From 1ccd7a2a33f2b47e46c51f4501e9623a51d28090 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:13 +0200 Subject: [PATCH 01/18] HID: uhid: introduce user-space I/O driver support for HID This adds a dummy driver that will support user-space I/O drivers for the HID subsystem. This allows to write transport-level drivers like USB-HID and Bluetooth-HID in user-space. Low-Energy Bluetooth needs this to feed HID data that is parsed in user-space back into the kernel. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/Kconfig | 21 +++++++++++ drivers/hid/Makefile | 1 + drivers/hid/uhid.c | 88 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 110 insertions(+) create mode 100644 drivers/hid/uhid.c diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig index e9c68fedfcff0b..8cca0af2dbd1b8 100644 --- a/drivers/hid/Kconfig +++ b/drivers/hid/Kconfig @@ -59,6 +59,27 @@ 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. + source "drivers/hid/usbhid/Kconfig" menu "Special HID drivers" diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile index ca6cc9f0485c90..d7061928325e30 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 00000000000000..5b02d6cb0e60f2 --- /dev/null +++ b/drivers/hid/uhid.c @@ -0,0 +1,88 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define UHID_NAME "uhid" + +static struct miscdevice uhid_misc; + +static int uhid_char_open(struct inode *inode, struct file *file) +{ + return 0; +} + +static int uhid_char_release(struct inode *inode, struct file *file) +{ + return 0; +} + +static ssize_t uhid_char_read(struct file *file, char __user *buffer, + size_t count, loff_t *ppos) +{ + return 0; +} + +static ssize_t uhid_char_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + return 0; +} + +static unsigned int uhid_char_poll(struct file *file, poll_table *wait) +{ + 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 "); +MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); From ace3d8614ab0e6544f5f85921085b55b915fe9aa Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:14 +0200 Subject: [PATCH 02/18] HID: uhid: add internal message buffer When receiving messages from the HID subsystem, we need to process them and store them in an internal buffer so user-space can read() on the char device to retrieve the messages. This adds a static buffer for 32 messages to each uhid device. Each message is dynamically allocated so the uhid_device structure does not get too big. uhid_queue() adds a message to the buffer. If the buffer is full, the message is discarded. uhid_queue_event() is an helper for messages without payload. This also adds a public header: uhid.h. It contains the declarations for the user-space API. It is built around "struct uhid_event" which contains a type field which specifies the event type and each event can then add a variable-length payload. For now, there is only a dummy event but later patches will add new event types and payloads. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 65 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/Kbuild | 1 + include/linux/uhid.h | 33 ++++++++++++++++++++++ 3 files changed, 99 insertions(+) create mode 100644 include/linux/uhid.h diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 5b02d6cb0e60f2..05ef4b05a63e0f 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -25,16 +25,81 @@ #include #define UHID_NAME "uhid" +#define UHID_BUFSIZE 32 + +struct uhid_device { + struct hid_device *hid; + + wait_queue_head_t waitq; + spinlock_t qlock; + __u8 head; + __u8 tail; + struct uhid_event *outq[UHID_BUFSIZE]; +}; 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_char_open(struct inode *inode, struct file *file) { + struct uhid_device *uhid; + + uhid = kzalloc(sizeof(*uhid), GFP_KERNEL); + if (!uhid) + return -ENOMEM; + + spin_lock_init(&uhid->qlock); + init_waitqueue_head(&uhid->waitq); + + 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; + + for (i = 0; i < UHID_BUFSIZE; ++i) + kfree(uhid->outq[i]); + + kfree(uhid); + return 0; } diff --git a/include/linux/Kbuild b/include/linux/Kbuild index 39737839ce2915..8cdabecfbe2746 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -373,6 +373,7 @@ 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 00000000000000..16b786a2b18fc6 --- /dev/null +++ b/include/linux/uhid.h @@ -0,0 +1,33 @@ +#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 +#include + +enum uhid_event_type { + UHID_DUMMY, +}; + +struct uhid_event { + __u32 type; +} __attribute__((__packed__)); + +#endif /* __UHID_H_ */ From 1f9dec1e0164b48da9b268a02197f38caa69b118 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:15 +0200 Subject: [PATCH 03/18] HID: uhid: allow poll()'ing on uhid devices As long as the internal buffer is not empty, we return POLLIN to user-space. uhid->head and uhid->tail are no atomics so the comparison may return inexact results. However, this doesn't matter here as user-space would need to poll() in two threads simultaneously to trigger this. And in this case it doesn't matter if a cached result is returned or the exact new result as user-space does not know which thread returns first from poll() and the following read(). So it is safe to compare the values without locking. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 05ef4b05a63e0f..b1a477f8260c6e 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -117,6 +117,13 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, 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; } From d937ae5fae17e63aaa97f029be221a6516b25475 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:16 +0200 Subject: [PATCH 04/18] HID: uhid: implement read() on uhid devices User-space can use read() to get a single event from uhid devices. read() does never return multiple events. This allows us to extend the event structure and still keep backwards compatibility. If user-space wants to get multiple events in one syscall, they should use the readv()/writev() syscalls which are supported by uhid. This introduces a new lock which helps us synchronizing simultaneous reads from user-space. We also correctly return -EINVAL/-EFAULT only on errors and retry the read() when some other thread captured the event faster than we did. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 46 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index b1a477f8260c6e..93860826d629d0 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -28,6 +28,7 @@ #define UHID_BUFSIZE 32 struct uhid_device { + struct mutex devlock; struct hid_device *hid; wait_queue_head_t waitq; @@ -81,6 +82,7 @@ static int uhid_char_open(struct inode *inode, struct file *file) if (!uhid) return -ENOMEM; + mutex_init(&uhid->devlock); spin_lock_init(&uhid->qlock); init_waitqueue_head(&uhid->waitq); @@ -106,7 +108,49 @@ static int uhid_char_release(struct inode *inode, struct file *file) static ssize_t uhid_char_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) { - return 0; + 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, From 6664ef72a47459f883d3409ca9b2fa200015704b Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:17 +0200 Subject: [PATCH 05/18] HID: uhid: implement write() on uhid devices Similar to read() you can only write() a single event with one call to an uhid device. To write multiple events use writev() which is supported by uhid. We currently always return -EOPNOTSUPP but other events will be added in later patches. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 93860826d629d0..31e8379cfd1599 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -30,6 +30,7 @@ struct uhid_device { struct mutex devlock; struct hid_device *hid; + struct uhid_event input_buf; wait_queue_head_t waitq; spinlock_t qlock; @@ -156,7 +157,35 @@ static ssize_t uhid_char_read(struct file *file, char __user *buffer, static ssize_t uhid_char_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { - return 0; + 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) { + 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) From d365c6cfd337a2bccdc65eacce271a311ea1072c Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:18 +0200 Subject: [PATCH 06/18] HID: uhid: add UHID_CREATE and UHID_DESTROY events UHID_CREATE and UHID_DESTROY are used to create and destroy a device on an open uhid char-device. Internally, we allocate and register an HID device with the HID core and immediately start the device. From now on events may be received or sent to the device. The UHID_CREATE event has a payload similar to the data used by Bluetooth-HIDP when creating a new connection. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 144 +++++++++++++++++++++++++++++++++++++++++++ include/linux/uhid.h | 21 ++++++- 2 files changed, 164 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 31e8379cfd1599..61ee7cc32ccfc7 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -29,6 +29,11 @@ struct uhid_device { struct mutex devlock; + bool running; + + __u8 *rd_data; + uint rd_size; + struct hid_device *hid; struct uhid_event input_buf; @@ -75,6 +80,136 @@ static int uhid_queue_event(struct uhid_device *uhid, __u32 event) return 0; } +static int uhid_hid_start(struct hid_device *hid) +{ + return 0; +} + +static void uhid_hid_stop(struct hid_device *hid) +{ +} + +static int uhid_hid_open(struct hid_device *hid) +{ + return 0; +} + +static void uhid_hid_close(struct hid_device *hid) +{ +} + +static int uhid_hid_input(struct input_dev *input, unsigned int type, + unsigned int code, int value) +{ + return 0; +} + +static int uhid_hid_parse(struct hid_device *hid) +{ + return 0; +} + +static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, + __u8 *buf, size_t count, unsigned char rtype) +{ + return 0; +} + +static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, + unsigned char report_type) +{ + return 0; +} + +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; + + uhid->running = false; + + hid_destroy_device(uhid->hid); + kfree(uhid->rd_data); + + return 0; +} + static int uhid_char_open(struct inode *inode, struct file *file) { struct uhid_device *uhid; @@ -86,6 +221,7 @@ static int uhid_char_open(struct inode *inode, struct file *file) mutex_init(&uhid->devlock); spin_lock_init(&uhid->qlock); init_waitqueue_head(&uhid->waitq); + uhid->running = false; file->private_data = uhid; nonseekable_open(inode, file); @@ -98,6 +234,8 @@ 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]); @@ -177,6 +315,12 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, } 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; default: ret = -EOPNOTSUPP; } diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 16b786a2b18fc6..8a493e604a7751 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -23,11 +23,30 @@ #include enum uhid_event_type { - UHID_DUMMY, + UHID_CREATE, + UHID_DESTROY, }; +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__)); + struct uhid_event { __u32 type; + + union { + struct uhid_create_req create; + } u; } __attribute__((__packed__)); #endif /* __UHID_H_ */ From 5e87a36ae375297b71cc21ac7e32846832bcfb34 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:19 +0200 Subject: [PATCH 07/18] HID: uhid: allow feeding input data into uhid devices This adds a new event type UHID_INPUT which allows user-space to feed raw HID reports into the HID subsystem. We copy the data into kernel memory and directly feed it into the HID core. There is no error handling of the events couldn't be parsed so user-space should consider all events successfull unless read() returns an error. