sio.c

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/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)com.c	7.5 (Berkeley) 5/16/91
 *	$\Id: sio.c,v 1.99.4.5 1996-11-15 16:36:37-07 jkh Exp $
 */

#include "sio.h"
#if NSIO > 0
/*
 * Serial driver, based on 386BSD-0.1 com driver.
 * Mostly rewritten to use pseudo-DMA.
 * Works for National Semiconductor NS8250-NS16550AF UARTs.
 * COM driver, based on HP dca driver.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/reboot.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/conf.h>
#include <sys/dkstat.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/devconf.h>
#include <sys/interrupt.h>

#include <machine/clock.h>

#include <i386/isa/icu.h>	/* XXX just to get at `imen' */
#include <i386/isa/isa.h>
#include <i386/isa/isa_device.h>
#include <i386/isa/sioreg.h>
#include <i386/isa/ic/ns16550.h>

#define	LOTS_OF_EVENTS	64	/* helps separate urgent events from input */
#define	RB_I_HIGH_WATER	(TTYHOG - 2 * RS_IBUFSIZE)
#define	RS_IBUFSIZE	256

#define	CALLOUT_MASK		0x80
#define	CONTROL_MASK		0x60
#define	CONTROL_INIT_STATE	0x20
#define	CONTROL_LOCK_STATE	0x40
#define	DEV_TO_UNIT(dev)	(MINOR_TO_UNIT(minor(dev)))
#define	MINOR_MAGIC_MASK	(CALLOUT_MASK | CONTROL_MASK)
#define	MINOR_TO_UNIT(mynor)	((mynor) & ~MINOR_MAGIC_MASK)

#ifdef COM_MULTIPORT
/* checks in flags for multiport and which is multiport "master chip"
 * for a given card
 */
#define	COM_ISMULTIPORT(dev)	((dev)->id_flags & 0x01)
#define	COM_MPMASTER(dev)	(((dev)->id_flags >> 8) & 0x0ff)
#define	COM_NOTAST4(dev)	((dev)->id_flags & 0x04)
#endif /* COM_MULTIPORT */

#define	COM_LOSESOUTINTS(dev)	((dev)->id_flags & 0x08)
#define	COM_NOFIFO(dev)		((dev)->id_flags & 0x02)
#define	COM_VERBOSE(dev)	((dev)->id_flags & 0x80)

#define	com_scr		7	/* scratch register for 16450-16550 (R/W) */

/*
 * Input buffer watermarks.
 * The external device is asked to stop sending when the buffer exactly reaches
 * high water, or when the high level requests it.
 * The high level is notified immediately (rather than at a later clock tick)
 * when this watermark is reached.
 * The buffer size is chosen so the watermark should almost never be reached.
 * The low watermark is invisibly 0 since the buffer is always emptied all at
 * once.
 */
#define	RS_IHIGHWATER (3 * RS_IBUFSIZE / 4)

/*
 * com state bits.
 * (CS_BUSY | CS_TTGO) and (CS_BUSY | CS_TTGO | CS_ODEVREADY) must be higher
 * than the other bits so that they can be tested as a group without masking
 * off the low bits.
 *
 * The following com and tty flags correspond closely:
 *	CS_BUSY		= TS_BUSY (maintained by comstart(), siopoll() and
 *				   siostop())
 *	CS_TTGO		= ~TS_TTSTOP (maintained by comparam() and comstart())
 *	CS_CTS_OFLOW	= CCTS_OFLOW (maintained by comparam())
 *	CS_RTS_IFLOW	= CRTS_IFLOW (maintained by comparam())
 * TS_FLUSH is not used.
 * XXX I think TIOCSETA doesn't clear TS_TTSTOP when it clears IXON.
 * XXX CS_*FLOW should be CF_*FLOW in com->flags (control flags not state).
 */
#define	CS_BUSY		0x80	/* output in progress */
#define	CS_TTGO		0x40	/* output not stopped by XOFF */
#define	CS_ODEVREADY	0x20	/* external device h/w ready (CTS) */
#define	CS_CHECKMSR	1	/* check of MSR scheduled */
#define	CS_CTS_OFLOW	2	/* use CTS output flow control */
#define	CS_DTR_OFF	0x10	/* DTR held off */
#define	CS_ODONE	4	/* output completed */
#define	CS_RTS_IFLOW	8	/* use RTS input flow control */

static	char const * const	error_desc[] = {
#define	CE_OVERRUN			0
	"silo overflow",
#define	CE_INTERRUPT_BUF_OVERFLOW	1
	"interrupt-level buffer overflow",
#define	CE_TTY_BUF_OVERFLOW		2
	"tty-level buffer overflow",
};

