> Unless they clarify the GPL violating license clause I'd suggest
> strongly it goes into /dev/null. The GPL states:
> 
> 
>   6. Each time you redistribute the Program (or any work based on the
> Program), the recipient automatically receives a license from the
> original licensor to copy, distribute or modify the Program subject to
> these terms and conditions.  You may not impose any further
> restrictions on the recipients' exercise of the rights granted herein.
> You are not responsible for enforcing compliance by third parties to
> this License.
> 
> I am perfectly permitted by the GPL to modify Linux and add other code
> to it, or to create a new product based on it that is GPL licensed. 
> 
> 
> SGI need to fix their boilerplate. I can kind of guess what they are
> trying to say but it needs tweaking.

Re: [PATCH] Altix console driver

[Alan Cox]

On Gwe, 2003-09-19 at 16:21, Jesse Barnes wrote:
> Well, according to the FSF our extra clauses are compatible with the GPL
> and LGPL.  See http://oss.sgi.com/projects/GenInfo/NoticeExplan/.  If
> you still disagree then we'll have to try to find another solution.

I think I need to discuss this with Eben, it certainly seems a problem
to me but he's the legal expert so I want to find out his view first.

Re: [PATCH] Altix console driver

[Jamie Lokier]

Alan Cox wrote:
> On Gwe, 2003-09-19 at 16:21, Jesse Barnes wrote:
> > Well, according to the FSF our extra clauses are compatible with the GPL
> > and LGPL.  See http://oss.sgi.com/projects/GenInfo/NoticeExplan/.  If
> > you still disagree then we'll have to try to find another solution.
> 
> I think I need to discuss this with Eben, it certainly seems a problem
> to me but he's the legal expert so I want to find out his view first.

My reading of the boilerplate is that I can't use their code in
another GPL program, because their patent grant doesn't extend to
other programs.

Even if that's permitted by the GPL, it doesn't mean you have to
accept it into the kernel like that.

If that's just a misunderstanding of the legalese on my part, then
IMHO the text needs to be clarified to ensure that everyone knows they
may take the code and use it in other GPL projects.

-- Jamie

Re: [PATCH] Altix console driver

[Alan Cox]

On Sad, 2003-09-20 at 20:24, Jamie Lokier wrote:
> If that's just a misunderstanding of the legalese on my part, then
> IMHO the text needs to be clarified to ensure that everyone knows they
> may take the code and use it in other GPL projects.

I'll let folks know when I hear back from the FSF folks or if SGI decide
to tweak it anyway.

Re: [PATCH] Altix console driver

[Christoph Hellwig]

On Wed, Oct 22, 2003 at 09:39:12AM -0500, Pat Gefre wrote:
> + > Were all the points which Christoph raised considered?
> + 
> + No.
> + 
> 
> Which item(s), specifically, do you have an issue with ?

You're still registering with the normal serial major/minor without
using serial core.  That means the normal serial driver can't be used
when sn_serial is loaded, e.g. for using a pci serial card in an
altix.  The irq mess still isn't fixed - this isn't exactly an issue
with this driver but I exposing the bloody mess outside arch/ia64/sn
is a very bad idea.  I'd suggest kicking ajm to fix that up.

pciio.h has no business beeing included in this driver that doesn't
use anything PCIish, again a core SN issue that needs fixing.

Also after reading through the new comment ontop of the file it might
be a good idea to rename it to sn_console.c, especially now that there
is a real ioc4 serial driver.

Re: [PATCH] Altix console driver

[Pat Gefre]

On Wed, 22 Oct 2003, Christoph Hellwig wrote:

+ On Tue, Oct 21, 2003 at 03:00:27PM -0700, Andrew Morton wrote:
+ > Patrick Gefre <pfg@sgi.com> wrote:
+ > >
+ > > 2.6 Altix serial console driver add
+ > 
+ > Were all the points which Christoph raised considered?
+ 
+ No.
+ 

Which item(s), specifically, do you have an issue with ?

Re: [PATCH] Altix console driver

[Christoph Hellwig]

On Tue, Oct 21, 2003 at 03:00:27PM -0700, Andrew Morton wrote:
> Patrick Gefre <pfg@sgi.com> wrote:
> >
> > 2.6 Altix serial console driver add
> 
> Were all the points which Christoph raised considered?

No.

Re: [PATCH] Altix console driver

[Pat Gefre]

On Tue, 21 Oct 2003, Andrew Morton wrote:

+ Patrick Gefre <pfg@sgi.com> wrote:
+ >
+ > 2.6 Altix serial console driver add
+ 
+ Were all the points which Christoph raised considered?
+ 
+ http://www.ussg.iu.edu/hypermail/linux/kernel/0309.2/0465.html
+ 

I addressed as many as I could - almost all of them I think. FWIW this
driver is very close to the one I sent for 2.4. I would like to,
eventually, convert the code to use the serial_core calls....

