con3215.c

linux-2.6.15.6

/*
 *  drivers/s390/char/con3215.c
 *    3215 line mode terminal driver.
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky ([e-mail]),
 *
 *  Updated:
 *   Aug-2000: Added tab support
 *	       Dan Morrison, IBM Corporation ([e-mail])
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/tty.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>

#include <linux/slab.h>
#include <linux/bootmem.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/io.h>
#include <asm/ebcdic.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>

#include "ctrlchar.h"

#define NR_3215		    1
#define NR_3215_REQ	    (4*NR_3215)
#define RAW3215_BUFFER_SIZE 65536     /* output buffer size */
#define RAW3215_INBUF_SIZE  256	      /* input buffer size */
#define RAW3215_MIN_SPACE   128	      /* minimum free space for wakeup */
#define RAW3215_MIN_WRITE   1024      /* min. length for immediate output */
#define RAW3215_MAX_BYTES   3968      /* max. bytes to write with one ssch */
#define RAW3215_MAX_NEWLINE 50	      /* max. lines to write with one ssch */
#define RAW3215_NR_CCWS	    3
#define RAW3215_TIMEOUT	    HZ/10     /* time for delayed output */

#define RAW3215_FIXED	    1	      /* 3215 console device is not be freed */
#define RAW3215_ACTIVE	    2	      /* set if the device is in use */
#define RAW3215_WORKING	    4	      /* set if a request is being worked on */
#define RAW3215_THROTTLED   8	      /* set if reading is disabled */
#define RAW3215_STOPPED	    16	      /* set if writing is disabled */
#define RAW3215_CLOSING	    32	      /* set while in close process */
#define RAW3215_TIMER_RUNS  64	      /* set if the output delay timer is on */
#define RAW3215_FLUSHING    128	      /* set to flush buffer (no delay) */

#define TAB_STOP_SIZE	    8	      /* tab stop size */

/*
 * Request types for a 3215 device
 */
enum raw3215_type {
	RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
};

/*
 * Request structure for a 3215 device
 */
struct raw3215_req {
	enum raw3215_type type;	      /* type of the request */
	int start, len;		      /* start index & len in output buffer */
	int delayable;		      /* indication to wait for more data */
	int residual;		      /* residual count for read request */
	struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
	struct raw3215_info *info;    /* pointer to main structure */
	struct raw3215_req *next;     /* pointer to next request */
} __attribute__ ((aligned(8)));

struct raw3215_info {
	struct ccw_device *cdev;      /* device for tty driver */
	spinlock_t *lock;	      /* pointer to irq lock */
	int flags;		      /* state flags */
	char *buffer;		      /* pointer to output buffer */
	char *inbuf;		      /* pointer to input buffer */
	int head;		      /* first free byte in output buffer */
	int count;		      /* number of bytes in output buffer */
	int written;		      /* number of bytes in write requests */
	struct tty_struct *tty;	      /* pointer to tty structure if present */
	struct tasklet_struct tasklet;
	struct raw3215_req *queued_read; /* pointer to queued read requests */
	struct raw3215_req *queued_write;/* pointer to queued write requests */
	wait_queue_head_t empty_wait; /* wait queue for flushing */
	struct timer_list timer;      /* timer for delayed output */
	char *message;		      /* pending message from raw3215_irq */
	int msg_dstat;		      /* dstat for pending message */
	int msg_cstat;		      /* cstat for pending message */
	int line_pos;		      /* position on the line (for tabs) */
	char ubuffer[80];	      /* copy_from_user buffer */
};

/* array of 3215 devices structures */
static struct raw3215_info *raw3215[NR_3215];
/* spinlock to protect the raw3215 array */
static DEFINE_SPINLOCK(raw3215_device_lock);
/* list of free request structures */
static struct raw3215_req *raw3215_freelist;
/* spinlock to protect free list */
static spinlock_t raw3215_freelist_lock;

static struct tty_driver *tty3215_driver;

/*
 * Get a request structure from the free list
 */
static inline struct raw3215_req *
raw3215_alloc_req(void) {
	struct raw3215_req *req;
	unsigned long flags;

	spin_lock_irqsave(&raw3215_freelist_lock, flags);
	req = raw3215_freelist;
	raw3215_freelist = req->next;
	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
	return req;
}

/*
 * Put a request structure back to the free list
 */
static inline void
raw3215_free_req(struct raw3215_req *req) {
	unsigned long flags;

	if (req->type == RAW3215_FREE)
		return;		/* don't free a free request */
	req->type = RAW3215_FREE;
	spin_lock_irqsave(&raw3215_freelist_lock, flags);
	req->next = raw3215_freelist;
	raw3215_freelist = req;
	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
}

