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56731c68f3
The variable retval is being initialized with a value that is never read and it is being updated later with a new value. The initialization is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/20200425124448.139532-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1085 lines
23 KiB
C
1085 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* drivers/uio/uio.c
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*
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* Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
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* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
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* Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
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*
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* Userspace IO
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*
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* Base Functions
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/poll.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/idr.h>
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#include <linux/sched/signal.h>
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#include <linux/string.h>
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#include <linux/kobject.h>
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#include <linux/cdev.h>
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#include <linux/uio_driver.h>
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#define UIO_MAX_DEVICES (1U << MINORBITS)
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static int uio_major;
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static struct cdev *uio_cdev;
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static DEFINE_IDR(uio_idr);
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static const struct file_operations uio_fops;
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/* Protect idr accesses */
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static DEFINE_MUTEX(minor_lock);
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/*
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* attributes
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*/
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struct uio_map {
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struct kobject kobj;
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struct uio_mem *mem;
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};
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#define to_map(map) container_of(map, struct uio_map, kobj)
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static ssize_t map_name_show(struct uio_mem *mem, char *buf)
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{
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if (unlikely(!mem->name))
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mem->name = "";
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return sprintf(buf, "%s\n", mem->name);
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}
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static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
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{
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return sprintf(buf, "%pa\n", &mem->addr);
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}
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static ssize_t map_size_show(struct uio_mem *mem, char *buf)
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{
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return sprintf(buf, "%pa\n", &mem->size);
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}
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static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
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{
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return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
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}
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struct map_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct uio_mem *, char *);
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ssize_t (*store)(struct uio_mem *, const char *, size_t);
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};
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static struct map_sysfs_entry name_attribute =
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__ATTR(name, S_IRUGO, map_name_show, NULL);
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static struct map_sysfs_entry addr_attribute =
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__ATTR(addr, S_IRUGO, map_addr_show, NULL);
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static struct map_sysfs_entry size_attribute =
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__ATTR(size, S_IRUGO, map_size_show, NULL);
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static struct map_sysfs_entry offset_attribute =
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__ATTR(offset, S_IRUGO, map_offset_show, NULL);
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static struct attribute *attrs[] = {
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&name_attribute.attr,
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&addr_attribute.attr,
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&size_attribute.attr,
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&offset_attribute.attr,
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NULL, /* need to NULL terminate the list of attributes */
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};
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static void map_release(struct kobject *kobj)
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{
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struct uio_map *map = to_map(kobj);
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kfree(map);
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}
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static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct uio_map *map = to_map(kobj);
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struct uio_mem *mem = map->mem;
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struct map_sysfs_entry *entry;
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entry = container_of(attr, struct map_sysfs_entry, attr);
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if (!entry->show)
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return -EIO;
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return entry->show(mem, buf);
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}
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static const struct sysfs_ops map_sysfs_ops = {
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.show = map_type_show,
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};
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static struct kobj_type map_attr_type = {
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.release = map_release,
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.sysfs_ops = &map_sysfs_ops,
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.default_attrs = attrs,
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};
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struct uio_portio {
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struct kobject kobj;
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struct uio_port *port;
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};
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#define to_portio(portio) container_of(portio, struct uio_portio, kobj)
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static ssize_t portio_name_show(struct uio_port *port, char *buf)
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{
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if (unlikely(!port->name))
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port->name = "";
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return sprintf(buf, "%s\n", port->name);
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}
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static ssize_t portio_start_show(struct uio_port *port, char *buf)
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{
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return sprintf(buf, "0x%lx\n", port->start);
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}
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static ssize_t portio_size_show(struct uio_port *port, char *buf)
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{
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return sprintf(buf, "0x%lx\n", port->size);
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}
