1 files changed, 488 insertions, 0 deletions
diff --git a/drivers/s390/char/tape_char.c b/drivers/s390/char/tape_char.c
new file mode 100644
index 000000000..cc8237afe
--- /dev/null
+++ b/drivers/s390/char/tape_char.c
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    character device frontend for tape device driver
+ *
+ *  S390 and zSeries version
+ *    Copyright IBM Corp. 2001, 2006
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *		 Michael Holzheu <holzheu@de.ibm.com>
+ *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "tape"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/proc_fs.h>
+#include <linux/mtio.h>
+#include <linux/compat.h>
+
+#include <linux/uaccess.h>
+
+#define TAPE_DBF_AREA	tape_core_dbf
+
+#include "tape.h"
+#include "tape_std.h"
+#include "tape_class.h"
+
+#define TAPECHAR_MAJOR		0	/* get dynamic major */
+
+/*
+ * file operation structure for tape character frontend
+ */
+static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
+static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
+static int tapechar_open(struct inode *,struct file *);
+static int tapechar_release(struct inode *,struct file *);
+static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
+#ifdef CONFIG_COMPAT
+static long tapechar_compat_ioctl(struct file *, unsigned int, unsigned long);
+#endif
+
+static const struct file_operations tape_fops =
+{
+	.owner = THIS_MODULE,
+	.read = tapechar_read,
+	.write = tapechar_write,
+	.unlocked_ioctl = tapechar_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = tapechar_compat_ioctl,
+#endif
+	.open = tapechar_open,
+	.release = tapechar_release,
+	.llseek = no_llseek,
+};
+
+static int tapechar_major = TAPECHAR_MAJOR;
+
+/*
+ * This function is called for every new tapedevice
+ */
+int
+tapechar_setup_device(struct tape_device * device)
+{
+	char	device_name[20];
+
+	sprintf(device_name, "ntibm%i", device->first_minor / 2);
+	device->nt = register_tape_dev(
+		&device->cdev->dev,
+		MKDEV(tapechar_major, device->first_minor),
+		&tape_fops,
+		device_name,
+		"non-rewinding"
+	);
+	device_name[0] = 'r';
+	device->rt = register_tape_dev(
+		&device->cdev->dev,
+		MKDEV(tapechar_major, device->first_minor + 1),
+		&tape_fops,
+		device_name,
+		"rewinding"
+	);
+
+	return 0;
+}
+
+void
+tapechar_cleanup_device(struct tape_device *device)
+{
+	unregister_tape_dev(&device->cdev->dev, device->rt);
+	device->rt = NULL;
+	unregister_tape_dev(&device->cdev->dev, device->nt);
+	device->nt = NULL;
+}
+
+static int
+tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
+{
+	struct idal_buffer *new;
+
+	if (device->char_data.idal_buf != NULL &&
+	    device->char_data.idal_buf->size == block_size)
+		return 0;
+
+	if (block_size > MAX_BLOCKSIZE) {
+		DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
+			block_size, MAX_BLOCKSIZE);
+		return -EINVAL;
+	}
+
+	/* The current idal buffer is not correct. Allocate a new one. */
+	new = idal_buffer_alloc(block_size, 0);
+	if (IS_ERR(new))
+		return -ENOMEM;
+
+	if (device->char_data.idal_buf != NULL)
+		idal_buffer_free(device->char_data.idal_buf);
+
+	device->char_data.idal_buf = new;
+
+	return 0;
+}
+
+/*
+ * Tape device read function
+ */
+static ssize_t
+tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
+{
+	struct tape_device *device;
+	struct tape_request *request;
+	size_t block_size;
+	int rc;
+
+	DBF_EVENT(6, "TCHAR:read\n");
+	device = (struct tape_device *) filp->private_data;
+
+	/*
+	 * If the tape isn't terminated yet, do it now. And since we then
+	 * are at the end of the tape there wouldn't be anything to read
+	 * anyways. So we return immediately.