#define	CE_NTYPES			3
#define	CE_RECORD(com, errnum)		(++(com)->delta_error_counts[errnum])

/* types.  XXX - should be elsewhere */
typedef u_int	Port_t;		/* hardware port */
typedef u_char	bool_t;		/* boolean */

/* queue of linear buffers */
struct lbq {
	u_char	*l_head;	/* next char to process */
	u_char	*l_tail;	/* one past the last char to process */
	struct lbq *l_next;	/* next in queue */
	bool_t	l_queued;	/* nonzero if queued */
};

/* com device structure */
struct com_s {
	u_char	state;		/* miscellaneous flag bits */
	bool_t  active_out;	/* nonzero if the callout device is open */
	u_char	cfcr_image;	/* copy of value written to CFCR */
	u_char	ftl;		/* current rx fifo trigger level */
	u_char	ftl_init;	/* ftl_max for next open() */
	u_char	ftl_max;	/* maximum ftl for curent open() */
	bool_t	hasfifo;	/* nonzero for 16550 UARTs */
	bool_t	loses_outints;	/* nonzero if device loses output interrupts */
	u_char	mcr_image;	/* copy of value written to MCR */
#ifdef COM_MULTIPORT
	bool_t	multiport;	/* is this unit part of a multiport device? */
#endif /* COM_MULTIPORT */
	bool_t	no_irq;		/* nonzero if irq is not attached */
	bool_t	poll;		/* nonzero if polling is required */
	bool_t	poll_output;	/* nonzero if polling for output is required */
	int	unit;		/* unit	number */
	int	dtr_wait;	/* time to hold DTR down on close (* 1/hz) */
	u_int	tx_fifo_size;
	u_int	wopeners;	/* # processes waiting for DCD in open() */

	/*
	 * The high level of the driver never reads status registers directly
	 * because there would be too many side effects to handle conveniently.
	 * Instead, it reads copies of the registers stored here by the
	 * interrupt handler.
	 */
	u_char	last_modem_status;	/* last MSR read by intr handler */
	u_char	prev_modem_status;	/* last MSR handled by high level */

	u_char	hotchar;	/* ldisc-specific char to be handled ASAP */
	u_char	*ibuf;		/* start of input buffer */
	u_char	*ibufend;	/* end of input buffer */
	u_char	*ihighwater;	/* threshold in input buffer */
	u_char	*iptr;		/* next free spot in input buffer */

	struct lbq	obufq;	/* head of queue of output buffers */
	struct lbq	obufs[2];	/* output buffers */

	Port_t	data_port;	/* i/o ports */
	Port_t	int_id_port;
	Port_t	iobase;
	Port_t	modem_ctl_port;
	Port_t	line_status_port;
	Port_t	modem_status_port;

	struct tty	*tp;	/* cross reference */

	/* Initial state. */
	struct termios	it_in;	/* should be in struct tty */
	struct termios	it_out;

	/* Lock state. */
	struct termios	lt_in;	/* should be in struct tty */
	struct termios	lt_out;

	bool_t	do_timestamp;
	struct timeval	timestamp;

	u_long	bytes_in;	/* statistics */
	u_long	bytes_out;
	u_int	delta_error_counts[CE_NTYPES];
	u_long	error_counts[CE_NTYPES];

	/*
	 * Ping-pong input buffers.  The extra factor of 2 in the sizes is
	 * to allow for an error byte for each input byte.
	 */
#define	CE_INPUT_OFFSET		RS_IBUFSIZE
	u_char	ibuf1[2 * RS_IBUFSIZE];
	u_char	ibuf2[2 * RS_IBUFSIZE];

	/*
	 * Data area for output buffers.  Someday we should build the output
	 * buffer queue without copying data.
	 */
	u_char	obuf1[256];
	u_char	obuf2[256];
};

/*
 * XXX public functions in drivers should be declared in headers produced
 * by `config', not here.
 */

/* Interrupt handling entry points. */
void	siointr		__P((int unit));
void	siointrts	__P((int unit));
void	siopoll		__P((void));