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static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
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{
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const char *porttypes[] = {"none", "x86", "gpio", "other"};
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if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
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return -EINVAL;
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return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
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}
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struct portio_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct uio_port *, char *);
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ssize_t (*store)(struct uio_port *, const char *, size_t);
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};
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static struct portio_sysfs_entry portio_name_attribute =
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__ATTR(name, S_IRUGO, portio_name_show, NULL);
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static struct portio_sysfs_entry portio_start_attribute =
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__ATTR(start, S_IRUGO, portio_start_show, NULL);
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static struct portio_sysfs_entry portio_size_attribute =
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__ATTR(size, S_IRUGO, portio_size_show, NULL);
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static struct portio_sysfs_entry portio_porttype_attribute =
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__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
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static struct attribute *portio_attrs[] = {
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&portio_name_attribute.attr,
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&portio_start_attribute.attr,
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&portio_size_attribute.attr,
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&portio_porttype_attribute.attr,
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NULL,
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};
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static void portio_release(struct kobject *kobj)
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{
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struct uio_portio *portio = to_portio(kobj);
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kfree(portio);
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}
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static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct uio_portio *portio = to_portio(kobj);
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struct uio_port *port = portio->port;
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struct portio_sysfs_entry *entry;
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entry = container_of(attr, struct portio_sysfs_entry, attr);
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if (!entry->show)
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return -EIO;
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return entry->show(port, buf);
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}
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static const struct sysfs_ops portio_sysfs_ops = {
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.show = portio_type_show,
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};
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static struct kobj_type portio_attr_type = {
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.release = portio_release,
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.sysfs_ops = &portio_sysfs_ops,
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.default_attrs = portio_attrs,
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};
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static ssize_t name_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct uio_device *idev = dev_get_drvdata(dev);
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int ret;
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mutex_lock(&idev->info_lock);
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if (!idev->info) {
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ret = -EINVAL;
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dev_err(dev, "the device has been unregistered\n");
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goto out;
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}
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ret = sprintf(buf, "%s\n", idev->info->name);
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out:
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mutex_unlock(&idev->info_lock);
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return ret;
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}
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static DEVICE_ATTR_RO(name);
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static ssize_t version_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct uio_device *idev = dev_get_drvdata(dev);
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int ret;
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mutex_lock(&idev->info_lock);
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if (!idev->info) {
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ret = -EINVAL;
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dev_err(dev, "the device has been unregistered\n");
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goto out;
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}
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ret = sprintf(buf, "%s\n", idev->info->version);
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out:
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mutex_unlock(&idev->info_lock);
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return ret;
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}
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static DEVICE_ATTR_RO(version);
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static ssize_t event_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct uio_device *idev = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
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}
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static DEVICE_ATTR_RO(event);
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static struct attribute *uio_attrs[] = {
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&dev_attr_name.attr,
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&dev_attr_version.attr,
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&dev_attr_event.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(uio);
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/* UIO class infrastructure */
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static struct class uio_class = {
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.name = "uio",
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.dev_groups = uio_groups,
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};
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static bool uio_class_registered;
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/*
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* device functions
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*/
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static int uio_dev_add_attributes(struct uio_device *idev)
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{
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int ret;
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int mi, pi;
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int map_found = 0;
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int portio_found = 0;
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struct uio_mem *mem;
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struct uio_map *map;
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struct uio_port *port;
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struct uio_portio *portio;
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for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
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mem = &idev->info->mem[mi];
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if (mem->size == 0)
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break;
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if (!map_found) {
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map_found = 1;
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idev->map_dir = kobject_create_and_add("maps",
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&idev->dev.kobj);