+	 */
+	if(device->required_tapemarks) {
+		return tape_std_terminate_write(device);
+	}
+
+	/* Find out block size to use */
+	if (device->char_data.block_size != 0) {
+		if (count < device->char_data.block_size) {
+			DBF_EVENT(3, "TCHAR:read smaller than block "
+				  "size was requested\n");
+			return -EINVAL;
+		}
+		block_size = device->char_data.block_size;
+	} else {
+		block_size = count;
+	}
+
+	rc = tapechar_check_idalbuffer(device, block_size);
+	if (rc)
+		return rc;
+
+	DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
+	/* Let the discipline build the ccw chain. */
+	request = device->discipline->read_block(device, block_size);
+	if (IS_ERR(request))
+		return PTR_ERR(request);
+	/* Execute it. */
+	rc = tape_do_io(device, request);
+	if (rc == 0) {
+		rc = block_size - request->rescnt;
+		DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
+		/* Copy data from idal buffer to user space. */
+		if (idal_buffer_to_user(device->char_data.idal_buf,
+					data, rc) != 0)
+			rc = -EFAULT;
+	}
+	tape_free_request(request);
+	return rc;
+}
+
+/*
+ * Tape device write function
+ */
+static ssize_t
+tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
+{
+	struct tape_device *device;
+	struct tape_request *request;
+	size_t block_size;
+	size_t written;
+	int nblocks;
+	int i, rc;
+
+	DBF_EVENT(6, "TCHAR:write\n");
+	device = (struct tape_device *) filp->private_data;
+	/* Find out block size and number of blocks */
+	if (device->char_data.block_size != 0) {
+		if (count < device->char_data.block_size) {
+			DBF_EVENT(3, "TCHAR:write smaller than block "
+				  "size was requested\n");
+			return -EINVAL;
+		}
+		block_size = device->char_data.block_size;
+		nblocks = count / block_size;
+	} else {
+		block_size = count;
+		nblocks = 1;
+	}
+
+	rc = tapechar_check_idalbuffer(device, block_size);
+	if (rc)
+		return rc;
+
+	DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
+	DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
+	/* Let the discipline build the ccw chain. */
+	request = device->discipline->write_block(device, block_size);
+	if (IS_ERR(request))
+		return PTR_ERR(request);
+	rc = 0;
+	written = 0;
+	for (i = 0; i < nblocks; i++) {
+		/* Copy data from user space to idal buffer. */
+		if (idal_buffer_from_user(device->char_data.idal_buf,
+					  data, block_size)) {
+			rc = -EFAULT;
+			break;
+		}
+		rc = tape_do_io(device, request);
+		if (rc)
+			break;
+		DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
+			  block_size - request->rescnt);
+		written += block_size - request->rescnt;
+		if (request->rescnt != 0)
+			break;
+		data += block_size;
+	}
+	tape_free_request(request);
+	if (rc == -ENOSPC) {
+		/*
+		 * Ok, the device has no more space. It has NOT written
+		 * the block.
+		 */
+		if (device->discipline->process_eov)
+			device->discipline->process_eov(device);
+		if (written > 0)
+			rc = 0;
+
+	}
+
+	/*
+	 * After doing a write we always need two tapemarks to correctly
+	 * terminate the tape (one to terminate the file, the second to
+	 * flag the end of recorded data.
+	 * Since process_eov positions the tape in front of the written
+	 * tapemark it doesn't hurt to write two marks again.
+	 */
+	if (!rc)
+		device->required_tapemarks = 2;
+
+	return rc ? rc : written;
+}
+
+/*
+ * Character frontend tape device open function.
+ */
+static int
+tapechar_open (struct inode *inode, struct file *filp)
+{
+	struct tape_device *device;
+	int minor, rc;
+
+	DBF_EVENT(6, "TCHAR:open: %i:%i\n",
+		imajor(file_inode(filp)),
+		iminor(file_inode(filp)));
+
+	if (imajor(file_inode(filp)) != tapechar_major)
+		return -ENODEV;
+
+	minor = iminor(file_inode(filp));
+	device = tape_find_device(minor / TAPE_MINORS_PER_DEV);
+	if (IS_ERR(device)) {
+		DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n");
+		return PTR_ERR(device);
+	}
+
+	rc = tape_open(device);
+	if (rc == 0) {
+		filp->private_data = device;
+		stream_open(inode, filp);
+	} else
+		tape_put_device(device);
+
+	return rc;
+}
+
+/*
+ * Character frontend tape device release function.
+ */
+
+static int
+tapechar_release(struct inode *inode, struct file *filp)
+{
+	struct tape_device *device;
+
+	DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
+	device = (struct tape_device *) filp->private_data;
+
+	/*
+	 * If this is the rewinding tape minor then rewind. In that case we
+	 * write all required tapemarks. Otherwise only one to terminate the
+	 * file.
