--- /dev/null
+/*
+ * 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.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 unsigned int 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 POLLIN | POLLRDNORM;
+ if (!reader->device->exist)
+ return POLLERR | POLLHUP;
+ 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;
+
+ 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;
+ }
+
+ 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");
+
+ roccat_major = MAJOR(dev_id);
+
+ if (retval < 0) {
+ pr_warn("can't get major number\n");
+ goto error;
+ }
+
+ 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");
Code Review / kvmfornfv.git / blobdiff