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if (!idev->map_dir) {
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ret = -ENOMEM;
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goto err_map;
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}
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}
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map = kzalloc(sizeof(*map), GFP_KERNEL);
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if (!map) {
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ret = -ENOMEM;
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goto err_map;
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}
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kobject_init(&map->kobj, &map_attr_type);
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map->mem = mem;
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mem->map = map;
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ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
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if (ret)
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goto err_map_kobj;
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ret = kobject_uevent(&map->kobj, KOBJ_ADD);
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if (ret)
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goto err_map_kobj;
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}
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for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
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port = &idev->info->port[pi];
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if (port->size == 0)
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break;
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if (!portio_found) {
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portio_found = 1;
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idev->portio_dir = kobject_create_and_add("portio",
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&idev->dev.kobj);
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if (!idev->portio_dir) {
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ret = -ENOMEM;
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goto err_portio;
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}
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}
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portio = kzalloc(sizeof(*portio), GFP_KERNEL);
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if (!portio) {
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ret = -ENOMEM;
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goto err_portio;
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}
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kobject_init(&portio->kobj, &portio_attr_type);
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portio->port = port;
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port->portio = portio;
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ret = kobject_add(&portio->kobj, idev->portio_dir,
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"port%d", pi);
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if (ret)
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goto err_portio_kobj;
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ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
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if (ret)
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goto err_portio_kobj;
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}
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return 0;
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err_portio:
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pi--;
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err_portio_kobj:
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for (; pi >= 0; pi--) {
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port = &idev->info->port[pi];
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portio = port->portio;
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kobject_put(&portio->kobj);
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}
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kobject_put(idev->portio_dir);
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err_map:
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mi--;
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err_map_kobj:
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for (; mi >= 0; mi--) {
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mem = &idev->info->mem[mi];
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map = mem->map;
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kobject_put(&map->kobj);
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}
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kobject_put(idev->map_dir);
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dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret);
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return ret;
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}
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static void uio_dev_del_attributes(struct uio_device *idev)
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{
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int i;
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struct uio_mem *mem;
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struct uio_port *port;
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for (i = 0; i < MAX_UIO_MAPS; i++) {
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mem = &idev->info->mem[i];
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if (mem->size == 0)
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break;
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kobject_put(&mem->map->kobj);
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}
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kobject_put(idev->map_dir);
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for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
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port = &idev->info->port[i];
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if (port->size == 0)
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break;
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kobject_put(&port->portio->kobj);
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}
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kobject_put(idev->portio_dir);
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}
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static int uio_get_minor(struct uio_device *idev)
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{
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int retval;
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mutex_lock(&minor_lock);
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retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
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if (retval >= 0) {
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idev->minor = retval;
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retval = 0;
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} else if (retval == -ENOSPC) {
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dev_err(&idev->dev, "too many uio devices\n");
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retval = -EINVAL;
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}
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mutex_unlock(&minor_lock);
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return retval;
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}
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static void uio_free_minor(struct uio_device *idev)
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{
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mutex_lock(&minor_lock);
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idr_remove(&uio_idr, idev->minor);
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mutex_unlock(&minor_lock);
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}
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/**
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* uio_event_notify - trigger an interrupt event
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* @info: UIO device capabilities
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*/
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void uio_event_notify(struct uio_info *info)
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{
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struct uio_device *idev = info->uio_dev;
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atomic_inc(&idev->event);
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wake_up_interruptible(&idev->wait);
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kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