-- Pat

Re: [PATCH] Altix console driver

[Andrew Morton]

Patrick Gefre <pfg@sgi.com> wrote:
>
> 2.6 Altix serial console driver add

Were all the points which Christoph raised considered?

http://www.ussg.iu.edu/hypermail/linux/kernel/0309.2/0465.html

[PATCH] Altix console driver

[Patrick Gefre]

[-- Attachment #1: Type: text/plain, Size: 37 bytes --]

2.6 Altix serial console driver add


[-- Attachment #2: console.patch --]
[-- Type: text/plain, Size: 28429 bytes --]

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.1347  -> 1.1348 
#	drivers/char/Kconfig	1.24    -> 1.25   
#	         MAINTAINERS	1.174   -> 1.175  
#	drivers/char/Makefile	1.60    -> 1.61   
#	               (new)	        -> 1.1     drivers/char/sn_serial.c
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/10/21	pfg@attica.americas.sgi.com	1.1348
# Altix serial console patch
# --------------------------------------------
#
diff -Nru a/MAINTAINERS b/MAINTAINERS
--- a/MAINTAINERS	Tue Oct 21 16:18:17 2003
+++ b/MAINTAINERS	Tue Oct 21 16:18:17 2003
@@ -1753,6 +1753,12 @@
 W:	http://www.nsa.gov/selinux
 S:	Supported
 
+SGI SN-IA64 (Altix) SERIAL CONSOLE DRIVER
+P:	Pat Gefre
+M:	pfg@sgi.com
+L:	linux-ia64@vger.kernel.org
+S:	Supported
+
 SGI VISUAL WORKSTATION 320 AND 540
 P:	Andrey Panin
 M:	pazke@donpac.ru
diff -Nru a/drivers/char/Kconfig b/drivers/char/Kconfig
--- a/drivers/char/Kconfig	Tue Oct 21 16:18:17 2003
+++ b/drivers/char/Kconfig	Tue Oct 21 16:18:17 2003
@@ -373,6 +373,22 @@
 	  If you have an Alchemy AU1000 processor (MIPS based) and you want
 	  to use serial ports, say Y.  Otherwise, say N.
 
+config SGI_L1_SERIAL
+	bool "SGI Altix L1 serial support"
+	depends on SERIAL_NONSTANDARD && IA64
+	help
+	  If you have an SGI Altix and you want to use the serial port
+	  connected to the system controller (you want this!), say Y.
+	  Otherwise, say N.
+
+config SGI_L1_SERIAL_CONSOLE
+	bool "SGI Altix L1 serial console support"
+	depends on SGI_L1_SERIAL
+	help
+	  If you have an SGI Altix and you would like to use the system
+	  controller serial port as your console (you want this!), 
+	  say Y.  Otherwise, say N.
+
 config AU1000_SERIAL_CONSOLE
 	bool "Enable Au1000 serial console"
 	depends on AU1000_UART
diff -Nru a/drivers/char/Makefile b/drivers/char/Makefile
--- a/drivers/char/Makefile	Tue Oct 21 16:18:17 2003
+++ b/drivers/char/Makefile	Tue Oct 21 16:18:17 2003
@@ -42,6 +42,7 @@
 obj-$(CONFIG_SH_SCI)		+= sh-sci.o generic_serial.o
 obj-$(CONFIG_HVC_CONSOLE)	+= hvc_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
+obj-$(CONFIG_SGI_L1_SERIAL)	+= sn_serial.o
 
