| /* |
| * Roccat driver for Linux |
| * |
| * Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net> |
| */ |
| |
| /* |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| */ |
| |
| /* |
| * Module roccat is a char device used to report special events of roccat |
| * hardware to userland. These events include requests for on-screen-display of |
| * profile or dpi settings or requests for execution of macro sequences that are |
| * not stored in device. The information in these events depends on hid device |
| * implementation and contains data that is not available in a single hid event |
| * or else hidraw could have been used. |
| * It is inspired by hidraw, but uses only one circular buffer for all readers. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/cdev.h> |
| #include <linux/poll.h> |
| #include <linux/sched/signal.h> |
| #include <linux/hid-roccat.h> |
| #include <linux/module.h> |
| |
| #define ROCCAT_FIRST_MINOR 0 |
| #define ROCCAT_MAX_DEVICES 8 |
| |
| /* should be a power of 2 for performance reason */ |
| #define ROCCAT_CBUF_SIZE 16 |
| |
| struct roccat_report { |
| uint8_t *value; |
| }; |
| |
| struct roccat_device { |
| unsigned int minor; |
| int report_size; |
| int open; |
| int exist; |
| wait_queue_head_t wait; |
| struct device *dev; |
| struct hid_device *hid; |
| struct list_head readers; |
| /* protects modifications of readers list */ |
| struct mutex readers_lock; |
| |
| /* |
| * circular_buffer has one writer and multiple readers with their own |
| * read pointers |
| */ |
| struct roccat_report cbuf[ROCCAT_CBUF_SIZE]; |
| int cbuf_end; |
| struct mutex cbuf_lock; |
| }; |
| |
| struct roccat_reader { |
| struct list_head node; |
| struct roccat_device *device; |
| int cbuf_start; |
| }; |
| |
| static int roccat_major; |
| static struct cdev roccat_cdev; |
| |
| static struct roccat_device *devices[ROCCAT_MAX_DEVICES]; |
| /* protects modifications of devices array */ |
| static DEFINE_MUTEX(devices_lock); |
| |
| static ssize_t roccat_read(struct file *file, char __user *buffer, |
| size_t count, loff_t *ppos) |
| { |
| struct roccat_reader *reader = file->private_data; |
| struct roccat_device *device = reader->device; |
| struct roccat_report *report; |
| ssize_t retval = 0, len; |
| DECLARE_WAITQUEUE(wait, current); |
| |
| mutex_lock(&device->cbuf_lock); |
| |
| /* no data? */ |
| if (reader->cbuf_start == device->cbuf_end) { |
| add_wait_queue(&device->wait, &wait); |
| set_current_state(TASK_INTERRUPTIBLE); |
| |
| /* wait for data */ |
| while (reader->cbuf_start == device->cbuf_end) { |
| if (file->f_flags & O_NONBLOCK) { |
| retval = -EAGAIN; |
| break; |
| } |
| if (signal_pending(current)) { |
| retval = -ERESTARTSYS; |
| break; |
| } |
| if (!device->exist) { |
| retval = -EIO; |
| break; |
| } |
| |
| mutex_unlock(&device->cbuf_lock); |
| schedule(); |
| mutex_lock(&device->cbuf_lock); |
| set_current_state(TASK_INTERRUPTIBLE); |
| } |
| |
| set_current_state(TASK_RUNNING); |
| remove_wait_queue(&device->wait, &wait); |
| } |
| |
| /* here we either have data or a reason to return if retval is set */ |
| if (retval) |
| goto exit_unlock; |
| |
| report = &device->cbuf[reader->cbuf_start]; |
| /* |
| * If report is larger than requested amount of data, rest of report |
| * is lost! |
| */ |
| len = device->report_size > count ? count : device->report_size; |
| |
| if (copy_to_user(buffer, report->value, len)) { |
| retval = -EFAULT; |
| goto exit_unlock; |
| } |
| retval += len; |
| reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; |
| |
| exit_unlock: |
| mutex_unlock(&device->cbuf_lock); |
| return retval; |
| } |
| |
| static __poll_t roccat_poll(struct file *file, poll_table *wait) |
| { |
| struct roccat_reader *reader = file->private_data; |
| poll_wait(file, &reader->device->wait, wait); |
| if (reader->cbuf_start != reader->device->cbuf_end) |
| return EPOLLIN | EPOLLRDNORM; |
| if (!reader->device->exist) |
| return EPOLLERR | EPOLLHUP; |
| return 0; |