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}
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EXPORT_SYMBOL_GPL(uio_event_notify);
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/**
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* uio_interrupt - hardware interrupt handler
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* @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
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* @dev_id: Pointer to the devices uio_device structure
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*/
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static irqreturn_t uio_interrupt(int irq, void *dev_id)
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{
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struct uio_device *idev = (struct uio_device *)dev_id;
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irqreturn_t ret;
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|
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ret = idev->info->handler(irq, idev->info);
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if (ret == IRQ_HANDLED)
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uio_event_notify(idev->info);
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return ret;
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}
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|
|
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struct uio_listener {
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struct uio_device *dev;
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s32 event_count;
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};
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|
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static int uio_open(struct inode *inode, struct file *filep)
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{
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struct uio_device *idev;
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struct uio_listener *listener;
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int ret = 0;
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|
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mutex_lock(&minor_lock);
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idev = idr_find(&uio_idr, iminor(inode));
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mutex_unlock(&minor_lock);
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if (!idev) {
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ret = -ENODEV;
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goto out;
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}
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|
|
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get_device(&idev->dev);
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|
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if (!try_module_get(idev->owner)) {
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ret = -ENODEV;
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goto err_module_get;
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}
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|
|
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listener = kmalloc(sizeof(*listener), GFP_KERNEL);
|
|
if (!listener) {
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ret = -ENOMEM;
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goto err_alloc_listener;
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}
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|
|
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listener->dev = idev;
|
|
listener->event_count = atomic_read(&idev->event);
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filep->private_data = listener;
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|
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mutex_lock(&idev->info_lock);
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|
if (!idev->info) {
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mutex_unlock(&idev->info_lock);
|
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ret = -EINVAL;
|
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goto err_infoopen;
|
|
}
|
|
|
|
if (idev->info->open)
|
|
ret = idev->info->open(idev->info, inode);
|
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mutex_unlock(&idev->info_lock);
|
|
if (ret)
|
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goto err_infoopen;
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|
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return 0;
|
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|
|
err_infoopen:
|
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kfree(listener);
|
|
|
|
err_alloc_listener:
|
|
module_put(idev->owner);
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|
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err_module_get:
|
|
put_device(&idev->dev);
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|
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out:
|
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return ret;
|
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}
|
|
|
|
static int uio_fasync(int fd, struct file *filep, int on)
|
|
{
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
|
|
return fasync_helper(fd, filep, on, &idev->async_queue);
|
|
}
|
|
|
|
static int uio_release(struct inode *inode, struct file *filep)
|
|
{
|
|
int ret = 0;
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
if (idev->info && idev->info->release)
|
|
ret = idev->info->release(idev->info, inode);
|
|
mutex_unlock(&idev->info_lock);
|
|
|
|
module_put(idev->owner);
|
|
kfree(listener);
|
|
put_device(&idev->dev);
|
|
return ret;
|
|
}
|
|
|
|
static __poll_t uio_poll(struct file *filep, poll_table *wait)
|
|
{
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
__poll_t ret = 0;
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
if (!idev->info || !idev->info->irq)
|
|
ret = -EIO;
|
|
mutex_unlock(&idev->info_lock);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
poll_wait(filep, &idev->wait, wait);
|
|
if (listener->event_count != atomic_read(&idev->event))
|
|
return EPOLLIN | EPOLLRDNORM;
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t uio_read(struct file *filep, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
ssize_t retval = 0;
|
|
s32 event_count;
|
|
|
|
if (count != sizeof(s32))
|
|
return -EINVAL;
|
|
|
|
add_wait_queue(&idev->wait, &wait);
|
|
|
|
do {
|
|
mutex_lock(&idev->info_lock);
|
|
if (!idev->info || !idev->info->irq) {
|
|
retval = -EIO;
|
|
mutex_unlock(&idev->info_lock);
|
|
break;
|
|
}
|
|
mutex_unlock(&idev->info_lock);
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
event_count = atomic_read(&idev->event);
|
|
if (event_count != listener->event_count) {
|
|
__set_current_state(TASK_RUNNING);
|
|
if (copy_to_user(buf, &event_count, count))
|
|
retval = -EFAULT;
|
|
else {
|
|
listener->event_count = event_count;
|
|
retval = count;
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (filep->f_flags & O_NONBLOCK) {
|
|
retval = -EAGAIN;
|
|
break;
|
|
}
|
|
|
|
if (signal_pending(current)) {
|
|
retval = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
schedule();
|
|
} while (1);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
remove_wait_queue(&idev->wait, &wait);
|
|
|
|
return retval;
|
|
}
|
|
|
|
static ssize_t uio_write(struct file *filep, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
ssize_t retval;
|
|
s32 irq_on;
|
|
|
|
if (count != sizeof(s32))
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&irq_on, buf, count))
|
|
return -EFAULT;
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
if (!idev->info) {
|
|
retval = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (!idev->info->irq) {
|
|
retval = -EIO;
|
|
goto out;
|
|
}
|
|
|
|
if (!idev->info->irqcontrol) {
|
|
retval = -ENOSYS;
|
|
goto out;
|
|
}
|
|
|
|
retval = idev->info->irqcontrol(idev->info, irq_on);
|
|
|
|
out:
|
|
mutex_unlock(&idev->info_lock);
|
|
return retval ? retval : sizeof(s32);
|
|
}
|
|
|
|
static int uio_find_mem_index(struct vm_area_struct *vma)
|
|
{
|
|
struct uio_device *idev = vma->vm_private_data;
|
|
|
|
if (vma->vm_pgoff < MAX_UIO_MAPS) {
|
|
if (idev->info->mem[vma->vm_pgoff].size == 0)
|
|
return -1;
|
|
return (int)vma->vm_pgoff;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static vm_fault_t uio_vma_fault(struct vm_fault *vmf)
|
|
{
|
|
struct uio_device *idev = vmf->vma->vm_private_data;
|
|
struct page *page;
|
|
unsigned long offset;
|
|
void *addr;
|
|
vm_fault_t ret = 0;
|
|
int mi;
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
if (!idev->info) {
|
|
ret = VM_FAULT_SIGBUS;
|
|
goto out;
|
|
}
|
|
|
|
mi = uio_find_mem_index(vmf->vma);
|
|
if (mi < 0) {
|
|
ret = VM_FAULT_SIGBUS;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* We need to subtract mi because userspace uses offset = N*PAGE_SIZE
|
|
* to use mem[N].