+	 */
+	if ((iminor(inode) & 1) != 0) {
+		if (device->required_tapemarks)
+			tape_std_terminate_write(device);
+		tape_mtop(device, MTREW, 1);
+	} else {
+		if (device->required_tapemarks > 1) {
+			if (tape_mtop(device, MTWEOF, 1) == 0)
+				device->required_tapemarks--;
+		}
+	}
+
+	if (device->char_data.idal_buf != NULL) {
+		idal_buffer_free(device->char_data.idal_buf);
+		device->char_data.idal_buf = NULL;
+	}
+	tape_release(device);
+	filp->private_data = NULL;
+	tape_put_device(device);
+
+	return 0;
+}
+
+/*
+ * Tape device io controls.
+ */
+static int
+__tapechar_ioctl(struct tape_device *device,
+		 unsigned int no, void __user *data)
+{
+	int rc;
+
+	if (no == MTIOCTOP) {
+		struct mtop op;
+
+		if (copy_from_user(&op, data, sizeof(op)) != 0)
+			return -EFAULT;
+		if (op.mt_count < 0)
+			return -EINVAL;
+
+		/*
+		 * Operations that change tape position should write final
+		 * tapemarks.
+		 */
+		switch (op.mt_op) {
+			case MTFSF:
+			case MTBSF:
+			case MTFSR:
+			case MTBSR:
+			case MTREW:
+			case MTOFFL:
+			case MTEOM:
+			case MTRETEN:
+			case MTBSFM:
+			case MTFSFM:
+			case MTSEEK:
+				if (device->required_tapemarks)
+					tape_std_terminate_write(device);
+		}
+		rc = tape_mtop(device, op.mt_op, op.mt_count);
+
+		if (op.mt_op == MTWEOF && rc == 0) {
+			if (op.mt_count > device->required_tapemarks)
+				device->required_tapemarks = 0;
+			else
+				device->required_tapemarks -= op.mt_count;
+		}
+		return rc;
+	}
+	if (no == MTIOCPOS) {
+		/* MTIOCPOS: query the tape position. */
+		struct mtpos pos;
+
+		rc = tape_mtop(device, MTTELL, 1);
+		if (rc < 0)
+			return rc;
+		pos.mt_blkno = rc;
+		return put_user_mtpos(data, &pos);
+	}
+	if (no == MTIOCGET) {
+		/* MTIOCGET: query the tape drive status. */
+		struct mtget get;
+
+		memset(&get, 0, sizeof(get));
+		get.mt_type = MT_ISUNKNOWN;
+		get.mt_resid = 0 /* device->devstat.rescnt */;
+		get.mt_dsreg =
+			((device->char_data.block_size << MT_ST_BLKSIZE_SHIFT)
+			 & MT_ST_BLKSIZE_MASK);
+		/* FIXME: mt_gstat, mt_erreg, mt_fileno */
+		get.mt_gstat = 0;
+		get.mt_erreg = 0;
+		get.mt_fileno = 0;
+		get.mt_gstat  = device->tape_generic_status;
+
+		if (device->medium_state == MS_LOADED) {
+			rc = tape_mtop(device, MTTELL, 1);
+
+			if (rc < 0)
+				return rc;
+
+			if (rc == 0)
+				get.mt_gstat |= GMT_BOT(~0);
+
+			get.mt_blkno = rc;
+		}
+
+		return put_user_mtget(data, &get);
+	}
+	/* Try the discipline ioctl function. */
+	if (device->discipline->ioctl_fn == NULL)
+		return -EINVAL;
+	return device->discipline->ioctl_fn(device, no, (unsigned long)data);
+}
+
+static long
+tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
+{
+	struct tape_device *device;
+	long rc;
+
+	DBF_EVENT(6, "TCHAR:ioct\n");
+
+	device = (struct tape_device *) filp->private_data;
+	mutex_lock(&device->mutex);
+	rc = __tapechar_ioctl(device, no, (void __user *)data);
+	mutex_unlock(&device->mutex);
+	return rc;
+}
+
+#ifdef CONFIG_COMPAT
+static long
+tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
+{
+	struct tape_device *device = filp->private_data;
+	long rc;
+
+	if (no == MTIOCPOS32)
+		no = MTIOCPOS;
+	else if (no == MTIOCGET32)
+		no = MTIOCGET;
+
+	mutex_lock(&device->mutex);
+	rc = __tapechar_ioctl(device, no, compat_ptr(data));
+	mutex_unlock(&device->mutex);
+	return rc;
+}
+#endif /* CONFIG_COMPAT */
+
+/*
+ * Initialize character device frontend.
+ */
+int
+tapechar_init (void)
+{
+	dev_t	dev;
+
+	if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
+		return -1;
+
+	tapechar_major = MAJOR(dev);
+
+	return 0;
+}
+
+/*
+ * cleanup
+ */
+void
+tapechar_exit(void)
+{
+	unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
+}