diff options
| -rw-r--r-- | Documentation/hid/uhid.txt | 169 | ||||
| -rw-r--r-- | MAINTAINERS | 7 | ||||
| -rw-r--r-- | drivers/hid/Kconfig | 21 | ||||
| -rw-r--r-- | drivers/hid/Makefile | 1 | ||||
| -rw-r--r-- | drivers/hid/uhid.c | 572 | ||||
| -rw-r--r-- | include/linux/Kbuild | 1 | ||||
| -rw-r--r-- | include/linux/uhid.h | 104 | ||||
| -rw-r--r-- | samples/uhid/Makefile | 10 | ||||
| -rw-r--r-- | samples/uhid/uhid-example.c | 381 |
9 files changed, 1266 insertions, 0 deletions
diff --git a/Documentation/hid/uhid.txt b/Documentation/hid/uhid.txt new file mode 100644 index 000000000000..4627c4241ece --- /dev/null +++ b/Documentation/hid/uhid.txt @@ -0,0 +1,169 @@ + UHID - User-space I/O driver support for HID subsystem + ======================================================== + +The HID subsystem needs two kinds of drivers. In this document we call them: + + 1. The "HID I/O Driver" is the driver that performs raw data I/O to the + low-level device. Internally, they register an hid_ll_driver structure with + the HID core. They perform device setup, read raw data from the device and + push it into the HID subsystem and they provide a callback so the HID + subsystem can send data to the device. + + 2. The "HID Device Driver" is the driver that parses HID reports and reacts on + them. There are generic drivers like "generic-usb" and "generic-bluetooth" + which adhere to the HID specification and provide the standardizes features. + But there may be special drivers and quirks for each non-standard device out + there. Internally, they use the hid_driver structure. + +Historically, the USB stack was the first subsystem to provide an HID I/O +Driver. However, other standards like Bluetooth have adopted the HID specs and +may provide HID I/O Drivers, too. The UHID driver allows to implement HID I/O +Drivers in user-space and feed the data into the kernel HID-subsystem. + +This allows user-space to operate on the same level as USB-HID, Bluetooth-HID +and similar. It does not provide a way to write HID Device Drivers, though. Use +hidraw for this purpose. + +There is an example user-space application in ./samples/uhid/uhid-example.c + +The UHID API +------------ + +UHID is accessed through a character misc-device. The minor-number is allocated +dynamically so you need to rely on udev (or similar) to create the device node. +This is /dev/uhid by default. + +If a new device is detected by your HID I/O Driver and you want to register this +device with the HID subsystem, then you need to open /dev/uhid once for each +device you want to register. All further communication is done by read()'ing or +write()'ing "struct uhid_event" objects. Non-blocking operations are supported +by setting O_NONBLOCK. + +struct uhid_event { + __u32 type; + union { + struct uhid_create_req create; + struct uhid_data_req data; + ... + } u; +}; + +The "type" field contains the ID of the event. Depending on the ID different +payloads are sent. You must not split a single event across multiple read()'s or +multiple write()'s. A single event must always be sent as a whole. Furthermore, +only a single event can be sent per read() or write(). Pending data is ignored. +If you want to handle multiple events in a single syscall, then use vectored +I/O with readv()/writev(). + +The first thing you should do is sending an UHID_CREATE event. This will +register the device. UHID will respond with an UHID_START event. You can now +start sending data to and reading data from UHID. However, unless UHID sends the +UHID_OPEN event, the internally attached HID Device Driver has no user attached. +That is, you might put your device asleep unless you receive the UHID_OPEN +event. If you receive the UHID_OPEN event, you should start I/O. If the last +user closes the HID device, you will receive an UHID_CLOSE event. This may be +followed by an UHID_OPEN event again and so on. There is no need to perform +reference-counting in user-space. That is, you will never receive multiple +UHID_OPEN events without an UHID_CLOSE event. The HID subsystem performs +ref-counting for you. +You may decide to ignore UHID_OPEN/UHID_CLOSE, though. I/O is allowed even +though the device may have no users. + +If you want to send data to the HID subsystem, you send an HID_INPUT event with +your raw data payload. If the