drivers/tty/hvc/hvc_opal.c - maze/linux - Git at Google

 /*
  * opal driver interface to hvc_console.c
  *
  * Copyright 2011 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  *
  */

 #undef DEBUG

 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/console.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/export.h>

 #include <asm/hvconsole.h>
 #include <asm/prom.h>
 #include <asm/firmware.h>
 #include <asm/hvsi.h>
 #include <asm/udbg.h>
 #include <asm/opal.h>

 #include "hvc_console.h"

 static const char hvc_opal_name[] = "hvc_opal";

 static struct of_device_id hvc_opal_match[] __devinitdata = {
 	{ .name = "serial", .compatible = "ibm,opal-console-raw" },
 	{ .name = "serial", .compatible = "ibm,opal-console-hvsi" },
 	{ },
 };

 typedef enum hv_protocol {
 	HV_PROTOCOL_RAW,
 	HV_PROTOCOL_HVSI
 } hv_protocol_t;

 struct hvc_opal_priv {
 	hv_protocol_t		proto;	/* Raw data or HVSI packets */
 	struct hvsi_priv	hvsi;	/* HVSI specific data */
 };
 static struct hvc_opal_priv *hvc_opal_privs[MAX_NR_HVC_CONSOLES];

 /* For early boot console */
 static struct hvc_opal_priv hvc_opal_boot_priv;
 static u32 hvc_opal_boot_termno;

 static const struct hv_ops hvc_opal_raw_ops = {
 	.get_chars = opal_get_chars,
 	.put_chars = opal_put_chars,
 	.notifier_add = notifier_add_irq,
 	.notifier_del = notifier_del_irq,
 	.notifier_hangup = notifier_hangup_irq,
 };

 static int hvc_opal_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

 	if (WARN_ON(!pv))
 		return -ENODEV;

 	return hvsilib_get_chars(&pv->hvsi, buf, count);
 }

 static int hvc_opal_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

 	if (WARN_ON(!pv))
 		return -ENODEV;

 	return hvsilib_put_chars(&pv->hvsi, buf, count);
 }

 static int hvc_opal_hvsi_open(struct hvc_struct *hp, int data)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
 	int rc;

 	pr_devel("HVSI@%x: do open !\n", hp->vtermno);

 	rc = notifier_add_irq(hp, data);
 	if (rc)
 		return rc;

 	return hvsilib_open(&pv->hvsi, hp);
 }

 static void hvc_opal_hvsi_close(struct hvc_struct *hp, int data)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

 	pr_devel("HVSI@%x: do close !\n", hp->vtermno);

 	hvsilib_close(&pv->hvsi, hp);

 	notifier_del_irq(hp, data);
 }

 void hvc_opal_hvsi_hangup(struct hvc_struct *hp, int data)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

 	pr_devel("HVSI@%x: do hangup !\n", hp->vtermno);

 	hvsilib_close(&pv->hvsi, hp);

 	notifier_hangup_irq(hp, data);
 }

 static int hvc_opal_hvsi_tiocmget(struct hvc_struct *hp)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

 	if (!pv)
 		return -EINVAL;
 	return pv->hvsi.mctrl;
 }

 static int hvc_opal_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
 				unsigned int clear)
 {
 	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

 	pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
 		 hp->vtermno, set, clear);

 	if (set & TIOCM_DTR)
 		hvsilib_write_mctrl(&pv->hvsi, 1);
 	else if (clear & TIOCM_DTR)
 		hvsilib_write_mctrl(&pv->hvsi, 0);

 	return 0;
 }

 static const struct hv_ops hvc_opal_hvsi_ops = {
 	.get_chars = hvc_opal_hvsi_get_chars,
 	.put_chars = hvc_opal_hvsi_put_chars,
 	.notifier_add = hvc_opal_hvsi_open,
 	.notifier_del = hvc_opal_hvsi_close,
 	.notifier_hangup = hvc_opal_hvsi_hangup,
 	.tiocmget = hvc_opal_hvsi_tiocmget,
 	.tiocmset = hvc_opal_hvsi_tiocmset,
 };

 static int __devinit hvc_opal_probe(struct platform_device *dev)
 {
 	const struct hv_ops *ops;
 	struct hvc_struct *hp;
 	struct hvc_opal_priv *pv;
 	hv_protocol_t proto;
 	unsigned int termno, boot = 0;
 	const __be32 *reg;