|
|
*/
|
|
offset = (vmf->pgoff - mi) << PAGE_SHIFT;
|
|
|
|
addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
|
|
if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
|
|
page = virt_to_page(addr);
|
|
else
|
|
page = vmalloc_to_page(addr);
|
|
get_page(page);
|
|
vmf->page = page;
|
|
|
|
out:
|
|
mutex_unlock(&idev->info_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct vm_operations_struct uio_logical_vm_ops = {
|
|
.fault = uio_vma_fault,
|
|
};
|
|
|
|
static int uio_mmap_logical(struct vm_area_struct *vma)
|
|
{
|
|
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
|
|
vma->vm_ops = &uio_logical_vm_ops;
|
|
return 0;
|
|
}
|
|
|
|
static const struct vm_operations_struct uio_physical_vm_ops = {
|
|
#ifdef CONFIG_HAVE_IOREMAP_PROT
|
|
.access = generic_access_phys,
|
|
#endif
|
|
};
|
|
|
|
static int uio_mmap_physical(struct vm_area_struct *vma)
|
|
{
|
|
struct uio_device *idev = vma->vm_private_data;
|
|
int mi = uio_find_mem_index(vma);
|
|
struct uio_mem *mem;
|
|
|
|
if (mi < 0)
|
|
return -EINVAL;
|
|
mem = idev->info->mem + mi;
|
|
|
|
if (mem->addr & ~PAGE_MASK)
|
|
return -ENODEV;
|
|
if (vma->vm_end - vma->vm_start > mem->size)
|
|
return -EINVAL;
|
|
|
|
vma->vm_ops = &uio_physical_vm_ops;
|
|
if (idev->info->mem[mi].memtype == UIO_MEM_PHYS)
|
|
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
|
|
|
|
/*
|
|
* We cannot use the vm_iomap_memory() helper here,
|
|
* because vma->vm_pgoff is the map index we looked
|
|
* up above in uio_find_mem_index(), rather than an
|
|
* actual page offset into the mmap.
|
|
*
|
|
* So we just do the physical mmap without a page
|
|
* offset.
|
|
*/
|
|
return remap_pfn_range(vma,
|
|
vma->vm_start,
|
|
mem->addr >> PAGE_SHIFT,
|
|
vma->vm_end - vma->vm_start,
|
|
vma->vm_page_prot);
|
|
}
|
|
|
|
static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
|
|
{
|
|
struct uio_listener *listener = filep->private_data;
|
|
struct uio_device *idev = listener->dev;
|
|
int mi;
|
|
unsigned long requested_pages, actual_pages;
|
|
int ret = 0;
|
|
|
|
if (vma->vm_end < vma->vm_start)
|
|
return -EINVAL;
|
|
|
|
vma->vm_private_data = idev;
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
if (!idev->info) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
mi = uio_find_mem_index(vma);
|
|
if (mi < 0) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
requested_pages = vma_pages(vma);
|
|
actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
|
|
+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
|
|
if (requested_pages > actual_pages) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (idev->info->mmap) {
|
|
ret = idev->info->mmap(idev->info, vma);
|
|
goto out;
|
|
}
|
|
|
|
switch (idev->info->mem[mi].memtype) {
|
|
case UIO_MEM_IOVA:
|
|
case UIO_MEM_PHYS:
|
|
ret = uio_mmap_physical(vma);
|
|
break;
|
|
case UIO_MEM_LOGICAL:
|
|
case UIO_MEM_VIRTUAL:
|
|
ret = uio_mmap_logical(vma);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
out:
|
|
mutex_unlock(&idev->info_lock);
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations uio_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = uio_open,
|
|
.release = uio_release,
|
|
.read = uio_read,
|
|
.write = uio_write,
|
|
.mmap = uio_mmap,
|
|
.poll = uio_poll,
|
|
.fasync = uio_fasync,
|
|
.llseek = noop_llseek,
|
|
};
|
|
|
|
static int uio_major_init(void)
|
|
{
|
|
static const char name[] = "uio";
|
|
struct cdev *cdev = NULL;
|
|
