Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 247 insertions, 0 deletions

diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
new file mode 100644
index 000000000..558890ada
--- /dev/null
+++ b/drivers/usb/core/file.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/usb/core/file.c
+ *
+ * (C) Copyright Linus Torvalds 1999
+ * (C) Copyright Johannes Erdfelt 1999-2001
+ * (C) Copyright Andreas Gal 1999
+ * (C) Copyright Gregory P. Smith 1999
+ * (C) Copyright Deti Fliegl 1999 (new USB architecture)
+ * (C) Copyright Randy Dunlap 2000
+ * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
+ *	more docs, etc)
+ * (C) Copyright Yggdrasil Computing, Inc. 2000
+ *     (usb_device_id matching changes by Adam J. Richter)
+ * (C) Copyright Greg Kroah-Hartman 2002-2003
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+
+#include "usb.h"
+
+#define MAX_USB_MINORS	256
+static const struct file_operations *usb_minors[MAX_USB_MINORS];
+static DECLARE_RWSEM(minor_rwsem);
+static DEFINE_MUTEX(init_usb_class_mutex);
+
+static int usb_open(struct inode *inode, struct file *file)
+{
+	int err = -ENODEV;
+	const struct file_operations *new_fops;
+
+	down_read(&minor_rwsem);
+	new_fops = fops_get(usb_minors[iminor(inode)]);
+
+	if (!new_fops)
+		goto done;
+
+	replace_fops(file, new_fops);
+	/* Curiouser and curiouser... NULL ->open() as "no device" ? */
+	if (file->f_op->open)
+		err = file->f_op->open(inode, file);
+ done:
+	up_read(&minor_rwsem);
+	return err;
+}
+
+static const struct file_operations usb_fops = {
+	.owner =	THIS_MODULE,
+	.open =		usb_open,
+	.llseek =	noop_llseek,
+};
+
+static struct usb_class {
+	struct kref kref;
+	struct class *class;
+} *usb_class;
+
+static char *usb_devnode(struct device *dev, umode_t *mode)
+{
+	struct usb_class_driver *drv;
+
+	drv = dev_get_drvdata(dev);
+	if (!drv || !drv->devnode)
+		return NULL;
+	return drv->devnode(dev, mode);
+}
+
+static int init_usb_class(void)
+{
+	int result = 0;
+
+	if (usb_class != NULL) {
+		kref_get(&usb_class->kref);
+		goto exit;
+	}
+
+	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
+	if (!usb_class) {
+		result = -ENOMEM;
+		goto exit;
+	}
+
+	kref_init(&usb_class->kref);
+	usb_class->class = class_create(THIS_MODULE, "usbmisc");
+	if (IS_ERR(usb_class->class)) {
+		result = PTR_ERR(usb_class->class);
+		printk(KERN_ERR "class_create failed for usb devices\n");
+		kfree(usb_class);
+		usb_class = NULL;
+		goto exit;
+	}
+	usb_class->class->devnode = usb_devnode;
+
+exit:
+	return result;
+}
+
+static void release_usb_class(struct kref *kref)
+{
+	/* Ok, we cheat as we know we only have one usb_class */
+	class_destroy(usb_class->class);
+	kfree(usb_class);
+	usb_class = NULL;
+}
+
+static void destroy_usb_class(void)
+{
+	mutex_lock(&init_usb_class_mutex);
+	kref_put(&usb_class->kref, release_usb_class);
+	mutex_unlock(&init_usb_class_mutex);
+}
+
+int usb_major_init(void)
+{
+	int error;
+
+	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
+	if (error)
+		printk(KERN_ERR "Unable to get major %d for usb devices\n",
+		       USB_MAJOR);
+
+	return error;
+}
+
+void usb_major_cleanup(void)
+{
+	unregister_chrdev(USB_MAJOR, "usb");
+}
+
+/**
+ * usb_register_dev - register a USB device, and ask for a minor number
+ * @intf: pointer to the usb_interface that is being registered
+ * @class_driver: pointer to the usb_class_driver for this device
+ *
+ * This should be called by all USB drivers that use the USB major number.
+ * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
+ * dynamically allocated out of the list of available ones.  If it is not
+ * enabled, the minor number will be based on the next available free minor,
+ * starting at the class_driver->minor_base.
+ *
+ * This function also creates a usb class device in the sysfs tree.
+ *
+ * usb_deregister_dev() must be called when the driver is done with
+ * the minor numbers given out by this function.
+ *
+ * Return: -EINVAL if something bad happens with trying to register a
+ * device, and 0 on success.
+ */
+int usb_register_dev(struct usb_interface *intf,
+		     struct usb_class_driver *class_driver)
+{
+	int retval;
+	int minor_base = class_driver->minor_base;
+	int minor;
+	char name[20];
+
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+	/*
+	 * We don't care what the device tries to start at, we want to start
+	 * at zero to pack the devices into the smallest available space with
+	 * no holes in the minor range.
+	 */
+	minor_base = 0;
+#endif
+
+	if (class_driver->fops == NULL)
+		return -EINVAL;
+	if (intf->minor >= 0)
+		return -EADDRINUSE;
+
+	mutex_lock(&init_usb_class_mutex);
+	retval = init_usb_class();
+	mutex_unlock(&init_usb_class_mutex);
+
+	if (retval)
+		return retval;
+
+	dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base);
+
+	down_write(&minor_rwsem);
+	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
+		if (usb_minors[minor])
+			continue;
+
+		usb_minors[minor] = class_driver->fops;
+		intf->minor = minor;
+		break;
+	}
+	if (intf->minor < 0) {
+		up_write(&minor_rwsem);
+		return -EXFULL;
+	}
+
+	/* create a usb class device for this usb interface */
+	snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
+	intf->usb_dev = device_create(usb_class->class, &intf->dev,
+				      MKDEV(USB_MAJOR, minor), class_driver,
+				      "%s", kbasename(name));
+	if (IS_ERR(intf->usb_dev)) {
+		usb_minors[minor] = NULL;
+		intf->minor = -1;
+		retval = PTR_ERR(intf->usb_dev);
+	}
+	up_write(&minor_rwsem);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_register_dev);
+
+/**
+ * usb_deregister_dev - deregister a USB device's dynamic minor.
+ * @intf: pointer to the usb_interface that is being deregistered
+ * @class_driver: pointer to the usb_class_driver for this device
+ *
+ * Used in conjunction with usb_register_dev().  This function is called
+ * when the USB driver is finished with the minor numbers gotten from a
+ * call to usb_register_dev() (usually when the device is disconnected
+ * from the system.)
+ *
+ * This function also removes the usb class device from the sysfs tree.
+ *
+ * This should be called by all drivers that use the USB major number.
+ */
+void usb_deregister_dev(struct usb_interface *intf,
+			struct usb_class_driver *class_driver)
+{
+	if (intf->minor == -1)
+		return;
+
+	dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);
+	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
+
+	down_write(&minor_rwsem);
+	usb_minors[intf->minor] = NULL;
+	up_write(&minor_rwsem);
+
+	intf->usb_dev = NULL;
+	intf->minor = -1;
+	destroy_usb_class();
+}
+EXPORT_SYMBOL_GPL(usb_deregister_dev);