 obj-$(CONFIG_PRINTER) += lp.o
 obj-$(CONFIG_TIPAR) += tipar.o
diff -Nru a/drivers/char/sn_serial.c b/drivers/char/sn_serial.c
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/drivers/char/sn_serial.c	Tue Oct 21 16:18:17 2003
@@ -0,0 +1,1000 @@
+/*
+ * C-Brick Serial Port (and console) driver for SGI Altix machines.
+ *
+ * This driver is NOT suitable for talking to the l1-controller for
+ * anything other than 'console activities' --- please use the l1
+ * driver for that.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2003 Silicon Graphics, Inc. All rights reserved.
+ */
+
+#include <linux/config.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/module.h>
+#include <linux/sysrq.h>
+#include <linux/circ_buf.h>
+#include <linux/serial_reg.h>
+#include <asm/sn/sn_sal.h>
+#include <asm/sn/pci/pciio.h>		/* this is needed for get_console_nasid */
+#include <asm/sn/simulator.h>
+#include <asm/sn/sn2/sn_private.h>
+
+#if defined(CONFIG_SGI_L1_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+static char sysrq_serial_str[] = "\eSYS";
+static char *sysrq_serial_ptr = sysrq_serial_str;
+static unsigned long sysrq_requested;
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE && CONFIG_MAGIC_SYSRQ */
+
+/* minor device number */
+#define SN_SAL_MINOR 64
+
+/* number of characters left in xmit buffer before we ask for more */
+#define WAKEUP_CHARS 128
+
+/* number of characters we can transmit to the SAL console at a time */
+#define SN_SAL_MAX_CHARS 120
+
+#define SN_SAL_EVENT_WRITE_WAKEUP 0
+
+/* 64K, when we're asynch, it must be at least printk's LOG_BUF_LEN to
+ * avoid losing chars, (always has to be a power of 2) */
+#define SN_SAL_BUFFER_SIZE (64 * (1 << 10))
+
+#define SN_SAL_UART_FIFO_DEPTH 16
+#define SN_SAL_UART_FIFO_SPEED_CPS 9600/10
+
+/* we don't kmalloc/get_free_page these as we want them available
+ * before either of those are initialized */
+static char sn_xmit_buff_mem[SN_SAL_BUFFER_SIZE];
+
+struct volatile_circ_buf {
+	char *cb_buf;
+	int cb_head;
+	int cb_tail;
+};
+
+static struct volatile_circ_buf xmit = { .cb_buf = sn_xmit_buff_mem };
+static char sn_tmp_buffer[SN_SAL_BUFFER_SIZE];
+
+static struct tty_struct *sn_sal_tty;
+
+static struct timer_list sn_sal_timer;
+static int sn_sal_event; /* event type for task queue */
+
+static int sn_sal_is_asynch;
+static int sn_sal_irq;
+static spinlock_t sn_sal_lock = SPIN_LOCK_UNLOCKED;
+static int sn_total_tx_count;
+static int sn_total_rx_count;
+
+static void sn_sal_tasklet_action(unsigned long data);
+static DECLARE_TASKLET(sn_sal_tasklet, sn_sal_tasklet_action, 0);
+
+static unsigned long sn_interrupt_timeout;
+
+extern u64 master_node_bedrock_address;
+
+static int sn_debug_printf(const char *fmt, ...);
+
+#undef DEBUG
+#ifdef DEBUG
+#define DPRINTF(x...) sn_debug_printf(x)
+#else
+#define DPRINTF(x...) do { } while (0)
+#endif
+
+struct sn_sal_ops {
+	int (*sal_puts)(const char *s, int len);
+	int (*sal_getc)(void);
+	int (*sal_input_pending)(void);
+	void (*sal_wakeup_transmit)(void);
+};
+
+/* This is the pointer used. It is assigned to point to one of
+ * the tables below.
+ */
+static struct sn_sal_ops *sn_func;
+
+/* Prototypes */
+static void __init sn_sal_serial_console_init(void);
+static int snt_hw_puts(const char *, int);
+static int snt_poll_getc(void);
+static int snt_poll_input_pending(void);
+static int snt_sim_puts(const char *, int);
+static int snt_sim_getc(void);
+static int snt_sim_input_pending(void);
+static int snt_intr_getc(void);
+static int snt_intr_input_pending(void);
+static void sn_intr_transmit_chars(void);
+
+/* A table for polling */
+static struct sn_sal_ops poll_ops = {
+	.sal_puts		= snt_hw_puts,
+	.sal_getc		= snt_poll_getc,
+	.sal_input_pending	= snt_poll_input_pending
+};
+
+/* A table for the simulator */
+static struct sn_sal_ops sim_ops = {
+	.sal_puts		= snt_sim_puts,
+	.sal_getc		= snt_sim_getc,
+	.sal_input_pending	= snt_sim_input_pending
+};
+
+/* A table for interrupts enabled */
+static struct sn_sal_ops intr_ops = {
+	.sal_puts		= snt_hw_puts,
+	.sal_getc		= snt_intr_getc,
+	.sal_input_pending	= snt_intr_input_pending,
+	.sal_wakeup_transmit	= sn_intr_transmit_chars
+};
+
+
+/* the console does output in two distinctly different ways:
+ * synchronous and asynchronous (buffered).  initally, early_printk