kernel wants to send data to the device, you will +read an UHID_OUTPUT or UHID_OUTPUT_EV event. + +If your device disconnects, you should send an UHID_DESTROY event. This will +unregister the device. You can now send UHID_CREATE again to register a new +device. +If you close() the fd, the device is automatically unregistered and destroyed +internally. + +write() +------- +write() allows you to modify the state of the device and feed input data into +the kernel. The following types are supported: UHID_CREATE, UHID_DESTROY and +UHID_INPUT. The kernel will parse the event immediately and if the event ID is +not supported, it will return -EOPNOTSUPP. If the payload is invalid, then +-EINVAL is returned, otherwise, the amount of data that was read is returned and +the request was handled successfully. + + UHID_CREATE: + This creates the internal HID device. No I/O is possible until you send this + event to the kernel. The payload is of type struct uhid_create_req and + contains information about your device. You can start I/O now. + + UHID_DESTROY: + This destroys the internal HID device. No further I/O will be accepted. There + may still be pending messages that you can receive with read() but no further + UHID_INPUT events can be sent to the kernel. + You can create a new device by sending UHID_CREATE again. There is no need to + reopen the character device. + + UHID_INPUT: + You must send UHID_CREATE before sending input to the kernel! This event + contains a data-payload. This is the raw data that you read from your device. + The kernel will parse the HID reports and react on it. + + UHID_FEATURE_ANSWER: + If you receive a UHID_FEATURE request you must answer with this request. You + must copy the "id" field from the request into the answer. Set the "err" field + to 0 if no error occured or to EIO if an I/O error occurred. + If "err" is 0 then you should fill the buffer of the answer with the results + of the feature request and set "size" correspondingly. + +read() +------ +read() will return a queued ouput report. These output reports can be of type +UHID_START, UHID_STOP, UHID_OPEN, UHID_CLOSE, UHID_OUTPUT or UHID_OUTPUT_EV. No +reaction is required to any of them but you should handle them according to your +needs. Only UHID_OUTPUT and UHID_OUTPUT_EV have payloads. + + UHID_START: + This is sent when the HID device is started. Consider this as an answer to + UHID_CREATE. This is always the first event that is sent. + + UHID_STOP: + This is sent when the HID device is stopped. Consider this as an answer to + UHID_DESTROY. + If the kernel HID device driver closes the device manually (that is, you + didn't send UHID_DESTROY) then you should consider this device closed and send + an UHID_DESTROY event. You may want to reregister your device, though. This is + always the last message that is sent to you unless you reopen the device with + UHID_CREATE. + + UHID_OPEN: + This is sent when the HID device is opened. That is, the data that the HID + device provides is read by some other process. You may ignore this event but + it is useful for power-management. As long as you haven't received this event + there is actually no other process that reads your data so there is no need to + send UHID_INPUT events to the kernel. + + UHID_CLOSE: + This is sent when there are no more processes which read the HID data. It is + the counterpart of UHID_OPEN and you may as well ignore this event. + + UHID_OUTPUT: + This is sent if the HID device driver wants to send raw data to the I/O + device. You should read the payload and forward it to the device. The payload + is of type "struct uhid_data_req". + This may be received even though you haven't received UHID_OPEN, yet. + + UHID_OUTPUT_EV: + Same as UHID_OUTPUT but this contains a "struct input_event" as payload. This + is called for force-feedback, LED or similar events which are received through + an input device by the HID subsystem. You should convert this into raw reports + and send them to your device similar to events of type UHID_OUTPUT. + + UHID_FEATURE: + This event is sent if the kernel driver wants to perform a feature request as + described in the HID specs. The report-type and report-number are available in + the payload. + The kernel serializes feature requests so there will never be two in