[PATCH] s390: 3270 fullscreen view

      Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix fullscreen view of the 3270 device driver.

Signed-off-by: Richard Hitt <rbh00@utsglobal.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 306 insertions, 69 deletions

diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c
index fc7a213e591f..c570a9f6ce9c 100644
--- a/drivers/s390/char/con3270.c
+++ b/drivers/s390/char/con3270.c
@@ -213,6 +213,9 @@ con3270_update(struct con3270 *cp)
         struct string *s, *n;
         int rc;
 
+        if (cp->view.dev)
+                raw3270_activate_view(&cp->view);
+
         wrq = xchg(&cp->write, 0);
         if (!wrq) {
                 con3270_set_timer(cp, 1);
@@ -489,8 +492,6 @@ con3270_write(struct console *co, const char *str, unsigned int count)
         unsigned char c;
 
         cp = condev;
-        if (cp->view.dev)
-                raw3270_activate_view(&cp->view);
         spin_lock_irqsave(&cp->view.lock, flags);
         while (count-- > 0) {
                 c = *str++;
@@ -620,7 +621,7 @@ con3270_init(void)
                      (void (*)(unsigned long)) con3270_read_tasklet,
                      (unsigned long) condev->read);
 
-        raw3270_add_view(&condev->view, &con3270_fn, 0);
+        raw3270_add_view(&condev->view, &con3270_fn, 1);
 
         INIT_LIST_HEAD(&condev->freemem);
         for (i = 0; i < CON3270_STRING_PAGES; i++) {
diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 60afcdcf91c2..735a7fcdeff5 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -33,8 +33,11 @@ struct fs3270 {
         int read_command;               /* ccw command to use for reads. */
         int write_command;              /* ccw command to use for writes. */
         int attention;                  /* Got attention. */
-        struct raw3270_request *clear;  /* single clear request. */
-        wait_queue_head_t attn_wait;    /* Attention wait queue. */
+        int active;                     /* Fullscreen view is active. */
+        struct raw3270_request *init;   /* single init request. */
+        wait_queue_head_t wait;         /* Init & attention wait queue. */
+        struct idal_buffer *rdbuf;      /* full-screen-deactivate buffer */
+        size_t rdbuf_size;              /* size of data returned by RDBUF */
 };
 
 static void
@@ -43,58 +46,172 @@ fs3270_wake_up(struct raw3270_request *rq, void *data)
         wake_up((wait_queue_head_t *) data);
 }
 
+static inline int
+fs3270_working(struct fs3270 *fp)
+{
+        /*
+         * The fullscreen view is in working order if the view
+         * has been activated AND the initial request is finished.
+         */
+        return fp->active && raw3270_request_final(fp->init);
+}
+
 static int
 fs3270_do_io(struct raw3270_view *view, struct raw3270_request *rq)
 {
-        wait_queue_head_t wq;
+        struct fs3270 *fp;
         int rc;
 
-        init_waitqueue_head(&wq);
+        fp = (struct fs3270 *) view;
         rq->callback = fs3270_wake_up;
-        rq->callback_data = &wq;
-        rc = raw3270_start(view, rq);
-        if (rc)
-                return rc;
-        /* Started sucessfully. Now wait for completion. */
-        wait_event(wq, raw3270_request_final(rq));
-        return rq->rc;
+        rq->callback_data = &fp->wait;
+
+        do {
+                if (!fs3270_working(fp)) {
+                        /* Fullscreen view isn't ready yet. */
+                        rc = wait_event_interruptible(fp->wait,
+                                                      fs3270_working(fp));
+                        if (rc != 0)
+                                break;
+                }
+                rc = raw3270_start(view, rq);
+                if (rc == 0) {
+                        /* Started sucessfully. Now wait for completion. */
+                        wait_event(fp->wait, raw3270_request_final(rq));
+                }
+        } while (rc == -EACCES);
+        return rc;
 }
 
+/*
+ * Switch to the fullscreen view.
+ */
 static void
 fs3270_reset_callback(struct raw3270_request *rq, void *data)
 {
+        struct fs3270 *fp;
+
+        fp = (struct fs3270 *) rq->view;
         raw3270_request_reset(rq);
+        wake_up(&fp->wait);
+}
+
+static void
+fs3270_restore_callback(struct raw3270_request *rq, void *data)
+{
+        struct fs3270 *fp;
+
+        fp = (struct fs3270 *) rq->view;
+        if (rq->rc != 0 || rq->rescnt != 0) {
+                if (fp->fs_pid)
+                        kill_proc(fp->fs_pid, SIGHUP, 1);
+        }
+        fp->rdbuf_size = 0;
+        raw3270_request_reset(rq);
+        wake_up(&fp->wait);
 }
 