| } |
| |
| static int roccat_open(struct inode *inode, struct file *file) |
| { |
| unsigned int minor = iminor(inode); |
| struct roccat_reader *reader; |
| struct roccat_device *device; |
| int error = 0; |
| |
| reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL); |
| if (!reader) |
| return -ENOMEM; |
| |
| mutex_lock(&devices_lock); |
| |
| device = devices[minor]; |
| |
| if (!device) { |
| pr_emerg("roccat device with minor %d doesn't exist\n", minor); |
| error = -ENODEV; |
| goto exit_err_devices; |
| } |
| |
| mutex_lock(&device->readers_lock); |
| |
| if (!device->open++) { |
| /* power on device on adding first reader */ |
| error = hid_hw_power(device->hid, PM_HINT_FULLON); |
| if (error < 0) { |
| --device->open; |
| goto exit_err_readers; |
| } |
| |
| error = hid_hw_open(device->hid); |
| if (error < 0) { |
| hid_hw_power(device->hid, PM_HINT_NORMAL); |
| --device->open; |
| goto exit_err_readers; |
| } |
| } |
| |
| reader->device = device; |
| /* new reader doesn't get old events */ |
| reader->cbuf_start = device->cbuf_end; |
| |
| list_add_tail(&reader->node, &device->readers); |
| file->private_data = reader; |
| |
| exit_err_readers: |
| mutex_unlock(&device->readers_lock); |
| exit_err_devices: |
| mutex_unlock(&devices_lock); |
| if (error) |
| kfree(reader); |
| return error; |
| } |
| |
| static int roccat_release(struct inode *inode, struct file *file) |
| { |
| unsigned int minor = iminor(inode); |
| struct roccat_reader *reader = file->private_data; |
| struct roccat_device *device; |
| |
| mutex_lock(&devices_lock); |
| |
| device = devices[minor]; |
| if (!device) { |
| mutex_unlock(&devices_lock); |
| pr_emerg("roccat device with minor %d doesn't exist\n", minor); |
| return -ENODEV; |
| } |
| |
| mutex_lock(&device->readers_lock); |
| list_del(&reader->node); |
| mutex_unlock(&device->readers_lock); |
| kfree(reader); |
| |
| if (!--device->open) { |
| /* removing last reader */ |
| if (device->exist) { |
| hid_hw_power(device->hid, PM_HINT_NORMAL); |
| hid_hw_close(device->hid); |
| } else { |
| kfree(device); |
| } |
| } |
| |
| mutex_unlock(&devices_lock); |
| |
| return 0; |
| } |
| |
| /* |
| * roccat_report_event() - output data to readers |
| * @minor: minor device number returned by roccat_connect() |
| * @data: pointer to data |
| * |
| * Return value is zero on success, a negative error code on failure. |
| * |
| * This is called from interrupt handler. |
| */ |
| int roccat_report_event(int minor, u8 const *data) |
| { |
| struct roccat_device *device; |
| struct roccat_reader *reader; |
| struct roccat_report *report; |
| uint8_t *new_value; |
| |
| device = devices[minor]; |
| |
| new_value = kmemdup(data, device->report_size, GFP_ATOMIC); |
| if (!new_value) |
| return -ENOMEM; |
| |
| mutex_lock(&device->cbuf_lock); |
| |
| report = &device->cbuf[device->cbuf_end]; |
| |
| /* passing NULL is safe */ |
| kfree(report->value); |
| |
| report->value = new_value; |
| device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE; |
| |
| list_for_each_entry(reader, &device->readers, node) { |
| /* |
| * As we already inserted one element, the buffer can't be |
| * empty. If start and end are equal, buffer is full and we |
| * increase start, so that slow reader misses one event, but |
| * gets the newer ones in the right order. |
| */ |
| if (reader->cbuf_start == device->cbuf_end) |
| reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; |
| } |
| |
| mutex_unlock(&device->cbuf_lock); |
| |
| wake_up_interruptible(&device->wait); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(roccat_report_event); |
| |
| /* |
| * roccat_connect() - create a char device for special event output |
| * @class: the class thats used to create the device. Meant to hold device |
| * specific sysfs attributes. |
| * @hid: the hid device the char device should be connected to. |
| * @report_size: size of reports |
| * |
| * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on |