parallel. + However, if you fail to respond with a UHID_FEATURE_ANSWER in a time-span of 5 + seconds, then the requests will be dropped and a new one might be sent. + Therefore, the payload also contains an "id" field that identifies every + request. + +Document by: + David Herrmann <dh.herrmann@googlemail.com> diff --git a/MAINTAINERS b/MAINTAINERS index c82c343168e8..12dde1f795dd 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6948,6 +6948,13 @@ S: Maintained F: Documentation/filesystems/ufs.txt F: fs/ufs/ +UHID USERSPACE HID IO DRIVER: +M: David Herrmann <dh.herrmann@googlemail.com> +L: linux-input@vger.kernel.org +S: Maintained +F: drivers/hid/uhid.c +F: include/linux/uhid.h + ULTRA-WIDEBAND (UWB) SUBSYSTEM: L: linux-usb@vger.kernel.org S: Orphan diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig index 00445bc3019c..fbf49503508d 100644 --- a/drivers/hid/Kconfig +++ b/drivers/hid/Kconfig @@ -53,6 +53,27 @@ config HIDRAW If unsure, say Y. +config UHID + tristate "User-space I/O driver support for HID subsystem" + depends on HID + default n + ---help--- + Say Y here if you want to provide HID I/O Drivers from user-space. + This allows to write I/O drivers in user-space and feed the data from + the device into the kernel. The kernel parses the HID reports, loads the + corresponding HID Device Driver or provides input devices on top of your + user-space device. + + This driver cannot be used to parse HID-reports in user-space and write + special HID-drivers. You should use hidraw for that. + Instead, this driver allows to write the transport-layer driver in + user-space like USB-HID and Bluetooth-HID do in kernel-space. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called uhid. + config HID_GENERIC tristate "Generic HID driver" depends on HID diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile index 02fa93896951..f975485f88b2 100644 --- a/drivers/hid/Makefile +++ b/drivers/hid/Makefile @@ -8,6 +8,7 @@ ifdef CONFIG_DEBUG_FS endif obj-$(CONFIG_HID) += hid.o +obj-$(CONFIG_UHID) += uhid.o obj-$(CONFIG_HID_GENERIC) += hid-generic.o diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c new file mode 100644 index 000000000000..714cd8cc9579 --- /dev/null +++ b/drivers/hid/uhid.c @@ -0,0 +1,572 @@ +/* + * User-space I/O driver support for HID subsystem + * Copyright (c) 2012 David Herrmann + */ + +/* + * 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. + */ + +#include <linux/atomic.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/hid.h> +#include <linux/input.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/poll.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/uhid.h> +#include <linux/wait.h> + +#define UHID_NAME "uhid" +#define UHID_BUFSIZE 32 + +struct uhid_device { + struct mutex devlock; + bool running; + + __u8 *rd_data; + uint rd_size; + + struct hid_device *hid; + struct uhid_event input_buf; + + wait_queue_head_t waitq; + spinlock_t qlock; + __u8 head; + __u8 tail; + struct uhid_event *outq[UHID_BUFSIZE]; + + struct mutex report_lock; + wait_queue_head_t report_wait; + atomic_t report_done; + atomic_t report_id; + struct uhid_event report_buf; +}; + +static struct miscdevice uhid_misc; + +static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev) +{ + __u8 newhead; + + newhead = (uhid->head + 1) % UHID_BUFSIZE; + + if (newhead != uhid->tail) { + uhid->outq[uhid->head] = ev; + uhid->head = newhead; + wake_up_interruptible(&uhid->waitq); + } else { + hid_warn(uhid->hid, "Output queue is full\n"); + kfree(ev); + } +} + +static int uhid_queue_event(struct uhid_device *uhid, __u32 event) +{ + unsigned long flags; + struct uhid_event *ev; + + ev = kzalloc(sizeof(*ev), GFP_KERNEL); + if (!ev) + return -ENOMEM; + + ev->type = event; + + spin_lock_irqsave(&uhid->qlock, flags); + uhid_queue(uhid, ev); + spin_unlock_irqrestore(&uhid->qlock, flags); + + return 0; +} + +static int uhid_hid_start(struct hid_device *hid) +{ + struct uhid_device *uhid = hid->driver_data; + + return uhid_queue_event(uhid, UHID_START); +} + +static void uhid_hid_stop(struct hid_device *hid) +{ + struct uhid_device *uhid = hid->driver_data; + + hid->claimed = 0; + uhid_queue_event(uhid, UHID_STOP); +} + +static int uhid_hid_open(struct hid_device *hid) +{ + struct uhid_device *uhid = hid->driver_data; + + return uhid_queue_event(uhid, UHID_OPEN); +} + +static