-/*
- * Switch to the fullscreen view.
- */
 static int
 fs3270_activate(struct raw3270_view *view)
 {
         struct fs3270 *fp;
+        char *cp;
+        int rc;
 
         fp = (struct fs3270 *) view;
-        raw3270_request_set_cmd(fp->clear, TC_EWRITEA);
-        fp->clear->callback = fs3270_reset_callback;
-        return raw3270_start(view, fp->clear);
+
+        /* If an old init command is still running just return. */
+        if (!raw3270_request_final(fp->init))
+                return 0;
+
+        if (fp->rdbuf_size == 0) {
+                /* No saved buffer. Just clear the screen. */
+                raw3270_request_set_cmd(fp->init, TC_EWRITEA);
+                fp->init->callback = fs3270_reset_callback;
+        } else {
+                /* Restore fullscreen buffer saved by fs3270_deactivate. */
+                raw3270_request_set_cmd(fp->init, TC_EWRITEA);
+                raw3270_request_set_idal(fp->init, fp->rdbuf);
+                fp->init->ccw.count = fp->rdbuf_size;
+                cp = fp->rdbuf->data[0];
+                cp[0] = TW_KR;
+                cp[1] = TO_SBA;
+                cp[2] = cp[6];
+                cp[3] = cp[7];
+                cp[4] = TO_IC;
+                cp[5] = TO_SBA;
+                cp[6] = 0x40;
+                cp[7] = 0x40;
+                fp->init->rescnt = 0;
+                fp->init->callback = fs3270_restore_callback;
+        }
+        rc = fp->init->rc = raw3270_start_locked(view, fp->init);
+        if (rc)
+                fp->init->callback(fp->init, NULL);
+        else
+                fp->active = 1;
+        return rc;
 }
 
 /*
  * Shutdown fullscreen view.
  */
 static void
+fs3270_save_callback(struct raw3270_request *rq, void *data)
+{
+        struct fs3270 *fp;
+
+        fp = (struct fs3270 *) rq->view;
+
+        /* Correct idal buffer element 0 address. */
+        fp->rdbuf->data[0] -= 5;
+        fp->rdbuf->size += 5;
+
+        /*
+         * If the rdbuf command failed or the idal buffer is
+         * to small for the amount of data returned by the
+         * rdbuf command, then we have no choice but to send
+         * a SIGHUP to the application.
+         */
+        if (rq->rc != 0 || rq->rescnt == 0) {
+                if (fp->fs_pid)
+                        kill_proc(fp->fs_pid, SIGHUP, 1);
+                fp->rdbuf_size = 0;
+        } else
+                fp->rdbuf_size = fp->rdbuf->size - rq->rescnt;
+        raw3270_request_reset(rq);
+        wake_up(&fp->wait);
+}
+
+static void
 fs3270_deactivate(struct raw3270_view *view)
 {
-        // FIXME: is this a good idea? The user program using fullscreen 3270
-        // will die just because a console message appeared. On the other
-        // hand the fullscreen device is unoperational now.
         struct fs3270 *fp;
 
         fp = (struct fs3270 *) view;
-        if (fp->fs_pid != 0)
-                kill_proc(fp->fs_pid, SIGHUP, 1);
-        fp->fs_pid = 0;
+        fp->active = 0;
+
+        /* If an old init command is still running just return. */
+        if (!raw3270_request_final(fp->init))
+                return;
+
+        /* Prepare read-buffer request. */
+        raw3270_request_set_cmd(fp->init, TC_RDBUF);
+        /*
+         * Hackish: skip first 5 bytes of the idal buffer to make
+         * room for the TW_KR/TO_SBA/<address>/<address>/TO_IC sequence
+         * in the activation command.
+         */
+        fp->rdbuf->data[0] += 5;
+        fp->rdbuf->size -= 5;
+        raw3270_request_set_idal(fp->init, fp->rdbuf);
+        fp->init->rescnt = 0;
+        fp->init->callback = fs3270_save_callback;
+
+        /* Start I/O to read in the 3270 buffer. */
+        fp->init->rc = raw3270_start_locked(view, fp->init);
+        if (fp->init->rc)
+                fp->init->callback(fp->init, NULL);
 }
 
