viocons.c

/* -*- linux-c -*-
 *
 *  drivers/char/viocons.c
 *
 *  iSeries Virtual Terminal
 *
 *  Authors: Dave Boutcher <boutcher@us.ibm.com>
 *           Ryan Arnold <ryanarn@us.ibm.com>
 *           Colin Devilbiss <devilbis@us.ibm.com>
 *           Stephen Rothwell <sfr@au1.ibm.com>
 *
 * (C) Copyright 2000, 2001, 2002, 2003, 2004 IBM Corporation
 *
 * 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) anyu 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
 */
#include <linux/config.h>
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <asm/ioctls.h>
#include <linux/kd.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/sysrq.h>

#include <asm/iSeries/vio.h>

#include <asm/iSeries/HvLpEvent.h>
#include <asm/iSeries/HvCallEvent.h>
#include <asm/iSeries/HvLpConfig.h>
#include <asm/iSeries/HvCall.h>

#ifdef CONFIG_VT
#error You must turn off CONFIG_VT to use CONFIG_VIOCONS
#endif

#define VIOTTY_MAGIC (0x0DCB)
#define VTTY_PORTS 10

#define VIOCONS_KERN_WARN	KERN_WARNING "viocons: "
#define VIOCONS_KERN_INFO	KERN_INFO "viocons: "

static DEFINE_SPINLOCK(consolelock);
static DEFINE_SPINLOCK(consoleloglock);

#ifdef CONFIG_MAGIC_SYSRQ
static int vio_sysrq_pressed;
extern int sysrq_enabled;
#endif

/*
 * The structure of the events that flow between us and OS/400.  You can't
 * mess with this unless the OS/400 side changes too
 */
struct viocharlpevent {
	struct HvLpEvent event;
	u32 reserved;
	u16 version;
	u16 subtype_result_code;
	u8 virtual_device;
	u8 len;
	u8 data[VIOCHAR_MAX_DATA];
};

#define VIOCHAR_WINDOW		10
#define VIOCHAR_HIGHWATERMARK	3

enum viocharsubtype {
	viocharopen = 0x0001,
	viocharclose = 0x0002,
	viochardata = 0x0003,
	viocharack = 0x0004,
	viocharconfig = 0x0005
};

enum viochar_rc {
	viochar_rc_ebusy = 1
};

#define VIOCHAR_NUM_BUF		16

/*
 * Our port information.  We store a pointer to one entry in the
 * tty_driver_data
 */
static struct port_info {
	int magic;
	struct tty_struct *tty;
	HvLpIndex lp;
	u8 vcons;
	u64 seq;	/* sequence number of last HV send */
	u64 ack;	/* last ack from HV */
/*
 * When we get writes faster than we can send it to the partition,
 * buffer the data here. Note that used is a bit map of used buffers.
 * It had better have enough bits to hold VIOCHAR_NUM_BUF the bitops assume
 * it is a multiple of unsigned long
 */
	unsigned long used;
	u8 *buffer[VIOCHAR_NUM_BUF];
	int bufferBytes[VIOCHAR_NUM_BUF];
	int curbuf;
	int bufferOverflow;
	int overflowMessage;
} port_info[VTTY_PORTS];

#define viochar_is_console(pi)	((pi) == &port_info[0])
#define viochar_port(pi)	((pi) - &port_info[0])

static void initDataEvent(struct viocharlpevent *viochar, HvLpIndex lp);

static struct tty_driver *viotty_driver;

void hvlog(char *fmt, ...)
{
	int i;
	unsigned long flags;
	va_list args;
	static char buf[256];

	spin_lock_irqsave(&consoleloglock, flags);
	va_start(args, fmt);
	i = vscnprintf(buf, sizeof(buf) - 1, fmt, args);
	va_end(args);
	buf[i++] = '\r';
	HvCall_writeLogBuffer(buf, i);
	spin_unlock_irqrestore(&consoleloglock, flags);
}

void hvlogOutput(const char *buf, int count)
{
	unsigned long flags;
	int begin;
	int index;
	static const char cr = '\r';

	begin = 0;
	spin_lock_irqsave(&consoleloglock, flags);
	for (index = 0; index < count; index++) {
		if (buf[index] == '\n') {
			/*
			 * Start right after the last '\n' or at the zeroth
			 * array position and output the number of characters
			 * including the newline.
			 */
			HvCall_writeLogBuffer(&buf[begin], index - begin + 1);
			begin = index + 1;
			HvCall_writeLogBuffer(&cr, 1);
		}
	}
	if ((index - begin) > 0)
		HvCall_writeLogBuffer(&buf[begin], index - begin);
	spin_unlock_irqrestore(&consoleloglock, flags);
}

/*
 * Make sure we're pointing to a valid port_info structure.  Shamelessly
 * plagerized from serial.c
 */
static inline int viotty_paranoia_check(struct port_info *pi,
					char *name, const char *routine)
{
	static const char *bad_pi_addr = VIOCONS_KERN_WARN
		"warning: bad address for port_info struct (%s) in %s\n";
	static const char *badmagic = VIOCONS_KERN_WARN
		"warning: bad magic number for port_info struct (%s) in %s\n";

	if ((pi < &port_info[0]) || (viochar_port(pi) > VTTY_PORTS)) {
		printk(bad_pi_addr, name, routine);
		return 1;
	}
	if (pi->magic != VIOTTY_MAGIC) {
		printk(badmagic, name, routine);
		return 1;
	}
	return 0;
}

/*