 	if (of_device_is_compatible(dev->dev.of_node, "ibm,opal-console-raw")) {
 		proto = HV_PROTOCOL_RAW;
 		ops = &hvc_opal_raw_ops;
 	} else if (of_device_is_compatible(dev->dev.of_node,
 					   "ibm,opal-console-hvsi")) {
 		proto = HV_PROTOCOL_HVSI;
 		ops = &hvc_opal_hvsi_ops;
 	} else {
 		pr_err("hvc_opal: Unkown protocol for %s\n",
 		       dev->dev.of_node->full_name);
 		return -ENXIO;
 	}

 	reg = of_get_property(dev->dev.of_node, "reg", NULL);
 	termno = reg ? be32_to_cpup(reg) : 0;

 	/* Is it our boot one ? */
 	if (hvc_opal_privs[termno] == &hvc_opal_boot_priv) {
 		pv = hvc_opal_privs[termno];
 		boot = 1;
 	} else if (hvc_opal_privs[termno] == NULL) {
 		pv = kzalloc(sizeof(struct hvc_opal_priv), GFP_KERNEL);
 		if (!pv)
 			return -ENOMEM;
 		pv->proto = proto;
 		hvc_opal_privs[termno] = pv;
 		if (proto == HV_PROTOCOL_HVSI)
 			hvsilib_init(&pv->hvsi, opal_get_chars, opal_put_chars,
 				     termno, 0);

 		/* Instanciate now to establish a mapping index==vtermno */
 		hvc_instantiate(termno, termno, ops);
 	} else {
 		pr_err("hvc_opal: Device %s has duplicate terminal number #%d\n",
 		       dev->dev.of_node->full_name, termno);
 		return -ENXIO;
 	}

 	pr_info("hvc%d: %s protocol on %s%s\n", termno,
 		proto == HV_PROTOCOL_RAW ? "raw" : "hvsi",
 		dev->dev.of_node->full_name,
 		boot ? " (boot console)" : "");

 	/* We don't do IRQ yet */
 	hp = hvc_alloc(termno, 0, ops, MAX_VIO_PUT_CHARS);
 	if (IS_ERR(hp))
 		return PTR_ERR(hp);
 	dev_set_drvdata(&dev->dev, hp);

 	return 0;
 }

 static int __devexit hvc_opal_remove(struct platform_device *dev)
 {
 	struct hvc_struct *hp = dev_get_drvdata(&dev->dev);
 	int rc, termno;

 	termno = hp->vtermno;
 	rc = hvc_remove(hp);
 	if (rc == 0) {
 		if (hvc_opal_privs[termno] != &hvc_opal_boot_priv)
 			kfree(hvc_opal_privs[termno]);
 		hvc_opal_privs[termno] = NULL;
 	}
 	return rc;
 }

 static struct platform_driver hvc_opal_driver = {
 	.probe		= hvc_opal_probe,
 	.remove		= __devexit_p(hvc_opal_remove),
 	.driver		= {
 		.name	= hvc_opal_name,
 		.owner	= THIS_MODULE,
 		.of_match_table	= hvc_opal_match,
 	}
 };

 static int __init hvc_opal_init(void)
 {
 	if (!firmware_has_feature(FW_FEATURE_OPAL))
 		return -ENODEV;

 	/* Register as a vio device to receive callbacks */
 	return platform_driver_register(&hvc_opal_driver);
 }
 module_init(hvc_opal_init);

 static void __exit hvc_opal_exit(void)
 {
 	platform_driver_unregister(&hvc_opal_driver);
 }
 module_exit(hvc_opal_exit);

 static void udbg_opal_putc(char c)
 {
 	unsigned int termno = hvc_opal_boot_termno;
 	int count = -1;

 	if (c == '\n')
 		udbg_opal_putc('\r');

 	do {
 		switch(hvc_opal_boot_priv.proto) {
 		case HV_PROTOCOL_RAW:
 			count = opal_put_chars(termno, &c, 1);
 			break;
 		case HV_PROTOCOL_HVSI:
 			count = hvc_opal_hvsi_put_chars(termno, &c, 1);
 			break;
 		}
 	} while(count == 0 || count == -EAGAIN);
 }

 static int udbg_opal_getc_poll(void)
 {
 	unsigned int termno = hvc_opal_boot_termno;
 	int rc = 0;
 	char c;