 static int
@@ -103,7 +220,7 @@ fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
         /* Handle ATTN. Set indication and wake waiters for attention. */
         if (irb->scsw.dstat & DEV_STAT_ATTENTION) {
                 fp->attention = 1;
-                wake_up(&fp->attn_wait);
+                wake_up(&fp->wait);
         }
 
         if (rq) {
@@ -125,7 +242,7 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
         struct fs3270 *fp;
         struct raw3270_request *rq;
         struct idal_buffer *ib;
-        int rc;
+        ssize_t rc;
         
         if (count == 0 || count > 65535)
                 return -EINVAL;
@@ -133,7 +250,7 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
         if (!fp)
                 return -ENODEV;
         ib = idal_buffer_alloc(count, 0);
-        if (!ib)
+        if (IS_ERR(ib))
                 return -ENOMEM;
         rq = raw3270_request_alloc(0);
         if (!IS_ERR(rq)) {
@@ -141,10 +258,19 @@ fs3270_read(struct file *filp, char *data, size_t count, loff_t *off)
                         fp->read_command = 6;
                 raw3270_request_set_cmd(rq, fp->read_command ? : 2);
                 raw3270_request_set_idal(rq, ib);
-                wait_event(fp->attn_wait, fp->attention);
-                rc = fs3270_do_io(&fp->view, rq);
-                if (rc == 0 && idal_buffer_to_user(ib, data, count))
-                        rc = -EFAULT;
+                rc = wait_event_interruptible(fp->wait, fp->attention);
+                fp->attention = 0;
+                if (rc == 0) {
+                        rc = fs3270_do_io(&fp->view, rq);
+                        if (rc == 0) {
+                                count -= rq->rescnt;
+                                if (idal_buffer_to_user(ib, data, count) != 0)
+                                        rc = -EFAULT;
+                                else
+                                        rc = count;
+
+                        }
+                }
                 raw3270_request_free(rq);
         } else
                 rc = PTR_ERR(rq);
@@ -162,13 +288,13 @@ fs3270_write(struct file *filp, const char *data, size_t count, loff_t *off)
         struct raw3270_request *rq;
         struct idal_buffer *ib;
         int write_command;
-        int rc;
+        ssize_t rc;
 
         fp = filp->private_data;
         if (!fp)
                 return -ENODEV;
         ib = idal_buffer_alloc(count, 0);
-        if (!ib)
+        if (IS_ERR(ib))
                 return -ENOMEM;
         rq = raw3270_request_alloc(0);
         if (!IS_ERR(rq)) {
@@ -179,6 +305,8 @@ fs3270_write(struct file *filp, const char *data, size_t count, loff_t *off)
                         raw3270_request_set_cmd(rq, write_command);
                         raw3270_request_set_idal(rq, ib);
                         rc = fs3270_do_io(&fp->view, rq);
+                        if (rc == 0)
+                                rc = count - rq->rescnt;
                 } else
                         rc = -EFAULT;
                 raw3270_request_free(rq);
@@ -232,7 +360,7 @@ fs3270_ioctl(struct inode *inode, struct file *filp,
 }
 
 /*
- * Allocate tty3270 structure.
+ * Allocate fs3270 structure.
  */
 static struct fs3270 *
 fs3270_alloc_view(void)
@@ -243,8 +371,8 @@ fs3270_alloc_view(void)
         if (!fp)
                 return ERR_PTR(-ENOMEM);
         memset(fp, 0, sizeof(struct fs3270));
-        fp->clear = raw3270_request_alloc(0);
-        if (!IS_ERR(fp->clear)) {
+        fp->init = raw3270_request_alloc(0);
+        if (IS_ERR(fp->init)) {
                 kfree(fp);
                 return ERR_PTR(-ENOMEM);
         }
@@ -252,12 +380,17 @@ fs3270_alloc_view(void)
 }
 