+ * does synchronous output.  any data written goes directly to the SAL
+ * to be output (incidentally, it is internally buffered by the SAL)
+ * after interrupts and timers are initialized and available for use,
+ * the console init code switches to asynchronous output.  this is
+ * also the earliest opportunity to begin polling for console input.
+ * after console initialization, console output and tty (serial port)
+ * output is buffered and sent to the SAL asynchronously (either by
+ * timer callback or by UART interrupt) */
+
+
+/* routines for running the console in polling mode */
+
+static int
+snt_hw_puts(const char *s, int len)
+{
+	/* looking at the PROM source code, putb calls the flush
+	 * routine, so if we send characters in FIFO sized chunks, it
+	 * should go out by the next time the timer gets called */
+	return ia64_sn_console_putb(s, len);
+}
+
+static int
+snt_poll_getc(void)
+{
+	int ch;
+	ia64_sn_console_getc(&ch);
+	return ch;
+}
+
+static int
+snt_poll_input_pending(void)
+{
+	int status, input;
+
+	status = ia64_sn_console_check(&input);
+	return !status && input;
+}
+
+
+/* routines for running the console on the simulator */
+
+static int
+snt_sim_puts(const char *str, int count)
+{
+	int counter = count;
+
+#ifdef FLAG_DIRECT_CONSOLE_WRITES
+	/* This is an easy way to pre-pend the output to know whether the output
+	 * was done via sal or directly */
+	writeb('[', master_node_bedrock_address + (UART_TX << 3));
+	writeb('+', master_node_bedrock_address + (UART_TX << 3));
+	writeb(']', master_node_bedrock_address + (UART_TX << 3));
+	writeb(' ', master_node_bedrock_address + (UART_TX << 3));
+#endif /* FLAG_DIRECT_CONSOLE_WRITES */
+	while (counter > 0) {
+		writeb(*str, master_node_bedrock_address + (UART_TX << 3));
+		counter--;
+		str++;
+	}
+
+	return count;
+}
+
+static int
+snt_sim_getc(void)
+{
+	return readb(master_node_bedrock_address + (UART_RX << 3));
+}
+
+static int
+snt_sim_input_pending(void)
+{
+	return readb(master_node_bedrock_address + (UART_LSR << 3)) & UART_LSR_DR;
+}
+
+
+/* routines for an interrupt driven console (normal) */
+
+static int
+snt_intr_getc(void)
+{
+	return ia64_sn_console_readc();
+}
+
+static int
+snt_intr_input_pending(void)
+{
+	return ia64_sn_console_intr_status() & SAL_CONSOLE_INTR_RECV;
+}
+
+/* The early printk (possible setup) and function call */
+
+void
+early_printk_sn_sal(const char *s, unsigned count)
+{
+	extern void early_sn_setup(void);
+
+	if (!sn_func) {
+		if (IS_RUNNING_ON_SIMULATOR())
+			sn_func = &sim_ops;
+		else
+			sn_func = &poll_ops;
+
+		early_sn_setup();
+	}
+	sn_func->sal_puts(s, count);
+}
+
+/* this is as "close to the metal" as we can get, used when the driver
+ * itself may be broken */
+static int
+sn_debug_printf(const char *fmt, ...)
+{
+	static char printk_buf[1024];
+	int printed_len;
+	va_list args;
+
+	va_start(args, fmt);
+	printed_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
+	early_printk_sn_sal(printk_buf, printed_len);
+	va_end(args);
+	return printed_len;
+}
+
+/*
+ * Interrupt handling routines.
+ */
+
+static void
+sn_sal_sched_event(int event)
+{
+	sn_sal_event |= (1 << event);
+	tasklet_schedule(&sn_sal_tasklet);
+}
+
+/* sn_receive_chars can be called before sn_sal_tty is initialized.  in
+ * that case, its only use is to trigger sysrq and kdb */
+static void
+sn_receive_chars(struct pt_regs *regs, unsigned long *flags)
+{
+	int ch;
+
+	while (sn_func->sal_input_pending()) {
+		ch = sn_func->sal_getc();
+		if (ch < 0) {
+			printk(KERN_ERR "sn_serial: An error occured while "
+			       "obtaining data from the console (0x%0x)\n", ch);
+			break;
+		}
+#if defined(CONFIG_SGI_L1_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+		if (sysrq_requested) {
+			unsigned long sysrq_timeout = sysrq_requested + HZ*5;
+
+			sysrq_requested = 0;
+			if (ch && time_before(jiffies, sysrq_timeout)) {
+				spin_unlock_irqrestore(&sn_sal_lock, *flags);
+				handle_sysrq(ch, regs, NULL);
+				spin_lock_irqsave(&sn_sal_lock, *flags);
+				/* don't record this char */
+				continue;
+			}
+		}
+		if (ch == *sysrq_serial_ptr) {
+			if (!(*++sysrq_serial_ptr)) {
+				sysrq_requested = jiffies;
+				sysrq_serial_ptr = sysrq_serial_str;
+			}
+		}
+		else