 	switch(hvc_opal_boot_priv.proto) {
 	case HV_PROTOCOL_RAW:
 		rc = opal_get_chars(termno, &c, 1);
 		break;
 	case HV_PROTOCOL_HVSI:
 		rc = hvc_opal_hvsi_get_chars(termno, &c, 1);
 		break;
 	}
 	if (!rc)
 		return -1;
 	return c;
 }

 static int udbg_opal_getc(void)
 {
 	int ch;
 	for (;;) {
 		ch = udbg_opal_getc_poll();
 		if (ch == -1) {
 			/* This shouldn't be needed...but... */
 			volatile unsigned long delay;
 			for (delay=0; delay < 2000000; delay++)
 				;
 		} else {
 			return ch;
 		}
 	}
 }

 static void udbg_init_opal_common(void)
 {
 	udbg_putc = udbg_opal_putc;
 	udbg_getc = udbg_opal_getc;
 	udbg_getc_poll = udbg_opal_getc_poll;
 	tb_ticks_per_usec = 0x200; /* Make udelay not suck */
 }

 void __init hvc_opal_init_early(void)
 {
 	struct device_node *stdout_node = NULL;
 	const u32 *termno;
 	const char *name = NULL;
 	const struct hv_ops *ops;
 	u32 index;

 	/* find the boot console from /chosen/stdout */
 	if (of_chosen)
 		name = of_get_property(of_chosen, "linux,stdout-path", NULL);
 	if (name) {
 		stdout_node = of_find_node_by_path(name);
 		if (!stdout_node) {
 			pr_err("hvc_opal: Failed to locate default console!\n");
 			return;
 		}
 	} else {
 		struct device_node *opal, *np;

 		/* Current OPAL takeover doesn't provide the stdout
 		 * path, so we hard wire it
 		 */
 		opal = of_find_node_by_path("/ibm,opal/consoles");
 		if (opal)
 			pr_devel("hvc_opal: Found consoles in new location\n");
 		if (!opal) {
 			opal = of_find_node_by_path("/ibm,opal");
 			if (opal)
 				pr_devel("hvc_opal: "
 					 "Found consoles in old location\n");
 		}
 		if (!opal)
 			return;
 		for_each_child_of_node(opal, np) {
 			if (!strcmp(np->name, "serial")) {
 				stdout_node = np;
 				break;
 			}
 		}
 		of_node_put(opal);
 	}
 	if (!stdout_node)
 		return;
 	termno = of_get_property(stdout_node, "reg", NULL);
 	index = termno ? *termno : 0;
 	if (index >= MAX_NR_HVC_CONSOLES)
 		return;
 	hvc_opal_privs[index] = &hvc_opal_boot_priv;

 	/* Check the protocol */
 	if (of_device_is_compatible(stdout_node, "ibm,opal-console-raw")) {
 		hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
 		ops = &hvc_opal_raw_ops;
 		pr_devel("hvc_opal: Found RAW console\n");
 	}
 	else if (of_device_is_compatible(stdout_node,"ibm,opal-console-hvsi")) {
 		hvc_opal_boot_priv.proto = HV_PROTOCOL_HVSI;
 		ops = &hvc_opal_hvsi_ops;
 		hvsilib_init(&hvc_opal_boot_priv.hvsi, opal_get_chars,
 			     opal_put_chars, index, 1);
 		/* HVSI, perform the handshake now */
 		hvsilib_establish(&hvc_opal_boot_priv.hvsi);
 		pr_devel("hvc_opal: Found HVSI console\n");
 	} else
 		goto out;
 	hvc_opal_boot_termno = index;
 	udbg_init_opal_common();
 	add_preferred_console("hvc", index, NULL);
 	hvc_instantiate(index, index, ops);
 out:
 	of_node_put(stdout_node);
 }

 #ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_RAW
 void __init udbg_init_debug_opal_raw(void)
 {
 	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
 	hvc_opal_privs[index] = &hvc_opal_boot_priv;
 	hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
 	hvc_opal_boot_termno = index;
 	udbg_init_opal_common();
 }
 #endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_RAW */

