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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2021 Xillybus Ltd, http://xillybus.com
*
* Driver for the Xillybus class
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include "xillybus_class.h"
MODULE_DESCRIPTION("Driver for Xillybus class");
MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
MODULE_ALIAS("xillybus_class");
MODULE_LICENSE("GPL v2");
static DEFINE_MUTEX(unit_mutex);
static LIST_HEAD(unit_list);
static struct class *xillybus_class;
#define UNITNAMELEN 16
struct xilly_unit {
struct list_head list_entry;
void *private_data;
struct cdev *cdev;
char name[UNITNAMELEN];
int major;
int lowest_minor;
int num_nodes;
};
int xillybus_init_chrdev(struct device *dev,
const struct file_operations *fops,
struct module *owner,
void *private_data,
unsigned char *idt, unsigned int len,
int num_nodes,
const char *prefix, bool enumerate)
{
int rc;
dev_t mdev;
int i;
char devname[48];
struct device *device;
size_t namelen;
struct xilly_unit *unit, *u;
unit = kzalloc(sizeof(*unit), GFP_KERNEL);
if (!unit)
return -ENOMEM;
mutex_lock(&unit_mutex);
if (!enumerate)
snprintf(unit->name, UNITNAMELEN, "%s", prefix);
for (i = 0; enumerate; i++) {
snprintf(unit->name, UNITNAMELEN, "%s_%02d",
prefix, i);
enumerate = false;
list_for_each_entry(u, &unit_list, list_entry)
if (!strcmp(unit->name, u->name)) {
enumerate = true;
break;
}
}
rc = alloc_chrdev_region(&mdev, 0, num_nodes, unit->name);
if (rc) {
dev_warn(dev, "Failed to obtain major/minors");
goto fail_obtain;
}
unit->major = MAJOR(mdev);
unit->lowest_minor = MINOR(mdev);
unit->num_nodes = num_nodes;
unit->private_data = private_data;
unit->cdev = cdev_alloc();
if (!unit->cdev) {
rc = -ENOMEM;
goto unregister_chrdev;
}
unit->cdev->ops = fops;
unit->cdev->owner = owner;
rc = cdev_add(unit->cdev, MKDEV(unit->major, unit->lowest_minor),
unit->num_nodes);
if (rc) {
dev_err(dev, "Failed to add cdev.\n");
/* kobject_put() is normally done by cdev_del() */
kobject_put(&unit->cdev->kobj);
goto unregister_chrdev;
}
for (i = 0; i < num_nodes; i++) {
namelen = strnlen(idt, len);
if (namelen == len) {
dev_err(dev, "IDT's list of names is too short. This is exceptionally weird, because its CRC is OK\n");
rc = -ENODEV;
goto unroll_device_create;
}
snprintf(devname, sizeof(devname), "%s_%s",
unit->name, idt);
len -= namelen + 1;
idt += namelen + 1;
device = device_create(xillybus_class,
NULL,
MKDEV(unit->major,
i + unit->lowest_minor),
NULL,
"%s", devname);
if (IS_ERR(device)) {
dev_err(dev, "Failed to create %s device. Aborting.\n",
devname);
rc = -ENODEV;
goto unroll_device_create;
}
}
if (len) {
dev_err(dev, "IDT's list of names is too long. This is exceptionally weird, because its CRC is OK\n");
rc = -ENODEV;
goto unroll_device_create;
}
list_add_tail(&unit->list_entry, &unit_list);
dev_info(dev, "Created %d device files.\n", num_nodes);
mutex_unlock(&unit_mutex);
return 0;
unroll_device_create:
for (i--; i >= 0; i--)
device_destroy(xillybus_class, MKDEV(unit->major,
i + unit->lowest_minor));
cdev_del(unit->cdev);
unregister_chrdev:
unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
unit->num_nodes);
fail_obtain:
mutex_unlock(&unit_mutex);
kfree(unit);
return rc;
}
EXPORT_SYMBOL(xillybus_init_chrdev);
void xillybus_cleanup_chrdev(void *private_data,
struct device *dev)
{
int minor;
struct xilly_unit *unit;
bool found = false;
mutex_lock(&unit_mutex);
list_for_each_entry(unit, &unit_list, list_entry)
if (unit->private_data == private_data) {
found = true;
break;
}
if (!found) {
dev_err(dev, "Weird bug: Failed to find unit\n");
mutex_unlock(&unit_mutex);
return;
}
for (minor = unit->lowest_minor;
minor < (unit->lowest_minor + unit->num_nodes);
minor++)
device_destroy(xillybus_class, MKDEV(unit->major, minor));
cdev_del(unit->cdev);
unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
unit->num_nodes);
dev_info(dev, "Removed %d device files.\n",
unit->num_nodes);
list_del(&unit->list_entry);
kfree(unit);
mutex_unlock(&unit_mutex);
}
EXPORT_SYMBOL(xillybus_cleanup_chrdev);
int xillybus_find_inode(struct inode *inode,
void **private_data, int *index)
{
int minor = iminor(inode);
int major = imajor(inode);
struct xilly_unit *unit;
bool found = false;
mutex_lock(&unit_mutex);
list_for_each_entry(unit, &unit_list, list_entry)
if (unit->major == major &&
minor >= unit->lowest_minor &&
minor < (unit->lowest_minor + unit->num_nodes)) {
found = true;
break;
}
mutex_unlock(&unit_mutex);
if (!found)
return -ENODEV;
*private_data = unit->private_data;
*index = minor - unit->lowest_minor;
return 0;
}
EXPORT_SYMBOL(xillybus_find_inode);
static int __init xillybus_class_init(void)
{
xillybus_class = class_create(THIS_MODULE, "xillybus");
if (IS_ERR(xillybus_class)) {
pr_warn("Failed to register xillybus class\n");
return PTR_ERR(xillybus_class);
}
return 0;
}
static void __exit xillybus_class_exit(void)
{
class_destroy(xillybus_class);
}
module_init(xillybus_class_init);
module_exit(xillybus_class_exit);
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