+			sysrq_serial_ptr = sysrq_serial_str;
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE && CONFIG_MAGIC_SYSRQ */
+
+		/* record the character to pass up to the tty layer */
+		if (sn_sal_tty) {
+			*sn_sal_tty->flip.char_buf_ptr = ch;
+			sn_sal_tty->flip.char_buf_ptr++;
+			sn_sal_tty->flip.count++;
+			if (sn_sal_tty->flip.count == TTY_FLIPBUF_SIZE)
+				break;
+		}
+		sn_total_rx_count++;
+	}
+
+	if (sn_sal_tty)
+		tty_flip_buffer_push((struct tty_struct *)sn_sal_tty);
+}
+
+
+/* synch_flush_xmit must be called with sn_sal_lock */
+static void
+synch_flush_xmit(void)
+{
+	int xmit_count, tail, head, loops, ii;
+	int result;
+	char *start;
+
+	if (xmit.cb_head == xmit.cb_tail)
+		return; /* Nothing to do. */
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	/* twice around gets the tail to the end of the buffer and
+	 * then to the head, if needed */
+	loops = (head < tail) ? 2 : 1;
+
+	for (ii = 0; ii < loops; ii++) {
+		xmit_count = (head < tail) ?  (SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+		if (xmit_count > 0) {
+			result = sn_func->sal_puts((char *)start, xmit_count);
+			if (!result)
+				sn_debug_printf("\n*** synch_flush_xmit failed to flush\n");
+			if (result > 0) {
+				xmit_count -= result;
+				sn_total_tx_count += result;
+				tail += result;
+				tail &= SN_SAL_BUFFER_SIZE - 1;
+				xmit.cb_tail = tail;
+				start = (char *)&xmit.cb_buf[tail];
+			}
+		}
+	}
+}
+
+/* must be called with a lock protecting the circular buffer and
+ * sn_sal_tty */
+static void
+sn_poll_transmit_chars(void)
+{
+	int xmit_count, tail, head;
+	int result;
+	char *start;
+
+	BUG_ON(!sn_sal_is_asynch);
+
+	if (xmit.cb_head == xmit.cb_tail ||
+	    (sn_sal_tty && (sn_sal_tty->stopped || sn_sal_tty->hw_stopped))) {
+		/* Nothing to do. */
+		return;
+	}
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	xmit_count = (head < tail) ?  (SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+	if (xmit_count == 0)
+		sn_debug_printf("\n*** empty xmit_count\n");
+
+	/* use the ops, as we could be on the simulator */
+	result = sn_func->sal_puts((char *)start, xmit_count);
+	if (!result)
+		sn_debug_printf("\n*** error in synchronous sal_puts\n");
+	/* XXX chadt clean this up */
+	if (result > 0) {
+		xmit_count -= result;
+		sn_total_tx_count += result;
+		tail += result;
+		tail &= SN_SAL_BUFFER_SIZE - 1;
+		xmit.cb_tail = tail;
+		start = &xmit.cb_buf[tail];
+	}
+
+	/* if there's few enough characters left in the xmit buffer
+	 * that we could stand for the upper layer to send us some
+	 * more, ask for it. */
+	if (sn_sal_tty)
+		if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) < WAKEUP_CHARS)
+			sn_sal_sched_event(SN_SAL_EVENT_WRITE_WAKEUP);
+}
+
+
+/* must be called with a lock protecting the circular buffer and
+ * sn_sal_tty */
+static void
+sn_intr_transmit_chars(void)
+{
+	int xmit_count, tail, head, loops, ii;
+	int result;
+	char *start;
+
+	BUG_ON(!sn_sal_is_asynch);
+
+	if (xmit.cb_head == xmit.cb_tail ||
+	    (sn_sal_tty && (sn_sal_tty->stopped || sn_sal_tty->hw_stopped))) {
+		/* Nothing to do. */
+		return;
+	}
+
+	head = xmit.cb_head;
+	tail = xmit.cb_tail;
+	start = &xmit.cb_buf[tail];
+
+	/* twice around gets the tail to the end of the buffer and
+	 * then to the head, if needed */
+	loops = (head < tail) ? 2 : 1;
+
+	for (ii = 0; ii < loops; ii++) {
+		xmit_count = (head < tail) ?
+			(SN_SAL_BUFFER_SIZE - tail) : (head - tail);
+
+		if (xmit_count > 0) {
+			result = ia64_sn_console_xmit_chars((char *)start, xmit_count);
+#ifdef DEBUG
+			if (!result)
+				sn_debug_printf("`");
+#endif
+			if (result > 0) {
+				xmit_count -= result;
+				sn_total_tx_count += result;
+				tail += result;
+				tail &= SN_SAL_BUFFER_SIZE - 1;
+				xmit.cb_tail = tail;
+				start = &xmit.cb_buf[tail];
+			}
+		}
+	}
+
+	/* if there's few enough characters left in the xmit buffer
+	 * that we could stand for the upper layer to send us some
+	 * more, ask for it. */
+	if (sn_sal_tty)
+		if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) < WAKEUP_CHARS)
+			sn_sal_sched_event(SN_SAL_EVENT_WRITE_WAKEUP);
+}
+
+
+static irqreturn_t
+sn_sal_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	/* this call is necessary to pass the interrupt back to the
+	 * SAL, since it doesn't intercept the UART interrupts