/* Device switch entry points. */
int	sioopen		__P((dev_t dev, int oflags, int devtype,
			     struct proc *p));
int	sioclose	__P((dev_t dev, int fflag, int devtype,
			     struct proc *p));
int	sioread		__P((dev_t dev, struct uio *uio, int ioflag));
int	siowrite	__P((dev_t dev, struct uio *uio, int ioflag));
int	sioioctl	__P((dev_t dev, int cmd, caddr_t data,
			     int fflag, struct proc *p));
void	siostop		__P((struct tty *tp, int rw));
#define	sioreset	noreset
struct tty *siodevtotty	__P((dev_t dev));
#define	siommap		nommap
#define	siostrategy	nostrategy

static	int	sioattach	__P((struct isa_device *dev));
static	timeout_t siodtrwakeup;
static	void	comhardclose	__P((struct com_s *com));
static	void	siointr1	__P((struct com_s *com));
static	int	commctl		__P((struct com_s *com, int bits, int how));
static	int	comparam	__P((struct tty *tp, struct termios *t));
static	int	sioprobe	__P((struct isa_device *dev));
static	void	sioregisterdev	__P((struct isa_device *id));
static	void	siosettimeout	__P((void));
static	void	comstart	__P((struct tty *tp));
static	timeout_t comwakeup;
static	void	disc_optim	__P((struct tty	*tp, struct termios *t,
				     struct com_s *com));

#ifdef DSI_SOFT_MODEM
static  int 	LoadSoftModem   __P((int unit,int base_io, u_long size, u_char *ptr));
#endif /* DSI_SOFT_MODEM */

/* table and macro for fast conversion from a unit number to its com struct */
static	struct com_s	*p_com_addr[NSIO];
#define	com_addr(unit)	(p_com_addr[unit])

static  struct timeval	intr_timestamp;

struct isa_driver	siodriver = {
	sioprobe, sioattach, "sio"
};

static	int	comconsole = -1;
#ifdef CONSPEED
static speed_t comdefaultrate = CONSPEED;
#else
static	speed_t	comdefaultrate = TTYDEF_SPEED;
#endif
static	u_int	com_events;	/* input chars + weighted output completions */
static	int	commajor;
static	int	sio_timeout;
static	int	sio_timeouts_until_log;
#if 0 /* XXX */
static struct tty	*sio_tty[NSIO];
#else
static struct tty	sio_tty[NSIO];
static	int	nsio_tty = NSIO;
#endif

#ifdef KGDB
#include <machine/remote-sl.h>

extern	int	kgdb_dev;
extern	int	kgdb_rate;
extern	int	kgdb_debug_init;
#endif

static	struct speedtab comspeedtab[] = {
	0,	0,
	50,	COMBRD(50),
	75,	COMBRD(75),
	110,	COMBRD(110),
	134,	COMBRD(134),
	150,	COMBRD(150),
	200,	COMBRD(200),
	300,	COMBRD(300),
	600,	COMBRD(600),
	1200,	COMBRD(1200),
	1800,	COMBRD(1800),
	2400,	COMBRD(2400),
	4800,	COMBRD(4800),
	9600,	COMBRD(9600),
	19200,	COMBRD(19200),
	38400,	COMBRD(38400),
	57600,	COMBRD(57600),
	115200,	COMBRD(115200),
	-1,	-1
};

static struct kern_devconf kdc_sio[NSIO] = { {
	0, 0, 0,		/* filled in by dev_attach */
	"sio", 0, { MDDT_ISA, 0, "tty" },
	isa_generic_externalize, 0, 0, ISA_EXTERNALLEN,
	&kdc_isa0,		/* parent */
	0,			/* parentdata */
	DC_UNCONFIGURED,	/* state */
	"RS-232 serial port",
	DC_CLS_SERIAL		/* class */
} };

static void
sioregisterdev(id)
	struct isa_device *id;
{
	int	unit;

	unit = id->id_unit;
	if (unit != 0)
		kdc_sio[unit] = kdc_sio[0];
	kdc_sio[unit].kdc_unit = unit;
	kdc_sio[unit].kdc_isa = id;
	dev_attach(&kdc_sio[unit]);
}

static int
sioprobe(dev)
	struct isa_device	*dev;
{
	static bool_t	already_init;
	bool_t		failures[10];
	int		fn;
	struct isa_device	*idev;
	Port_t		iobase;
	u_char		mcr_image;
	int		result;
	struct isa_device	*xdev;

	sioregisterdev(dev);

	if (!already_init) {
		/*
		 * Turn off MCR_IENABLE for all likely serial ports.  An unused
		 * port with its MCR_IENABLE gate open will inhibit interrupts
		 * from any used port that shares the interrupt vector.
		 * XXX the gate enable is elsewhere for some multiports.
		 */
		for (xdev = isa_devtab_tty; xdev->id_driver != NULL; xdev++)
			if (xdev->id_driver == &siodriver && xdev->id_enabled)
				outb(xdev->id_iobase + com_mcr, 0);
		already_init = TRUE;
	}