 #ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI
 void __init udbg_init_debug_opal_hvsi(void)
 {
 	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
 	hvc_opal_privs[index] = &hvc_opal_boot_priv;
 	hvc_opal_boot_termno = index;
 	udbg_init_opal_common();
 	hvsilib_init(&hvc_opal_boot_priv.hvsi, opal_get_chars, opal_put_chars,
 		     index, 1);
 	hvsilib_establish(&hvc_opal_boot_priv.hvsi);
 }
 #endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI */
	/*
	* opal driver interface to hvc_console.c
	*
	* Copyright 2011 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#undef DEBUG

	#include <linux/types.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/slab.h>
	#include <linux/console.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/export.h>

	#include <asm/hvconsole.h>
	#include <asm/prom.h>
	#include <asm/firmware.h>
	#include <asm/hvsi.h>
	#include <asm/udbg.h>
	#include <asm/opal.h>

	#include "hvc_console.h"

	static const char hvc_opal_name[] = "hvc_opal";

	static struct of_device_id hvc_opal_match[] __devinitdata = {
	{ .name = "serial", .compatible = "ibm,opal-console-raw" },
	{ .name = "serial", .compatible = "ibm,opal-console-hvsi" },
	{ },
	};

	typedef enum hv_protocol {
	HV_PROTOCOL_RAW,
	HV_PROTOCOL_HVSI
	} hv_protocol_t;

	struct hvc_opal_priv {
	hv_protocol_t proto; /* Raw data or HVSI packets */
	struct hvsi_priv hvsi; /* HVSI specific data */
	};
	static struct hvc_opal_priv *hvc_opal_privs[MAX_NR_HVC_CONSOLES];

	/* For early boot console */
	static struct hvc_opal_priv hvc_opal_boot_priv;
	static u32 hvc_opal_boot_termno;

	static const struct hv_ops hvc_opal_raw_ops = {
	.get_chars = opal_get_chars,
	.put_chars = opal_put_chars,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
	};

	static int hvc_opal_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

	if (WARN_ON(!pv))
	return -ENODEV;

	return hvsilib_get_chars(&pv->hvsi, buf, count);
	}

	static int hvc_opal_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[vtermno];

	if (WARN_ON(!pv))
	return -ENODEV;

	return hvsilib_put_chars(&pv->hvsi, buf, count);
	}

	static int hvc_opal_hvsi_open(struct hvc_struct *hp, int data)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];
	int rc;

	pr_devel("HVSI@%x: do open !\n", hp->vtermno);

	rc = notifier_add_irq(hp, data);
	if (rc)
	return rc;

	return hvsilib_open(&pv->hvsi, hp);
	}

	static void hvc_opal_hvsi_close(struct hvc_struct *hp, int data)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

	pr_devel("HVSI@%x: do close !\n", hp->vtermno);

	hvsilib_close(&pv->hvsi, hp);

	notifier_del_irq(hp, data);
	}

	void hvc_opal_hvsi_hangup(struct hvc_struct *hp, int data)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

	pr_devel("HVSI@%x: do hangup !\n", hp->vtermno);

	hvsilib_close(&pv->hvsi, hp);

	notifier_hangup_irq(hp, data);
	}

	static int hvc_opal_hvsi_tiocmget(struct hvc_struct *hp)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

	if (!pv)
	return -EINVAL;
	return pv->hvsi.mctrl;
	}

	static int hvc_opal_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
	unsigned int clear)
	{
	struct hvc_opal_priv *pv = hvc_opal_privs[hp->vtermno];

	pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
	hp->vtermno, set, clear);

	if (set & TIOCM_DTR)
	hvsilib_write_mctrl(&pv->hvsi, 1);
	else if (clear & TIOCM_DTR)
	hvsilib_write_mctrl(&pv->hvsi, 0);

	return 0;
	}

	static const struct hv_ops hvc_opal_hvsi_ops = {
	.get_chars = hvc_opal_hvsi_get_chars,
	.put_chars = hvc_opal_hvsi_put_chars,
	.notifier_add = hvc_opal_hvsi_open,
	.notifier_del = hvc_opal_hvsi_close,
	.notifier_hangup = hvc_opal_hvsi_hangup,
	.tiocmget = hvc_opal_hvsi_tiocmget,
	.tiocmset = hvc_opal_hvsi_tiocmset,
	};

	static int __devinit hvc_opal_probe(struct platform_device *dev)
	{
	const struct hv_ops *ops;
	struct hvc_struct *hp;
	struct hvc_opal_priv *pv;
	hv_protocol_t proto;
	unsigned int termno, boot = 0;
	const __be32 *reg;