/*
 * Set up a read request that reads up to 160 byte from the 3215 device.
 * If there is a queued read request it is used, but that shouldn't happen
 * because a 3215 terminal won't accept a new read before the old one is
 * completed.
 */
static void
raw3215_mk_read_req(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	struct ccw1 *ccw;

	/* there can only be ONE read request at a time */
	req = raw->queued_read;
	if (req == NULL) {
		/* no queued read request, use new req structure */
		req = raw3215_alloc_req();
		req->type = RAW3215_READ;
		req->info = raw;
		raw->queued_read = req;
	}

	ccw = req->ccws;
	ccw->cmd_code = 0x0A; /* read inquiry */
	ccw->flags = 0x20;    /* ignore incorrect length */
	ccw->count = 160;
	ccw->cda = (__u32) __pa(raw->inbuf);
}

/*
 * Set up a write request with the information from the main structure.
 * A ccw chain is created that writes as much as possible from the output
 * buffer to the 3215 device. If a queued write exists it is replaced by
 * the new, probably lengthened request.
 */
static void
raw3215_mk_write_req(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	struct ccw1 *ccw;
	int len, count, ix, lines;

	if (raw->count <= raw->written)
		return;
	/* check if there is a queued write request */
	req = raw->queued_write;
	if (req == NULL) {
		/* no queued write request, use new req structure */
		req = raw3215_alloc_req();
		req->type = RAW3215_WRITE;
		req->info = raw;
		raw->queued_write = req;
	} else {
		raw->written -= req->len;
	}

	ccw = req->ccws;
	req->start = (raw->head - raw->count + raw->written) &
		     (RAW3215_BUFFER_SIZE - 1);
	/*
	 * now we have to count newlines. We can at max accept
	 * RAW3215_MAX_NEWLINE newlines in a single ssch due to
	 * a restriction in VM
	 */
	lines = 0;
	ix = req->start;
	while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
		if (raw->buffer[ix] == 0x15)
			lines++;
		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
	}
	len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
	if (len > RAW3215_MAX_BYTES)
		len = RAW3215_MAX_BYTES;
	req->len = len;
	raw->written += len;

	/* set the indication if we should try to enlarge this request */
	req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);

	ix = req->start;
	while (len > 0) {
		if (ccw > req->ccws)
			ccw[-1].flags |= 0x40; /* use command chaining */
		ccw->cmd_code = 0x01; /* write, auto carrier return */
		ccw->flags = 0x20;    /* ignore incorrect length ind.  */
		ccw->cda =
			(__u32) __pa(raw->buffer + ix);
		count = len;
		if (ix + count > RAW3215_BUFFER_SIZE)
			count = RAW3215_BUFFER_SIZE - ix;
		ccw->count = count;
		len -= count;
		ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
		ccw++;
	}
	/*
	 * Add a NOP to the channel program. 3215 devices are purely
	 * emulated and its much better to avoid the channel end
	 * interrupt in this case.
	 */
	if (ccw > req->ccws)
		ccw[-1].flags |= 0x40; /* use command chaining */
	ccw->cmd_code = 0x03; /* NOP */
	ccw->flags = 0;
	ccw->cda = 0;
	ccw->count = 1;
}

/*
 * Start a read or a write request
 */
static void
raw3215_start_io(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	int res;

	req = raw->queued_read;
	if (req != NULL &&
	    !(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
		/* dequeue request */
		raw->queued_read = NULL;
		res = ccw_device_start(raw->cdev, req->ccws,
				       (unsigned long) req, 0, 0);
		if (res != 0) {
			/* do_IO failed, put request back to queue */
			raw->queued_read = req;
		} else {
			raw->flags |= RAW3215_WORKING;
		}
	}
	req = raw->queued_write;
	if (req != NULL &&
	    !(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
		/* dequeue request */
		raw->queued_write = NULL;
		res = ccw_device_start(raw->cdev, req->ccws,
				       (unsigned long) req, 0, 0);
		if (res != 0) {
			/* do_IO failed, put request back to queue */
			raw->queued_write = req;
		} else {
			raw->flags |= RAW3215_WORKING;
		}
	}
}

/*
 * Function to start a delayed output after RAW3215_TIMEOUT seconds
 */
static void
raw3215_timeout(unsigned long __data)
{
	struct raw3215_info *raw = (struct raw3215_info *) __data;
	unsigned long flags;

	spin_lock_irqsave(raw->lock, flags);
	if (raw->flags & RAW3215_TIMER_RUNS) {
		del_timer(&raw->timer);
		raw->flags &= ~RAW3215_TIMER_RUNS;
		raw3215_mk_write_req(raw);
		raw3215_start_io(raw);
	}
	spin_unlock_irqrestore(raw->lock, flags);
}