void uhid_hid_close(struct hid_device *hid) +{ + struct uhid_device *uhid = hid->driver_data; + + uhid_queue_event(uhid, UHID_CLOSE); +} + +static int uhid_hid_input(struct input_dev *input, unsigned int type, + unsigned int code, int value) +{ + struct hid_device *hid = input_get_drvdata(input); + struct uhid_device *uhid = hid->driver_data; + unsigned long flags; + struct uhid_event *ev; + + ev = kzalloc(sizeof(*ev), GFP_ATOMIC); + if (!ev) + return -ENOMEM; + + ev->type = UHID_OUTPUT_EV; + ev->u.output_ev.type = type; + ev->u.output_ev.code = code; + ev->u.output_ev.value = value; + + spin_lock_irqsave(&uhid->qlock, flags); + uhid_queue(uhid, ev); + spin_unlock_irqrestore(&uhid->qlock, flags); + + return 0; +} + +static int uhid_hid_parse(struct hid_device *hid) +{ + struct uhid_device *uhid = hid->driver_data; + + return hid_parse_report(hid, uhid->rd_data, uhid->rd_size); +} + +static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, + __u8 *buf, size_t count, unsigned char rtype) +{ + struct uhid_device *uhid = hid->driver_data; + __u8 report_type; + struct uhid_event *ev; + unsigned long flags; + int ret; + size_t uninitialized_var(len); + struct uhid_feature_answer_req *req; + + if (!uhid->running) + return -EIO; + + switch (rtype) { + case HID_FEATURE_REPORT: + report_type = UHID_FEATURE_REPORT; + break; + case HID_OUTPUT_REPORT: + report_type = UHID_OUTPUT_REPORT; + break; + case HID_INPUT_REPORT: + report_type = UHID_INPUT_REPORT; + break; + default: + return -EINVAL; + } + + ret = mutex_lock_interruptible(&uhid->report_lock); + if (ret) + return ret; + + ev = kzalloc(sizeof(*ev), GFP_KERNEL); + if (!ev) { + ret = -ENOMEM; + goto unlock; + } + + spin_lock_irqsave(&uhid->qlock, flags); + ev->type = UHID_FEATURE; + ev->u.feature.id = atomic_inc_return(&uhid->report_id); + ev->u.feature.rnum = rnum; + ev->u.feature.rtype = report_type; + + atomic_set(&uhid->report_done, 0); + uhid_queue(uhid, ev); + spin_unlock_irqrestore(&uhid->qlock, flags); + + ret = wait_event_interruptible_timeout(uhid->report_wait, + atomic_read(&uhid->report_done), 5 * HZ); + + /* + * Make sure "uhid->running" is cleared on shutdown before + * "uhid->report_done" is set. + */ + smp_rmb(); + if (!ret || !uhid->running) { + ret = -EIO; + } else if (ret < 0) { + ret = -ERESTARTSYS; + } else { + spin_lock_irqsave(&uhid->qlock, flags); + req = &uhid->report_buf.u.feature_answer; + + if (req->err) { + ret = -EIO; + } else { + ret = 0; + len = min(count, + min_t(size_t, req->size, UHID_DATA_MAX)); + memcpy(buf, req->data, len); + } + + spin_unlock_irqrestore(&uhid->qlock, flags); + } + + atomic_set(&uhid->report_done, 1); + +unlock: + mutex_unlock(&uhid->report_lock); + return ret ? ret : len; +} + +static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, + unsigned char report_type) +{ + struct uhid_device *uhid = hid->driver_data; + __u8 rtype; + unsigned long flags; + struct uhid_event *ev; + + switch (report_type) { + case HID_FEATURE_REPORT: + rtype = UHID_FEATURE_REPORT; + break; + case HID_OUTPUT_REPORT: + rtype = UHID_OUTPUT_REPORT; + break; + default: + return -EINVAL; + } + + if (count < 1 || count > UHID_DATA_MAX) + return -EINVAL; + + ev = kzalloc(sizeof(*ev), GFP_KERNEL); + if (!ev) + return -ENOMEM; + + ev->type = UHID_OUTPUT; + ev->u.output.size = count; + ev->u.output.rtype = rtype; + memcpy(ev->u.output.data, buf, count); + + spin_lock_irqsave(&uhid->qlock, flags); + uhid_queue(uhid, ev); + spin_unlock_irqrestore(&uhid->qlock, flags); + + return count; +} + +static struct hid_ll_driver uhid_hid_driver = { + .start = uhid_hid_start, + .stop = uhid_hid_stop, + .open = uhid_hid_open, + .close = uhid_hid_close, + .hidinput_input_event = uhid_hid_input, + .parse = uhid_hid_parse, +}; + +static int uhid_dev_create(struct uhid_device *uhid, + const struct uhid_event *ev) +{ + struct hid_device *hid; + int ret; + + if (uhid->running) + return -EALREADY; + + uhid->rd_size = ev->u.create.rd_size; + if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE) + return -EINVAL; + + uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL); + if (!uhid->rd_data) + return -ENOMEM; + + if (copy_from_user(uhid->rd_data, ev->u.create.rd_data, + uhid->rd_size)) { + ret = -EFAULT; + goto err_free; + } + + hid = hid_allocate_device(); + if (IS_ERR(hid)) { + ret = PTR_ERR(hid); + goto err_free; + } + + strncpy(hid->name, ev->u.create.name, 127); + hid->name[127] = 0; + strncpy(hid->phys, ev->u.create.phys, 63); + hid->phys[63] = 0; + strncpy(hid->uniq, ev->u.create.uniq, 63); + hid->uniq[63] = 0; + + hid->ll_driver = &uhid_hid_driver; + hid->hid_get_raw_report = uhid_hid_get_raw; + hid->hid_output_raw_report = uhid_hid_output_raw; + hid->bus = ev->u.create.bus; + hid->vendor = ev->u.create.vendor; + hid->product = ev->u.create.product; + hid->version = ev->u.create.version; + hid->country = ev->u.create.country; + hid->driver_data = uhid; + hid->dev.parent = uhid_misc.this_device; + + uhid->hid = hid; + uhid->running = true; + + ret = hid_add_device(hid); + if (ret) { + hid_err(hid, "Cannot register HID device\n"); + goto err_hid; + } + + return 0; + +err_hid: + hid_destroy_device(hid); + uhid->hid = NULL; + uhid->running = false; +err_free: + kfree(uhid->rd_data); + return ret; +} + +static int uhid_dev_destroy(struct uhid_device *uhid) +{ + if (!uhid->running) + return -EINVAL; + + /* clear "running" before setting "report_done" */ + uhid->running = false; + smp_wmb(); + atomic_set(&uhid->report_done, 1); + wake_up_interruptible(&uhid->report_wait); + + hid_destroy_device(uhid->hid); + kfree(uhid->rd_data); + + return 0; +} + +static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) +{ + if (!uhid->running) + return -EINVAL; + + hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, + min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0); + + return 0; +} + +static int uhid_dev_feature_answer(struct uhid_device *uhid, + struct uhid_event *ev) +{ + unsigned long flags; + + if (!uhid->running) + return -EINVAL; + + spin_lock_irqsave(&uhid->qlock, flags); + + /* id for old report; drop it silently */ + if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id) + goto unlock; + if (atomic_read(&uhid->report_done)) + goto unlock; + + memcpy(&uhid->report_buf, ev, sizeof(*ev)); + atomic_set(&uhid->report_done, 1); + wake_up_interruptible(&uhid->report_wait); + +unlock: + spin_unlock_irqrestore(&uhid->qlock, flags); + return 0; +} + +static int uhid_char_open(struct inode *inode, struct file *file) +{ + struct uhid_device *uhid; + + uhid = kzalloc(sizeof(*uhid), GFP_KERNEL); + if (!uhid) + return -ENOMEM; + + mutex_init(&uhid->devlock); + mutex_init(&uhid->report_lock); + spin_lock_init(&uhid->qlock); + init_waitqueue_head(&uhid->waitq); + init_waitqueue_head(&uhid->report_wait); + uhid->running = false; + atomic_set(&uhid->report_done, 1); + + file->private_data = uhid; + nonseekable_open(inode, file); + + return 0; +} + +static int uhid_char_release(struct inode *inode, struct file *file) +{ + struct uhid_device *uhid = file->private_data; + unsigned int i; + + uhid_dev_destroy(uhid); + + for (i = 0; i < UHID_BUFSIZE; ++i) + kfree(uhid->outq[i]); + + kfree(uhid); + + return 0; +} + +static ssize_t uhid_char_read(struct file *file, char __user *buffer, + size_t count, loff_t *ppos) +{ + struct uhid_device *uhid = file->private_data; + int ret; + unsigned long flags; + size_t len; + + /* they need at least the "type" member of uhid_event */ + if (count < sizeof(__u32)) + return -EINVAL; + +try_again: + if (file->f_flags & O_NONBLOCK) { + if (uhid->head == uhid->tail) + return -EAGAIN; + } else { + ret = wait_event_interruptible(uhid->waitq, + uhid->head != uhid->tail); + if (ret) + return ret; + } + + ret = mutex_lock_interruptible(&uhid->devlock); + if (ret) + return ret; + + if (uhid->head == uhid->tail) { + mutex_unlock(&uhid->devlock); + goto try_again; + } else { + len = min(count, sizeof(**uhid->outq)); + if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { + ret = -EFAULT; + } else { + kfree(uhid->outq[uhid->tail]); + uhid->outq[uhid->tail] = NULL; + + spin_lock_irqsave(&uhid->qlock, flags); + uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE; + spin_unlock_irqrestore(&uhid->qlock, flags); + } + } + + mutex_unlock(&uhid->devlock); + return ret ? ret : len; +} + +static ssize_t uhid_char_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + struct uhid_device *uhid = file->private_data; + int ret; + size_t len; + + /* we need at least the "type" member of uhid_event */ + if (count < sizeof(__u32)) + return -EINVAL; + + ret = mutex_lock_interruptible(&uhid->devlock); + if (ret) + return ret; + + memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); + len = min(count, sizeof(uhid->input_buf)); + if (copy_from_user(&uhid->input_buf, buffer, len)) { + ret = -EFAULT; + goto unlock; + } + + switch (uhid->input_buf.type) { + case UHID_CREATE: + ret = uhid_dev_create(uhid, &uhid->input_buf); + break; + case UHID_DESTROY: + ret = uhid_dev_destroy(uhid); + break; + case UHID_INPUT: + ret = uhid_dev_input(uhid, &uhid->input_buf); + break; + case UHID_FEATURE_ANSWER: + ret = uhid_dev_feature_answer(uhid, &uhid->input_buf); + break; + default: + ret = -EOPNOTSUPP; + } + +unlock: + mutex_unlock(&uhid->devlock); + + /* return "count" not "len" to not confuse the caller */ + return ret ? ret : count; +} + +static unsigned int uhid_char_poll(struct file *file, poll_table *wait) +{ + struct uhid_device *uhid = file->private_data; + + poll_wait(file, &uhid->waitq, wait); + + if (uhid->head != uhid->tail) + return POLLIN | POLLRDNORM; + + return 0; +} + +static const struct file_operations uhid_fops = { + .owner = THIS_MODULE, + .open = uhid_char_open, + .release = uhid_char_release, + .read = uhid_char_read, + .write = uhid_char_write, + .poll = uhid_char_poll, + .llseek = no_llseek, +}; + +static struct miscdevice uhid_misc = { + .fops = &uhid_fops, + .minor = MISC_DYNAMIC_MINOR, + .name = UHID_NAME, +}; + +static int __init uhid_init(void) +{ + return misc_register(&uhid_misc); +} + +static void __exit uhid_exit(void) +{ + misc_deregister(&uhid_misc); +} + +module_init(uhid_init); +module_exit(uhid_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>"); +MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); diff --git a/include/linux/Kbuild b/include/linux/Kbuild index 8760be30b375..cb2a7d1ad47b 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -376,6 +376,7 @@ header-y += tty.h header-y += types.h header-y += udf_fs_i.h header-y += udp.h +header-y += uhid.h header-y += uinput.h header-y += uio.h header-y += ultrasound.h diff --git a/include/linux/uhid.h b/include/linux/uhid.h new file mode 100644 index 000000000000..9c6974f16966 --- /dev/null +++ b/include/linux/uhid.h @@ -0,0 +1,104 @@ +#ifndef __UHID_H_ +#define __UHID_H_ + +/* + * User-space I/O driver support for HID subsystem + * Copyright (c) 2012 David Herrmann + */ + +/* + * 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. + */ + +/* + * Public header for user-space communication. We try to keep every structure + * aligned but to be safe we also use __attribute__((__packed__)). Therefore, + * the communication should be ABI compatible even between architectures. + */ + +#include <linux/input.h> +#include <linux/types.h> + +enum uhid_event_type { + UHID_CREATE, + UHID_DESTROY, + UHID_START, + UHID_STOP, + UHID_OPEN, + UHID_CLOSE, + UHID_OUTPUT, + UHID_OUTPUT_EV, + UHID_INPUT, + UHID_FEATURE, + UHID_FEATURE_ANSWER, +}; + +struct uhid_create_req { + __u8 name[128]; + __u8 phys[64]; + __u8 uniq[64]; + __u8 __user *rd_data; + __u16 rd_size; + + __u16 bus; + __u32 vendor; + __u32 product; + __u32 version; + __u32 country; +} __attribute__((__packed__)); + +#define UHID_DATA_MAX 4096 + +enum uhid_report_type { + UHID_FEATURE_REPORT, + UHID_OUTPUT_REPORT, + UHID_INPUT_REPORT, +}; + +struct uhid_input_req { + __u8 data[UHID_DATA_MAX]; + __u16 size; +} __attribute__((__packed__)); + +struct uhid_output_req { + __u8 data[UHID_DATA_MAX]; + __u16 size; + __u8 rtype; +} __attribute__((__packed__)); + +struct uhid_output_ev_req { + __u16 type; + __u16 code; + __s32 value; +} __attribute__((__packed__)); + +struct uhid_feature_req { + __u32 id; + __u8 rnum; + __u8 rtype; +} __attribute__((__packed__)); + +struct uhid_feature_answer_req { + __u32 id; + __u16 err; + __u16 size; + __u8 data[UHID_DATA_MAX]; +}; + +struct uhid_event { + __u32 type; + + union { + struct uhid_create_req create; + struct uhid_input_req input; + struct uhid_output_req output; + struct uhid_output_ev_req output_ev; + struct uhid_feature_req feature; + struct uhid_feature_answer_req feature_answer; + } u; +} __attribute__((__packed__)); + +#endif /* __UHID_H_ */ diff --git a/samples/uhid/Makefile b/samples/uhid/Makefile new file mode 100644 index 000000000000..c95a696560a7 --- /dev/null +++ b/samples/uhid/Makefile @@ -0,0 +1,10 @@ +# kbuild trick to avoid linker error. Can be omitted if