diff options
Diffstat (limited to 'drivers/char/xillybus/xillybus_class.c')
| -rw-r--r-- | drivers/char/xillybus/xillybus_class.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c new file mode 100644 index 0000000000..c92a628e38 --- /dev/null +++ b/drivers/char/xillybus/xillybus_class.c @@ -0,0 +1,256 @@ +// 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 const struct class xillybus_class = { + .name = "xillybus", +}; + +#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 = NULL, *iter; + + mutex_lock(&unit_mutex); + + list_for_each_entry(iter, &unit_list, list_entry) + if (iter->private_data == private_data) { + unit = iter; + break; + } + + if (!unit) { + 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 = NULL, *iter; + + mutex_lock(&unit_mutex); + + list_for_each_entry(iter, &unit_list, list_entry) + if (iter->major == major && + minor >= iter->lowest_minor && + minor < (iter->lowest_minor + iter->num_nodes)) { + unit = iter; + break; + } + + if (!unit) { + mutex_unlock(&unit_mutex); + return -ENODEV; + } + + *private_data = unit->private_data; + *index = minor - unit->lowest_minor; + + mutex_unlock(&unit_mutex); + return 0; +} +EXPORT_SYMBOL(xillybus_find_inode); + +static int __init xillybus_class_init(void) +{ + return class_register(&xillybus_class); +} + +static void __exit xillybus_class_exit(void) +{ + class_unregister(&xillybus_class); +} + +module_init(xillybus_class_init); +module_exit(xillybus_class_exit); |