/*
 * Function to conditionally start an IO. A read is started immediately,
 * a write is only started immediately if the flush flag is on or the
 * amount of data is bigger than RAW3215_MIN_WRITE. If a write is not
 * done immediately a timer is started with a delay of RAW3215_TIMEOUT.
 */
static inline void
raw3215_try_io(struct raw3215_info *raw)
{
	if (!(raw->flags & RAW3215_ACTIVE))
		return;
	if (raw->queued_read != NULL)
		raw3215_start_io(raw);
	else if (raw->queued_write != NULL) {
		if ((raw->queued_write->delayable == 0) ||
		    (raw->flags & RAW3215_FLUSHING)) {
			/* execute write requests bigger than minimum size */
			raw3215_start_io(raw);
			if (raw->flags & RAW3215_TIMER_RUNS) {
				del_timer(&raw->timer);
				raw->flags &= ~RAW3215_TIMER_RUNS;
			}
		} else if (!(raw->flags & RAW3215_TIMER_RUNS)) {
			/* delay small writes */
			init_timer(&raw->timer);
			raw->timer.expires = RAW3215_TIMEOUT + jiffies;
			raw->timer.data = (unsigned long) raw;
			raw->timer.function = raw3215_timeout;
			add_timer(&raw->timer);
			raw->flags |= RAW3215_TIMER_RUNS;
		}
	}
}

/*
 * The bottom half handler routine for 3215 devices. It tries to start
 * the next IO and wakes up processes waiting on the tty.
 */
static void
raw3215_tasklet(void *data)
{
	struct raw3215_info *raw;
	struct tty_struct *tty;
	unsigned long flags;

	raw = (struct raw3215_info *) data;
	spin_lock_irqsave(raw->lock, flags);
	raw3215_mk_write_req(raw);
	raw3215_try_io(raw);
	spin_unlock_irqrestore(raw->lock, flags);
	/* Check for pending message from raw3215_irq */
	if (raw->message != NULL) {
		printk(raw->message, raw->msg_dstat, raw->msg_cstat);
		raw->message = NULL;
	}
	tty = raw->tty;
	if (tty != NULL &&
	    RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE) {
	    	tty_wakeup(tty);
	}
}

/*
 * Interrupt routine, called from common io layer
 */
static void
raw3215_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
{
	struct raw3215_info *raw;
	struct raw3215_req *req;
	struct tty_struct *tty;
	int cstat, dstat;
	int count, slen;

	raw = cdev->dev.driver_data;
	req = (struct raw3215_req *) intparm;
	cstat = irb->scsw.cstat;
	dstat = irb->scsw.dstat;
	if (cstat != 0) {
		raw->message = KERN_WARNING
			"Got nonzero channel status in raw3215_irq "
			"(dev sts 0x%2x, sch sts 0x%2x)";
		raw->msg_dstat = dstat;
		raw->msg_cstat = cstat;
		tasklet_schedule(&raw->tasklet);
	}
	if (dstat & 0x01) { /* we got a unit exception */
		dstat &= ~0x01;	 /* we can ignore it */
	}
	switch (dstat) {
	case 0x80:
		if (cstat != 0)
			break;
		/* Attention interrupt, someone hit the enter key */
		raw3215_mk_read_req(raw);
		if (MACHINE_IS_P390)
			memset(raw->inbuf, 0, RAW3215_INBUF_SIZE);
		tasklet_schedule(&raw->tasklet);
		break;
	case 0x08:
	case 0x0C:
		/* Channel end interrupt. */
		if ((raw = req->info) == NULL)
			return;		     /* That shouldn't happen ... */
		if (req->type == RAW3215_READ) {
			/* store residual count, then wait for device end */
			req->residual = irb->scsw.count;
		}
		if (dstat == 0x08)
			break;
	case 0x04:
		/* Device end interrupt. */
		if ((raw = req->info) == NULL)
			return;		     /* That shouldn't happen ... */
		if (req->type == RAW3215_READ && raw->tty != NULL) {
			unsigned int cchar;

			tty = raw->tty;
			count = 160 - req->residual;
			if (MACHINE_IS_P390) {
				slen = strnlen(raw->inbuf, RAW3215_INBUF_SIZE);
				if (count > slen)
					count = slen;
			} else
			if (count >= TTY_FLIPBUF_SIZE - tty->flip.count)
				count = TTY_FLIPBUF_SIZE - tty->flip.count - 1;
			EBCASC(raw->inbuf, count);
			cchar = ctrlchar_handle(raw->inbuf, count, tty);
			switch (cchar & CTRLCHAR_MASK) {
			case CTRLCHAR_SYSRQ:
				break;

			case CTRLCHAR_CTRL:
				tty->flip.count++;
				*tty->flip.flag_buf_ptr++ = TTY_NORMAL;
				*tty->flip.char_buf_ptr++ = cchar;
				tty_flip_buffer_push(raw->tty);
				break;