a module is built. +obj- := dummy.o + +# List of programs to build +hostprogs-y := uhid-example + +# Tell kbuild to always build the programs +always := $(hostprogs-y) + +HOSTCFLAGS_uhid-example.o += -I$(objtree)/usr/include diff --git a/samples/uhid/uhid-example.c b/samples/uhid/uhid-example.c new file mode 100644 index 000000000000..03ce3c059a5e --- /dev/null +++ b/samples/uhid/uhid-example.c @@ -0,0 +1,381 @@ +/* + * UHID Example + * + * Copyright (c) 2012 David Herrmann <dh.herrmann@googlemail.com> + * + * The code may be used by anyone for any purpose, + * and can serve as a starting point for developing + * applications using uhid. + */ + +/* UHID Example + * This example emulates a basic 3 buttons mouse with wheel over UHID. Run this + * program as root and then use the following keys to control the mouse: + * q: Quit the application + * 1: Toggle left button (down, up, ...) + * 2: Toggle right button + * 3: Toggle middle button + * a: Move mouse left + * d: Move mouse right + * w: Move mouse up + * s: Move mouse down + * r: Move wheel up + * f: Move wheel down + * + * If uhid is not available as /dev/uhid, then you can pass a different path as + * first argument. + * If <linux/uhid.h> is not installed in /usr, then compile this with: + * gcc -o ./uhid_test -Wall -I./include ./samples/uhid/uhid-example.c + * And ignore the warning about kernel headers. However, it is recommended to + * use the installed uhid.h if available. + */ + +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <termios.h> +#include <unistd.h> +#include <linux/uhid.h> + +/* HID Report Desciptor + * We emulate a basic 3 button mouse with wheel. This is the report-descriptor + * as the kernel will parse it: + * + * INPUT[INPUT] + * Field(0) + * Physical(GenericDesktop.Pointer) + * Application(GenericDesktop.Mouse) + * Usage(3) + * Button.0001 + * Button.0002 + * Button.0003 + * Logical Minimum(0) + * Logical Maximum(1) + * Report Size(1) + * Report Count(3) + * Report Offset(0) + * Flags( Variable Absolute ) + * Field(1) + * Physical(GenericDesktop.Pointer) + * Application(GenericDesktop.Mouse) + * Usage(3) + * GenericDesktop.X + * GenericDesktop.Y + * GenericDesktop.Wheel + * Logical Minimum(-128) + * Logical Maximum(127) + * Report Size(8) + * Report Count(3) + * Report Offset(8) + * Flags( Variable Relative ) + * + * This is the mapping that we expect: + * Button.0001 ---> Key.LeftBtn + * Button.0002 ---> Key.RightBtn + * Button.0003 ---> Key.MiddleBtn + * GenericDesktop.X ---> Relative.X + * GenericDesktop.Y ---> Relative.Y + * GenericDesktop.Wheel ---> Relative.Wheel + * + * This information can be verified by reading /sys/kernel/debug/hid/<dev>/rdesc + * This file should print the same information as showed above. + */ + +static unsigned char rdesc[] = { + 0x05, 0x01, 0x09, 0x02, 0xa1, 0x01, 0x09, 0x01, + 0xa1, 0x00, 0x05, 0x09, 0x19, 0x01, 0x29, 0x03, + 0x15, 0x00, 0x25, 0x01, 0x95, 0x03, 0x75, 0x01, + 0x81, 0x02, 0x95, 0x01, 0x75, 0x05, 0x81, 0x01, + 0x05, 0x01, 0x09, 0x30, 0x09, 0x31, 0x09, 0x38, + 0x15, 0x80, 0x25, 0x7f, 0x75, 0x08, 0x95, 0x03, + 0x81, 0x06, 0xc0, 0xc0, +}; + +static int uhid_write(int fd, const struct uhid_event *ev) +{ + ssize_t ret; + + ret = write(fd, ev, sizeof(*ev)); + if (ret < 0) { + fprintf(stderr, "Cannot write to uhid: %m\n"); + return -errno; + } else if (ret != sizeof(*ev)) { + fprintf(stderr, "Wrong size written to uhid: %ld != %lu\n", + ret, sizeof(ev)); + return -EFAULT; + } else { + return 0; + } +} + +static int create(int fd) +{ + struct uhid_event ev; + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_CREATE; + strcpy((char*)ev.u.create.name, "test-uhid-device"); + ev.u.create.rd_data = rdesc; + ev.u.create.rd_size = sizeof(rdesc); + ev.u.create.bus = BUS_USB; + ev.u.create.vendor = 0x15d9; + ev.u.create.product = 0x0a37; + ev.u.create.version = 0; + ev.u.create.country = 0; + + return uhid_write(fd, &ev); +} + +static void destroy(int fd) +{ + struct uhid_event ev; + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_DESTROY; + + uhid_write(fd, &ev); +} + +static int event(int fd) +{ + struct uhid_event ev; + ssize_t ret; + + memset(&ev, 0, sizeof(ev)); + ret = read(fd, &ev, sizeof(ev)); + if (ret == 0) { + fprintf(stderr, "Read HUP on uhid-cdev\n"); + return -EFAULT; + } else if (ret < 0) { + fprintf(stderr, "Cannot