dev_t uio_dev = 0;
|
|
int result;
|
|
|
|
result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
|
|
if (result)
|
|
goto out;
|
|
|
|
result = -ENOMEM;
|
|
cdev = cdev_alloc();
|
|
if (!cdev)
|
|
goto out_unregister;
|
|
|
|
cdev->owner = THIS_MODULE;
|
|
cdev->ops = &uio_fops;
|
|
kobject_set_name(&cdev->kobj, "%s", name);
|
|
|
|
result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
|
|
if (result)
|
|
goto out_put;
|
|
|
|
uio_major = MAJOR(uio_dev);
|
|
uio_cdev = cdev;
|
|
return 0;
|
|
out_put:
|
|
kobject_put(&cdev->kobj);
|
|
out_unregister:
|
|
unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
|
|
out:
|
|
return result;
|
|
}
|
|
|
|
static void uio_major_cleanup(void)
|
|
{
|
|
unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
|
|
cdev_del(uio_cdev);
|
|
}
|
|
|
|
static int init_uio_class(void)
|
|
{
|
|
int ret;
|
|
|
|
/* This is the first time in here, set everything up properly */
|
|
ret = uio_major_init();
|
|
if (ret)
|
|
goto exit;
|
|
|
|
ret = class_register(&uio_class);
|
|
if (ret) {
|
|
printk(KERN_ERR "class_register failed for uio\n");
|
|
goto err_class_register;
|
|
}
|
|
|
|
uio_class_registered = true;
|
|
|
|
return 0;
|
|
|
|
err_class_register:
|
|
uio_major_cleanup();
|
|
exit:
|
|
return ret;
|
|
}
|
|
|
|
static void release_uio_class(void)
|
|
{
|
|
uio_class_registered = false;
|
|
class_unregister(&uio_class);
|
|
uio_major_cleanup();
|
|
}
|
|
|
|
static void uio_device_release(struct device *dev)
|
|
{
|
|
struct uio_device *idev = dev_get_drvdata(dev);
|
|
|
|
kfree(idev);
|
|
}
|
|
|
|
/**
|
|
* uio_register_device - register a new userspace IO device
|
|
* @owner: module that creates the new device
|
|
* @parent: parent device
|
|
* @info: UIO device capabilities
|
|
*
|
|
* returns zero on success or a negative error code.
|
|
*/
|
|
int __uio_register_device(struct module *owner,
|
|
struct device *parent,
|
|
struct uio_info *info)
|
|
{
|
|
struct uio_device *idev;
|
|
int ret = 0;
|
|
|
|
if (!uio_class_registered)
|
|
return -EPROBE_DEFER;
|
|
|
|
if (!parent || !info || !info->name || !info->version)
|
|
return -EINVAL;
|
|
|
|
info->uio_dev = NULL;
|
|
|
|
idev = kzalloc(sizeof(*idev), GFP_KERNEL);
|
|
if (!idev) {
|
|
return -ENOMEM;
|
|
}
|
|
|
|
idev->owner = owner;
|
|
idev->info = info;
|
|
mutex_init(&idev->info_lock);
|
|
init_waitqueue_head(&idev->wait);
|
|
atomic_set(&idev->event, 0);
|
|
|
|
ret = uio_get_minor(idev);
|
|
if (ret) {
|
|
kfree(idev);
|
|
return ret;
|
|
}
|
|
|
|
device_initialize(&idev->dev);
|
|
idev->dev.devt = MKDEV(uio_major, idev->minor);
|
|
idev->dev.class = &uio_class;
|
|
idev->dev.parent = parent;
|
|
idev->dev.release = uio_device_release;
|
|
dev_set_drvdata(&idev->dev, idev);
|
|
|
|
ret = dev_set_name(&idev->dev, "uio%d", idev->minor);
|
|
if (ret)
|
|
goto err_device_create;
|
|
|
|
ret = device_add(&idev->dev);
|
|
if (ret)
|
|
goto err_device_create;
|
|
|
|
ret = uio_dev_add_attributes(idev);
|
|
if (ret)
|
|
goto err_uio_dev_add_attributes;
|
|
|
|
info->uio_dev = idev;
|
|
|
|
if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
|
|
/*
|
|
* Note that we deliberately don't use devm_request_irq
|
|
* here. The parent module can unregister the UIO device
|
|
* and call pci_disable_msi, which requires that this
|
|
* irq has been freed. However, the device may have open
|
|
* FDs at the time of unregister and therefore may not be
|
|
* freed until they are released.