			case CTRLCHAR_NONE:
				memcpy(tty->flip.char_buf_ptr,
				       raw->inbuf, count);
				if (count < 2 ||
				    (strncmp(raw->inbuf+count-2, "^n", 2) &&
				    strncmp(raw->inbuf+count-2, "\252n", 2)) ) {
					/* don't add the auto \n */
					tty->flip.char_buf_ptr[count] = '\n';
					memset(tty->flip.flag_buf_ptr,
					       TTY_NORMAL, count + 1);
					count++;
				} else
					count-=2;
				tty->flip.char_buf_ptr += count;
				tty->flip.flag_buf_ptr += count;
				tty->flip.count += count;
				tty_flip_buffer_push(raw->tty);
				break;
			}
		} else if (req->type == RAW3215_WRITE) {
			raw->count -= req->len;
			raw->written -= req->len;
		}
		raw->flags &= ~RAW3215_WORKING;
		raw3215_free_req(req);
		/* check for empty wait */
		if (waitqueue_active(&raw->empty_wait) &&
		    raw->queued_write == NULL &&
		    raw->queued_read == NULL) {
			wake_up_interruptible(&raw->empty_wait);
		}
		tasklet_schedule(&raw->tasklet);
		break;
	default:
		/* Strange interrupt, I'll do my best to clean up */
		if (req != NULL && req->type != RAW3215_FREE) {
			if (req->type == RAW3215_WRITE) {
				raw->count -= req->len;
				raw->written -= req->len;
			}
			raw->flags &= ~RAW3215_WORKING;
			raw3215_free_req(req);
		}
		raw->message = KERN_WARNING
			"Spurious interrupt in in raw3215_irq "
			"(dev sts 0x%2x, sch sts 0x%2x)";
		raw->msg_dstat = dstat;
		raw->msg_cstat = cstat;
		tasklet_schedule(&raw->tasklet);
	}
	return;
}

/*
 * Wait until length bytes are available int the output buffer.
 * Has to be called with the s390irq lock held. Can be called
 * disabled.
 */
static void
raw3215_make_room(struct raw3215_info *raw, unsigned int length)
{
	while (RAW3215_BUFFER_SIZE - raw->count < length) {
		/* there might be a request pending */
		raw->flags |= RAW3215_FLUSHING;
		raw3215_mk_write_req(raw);
		raw3215_try_io(raw);
		raw->flags &= ~RAW3215_FLUSHING;
#ifdef CONFIG_TN3215_CONSOLE
		wait_cons_dev();
#endif
		/* Enough room freed up ? */
		if (RAW3215_BUFFER_SIZE - raw->count >= length)
			break;
		/* there might be another cpu waiting for the lock */
		spin_unlock(raw->lock);
		udelay(100);
		spin_lock(raw->lock);
	}
}

/*
 * String write routine for 3215 devices
 */
static void
raw3215_write(struct raw3215_info *raw, const char *str, unsigned int length)
{
	unsigned long flags;
	int c, count;

	while (length > 0) {
		spin_lock_irqsave(raw->lock, flags);
		count = (length > RAW3215_BUFFER_SIZE) ?
					     RAW3215_BUFFER_SIZE : length;
		length -= count;

		raw3215_make_room(raw, count);

		/* copy string to output buffer and convert it to EBCDIC */
		while (1) {
			c = min_t(int, count,
				  min(RAW3215_BUFFER_SIZE - raw->count,
				      RAW3215_BUFFER_SIZE - raw->head));
			if (c <= 0)
				break;
			memcpy(raw->buffer + raw->head, str, c);
			ASCEBC(raw->buffer + raw->head, c);
			raw->head = (raw->head + c) & (RAW3215_BUFFER_SIZE - 1);
			raw->count += c;
			raw->line_pos += c;
			str += c;
			count -= c;
		}
		if (!(raw->flags & RAW3215_WORKING)) {
			raw3215_mk_write_req(raw);
			/* start or queue request */
			raw3215_try_io(raw);
		}
		spin_unlock_irqrestore(raw->lock, flags);
	}
}

/*
 * Put character routine for 3215 devices
 */
static void
raw3215_putchar(struct raw3215_info *raw, unsigned char ch)
{
	unsigned long flags;
	unsigned int length, i;

	spin_lock_irqsave(raw->lock, flags);
	if (ch == '\t') {
		length = TAB_STOP_SIZE - (raw->line_pos%TAB_STOP_SIZE);
		raw->line_pos += length;
		ch = ' ';
	} else if (ch == '\n') {
		length = 1;
		raw->line_pos = 0;
	} else {
		length = 1;
		raw->line_pos++;
	}
	raw3215_make_room(raw, length);

	for (i = 0; i < length; i++) {
		raw->buffer[raw->head] = (char) _ascebc[(int) ch];
		raw->head = (raw->head + 1) & (RAW3215_BUFFER_SIZE - 1);