read uhid-cdev: %m\n"); + return -errno; + } else if (ret != sizeof(ev)) { + fprintf(stderr, "Invalid size read from uhid-dev: %ld != %lu\n", + ret, sizeof(ev)); + return -EFAULT; + } + + switch (ev.type) { + case UHID_START: + fprintf(stderr, "UHID_START from uhid-dev\n"); + break; + case UHID_STOP: + fprintf(stderr, "UHID_STOP from uhid-dev\n"); + break; + case UHID_OPEN: + fprintf(stderr, "UHID_OPEN from uhid-dev\n"); + break; + case UHID_CLOSE: + fprintf(stderr, "UHID_CLOSE from uhid-dev\n"); + break; + case UHID_OUTPUT: + fprintf(stderr, "UHID_OUTPUT from uhid-dev\n"); + break; + case UHID_OUTPUT_EV: + fprintf(stderr, "UHID_OUTPUT_EV from uhid-dev\n"); + break; + default: + fprintf(stderr, "Invalid event from uhid-dev: %u\n", ev.type); + } + + return 0; +} + +static bool btn1_down; +static bool btn2_down; +static bool btn3_down; +static signed char abs_hor; +static signed char abs_ver; +static signed char wheel; + +static int send_event(int fd) +{ + struct uhid_event ev; + + memset(&ev, 0, sizeof(ev)); + ev.type = UHID_INPUT; + ev.u.input.size = 4; + + if (btn1_down) + ev.u.input.data[0] |= 0x1; + if (btn2_down) + ev.u.input.data[0] |= 0x2; + if (btn3_down) + ev.u.input.data[0] |= 0x4; + + ev.u.input.data[1] = abs_hor; + ev.u.input.data[2] = abs_ver; + ev.u.input.data[3] = wheel; + + return uhid_write(fd, &ev); +} + +static int keyboard(int fd) +{ + char buf[128]; + ssize_t ret, i; + + ret = read(STDIN_FILENO, buf, sizeof(buf)); + if (ret == 0) { + fprintf(stderr, "Read HUP on stdin\n"); + return -EFAULT; + } else if (ret < 0) { + fprintf(stderr, "Cannot read stdin: %m\n"); + return -errno; + } + + for (i = 0; i < ret; ++i) { + switch (buf[i]) { + case '1': + btn1_down = !btn1_down; + ret = send_event(fd); + if (ret) + return ret; + break; + case '2': + btn2_down = !btn2_down; + ret = send_event(fd); + if (ret) + return ret; + break; + case '3': + btn3_down = !btn3_down; + ret = send_event(fd); + if (ret) + return ret; + break; + case 'a': + abs_hor = -20; + ret = send_event(fd); + abs_hor = 0; + if (ret) + return ret; + break; + case 'd': + abs_hor = 20; + ret = send_event(fd); + abs_hor = 0; + if (ret) + return ret; + break; + case 'w': + abs_ver = -20; + ret = send_event(fd); + abs_ver = 0; + if (ret) + return ret; + break; + case 's': + abs_ver = 20; + ret = send_event(fd); + abs_ver = 0; + if (ret) + return ret; + break; + case 'r': + wheel = 1; + ret = send_event(fd); + wheel = 0; + if (ret) + return ret; + break; + case 'f': + wheel = -1; + ret = send_event(fd); + wheel = 0; + if (ret) + return ret; + break; + case 'q': + return -ECANCELED; + default: + fprintf(stderr, "Invalid input: %c\n", buf[i]); + } + } + + return 0; +} + +int main(int argc, char **argv) +{ + int fd; + const char *path = "/dev/uhid"; + struct pollfd pfds[2]; + int ret; + struct termios state; + + ret = tcgetattr(STDIN_FILENO, &state); + if (ret) { + fprintf(stderr, "Cannot get tty state\n"); + } else { + state.c_lflag &= ~ICANON; + state.c_cc[VMIN] = 1; + ret = tcsetattr(STDIN_FILENO, TCSANOW, &state); + if (ret) + fprintf(stderr, "Cannot set tty state\n"); + } + + if (argc >= 2) { + if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) { + fprintf(stderr, "Usage: %s [%s]\n", argv[0], path); + return EXIT_SUCCESS; + } else { + path = argv[1]; + } + } + + fprintf(stderr, "Open uhid-cdev %s\n", path); + fd = open(path, O_RDWR | O_CLOEXEC); + if (fd < 0) { + fprintf(stderr, "Cannot open uhid-cdev %s: %m\n", path); + return EXIT_FAILURE; + } + + fprintf(stderr, "Create uhid device\n"); + ret = create(fd); + if (ret) { + close(fd); + return EXIT_FAILURE; + } + + pfds[0].fd = STDIN_FILENO; + pfds[0].events = POLLIN; + pfds[1].fd = fd; + pfds[1].events = POLLIN; + + fprintf(stderr, "Press 'q' to quit...\n"); + while (1) { + ret = poll(pfds, 2, -1); + if (ret < 0) { + fprintf(stderr, "Cannot poll for fds: %m\n"); + break; + } + if (pfds[0].revents & POLLHUP) { + fprintf(stderr, "Received HUP on stdin\n"); + break; + } + if (pfds[1].revents & POLLHUP) { + fprintf(stderr, "Received HUP on uhid-cdev\n"); + break; + } + + if (pfds[0].revents & POLLIN) { + ret = keyboard(fd); + if (ret) + break; + } + if (pfds[1].revents & POLLIN) { + ret = event(fd); + if (ret) + break; + } + } + + fprintf(stderr, "Destroy uhid device\n"); + destroy(fd); + return EXIT_SUCCESS; +} |