+	 * itself */
+	int status = ia64_sn_console_intr_status();
+	unsigned long flags;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (status & SAL_CONSOLE_INTR_RECV)
+		sn_receive_chars(regs, &flags);
+	if (status & SAL_CONSOLE_INTR_XMIT)
+		sn_intr_transmit_chars();
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+	return IRQ_HANDLED;
+}
+
+
+/* returns the console irq if interrupt is successfully registered,
+ * else 0 */
+static int
+sn_sal_connect_interrupt(void)
+{
+	cpuid_t intr_cpuid;
+	unsigned int intr_cpuloc;
+	nasid_t console_nasid;
+	unsigned int console_irq;
+	int result;
+
+	console_nasid = ia64_sn_get_console_nasid();
+	intr_cpuid = NODEPDA(NASID_TO_COMPACT_NODEID(console_nasid))->node_first_cpu;
+	intr_cpuloc = cpu_physical_id(intr_cpuid);
+	console_irq = CPU_VECTOR_TO_IRQ(intr_cpuloc, SGI_UART_VECTOR);
+
+	result = intr_connect_level(intr_cpuid, SGI_UART_VECTOR);
+	BUG_ON(result != SGI_UART_VECTOR);
+
+	result = request_irq(console_irq, sn_sal_interrupt, SA_INTERRUPT,  "SAL console driver", &sn_sal_tty);
+	if (result >= 0)
+		return console_irq;
+
+	printk(KERN_INFO "sn_serial: console proceeding in polled mode\n");
+	return 0;
+}
+
+static void
+sn_sal_tasklet_action(unsigned long data)
+{
+	unsigned long flags;
+
+	if (sn_sal_tty) {
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		if (sn_sal_tty) {
+			if (test_and_clear_bit(SN_SAL_EVENT_WRITE_WAKEUP, &sn_sal_event)) {
+				if ((sn_sal_tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && sn_sal_tty->ldisc.write_wakeup)
+					(sn_sal_tty->ldisc.write_wakeup)((struct tty_struct *)sn_sal_tty);
+				wake_up_interruptible((wait_queue_head_t *)&sn_sal_tty->write_wait);
+			}
+		}
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+
+/*
+ * This function handles polled mode.
+ */
+static void
+sn_sal_timer_poll(unsigned long dummy)
+{
+	unsigned long flags;
+
+	if (!sn_sal_irq) {
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		sn_receive_chars(NULL, &flags);
+		sn_poll_transmit_chars();
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+		mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+	}
+}
+
+
+/*
+ * User-level console routines
+ */
+
+static int
+sn_sal_open(struct tty_struct *tty, struct file *filp)
+{
+	unsigned long flags;
+
+	DPRINTF("sn_sal_open: sn_sal_tty = %p, tty = %p, filp = %p\n",
+		sn_sal_tty, tty, filp);
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (!sn_sal_tty)
+		sn_sal_tty = tty;
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	return 0;
+}
+
+
+/* We're keeping all our resources.  We're keeping interrupts turned
+ * on.  Maybe just let the tty layer finish its stuff...? GMSH
+ */
+static void
+sn_sal_close(struct tty_struct *tty, struct file * filp)
+{
+	if (tty->count == 1) {
+		unsigned long flags;
+		tty->closing = 1;
+		if (tty->driver->flush_buffer)
+			tty->driver->flush_buffer(tty);
+		if (tty->ldisc.flush_buffer)
+			tty->ldisc.flush_buffer(tty);
+		tty->closing = 0;
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		sn_sal_tty = NULL;
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+
+static int
+sn_sal_write(struct tty_struct *tty, int from_user,
+	     const unsigned char *buf, int count)
+{
+	int c, ret = 0;
+	unsigned long flags;
+
+	if (from_user) {
+		while (1) {
+			int c1;
+			c = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail,
+					      SN_SAL_BUFFER_SIZE);
+
+			if (count < c)
+				c = count;
+			if (c <= 0)
+				break;
+
+			c -= copy_from_user(sn_tmp_buffer, buf, c);
+			if (!c) {
+				if (!ret)
+					ret = -EFAULT;
+				break;
+			}
+
+			/* Turn off interrupts and see if the xmit buffer has
+			 * moved since the last time we looked.
+			 */
+			spin_lock_irqsave(&sn_sal_lock, flags);
+			c1 = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+
+			if (c1 < c)
+				c = c1;
+
+			memcpy(xmit.cb_buf + xmit.cb_head, sn_tmp_buffer, c);
+			xmit.cb_head = ((xmit.cb_head + c) & (SN_SAL_BUFFER_SIZE - 1));
+			spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+			buf += c;
+			count -= c;
+			ret += c;
+		}
+	}
+	else {
+		/* The buffer passed in isn't coming from userland,
+		 * so cut out the middleman (sn_tmp_buffer).
+		 */
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		while (1) {