	/*
	 * If the device is on a multiport card and has an AST/4
	 * compatible interrupt control register, initialize this
	 * register and prepare to leave MCR_IENABLE clear in the mcr.
	 * Otherwise, prepare to set MCR_IENABLE in the mcr.
	 * Point idev to the device struct giving the correct id_irq.
	 * This is the struct for the master device if there is one.
	 */
	idev = dev;
	mcr_image = MCR_IENABLE;
#ifdef COM_MULTIPORT
	if (COM_ISMULTIPORT(dev)) {
		idev = find_isadev(isa_devtab_tty, &siodriver,
				   COM_MPMASTER(dev));
		if (idev == NULL) {
			printf("sio%d: master device %d not configured\n",
			       dev->id_unit, COM_MPMASTER(dev));
			return (0);
		}
		if (!COM_NOTAST4(dev)) {
			outb(idev->id_iobase + com_scr,
			     idev->id_irq ? 0x80 : 0);
			mcr_image = 0;
		}
	}
#endif /* COM_MULTIPORT */
	if (idev->id_irq == 0)
		mcr_image = 0;

	bzero(failures, sizeof failures);
	iobase = dev->id_iobase;

	/*
	 * We don't want to get actual interrupts, just masked ones.
	 * Interrupts from this line should already be masked in the ICU,
	 * but mask them in the processor as well in case there are some
	 * (misconfigured) shared interrupts.
	 */
	disable_intr();
/* EXTRA DELAY? */

#ifndef OSKIT
	/*
	 * XXX DELAY() reenables CPU interrupts.  This is a problem for
	 * shared interrupts after the first device using one has been
	 * successfully probed - config_isadev() has enabled the interrupt
	 * in the ICU.
	 */
	outb(IO_ICU1 + 1, 0xff);
#endif /* OSKIT */

	/*
	 * Initialize the speed and the word size and wait long enough to
	 * drain the maximum of 16 bytes of junk in device output queues.
	 * The speed is undefined after a master reset and must be set
	 * before relying on anything related to output.  There may be
	 * junk after a (very fast) soft reboot and (apparently) after
	 * master reset.
	 * XXX what about the UART bug avoided by waiting in comparam()?
	 * We don't want to to wait long enough to drain at 2 bps.
	 */
	outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
	outb(iobase + com_dlbl, COMBRD(9600) & 0xff);
	outb(iobase + com_dlbh, (u_int) COMBRD(9600) >> 8);
	outb(iobase + com_cfcr, CFCR_8BITS);
	DELAY((16 + 1) * 1000000 / (9600 / 10));

	/*
	 * Enable the interrupt gate and disable device interupts.  This
	 * should leave the device driving the interrupt line low and
	 * guarantee an edge trigger if an interrupt can be generated.
	 */
/* EXTRA DELAY? */
	outb(iobase + com_mcr, mcr_image);
	outb(iobase + com_ier, 0);

	/*
	 * Attempt to set loopback mode so that we can send a null byte
	 * without annoying any external device.
	 */
/* EXTRA DELAY? */
	outb(iobase + com_mcr, mcr_image | MCR_LOOPBACK);

	/*
	 * Attempt to generate an output interrupt.  On 8250's, setting
	 * IER_ETXRDY generates an interrupt independent of the current
	 * setting and independent of whether the THR is empty.  On 16450's,
	 * setting IER_ETXRDY generates an interrupt independent of the
	 * current setting.  On 16550A's, setting IER_ETXRDY only
	 * generates an interrupt when IER_ETXRDY is not already set.
	 */
	outb(iobase + com_ier, IER_ETXRDY);

	/*
	 * On some 16x50 incompatibles, setting IER_ETXRDY doesn't generate
	 * an interrupt.  They'd better generate one for actually doing
	 * output.  Loopback may be broken on the same incompatibles but
	 * it's unlikely to do more than allow the null byte out.