 /*
- * Free tty3270 structure.
+ * Free fs3270 structure.
  */
 static void
 fs3270_free_view(struct raw3270_view *view)
 {
-        raw3270_request_free(((struct fs3270 *) view)->clear);
+        struct fs3270 *fp;
+
+        fp = (struct fs3270 *) view;
+        if (fp->rdbuf)
+                idal_buffer_free(fp->rdbuf);
+        raw3270_request_free(((struct fs3270 *) view)->init);
         kfree(view);
 }
 
@@ -285,11 +418,20 @@ static int
 fs3270_open(struct inode *inode, struct file *filp)
 {
         struct fs3270 *fp;
+        struct idal_buffer *ib;
         int minor, rc;
 
         if (imajor(filp->f_dentry->d_inode) != IBM_FS3270_MAJOR)
                 return -ENODEV;
         minor = iminor(filp->f_dentry->d_inode);
+        /* Check for minor 0 multiplexer. */
+        if (minor == 0) {
+                if (!current->signal->tty)
+                        return -ENODEV;
+                if (current->signal->tty->driver->major != IBM_TTY3270_MAJOR)
+                        return -ENODEV;
+                minor = current->signal->tty->index + RAW3270_FIRSTMINOR;
+        }
         /* Check if some other program is already using fullscreen mode. */
         fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);
         if (!IS_ERR(fp)) {
@@ -301,7 +443,7 @@ fs3270_open(struct inode *inode, struct file *filp)
         if (IS_ERR(fp))
                 return PTR_ERR(fp);
 
-        init_waitqueue_head(&fp->attn_wait);
+        init_waitqueue_head(&fp->wait);
         fp->fs_pid = current->pid;
         rc = raw3270_add_view(&fp->view, &fs3270_fn, minor);
         if (rc) {
@@ -309,8 +451,18 @@ fs3270_open(struct inode *inode, struct file *filp)
                 return rc;
         }
 
+        /* Allocate idal-buffer. */
+        ib = idal_buffer_alloc(2*fp->view.rows*fp->view.cols + 5, 0);
+        if (IS_ERR(ib)) {
+                raw3270_put_view(&fp->view);
+                raw3270_del_view(&fp->view);
+                return PTR_ERR(fp);
+        }
+        fp->rdbuf = ib;
+
         rc = raw3270_activate_view(&fp->view);
         if (rc) {
+                raw3270_put_view(&fp->view);
                 raw3270_del_view(&fp->view);
                 return rc;
         }
@@ -329,8 +481,12 @@ fs3270_close(struct inode *inode, struct file *filp)
 
         fp = filp->private_data;
         filp->private_data = 0;
-        if (fp)
+        if (fp) {
+                fp->fs_pid = 0;
+                raw3270_reset(&fp->view);
+                raw3270_put_view(&fp->view);
                 raw3270_del_view(&fp->view);
+        }
         return 0;
 }
 
diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index 328d9cbc56a3..d66946443dfc 100644
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -25,6 +25,12 @@
 
 #include "raw3270.h"
 
+#include <linux/major.h>
+#include <linux/kdev_t.h>
+#include <linux/device.h>
+
+struct class *class3270;
+
 /* The main 3270 data structure. */
 struct raw3270 {
         struct list_head list;
@@ -41,6 +47,8 @@ struct raw3270 {
         struct timer_list timer;        /* Device timer. */
 
         unsigned char *ascebc;          /* ascii -> ebcdic table */
+        struct class_device *clttydev;  /* 3270-class tty device ptr */
+        struct class_device *cltubdev;  /* 3270-class tub device ptr */
 };
 
 /* raw3270->flags */
@@ -317,6 +325,22 @@ raw3270_start(struct raw3270_view *view, struct raw3270_request *rq)
 }
 
 int
+raw3270_start_locked(struct raw3270_view *view, struct raw3270_request *rq)
+{
+        struct raw3270 *rp;
+        int rc;
+
+        rp = view->dev;
+        if (!rp || rp->view != view)
+                rc = -EACCES;
+        else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
+                rc = -ENODEV;
+        else
+                rc =  __raw3270_start(rp, view, rq);
+        return rc;
+}
+
+int
 raw3270_start_irq(struct raw3270_view *view, struct raw3270_request *rq)
 {
         struct raw3270 *rp;
@@ -744,6 +768,22 @@ raw3270_reset_device(struct raw3270 *rp)
         return rc;
 }
 
+int
+raw3270_reset(struct raw3270_view *view)
+{
+        struct raw3270 *rp;
+        int rc;
+
+        rp = view->dev;
+        if (!rp || rp->view != view)
+                rc = -EACCES;
+        else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
+                rc = -ENODEV;
+        else
+                rc = raw3270_reset_device(view->dev);
+        return rc;
+}
+
 /*
  * Setup new 3270 device.
  */
@@ -774,11 +814,12 @@ raw3270_setup_device(struct ccw_device *cdev, struct raw3270 *rp, char *ascebc)
 
         /*
          * Add device to list and find the smallest unused minor
-         * number for it.
+         * number for it. Note: there is no device with minor 0,
+         * see special case for fs3270.c:fs3270_open().
          */
         down(&raw3270_sem);
         /* Keep the list sorted. */
-        minor = 0;
+        minor = RAW3270_FIRSTMINOR;
         rp->minor = -1;
         list_for_each(l, &raw3270_devices) {
                 tmp = list_entry(l, struct raw3270, list);
@@ -789,7 +830,7 @@ raw3270_setup_device(struct ccw_device *cdev, struct raw3270 *rp, char *ascebc)
                 }
                 minor++;
         }
-        if (rp->minor == -1 && minor < RAW3270_MAXDEVS) {
+        if (rp->minor == -1 && minor < RAW3270_MAXDEVS + RAW3270_FIRSTMINOR) {
                 rp->minor = minor;
                 list_add_tail(&rp->list, &raw3270_devices);
         }
@@ -941,11 +982,12 @@ raw3270_deactivate_view(struct raw3270_view *view)
                 list_add_tail(&view->list, &rp->view_list);
                 /* Try to activate another view. */
                 if (test_bit(RAW3270_FLAGS_READY, &rp->flags)) {
-                        list_for_each_entry(view, &rp->view_list, list)
-                                if (view->fn->activate(view) == 0) {
-                                        rp->view = view;
+                        list_for_each_entry(view, &rp->view_list, list) {
+                                rp->view = view;
+                                if (view->fn->activate(view) == 0)
                                         break;
-                                }
+                                rp->view = 0;
+                        }
                 }
         }
         spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
@@ -961,6 +1003,8 @@ raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor)
         struct raw3270 *rp;
         int rc;
 
+        if (minor <= 0)
+                return -ENODEV;
         down(&raw3270_sem);
         rc = -ENODEV;
         list_for_each_entry(rp, &raw3270_devices, list) {
@@ -976,7 +1020,7 @@ raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor)
                         view->cols = rp->cols;
                         view->ascebc = rp->ascebc;
                         spin_lock_init(&view->lock);
-                        list_add_tail(&view->list, &rp->view_list);
+                        list_add(&view->list, &rp->view_list);
                         rc = 0;
                 }
                 spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
@@ -1039,7 +1083,7 @@ raw3270_del_view(struct raw3270_view *view)
         if (!rp->view && test_bit(RAW3270_FLAGS_READY, &rp->flags)) {
                 /* Try to activate another view. */
                 list_for_each_entry(nv, &rp->view_list, list) {
-                        if (nv->fn->activate(view) == 0) {
+                        if (nv->fn->activate(nv) == 0) {
                                 rp->view = nv;
                                 break;
                         }
@@ -1063,6 +1107,12 @@ raw3270_delete_device(struct raw3270 *rp)
 
         /* Remove from device chain. */
         down(&raw3270_sem);
+        if (rp->clttydev)
+                class_device_destroy(class3270,
+                                     MKDEV(IBM_TTY3270_MAJOR, rp->minor));
+        if (rp->cltubdev)
+                class_device_destroy(class3270,
+                                     MKDEV(IBM_FS3270_MAJOR, rp->minor));
         list_del_init(&rp->list);
         up(&raw3270_sem);
 
@@ -1129,6 +1179,16 @@ raw3270_create_attributes(struct raw3270 *rp)
 {
         //FIXME: check return code
         sysfs_create_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
+        rp->clttydev =
+                class_device_create(class3270,
+                                    MKDEV(IBM_TTY3270_MAJOR, rp->minor),
+                                    &rp->cdev->dev, "tty%s",
+                                    rp->cdev->dev.bus_id);
+        rp->cltubdev =
+                class_device_create(class3270,
+                                    MKDEV(IBM_FS3270_MAJOR, rp->minor),
+                                    &rp->cdev->dev, "tub%s",
+                                    rp->cdev->dev.bus_id);
 }
 
 /*
@@ -1189,13 +1249,13 @@ raw3270_set_online (struct ccw_device *cdev)
                 return PTR_ERR(rp);
         rc = raw3270_reset_device(rp);
         if (rc)
-                return rc;
+                goto failure;
         rc = raw3270_size_device(rp);
         if (rc)
-                return rc;
+                goto failure;
         rc = raw3270_reset_device(rp);
         if (rc)
-                return rc;
+                goto failure;
         raw3270_create_attributes(rp);
         set_bit(RAW3270_FLAGS_READY, &rp->flags);
         down(&raw3270_sem);
@@ -1203,6 +1263,10 @@ raw3270_set_online (struct ccw_device *cdev)
                 np->notifier(rp->minor, 1);
         up(&raw3270_sem);
         return 0;
+
+failure:
+        raw3270_delete_device(rp);
+        return rc;
 }
 
 /*
@@ -1217,6 +1281,14 @@ raw3270_remove (struct ccw_device *cdev)
         struct raw3270_notifier *np;
 
         rp = cdev->dev.driver_data;
+        /*
+         * _remove is the opposite of _probe; it's probe that
+         * should set up rp.  raw3270_remove gets entered for
+         * devices even if they haven't been varied online.
+         * Thus, rp may validly be NULL here.
+         */
+        if (rp == NULL)
+                return;
         clear_bit(RAW3270_FLAGS_READY, &rp->flags);
 
         sysfs_remove_group(&cdev->dev.kobj, &raw3270_attr_group);
@@ -1301,6 +1373,7 @@ raw3270_init(void)
         if (rc == 0) {
                 /* Create attributes for early (= console) device. */
                 down(&raw3270_sem);
+                class3270 = class_create(THIS_MODULE, "3270");
                 list_for_each_entry(rp, &raw3270_devices, list) {
                         get_device(&rp->cdev->dev);
                         raw3270_create_attributes(rp);
@@ -1314,6 +1387,7 @@ static void
 raw3270_exit(void)
 {
         ccw_driver_unregister(&raw3270_ccw_driver);
+        class_destroy(class3270);
 }
 
 MODULE_LICENSE("GPL");
@@ -1335,7 +1409,9 @@ EXPORT_SYMBOL(raw3270_find_view);
 EXPORT_SYMBOL(raw3270_activate_view);
 EXPORT_SYMBOL(raw3270_deactivate_view);
 EXPORT_SYMBOL(raw3270_start);
+EXPORT_SYMBOL(raw3270_start_locked);
 EXPORT_SYMBOL(raw3270_start_irq);
+EXPORT_SYMBOL(raw3270_reset);
 EXPORT_SYMBOL(raw3270_register_notifier);
 EXPORT_SYMBOL(raw3270_unregister_notifier);
 EXPORT_SYMBOL(raw3270_wait_queue);
diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h
index ed5d4eb9f623..b635bf8e7775 100644
--- a/drivers/s390/char/raw3270.h
+++ b/drivers/s390/char/raw3270.h
@@ -21,6 +21,7 @@
 
 /* Local Channel Commands */
 #define TC_WRITE        0x01            /* Write */
+#define TC_RDBUF        0x02            /* Read Buffer */
 #define TC_EWRITE       0x05            /* Erase write */
 #define TC_READMOD      0x06            /* Read modified */
 #define TC_EWRITEA      0x0d            /* Erase write alternate */
@@ -76,7 +77,8 @@
 #define TW_KR           0xc2            /* Keyboard restore */
 #define TW_PLUSALARM    0x04            /* Add this bit for alarm */
 
-#define RAW3270_MAXDEVS 256
+#define RAW3270_FIRSTMINOR      1       /* First minor number */
+#define RAW3270_MAXDEVS         255     /* Max number of 3270 devices */
 
 /* For TUBGETMOD and TUBSETMOD. Should include. */
 struct raw3270_iocb {
@@ -166,7 +168,10 @@ void raw3270_del_view(struct raw3270_view *);
 void raw3270_deactivate_view(struct raw3270_view *);
 struct raw3270_view *raw3270_find_view(struct raw3270_fn *, int);
 int raw3270_start(struct raw3270_view *, struct raw3270_request *);
+int raw3270_start_locked(struct raw3270_view *, struct raw3270_request *);
 int raw3270_start_irq(struct raw3270_view *, struct raw3270_request *);
+int raw3270_reset(struct raw3270_view *);
+struct raw3270_view *raw3270_view(struct raw3270_view *);
 