+			c = CIRC_SPACE_TO_END(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+
+			if (count < c)
+				c = count;
+			if (c <= 0) {
+				break;
+			}
+			memcpy(xmit.cb_buf + xmit.cb_head, buf, c);
+			xmit.cb_head = ((xmit.cb_head + c) & (SN_SAL_BUFFER_SIZE - 1));
+			buf += c;
+			count -= c;
+			ret += c;
+		}
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (xmit.cb_head != xmit.cb_tail && !(tty && (tty->stopped || tty->hw_stopped)))
+		if (sn_func->sal_wakeup_transmit)
+			sn_func->sal_wakeup_transmit();
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	return ret;
+}
+
+
+static void
+sn_sal_put_char(struct tty_struct *tty, unsigned char ch)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (CIRC_SPACE(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE) != 0) {
+		xmit.cb_buf[xmit.cb_head] = ch;
+		xmit.cb_head = (xmit.cb_head + 1) & (SN_SAL_BUFFER_SIZE-1);
+		if ( sn_func->sal_wakeup_transmit )
+			sn_func->sal_wakeup_transmit();
+	}
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+
+static void
+sn_sal_flush_chars(struct tty_struct *tty)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	if (CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE))
+		if (sn_func->sal_wakeup_transmit)
+			sn_func->sal_wakeup_transmit();
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+
+static int
+sn_sal_write_room(struct tty_struct *tty)
+{
+	unsigned long flags;
+	int space;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	space = CIRC_SPACE(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+	return space;
+}
+
+
+static int
+sn_sal_chars_in_buffer(struct tty_struct *tty)
+{
+	unsigned long flags;
+	int space;
+
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	space = CIRC_CNT(xmit.cb_head, xmit.cb_tail, SN_SAL_BUFFER_SIZE);
+	DPRINTF("<%d>", space);
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+	return space;
+}
+
+
+static void
+sn_sal_flush_buffer(struct tty_struct *tty)
+{
+	unsigned long flags;
+
+	/* drop everything */
+	spin_lock_irqsave(&sn_sal_lock, flags);
+	xmit.cb_head = xmit.cb_tail = 0;
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+
+	/* wake up tty level */
+	wake_up_interruptible(&tty->write_wait);
+	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup)
+		(tty->ldisc.write_wakeup)(tty);
+}
+
+
+static void
+sn_sal_hangup(struct tty_struct *tty)
+{
+	sn_sal_flush_buffer(tty);
+}
+
+
+static void
+sn_sal_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+	/* this is SAL's problem */
+	DPRINTF("<sn_serial: should wait until sent>");
+}
+
+
+/*
+ * sn_sal_read_proc
+ *
+ * Console /proc interface
+ */
+
+static int
+sn_sal_read_proc(char *page, char **start, off_t off, int count,
+		   int *eof, void *data)
+{
+	int len = 0;
+	off_t	begin = 0;
+
+	len += sprintf(page, "sn_serial: nasid:%d irq:%d tx:%d rx:%d\n",
+		       get_console_nasid(), sn_sal_irq,
+		       sn_total_tx_count, sn_total_rx_count);
+	*eof = 1;
+
+	if (off >= len+begin)
+		return 0;
+	*start = page + (off-begin);
+
+	return count < begin+len-off ? count : begin+len-off;
+}
+
+
+static struct tty_operations sn_sal_driver_ops = {
+	.open		 = sn_sal_open,
+	.close		 = sn_sal_close,
+	.write		 = sn_sal_write,
+	.put_char	 = sn_sal_put_char,
+	.flush_chars	 = sn_sal_flush_chars,
+	.write_room	 = sn_sal_write_room,
+	.chars_in_buffer = sn_sal_chars_in_buffer,
+	.hangup		 = sn_sal_hangup,
+	.wait_until_sent = sn_sal_wait_until_sent,
+	.read_proc	 = sn_sal_read_proc,
+};
+static struct tty_driver *sn_sal_driver;
+
+/* sn_sal_init wishlist:
+ * - allocate sn_tmp_buffer
+ * - fix up the tty_driver struct
+ * - turn on receive interrupts
+ * - do any termios twiddling once and for all
+ */
+
+/*
+ * Boot-time initialization code
+ */
+
+static void __init
+sn_sal_switch_to_asynch(void)
+{
+	unsigned long flags;
+
+	sn_debug_printf("sn_serial: about to switch to asynchronous console\n");
+
+	/* without early_printk, we may be invoked late enough to race
+	 * with other cpus doing console IO at this point, however
+	 * console interrupts will never be enabled */
+	spin_lock_irqsave(&sn_sal_lock, flags);
+
+	/* early_printk invocation may have done this for us */
+	if (!sn_func) {
+		if (IS_RUNNING_ON_SIMULATOR())
+			sn_func = &sim_ops;
+		else
+			sn_func = &poll_ops;
+	}
+
