path: root/drivers/uio/uio.c

// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/uio/uio.c
 *
 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
 *
 * Userspace IO
 *
 * Base Functions
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/idr.h>
#include <linux/sched/signal.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/cdev.h>
#include <linux/uio_driver.h>

#define UIO_MAX_DEVICES		(1U << MINORBITS)

static int uio_major;
static struct cdev *uio_cdev;
static DEFINE_IDR(uio_idr);
static const struct file_operations uio_fops;

/* Protect idr accesses */
static DEFINE_MUTEX(minor_lock);

/*
 * attributes
 */

struct uio_map {
	struct kobject kobj;
	struct uio_mem *mem;
};
#define to_map(map) container_of(map, struct uio_map, kobj)

static ssize_t map_name_show(struct uio_mem *mem, char *buf)
{
	if (unlikely(!mem->name))
		mem->name = "";

	return sprintf(buf, "%s\n", mem->name);
}

static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "%pa\n", &mem->addr);
}

static ssize_t map_size_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "%pa\n", &mem->size);
}

static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
}

struct map_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct uio_mem *, char *);
	ssize_t (*store)(struct uio_mem *, const char *, size_t);
};

static struct map_sysfs_entry name_attribute =
	__ATTR(name, S_IRUGO, map_name_show, NULL);
static struct map_sysfs_entry addr_attribute =
	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
static struct map_sysfs_entry size_attribute =
	__ATTR(size, S_IRUGO, map_size_show, NULL);
static struct map_sysfs_entry offset_attribute =
	__ATTR(offset, S_IRUGO, map_offset_show, NULL);

static struct attribute *attrs[] = {
	&name_attribute.attr,
	&addr_attribute.attr,
	&size_attribute.attr,
	&offset_attribute.attr,
	NULL,	/* need to NULL terminate the list of attributes */
};

static void map_release(struct kobject *kobj)
{
	struct uio_map *map = to_map(kobj);
	kfree(map);
}

static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
{
	struct uio_map *map = to_map(kobj);
	struct uio_mem *mem = map->mem;
	struct map_sysfs_entry *entry;

	entry = container_of(attr, struct map_sysfs_entry, attr);

	if (!entry->show)
		return -EIO;

	return entry->show(mem, buf);
}

static const struct sysfs_ops map_sysfs_ops = {
	.show = map_type_show,
};

static struct kobj_type map_attr_type = {
	.release	= map_release,
	.sysfs_ops	= &map_sysfs_ops,
	.default_attrs	= attrs,
};

struct uio_portio {
	struct kobject kobj;
	struct uio_port *port;
};
#define to_portio(portio) container_of(portio, struct uio_portio, kobj)

static ssize_t portio_name_show(struct uio_port *port, char *buf)
{
	if (unlikely(!port->name))
		port->name = "";

	return sprintf(buf, "%s\n", port->name);
}

static ssize_t portio_start_show(struct uio_port *port, char *buf)
{
	return sprintf(buf, "0x%lx\n", port->start);
}

static ssize_t portio_size_show(struct uio_port *port, char *buf)
{
	return sprintf(buf, "0x%lx\n", port->size);
}

static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
{
	const char *porttypes[] = {"none", "x86", "gpio", "other"};

	if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
		return -EINVAL;

	return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
}

struct portio_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct uio_port *, char *);
	ssize_t (*store)(struct uio_port *, const char *, size_t);
};

static struct portio_sysfs_entry portio_name_attribute =
	__ATTR(name, S_IRUGO, portio_name_show, NULL);
static struct portio_sysfs_entry portio_start_attribute =
	__ATTR(start, S_IRUGO, portio_start_show, NULL);
static struct portio_sysfs_entry portio_size_attribute =