	if (of_device_is_compatible(dev->dev.of_node, "ibm,opal-console-raw")) {
	proto = HV_PROTOCOL_RAW;
	ops = &hvc_opal_raw_ops;
	} else if (of_device_is_compatible(dev->dev.of_node,
	"ibm,opal-console-hvsi")) {
	proto = HV_PROTOCOL_HVSI;
	ops = &hvc_opal_hvsi_ops;
	} else {
	pr_err("hvc_opal: Unkown protocol for %s\n",
	dev->dev.of_node->full_name);
	return -ENXIO;
	}

	reg = of_get_property(dev->dev.of_node, "reg", NULL);
	termno = reg ? be32_to_cpup(reg) : 0;

	/* Is it our boot one ? */
	if (hvc_opal_privs[termno] == &hvc_opal_boot_priv) {
	pv = hvc_opal_privs[termno];
	boot = 1;
	} else if (hvc_opal_privs[termno] == NULL) {
	pv = kzalloc(sizeof(struct hvc_opal_priv), GFP_KERNEL);
	if (!pv)
	return -ENOMEM;
	pv->proto = proto;
	hvc_opal_privs[termno] = pv;
	if (proto == HV_PROTOCOL_HVSI)
	hvsilib_init(&pv->hvsi, opal_get_chars, opal_put_chars,
	termno, 0);

	/* Instanciate now to establish a mapping index==vtermno */
	hvc_instantiate(termno, termno, ops);
	} else {
	pr_err("hvc_opal: Device %s has duplicate terminal number #%d\n",
	dev->dev.of_node->full_name, termno);
	return -ENXIO;
	}

	pr_info("hvc%d: %s protocol on %s%s\n", termno,
	proto == HV_PROTOCOL_RAW ? "raw" : "hvsi",
	dev->dev.of_node->full_name,
	boot ? " (boot console)" : "");

	/* We don't do IRQ yet */
	hp = hvc_alloc(termno, 0, ops, MAX_VIO_PUT_CHARS);
	if (IS_ERR(hp))
	return PTR_ERR(hp);
	dev_set_drvdata(&dev->dev, hp);

	return 0;
	}

	static int __devexit hvc_opal_remove(struct platform_device *dev)
	{
	struct hvc_struct *hp = dev_get_drvdata(&dev->dev);
	int rc, termno;

	termno = hp->vtermno;
	rc = hvc_remove(hp);
	if (rc == 0) {
	if (hvc_opal_privs[termno] != &hvc_opal_boot_priv)
	kfree(hvc_opal_privs[termno]);
	hvc_opal_privs[termno] = NULL;
	}
	return rc;
	}

	static struct platform_driver hvc_opal_driver = {
	.probe = hvc_opal_probe,
	.remove = __devexit_p(hvc_opal_remove),
	.driver = {
	.name = hvc_opal_name,
	.owner = THIS_MODULE,
	.of_match_table = hvc_opal_match,
	}
	};

	static int __init hvc_opal_init(void)
	{
	if (!firmware_has_feature(FW_FEATURE_OPAL))
	return -ENODEV;

	/* Register as a vio device to receive callbacks */
	return platform_driver_register(&hvc_opal_driver);
	}
	module_init(hvc_opal_init);

	static void __exit hvc_opal_exit(void)
	{
	platform_driver_unregister(&hvc_opal_driver);
	}
	module_exit(hvc_opal_exit);

	static void udbg_opal_putc(char c)
	{
	unsigned int termno = hvc_opal_boot_termno;
	int count = -1;

	if (c == '\n')
	udbg_opal_putc('\r');

	do {
	switch(hvc_opal_boot_priv.proto) {
	case HV_PROTOCOL_RAW:
	count = opal_put_chars(termno, &c, 1);
	break;
	case HV_PROTOCOL_HVSI:
	count = hvc_opal_hvsi_put_chars(termno, &c, 1);
	break;
	}
	} while(count == 0 \|\| count == -EAGAIN);
	}

	static int udbg_opal_getc_poll(void)
	{
	unsigned int termno = hvc_opal_boot_termno;
	int rc = 0;
	char c;