+	/* we can't turn on the console interrupt (as request_irq
+	 * calls kmalloc, which isn't set up yet), so we rely on a
+	 * timer to poll for input and push data from the console
+	 * buffer.
+	 */
+	init_timer(&sn_sal_timer);
+	sn_sal_timer.function = sn_sal_timer_poll;
+
+	if (IS_RUNNING_ON_SIMULATOR())
+		sn_interrupt_timeout = 6;
+	else {
+		/* 960cps / 16 char FIFO = 60HZ 
+		 * HZ / (SN_SAL_FIFO_SPEED_CPS / SN_SAL_FIFO_DEPTH) */
+		sn_interrupt_timeout = HZ * SN_SAL_UART_FIFO_DEPTH / SN_SAL_UART_FIFO_SPEED_CPS;
+	}
+	mod_timer(&sn_sal_timer, jiffies + sn_interrupt_timeout);
+
+	sn_sal_is_asynch = 1;
+	spin_unlock_irqrestore(&sn_sal_lock, flags);
+}
+
+static void __init
+sn_sal_switch_to_interrupts(void)
+{
+	int irq;
+
+	sn_debug_printf("sn_serial: switching to interrupt driven console\n");
+
+	irq = sn_sal_connect_interrupt();
+	if (irq) {
+		unsigned long flags;
+		spin_lock_irqsave(&sn_sal_lock, flags);
+
+		/* sn_sal_irq is a global variable.  When it's set to
+		 * a non-zero value, we stop polling for input (since
+		 * interrupts should now be enabled). */
+		sn_sal_irq = irq;
+		sn_func = &intr_ops;
+
+		/* turn on receive interrupts */
+		ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+	}
+}
+
+static int __init
+sn_sal_module_init(void)
+{
+	int retval;
+
+	printk("sn_serial: sn_sal_module_init\n");
+
+	if (!ia64_platform_is("sn2"))
+		return -ENODEV;
+
+	sn_sal_driver = alloc_tty_driver(1);
+	if ( !sn_sal_driver )
+		return -ENOMEM;
+
+	sn_sal_driver->owner = THIS_MODULE;
+	sn_sal_driver->driver_name = "sn_serial";
+	sn_sal_driver->name = "ttyS";
+	sn_sal_driver->major = TTY_MAJOR;
+	sn_sal_driver->minor_start = SN_SAL_MINOR;
+	sn_sal_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	sn_sal_driver->subtype = SERIAL_TYPE_NORMAL;
+	sn_sal_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+
+	tty_set_operations(sn_sal_driver, &sn_sal_driver_ops);
+
+	/* when this driver is compiled in, the console initialization
+	 * will have already switched us into asynchronous operation
+	 * before we get here through the module initcalls */
+	if (!sn_sal_is_asynch)
+		sn_sal_switch_to_asynch();
+
+	/* at this point (module_init) we can try to turn on interrupts */
+	if (!IS_RUNNING_ON_SIMULATOR())
+	    sn_sal_switch_to_interrupts();
+
+	sn_sal_driver->init_termios = tty_std_termios;
+	sn_sal_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+
+	if ((retval = tty_register_driver(sn_sal_driver))) {
+		printk(KERN_ERR "sn_serial: Unable to register tty driver\n");
+		return retval;
+	}
+#ifdef CONFIG_SGI_L1_SERIAL_CONSOLE
+	sn_sal_serial_console_init();
+#endif	/* CONFIG_SGI_L1_SERIAL_CONSOLE */
+	return 0;
+}
+
+
+static void __exit
+sn_sal_module_exit(void)
+{
+	del_timer_sync(&sn_sal_timer);
+	tty_unregister_driver(sn_sal_driver);
+	put_tty_driver(sn_sal_driver);
+}
+
+module_init(sn_sal_module_init);
+module_exit(sn_sal_module_exit);
+
+/*
+ * Kernel console definitions
+ */
+
+#ifdef CONFIG_SGI_L1_SERIAL_CONSOLE
+/*
+ * Print a string to the SAL console.  The console_lock must be held
+ * when we get here.
+ */
+static void
+sn_sal_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	BUG_ON(!sn_sal_is_asynch);
+
+	/* somebody really wants this output, might be an
+	 * oops, kdb, panic, etc.  make sure they get it. */
+	if (spin_is_locked(&sn_sal_lock)) {
+		synch_flush_xmit();
+		sn_func->sal_puts(s, count);
+	}
+	else if (in_interrupt()) {
+		spin_lock_irqsave(&sn_sal_lock, flags);
+		synch_flush_xmit();
+		spin_unlock_irqrestore(&sn_sal_lock, flags);
+		sn_func->sal_puts(s, count);
+	}
+	else
+		sn_sal_write(NULL, 0, s, count);
+}
+
+static struct tty_driver *
+sn_sal_console_device(struct console *c, int *index)
+{
+	*index = c->index;
+	return sn_sal_driver;
+}
+
+static int __init
+sn_sal_console_setup(struct console *co, char *options)
+{
+	return 0;
+}
+
+
+static struct console sal_console = {
+	.name = "ttyS",
+	.write = sn_sal_console_write,
+	.device = sn_sal_console_device,
+	.setup = sn_sal_console_setup,
+	.index = -1
+};
+
+static void __init
+sn_sal_serial_console_init(void)
+{
+	if (ia64_platform_is("sn2")) {
+		sn_sal_switch_to_asynch();
+		sn_debug_printf("sn_sal_serial_console_init : register console\n");
+		register_console(&sal_console);
+	}
+}
+
+#endif /* CONFIG_SGI_L1_SERIAL_CONSOLE */