1 files changed, 461 insertions, 0 deletions
diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
new file mode 100644
index 000000000..6da80e442
--- /dev/null
+++ b/drivers/hid/hid-roccat.c
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Roccat driver for Linux
+ *
+ * Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net>
+ */
+
+/*
+ */
+
+/*
+ * 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");