|
|
*/
|
|
ret = request_irq(info->irq, uio_interrupt,
|
|
info->irq_flags, info->name, idev);
|
|
if (ret) {
|
|
info->uio_dev = NULL;
|
|
goto err_request_irq;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
err_request_irq:
|
|
uio_dev_del_attributes(idev);
|
|
err_uio_dev_add_attributes:
|
|
device_del(&idev->dev);
|
|
err_device_create:
|
|
uio_free_minor(idev);
|
|
put_device(&idev->dev);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__uio_register_device);
|
|
|
|
static void devm_uio_unregister_device(struct device *dev, void *res)
|
|
{
|
|
uio_unregister_device(*(struct uio_info **)res);
|
|
}
|
|
|
|
/**
|
|
* devm_uio_register_device - Resource managed uio_register_device()
|
|
* @owner: module that creates the new device
|
|
* @parent: parent device
|
|
* @info: UIO device capabilities
|
|
*
|
|
* returns zero on success or a negative error code.
|
|
*/
|
|
int __devm_uio_register_device(struct module *owner,
|
|
struct device *parent,
|
|
struct uio_info *info)
|
|
{
|
|
struct uio_info **ptr;
|
|
int ret;
|
|
|
|
ptr = devres_alloc(devm_uio_unregister_device, sizeof(*ptr),
|
|
GFP_KERNEL);
|
|
if (!ptr)
|
|
return -ENOMEM;
|
|
|
|
*ptr = info;
|
|
ret = __uio_register_device(owner, parent, info);
|
|
if (ret) {
|
|
devres_free(ptr);
|
|
return ret;
|
|
}
|
|
|
|
devres_add(parent, ptr);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__devm_uio_register_device);
|
|
|
|
/**
|
|
* uio_unregister_device - unregister a industrial IO device
|
|
* @info: UIO device capabilities
|
|
*
|
|
*/
|
|
void uio_unregister_device(struct uio_info *info)
|
|
{
|
|
struct uio_device *idev;
|
|
|
|
if (!info || !info->uio_dev)
|
|
return;
|
|
|
|
idev = info->uio_dev;
|
|
|
|
uio_free_minor(idev);
|
|
|
|
mutex_lock(&idev->info_lock);
|
|
uio_dev_del_attributes(idev);
|
|
|
|
if (info->irq && info->irq != UIO_IRQ_CUSTOM)
|
|
free_irq(info->irq, idev);
|
|
|
|
idev->info = NULL;
|
|
mutex_unlock(&idev->info_lock);
|
|
|
|
wake_up_interruptible(&idev->wait);
|
|
kill_fasync(&idev->async_queue, SIGIO, POLL_HUP);
|
|
|
|
device_unregister(&idev->dev);
|
|
|
|
return;
|
|
}
|
|
EXPORT_SYMBOL_GPL(uio_unregister_device);
|
|
|
|
static int __init uio_init(void)
|
|
{
|
|
return init_uio_class();
|
|
}
|
|
|
|
static void __exit uio_exit(void)
|
|
{
|
|
release_uio_class();
|
|
idr_destroy(&uio_idr);
|
|
}
|
|
|
|
module_init(uio_init)
|
|
module_exit(uio_exit)
|
|
MODULE_LICENSE("GPL v2");
|