	switch(hvc_opal_boot_priv.proto) {
	case HV_PROTOCOL_RAW:
	rc = opal_get_chars(termno, &c, 1);
	break;
	case HV_PROTOCOL_HVSI:
	rc = hvc_opal_hvsi_get_chars(termno, &c, 1);
	break;
	}
	if (!rc)
	return -1;
	return c;
	}

	static int udbg_opal_getc(void)
	{
	int ch;
	for (;;) {
	ch = udbg_opal_getc_poll();
	if (ch == -1) {
	/* This shouldn't be needed...but... */
	volatile unsigned long delay;
	for (delay=0; delay < 2000000; delay++)
	;
	} else {
	return ch;
	}
	}
	}

	static void udbg_init_opal_common(void)
	{
	udbg_putc = udbg_opal_putc;
	udbg_getc = udbg_opal_getc;
	udbg_getc_poll = udbg_opal_getc_poll;
	tb_ticks_per_usec = 0x200; /* Make udelay not suck */
	}

	void __init hvc_opal_init_early(void)
	{
	struct device_node *stdout_node = NULL;
	const u32 *termno;
	const char *name = NULL;
	const struct hv_ops *ops;
	u32 index;

	/* find the boot console from /chosen/stdout */
	if (of_chosen)
	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
	if (name) {
	stdout_node = of_find_node_by_path(name);
	if (!stdout_node) {
	pr_err("hvc_opal: Failed to locate default console!\n");
	return;
	}
	} else {
	struct device_node opal, np;

	/* Current OPAL takeover doesn't provide the stdout
	* path, so we hard wire it
	*/
	opal = of_find_node_by_path("/ibm,opal/consoles");
	if (opal)
	pr_devel("hvc_opal: Found consoles in new location\n");
	if (!opal) {
	opal = of_find_node_by_path("/ibm,opal");
	if (opal)
	pr_devel("hvc_opal: "
	"Found consoles in old location\n");
	}
	if (!opal)
	return;
	for_each_child_of_node(opal, np) {
	if (!strcmp(np->name, "serial")) {
	stdout_node = np;
	break;
	}
	}
	of_node_put(opal);
	}
	if (!stdout_node)
	return;
	termno = of_get_property(stdout_node, "reg", NULL);
	index = termno ? *termno : 0;
	if (index >= MAX_NR_HVC_CONSOLES)
	return;
	hvc_opal_privs[index] = &hvc_opal_boot_priv;

	/* Check the protocol */
	if (of_device_is_compatible(stdout_node, "ibm,opal-console-raw")) {
	hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
	ops = &hvc_opal_raw_ops;
	pr_devel("hvc_opal: Found RAW console\n");
	}
	else if (of_device_is_compatible(stdout_node,"ibm,opal-console-hvsi")) {
	hvc_opal_boot_priv.proto = HV_PROTOCOL_HVSI;
	ops = &hvc_opal_hvsi_ops;
	hvsilib_init(&hvc_opal_boot_priv.hvsi, opal_get_chars,
	opal_put_chars, index, 1);
	/* HVSI, perform the handshake now */
	hvsilib_establish(&hvc_opal_boot_priv.hvsi);
	pr_devel("hvc_opal: Found HVSI console\n");
	} else
	goto out;
	hvc_opal_boot_termno = index;
	udbg_init_opal_common();
	add_preferred_console("hvc", index, NULL);
	hvc_instantiate(index, index, ops);
	out:
	of_node_put(stdout_node);
	}

	#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_RAW
	void __init udbg_init_debug_opal_raw(void)
	{
	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
	hvc_opal_privs[index] = &hvc_opal_boot_priv;
	hvc_opal_boot_priv.proto = HV_PROTOCOL_RAW;
	hvc_opal_boot_termno = index;
	udbg_init_opal_common();
	}
	#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_RAW */

	#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI
	void __init udbg_init_debug_opal_hvsi(void)
	{
	u32 index = CONFIG_PPC_EARLY_DEBUG_OPAL_VTERMNO;
	hvc_opal_privs[index] = &hvc_opal_boot_priv;
	hvc_opal_boot_termno = index;
	udbg_init_opal_common();
	hvsilib_init(&hvc_opal_boot_priv.hvsi, opal_get_chars, opal_put_chars,
	index, 1);
	hvsilib_establish(&hvc_opal_boot_priv.hvsi);
	}
	#endif /* CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI */