linux/drivers/s390/char/fs3270.c
Arjan van de Ven d54b1fdb1d [PATCH] mark struct file_operations const 5
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

534 lines
12 KiB
C

/*
* drivers/s390/char/fs3270.c
* IBM/3270 Driver - fullscreen driver.
*
* Author(s):
* Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
* Rewritten for 2.5/2.6 by Martin Schwidefsky <schwidefsky@de.ibm.com>
* -- Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
*/
#include <linux/bootmem.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/types.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/ebcdic.h>
#include <asm/idals.h>
#include "raw3270.h"
#include "ctrlchar.h"
static struct raw3270_fn fs3270_fn;
struct fs3270 {
struct raw3270_view view;
struct pid *fs_pid; /* Pid of controlling program. */
int read_command; /* ccw command to use for reads. */
int write_command; /* ccw command to use for writes. */
int attention; /* Got attention. */
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
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)
{
struct fs3270 *fp;
int rc;
fp = (struct fs3270 *) view;
rq->callback = fs3270_wake_up;
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_pid(fp->fs_pid, SIGHUP, 1);
}
fp->rdbuf_size = 0;
raw3270_request_reset(rq);
wake_up(&fp->wait);
}
static int
fs3270_activate(struct raw3270_view *view)
{
struct fs3270 *fp;
char *cp;
int rc;
fp = (struct fs3270 *) view;
/* 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_pid(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)
{
struct fs3270 *fp;
fp = (struct fs3270 *) view;
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
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->wait);
}
if (rq) {
if (irb->scsw.dstat & DEV_STAT_UNIT_CHECK)
rq->rc = -EIO;
else
/* Normal end. Copy residual count. */
rq->rescnt = irb->scsw.count;
}
return RAW3270_IO_DONE;
}
/*
* Process reads from fullscreen 3270.
*/
static ssize_t
fs3270_read(struct file *filp, char __user *data, size_t count, loff_t *off)
{
struct fs3270 *fp;
struct raw3270_request *rq;
struct idal_buffer *ib;
ssize_t rc;
if (count == 0 || count > 65535)
return -EINVAL;
fp = filp->private_data;
if (!fp)
return -ENODEV;
ib = idal_buffer_alloc(count, 0);
if (IS_ERR(ib))
return -ENOMEM;
rq = raw3270_request_alloc(0);
if (!IS_ERR(rq)) {
if (fp->read_command == 0 && fp->write_command != 0)
fp->read_command = 6;
raw3270_request_set_cmd(rq, fp->read_command ? : 2);
raw3270_request_set_idal(rq, ib);
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);
idal_buffer_free(ib);
return rc;
}
/*
* Process writes to fullscreen 3270.
*/
static ssize_t
fs3270_write(struct file *filp, const char __user *data, size_t count, loff_t *off)
{
struct fs3270 *fp;
struct raw3270_request *rq;
struct idal_buffer *ib;
int write_command;
ssize_t rc;
fp = filp->private_data;
if (!fp)
return -ENODEV;
ib = idal_buffer_alloc(count, 0);
if (IS_ERR(ib))
return -ENOMEM;
rq = raw3270_request_alloc(0);
if (!IS_ERR(rq)) {
if (idal_buffer_from_user(ib, data, count) == 0) {
write_command = fp->write_command ? : 1;
if (write_command == 5)
write_command = 13;
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);
} else
rc = PTR_ERR(rq);
idal_buffer_free(ib);
return rc;
}
/*
* process ioctl commands for the tube driver
*/
static long
fs3270_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct fs3270 *fp;
struct raw3270_iocb iocb;
int rc;
fp = filp->private_data;
if (!fp)
return -ENODEV;
rc = 0;
lock_kernel();
switch (cmd) {
case TUBICMD:
fp->read_command = arg;
break;
case TUBOCMD:
fp->write_command = arg;
break;
case TUBGETI:
rc = put_user(fp->read_command, (char __user *) arg);
break;
case TUBGETO:
rc = put_user(fp->write_command,(char __user *) arg);
break;
case TUBGETMOD:
iocb.model = fp->view.model;
iocb.line_cnt = fp->view.rows;
iocb.col_cnt = fp->view.cols;
iocb.pf_cnt = 24;
iocb.re_cnt = 20;
iocb.map = 0;
if (copy_to_user((char __user *) arg, &iocb,
sizeof(struct raw3270_iocb)))
rc = -EFAULT;
break;
}
unlock_kernel();
return rc;
}
/*
* Allocate fs3270 structure.
*/
static struct fs3270 *
fs3270_alloc_view(void)
{
struct fs3270 *fp;
fp = kzalloc(sizeof(struct fs3270),GFP_KERNEL);
if (!fp)
return ERR_PTR(-ENOMEM);
fp->init = raw3270_request_alloc(0);
if (IS_ERR(fp->init)) {
kfree(fp);
return ERR_PTR(-ENOMEM);
}
return fp;
}
/*
* Free fs3270 structure.
*/
static void
fs3270_free_view(struct raw3270_view *view)
{
struct fs3270 *fp;
fp = (struct fs3270 *) view;
if (fp->rdbuf)
idal_buffer_free(fp->rdbuf);
raw3270_request_free(((struct fs3270 *) view)->init);
kfree(view);
}
/*
* Unlink fs3270 data structure from filp.
*/
static void
fs3270_release(struct raw3270_view *view)
{
}
/* View to a 3270 device. Can be console, tty or fullscreen. */
static struct raw3270_fn fs3270_fn = {
.activate = fs3270_activate,
.deactivate = fs3270_deactivate,
.intv = (void *) fs3270_irq,
.release = fs3270_release,
.free = fs3270_free_view
};
/*
* This routine is called whenever a 3270 fullscreen device is opened.
*/
static int
fs3270_open(struct inode *inode, struct file *filp)
{
struct fs3270 *fp;
struct idal_buffer *ib;
int minor, rc;
if (imajor(filp->f_path.dentry->d_inode) != IBM_FS3270_MAJOR)
return -ENODEV;
minor = iminor(filp->f_path.dentry->d_inode);
/* Check for minor 0 multiplexer. */
if (minor == 0) {
struct tty_struct *tty;
mutex_lock(&tty_mutex);
tty = get_current_tty();
if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
mutex_unlock(&tty_mutex);
return -ENODEV;
}
minor = tty->index + RAW3270_FIRSTMINOR;
mutex_unlock(&tty_mutex);
}
/* Check if some other program is already using fullscreen mode. */
fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);
if (!IS_ERR(fp)) {
raw3270_put_view(&fp->view);
return -EBUSY;
}
/* Allocate fullscreen view structure. */
fp = fs3270_alloc_view();
if (IS_ERR(fp))
return PTR_ERR(fp);
init_waitqueue_head(&fp->wait);
fp->fs_pid = get_pid(task_pid(current));
rc = raw3270_add_view(&fp->view, &fs3270_fn, minor);
if (rc) {
fs3270_free_view(&fp->view);
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;
}
filp->private_data = fp;
return 0;
}
/*
* This routine is called when the 3270 tty is closed. We wait
* for the remaining request to be completed. Then we clean up.
*/
static int
fs3270_close(struct inode *inode, struct file *filp)
{
struct fs3270 *fp;
fp = filp->private_data;
filp->private_data = NULL;
if (fp) {
put_pid(fp->fs_pid);
fp->fs_pid = NULL;
raw3270_reset(&fp->view);
raw3270_put_view(&fp->view);
raw3270_del_view(&fp->view);
}
return 0;
}
static const struct file_operations fs3270_fops = {
.owner = THIS_MODULE, /* owner */
.read = fs3270_read, /* read */
.write = fs3270_write, /* write */
.unlocked_ioctl = fs3270_ioctl, /* ioctl */
.compat_ioctl = fs3270_ioctl, /* ioctl */
.open = fs3270_open, /* open */
.release = fs3270_close, /* release */
};
/*
* 3270 fullscreen driver initialization.
*/
static int __init
fs3270_init(void)
{
int rc;
rc = register_chrdev(IBM_FS3270_MAJOR, "fs3270", &fs3270_fops);
if (rc) {
printk(KERN_ERR "fs3270 can't get major number %d: errno %d\n",
IBM_FS3270_MAJOR, rc);
return rc;
}
return 0;
}
static void __exit
fs3270_exit(void)
{
unregister_chrdev(IBM_FS3270_MAJOR, "fs3270");
}
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(IBM_FS3270_MAJOR);
module_init(fs3270_init);
module_exit(fs3270_exit);