| * success, a negative error code on failure. |
| */ |
| int roccat_connect(struct class *klass, struct hid_device *hid, int report_size) |
| { |
| unsigned int minor; |
| struct roccat_device *device; |
| int temp; |
| |
| device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL); |
| if (!device) |
| return -ENOMEM; |
| |
| mutex_lock(&devices_lock); |
| |
| for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) { |
| if (devices[minor]) |
| continue; |
| break; |
| } |
| |
| if (minor < ROCCAT_MAX_DEVICES) { |
| devices[minor] = device; |
| } else { |
| mutex_unlock(&devices_lock); |
| kfree(device); |
| return -EINVAL; |
| } |
| |
| device->dev = device_create(klass, &hid->dev, |
| MKDEV(roccat_major, minor), NULL, |
| "%s%s%d", "roccat", hid->driver->name, minor); |
| |
| if (IS_ERR(device->dev)) { |
| devices[minor] = NULL; |
| mutex_unlock(&devices_lock); |
| temp = PTR_ERR(device->dev); |
| kfree(device); |
| return temp; |
| } |
| |
| mutex_unlock(&devices_lock); |
| |
| init_waitqueue_head(&device->wait); |
| INIT_LIST_HEAD(&device->readers); |
| mutex_init(&device->readers_lock); |
| mutex_init(&device->cbuf_lock); |
| device->minor = minor; |
| device->hid = hid; |
| device->exist = 1; |
| device->cbuf_end = 0; |
| device->report_size = report_size; |
| |
| return minor; |
| } |
| EXPORT_SYMBOL_GPL(roccat_connect); |
| |
| /* roccat_disconnect() - remove char device from hid device |
| * @minor: the minor device number returned by roccat_connect() |
| */ |
| void roccat_disconnect(int minor) |
| { |
| struct roccat_device *device; |
| |
| mutex_lock(&devices_lock); |
| device = devices[minor]; |
| mutex_unlock(&devices_lock); |
| |
| device->exist = 0; /* TODO exist maybe not needed */ |
| |
| device_destroy(device->dev->class, MKDEV(roccat_major, minor)); |
| |
| mutex_lock(&devices_lock); |
| devices[minor] = NULL; |
| mutex_unlock(&devices_lock); |
| |
| if (device->open) { |
| hid_hw_close(device->hid); |
| wake_up_interruptible(&device->wait); |
| } else { |
| kfree(device); |
| } |
| } |
| EXPORT_SYMBOL_GPL(roccat_disconnect); |
| |
| static long roccat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct inode *inode = file_inode(file); |
| struct roccat_device *device; |
| unsigned int minor = iminor(inode); |
| long retval = 0; |
| |
| mutex_lock(&devices_lock); |
| |
| device = devices[minor]; |
| if (!device) { |
| retval = -ENODEV; |
| goto out; |
| } |
| |
| switch (cmd) { |
| case ROCCATIOCGREPSIZE: |
| if (put_user(device->report_size, (int __user *)arg)) |
| retval = -EFAULT; |
| break; |
| default: |
| retval = -ENOTTY; |
| } |
| out: |
| mutex_unlock(&devices_lock); |
| return retval; |
| } |
| |
| static const struct file_operations roccat_ops = { |
| .owner = THIS_MODULE, |
| .read = roccat_read, |
| .poll = roccat_poll, |
| .open = roccat_open, |
| .release = roccat_release, |
| .llseek = noop_llseek, |
| .unlocked_ioctl = roccat_ioctl, |
| }; |
| |
| static int __init roccat_init(void) |
| { |
| int retval; |
| dev_t dev_id; |
| |
| retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, |
| ROCCAT_MAX_DEVICES, "roccat"); |
| if (retval < 0) { |
| pr_warn("can't get major number\n"); |
| goto error; |
| } |
| |
| roccat_major = MAJOR(dev_id); |
| |
| cdev_init(&roccat_cdev, &roccat_ops); |
| retval = cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); |
| |
| if (retval < 0) { |
| pr_warn("cannot add cdev\n"); |
| goto cleanup_alloc_chrdev_region; |
| } |
| return 0; |
| |
| |
| cleanup_alloc_chrdev_region: |
| unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); |
| error: |
| return retval; |
| } |
| |
| static void __exit roccat_exit(void) |
| { |
| dev_t dev_id = MKDEV(roccat_major, 0); |
| |
| cdev_del(&roccat_cdev); |
| unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); |
| } |
| |
| module_init(roccat_init); |
| module_exit(roccat_exit); |
| |
| MODULE_AUTHOR("Stefan Achatz"); |
| MODULE_DESCRIPTION("USB Roccat char device"); |
| MODULE_LICENSE("GPL v2"); |