 /* Reference count inliner for view structures. */
 static inline void
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 7db5ebce7f0f..4b9069370388 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -653,18 +653,12 @@ tty3270_activate(struct raw3270_view *view)
         tp->update_flags = TTY_UPDATE_ALL;
         tty3270_set_timer(tp, 1);
         spin_unlock_irqrestore(&tp->view.lock, flags);
-        start_tty(tp->tty);
         return 0;
 }
 
 static void
 tty3270_deactivate(struct raw3270_view *view)
 {
-        struct tty3270 *tp;
-
-        tp = (struct tty3270 *) view;
-        if (tp && tp->tty)
-                stop_tty(tp->tty);
 }
 
 static int
@@ -716,13 +710,13 @@ tty3270_alloc_view(void)
                                   tp->freemem_pages[pages], PAGE_SIZE);
         }
         tp->write = raw3270_request_alloc(TTY3270_OUTPUT_BUFFER_SIZE);
-        if (!tp->write)
+        if (IS_ERR(tp->write))
                 goto out_pages;
         tp->read = raw3270_request_alloc(0);
-        if (!tp->read)
+        if (IS_ERR(tp->read))
                 goto out_write;
         tp->kreset = raw3270_request_alloc(1);
-        if (!tp->kreset)
+        if (IS_ERR(tp->kreset))
                 goto out_read;
         tp->kbd = kbd_alloc();
         if (!tp->kbd)
@@ -845,7 +839,8 @@ tty3270_del_views(void)
         int i;
 
         for (i = 0; i < tty3270_max_index; i++) {
-                tp = (struct tty3270 *) raw3270_find_view(&tty3270_fn, i);
+                tp = (struct tty3270 *)
+                        raw3270_find_view(&tty3270_fn, i + RAW3270_FIRSTMINOR);
                 if (!IS_ERR(tp))
                         raw3270_del_view(&tp->view);
         }
@@ -871,7 +866,9 @@ tty3270_open(struct tty_struct *tty, struct file * filp)
         if (tty->count > 1)
                 return 0;
         /* Check if the tty3270 is already there. */
-        tp = (struct tty3270 *) raw3270_find_view(&tty3270_fn, tty->index);
+        tp = (struct tty3270 *)
+                raw3270_find_view(&tty3270_fn,
+                                  tty->index + RAW3270_FIRSTMINOR);
         if (!IS_ERR(tp)) {
                 tty->driver_data = tp;
                 tty->winsize.ws_row = tp->view.rows - 2;
@@ -903,7 +900,8 @@ tty3270_open(struct tty_struct *tty, struct file * filp)
                      (void (*)(unsigned long)) tty3270_read_tasklet,
                      (unsigned long) tp->read);
 
-        rc = raw3270_add_view(&tp->view, &tty3270_fn, tty->index);
+        rc = raw3270_add_view(&tp->view, &tty3270_fn,
+                              tty->index + RAW3270_FIRSTMINOR);
         if (rc) {
                 tty3270_free_view(tp);
                 return rc;
@@ -911,8 +909,8 @@ tty3270_open(struct tty_struct *tty, struct file * filp)
 
         rc = tty3270_alloc_screen(tp);
         if (rc) {
-                raw3270_del_view(&tp->view);
                 raw3270_put_view(&tp->view);
+                raw3270_del_view(&tp->view);
                 return rc;
         }
 
@@ -1780,7 +1778,7 @@ tty3270_init(void)
         struct tty_driver *driver;
         int ret;
 
-        driver = alloc_tty_driver(256);
+        driver = alloc_tty_driver(RAW3270_MAXDEVS);
         if (!driver)
                 return -ENOMEM;
 
@@ -1794,6 +1792,7 @@ tty3270_init(void)
         driver->driver_name = "ttyTUB";
         driver->name = "ttyTUB";
         driver->major = IBM_TTY3270_MAJOR;
+        driver->minor_start = RAW3270_FIRSTMINOR;
         driver->type = TTY_DRIVER_TYPE_SYSTEM;
         driver->subtype = SYSTEM_TYPE_TTY;
         driver->init_termios = tty_std_termios;