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 14 ++++++++++++++ include/linux/uhid.h | 9 +++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 61ee7cc32ccfc7..3d1ebda122e597 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -210,6 +210,17 @@ static int uhid_dev_destroy(struct uhid_device *uhid) 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_char_open(struct inode *inode, struct file *file) { struct uhid_device *uhid; @@ -321,6 +332,9 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, case UHID_DESTROY: ret = uhid_dev_destroy(uhid); break; + case UHID_INPUT: + ret = uhid_dev_input(uhid, &uhid->input_buf); + break; default: ret = -EOPNOTSUPP; } diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 8a493e604a7751..6eb42bea86a25b 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -25,6 +25,7 @@ enum uhid_event_type { UHID_CREATE, UHID_DESTROY, + UHID_INPUT, }; struct uhid_create_req { @@ -41,11 +42,19 @@ struct uhid_create_req { __u32 country; } __attribute__((__packed__)); +#define UHID_DATA_MAX 4096 + +struct uhid_input_req { + __u8 data[UHID_DATA_MAX]; + __u16 size; +} __attribute__((__packed__)); + struct uhid_event { __u32 type; union { struct uhid_create_req create; + struct uhid_input_req input; } u; } __attribute__((__packed__)); From 037c061bca06cbfe9998476fb593090300fbbe87 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:20 +0200 Subject: [PATCH 08/18] HID: uhid: forward hid report-descriptor to hid core When the uhid_hid_parse callback is called we simply forward it to hid_parse_report() with the data that we got in the UHID_CREATE event. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 3d1ebda122e597..0d011db30a4658 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -106,7 +106,9 @@ static int uhid_hid_input(struct input_dev *input, unsigned int type, static int uhid_hid_parse(struct hid_device *hid) { - return 0; + 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, From ec4b7dea453e0f9fd0fbf1761b2d01eff64f264b Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:21 +0200 Subject: [PATCH 09/18] HID: uhid: add UHID_START and UHID_STOP events We send UHID_START and UHID_STOP events to user-space when the HID core starts/stops the device. This notifies user-space about driver readiness and data-I/O can start now. This directly forwards the callbacks from hid-core to user-space. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 8 +++++++- include/linux/uhid.h | 2 ++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 0d011db30a4658..2e7f3a02397539 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -82,11 +82,17 @@ static int uhid_queue_event(struct uhid_device *uhid, __u32 event) static int uhid_hid_start(struct hid_device *hid) { - return 0; + 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) diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 6eb42bea86a25b..f8ce6f7571d858 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -25,6 +25,8 @@ enum uhid_event_type { UHID_CREATE, UHID_DESTROY, + UHID_START, + UHID_STOP, UHID_INPUT, }; From e7191474a5459e6ba7039fadca6a32f3a5731909 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:22 +0200 Subject: [PATCH 10/18] HID: uhid: forward open/close events to user-space HID core notifies us with *_open/*_close callbacks when there is an actual user of our device. We forward these to user-space so they can react on this. This allows user-space to skip I/O unless they receive an OPEN event. When they receive a CLOSE event they can stop I/O again to save energy. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 7 ++++++- include/linux/uhid.h | 2 ++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 2e7f3a02397539..0226ba3f530700 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -97,11 +97,16 @@ static void uhid_hid_stop(struct hid_device *hid) static int uhid_hid_open(struct hid_device *hid) { - return 0; + 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, diff --git a/include/linux/uhid.h b/include/linux/uhid.h index f8ce6f7571d858..351650b7a0f696 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -27,6 +27,8 @@ enum uhid_event_type { UHID_DESTROY, UHID_START, UHID_STOP, + UHID_OPEN, + UHID_CLOSE, UHID_INPUT, }; From f80e13601c51a836b2aac583b8a3b4327c0c27ce Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:23 +0200 Subject: [PATCH 11/18] HID: uhid: forward output request to user-space If the hid-driver wants to send standardized data to the device it uses a linux input_event. We forward this to the user-space transport-level driver so they can perform the requested action on the device. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 18 ++++++++++++++++++ include/linux/uhid.h | 8 ++++++++ 2 files changed, 26 insertions(+) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 0226ba3f530700..4dd693e1c8b8a4 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -112,6 +112,24 @@ static void uhid_hid_close(struct hid_device *hid) 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; } diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 351650b7a0f696..3fa48492101039 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -29,6 +29,7 @@ enum uhid_event_type { UHID_STOP, UHID_OPEN, UHID_CLOSE, + UHID_OUTPUT_EV, UHID_INPUT, }; @@ -53,12 +54,19 @@ struct uhid_input_req { __u16 size; } __attribute__((__packed__)); +struct uhid_output_ev_req { + __u16 type; + __u16 code; + __s32 value; +} __attribute__((__packed__)); + struct uhid_event { __u32 type; union { struct uhid_create_req create; struct uhid_input_req input; + struct uhid_output_ev_req output_ev; } u; } __attribute__((__packed__)); From 3b3baa82e4306b5160692643fab2fa322ceb94f9 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:24 +0200 Subject: [PATCH 12/18] HID: uhid: forward raw output reports to user-space Some drivers that use non-standard HID features require raw output reports sent to the device. We now forward these requests directly to user-space so the transport-level driver can correctly send it to the device or handle it correspondingly. There is no way to signal back whether the transmission was successful, moreover, there might be lots of messages coming out from the driver flushing the output-queue. However, there is currently no driver that causes this so we are safe. If some drivers need to transmit lots of data this way, we need a method to synchronize this and can implement another UHID_OUTPUT_SYNC event. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 34 +++++++++++++++++++++++++++++++++- include/linux/uhid.h | 14 ++++++++++++++ 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 4dd693e1c8b8a4..421c492dc82461 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -149,7 +149,39 @@ static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, unsigned char report_type) { - return 0; + 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 = { diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 3fa48492101039..2c972550a62459 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -29,6 +29,7 @@ enum uhid_event_type { UHID_STOP, UHID_OPEN, UHID_CLOSE, + UHID_OUTPUT, UHID_OUTPUT_EV, UHID_INPUT, }; @@ -49,11 +50,23 @@ struct uhid_create_req { #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; @@ -66,6 +79,7 @@ struct uhid_event { union { struct uhid_create_req create; struct uhid_input_req input; + struct uhid_output_req output; struct uhid_output_ev_req output_ev; } u; } __attribute__((__packed__)); From fcfcf0deb89ece6eb9ae23768fec1bc1718f9b7f Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:25 +0200 Subject: [PATCH 13/18] HID: uhid: implement feature requests HID standard allows sending a feature request to the device which is answered by an HID report. uhid implements this by sending a UHID_FEATURE event to user-space which then must answer with UHID_FEATURE_ANSWER. If it doesn't do this in a timely manner, the request is discarded silently. We serialize the feature requests, that is, there is always only a single active feature-request sent to user-space, other requests have to wait. HIDP and USB-HID do it the same way. Because we discard feature-requests silently, we must make sure to match a response to the corresponding request. We use sequence-IDs for this so user-space must copy the ID from the request into the answer. Feature-answers are ignored if they do not contain the same ID as the currently pending feature request. Internally, we must make sure that feature-requests are synchronized with UHID_DESTROY and close() events. We must not dead-lock when closing the HID device, either, so we have to use separate locks. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 120 ++++++++++++++++++++++++++++++++++++++++++- include/linux/uhid.h | 17 ++++++ 2 files changed, 136 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 421c492dc82461..ea560bfa033d2a 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -42,6 +42,12 @@ struct uhid_device { __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; @@ -143,7 +149,84 @@ static int uhid_hid_parse(struct hid_device *hid) static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, __u8 *buf, size_t count, unsigned char rtype) { - return 0; + struct uhid_device *uhid = hid->driver_data; + __u8 report_type; + struct uhid_event *ev; + unsigned long flags; + int ret; + size_t 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, @@ -265,7 +348,11 @@ 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); @@ -284,6 +371,31 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) 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; @@ -293,9 +405,12 @@ static int uhid_char_open(struct inode *inode, struct file *file) 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); @@ -398,6 +513,9 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, 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; } diff --git a/include/linux/uhid.h b/include/linux/uhid.h index 2c972550a62459..9c6974f169661d 100644 --- a/include/linux/uhid.h +++ b/include/linux/uhid.h @@ -32,6 +32,8 @@ enum uhid_event_type { UHID_OUTPUT, UHID_OUTPUT_EV, UHID_INPUT, + UHID_FEATURE, + UHID_FEATURE_ANSWER, }; struct uhid_create_req { @@ -73,6 +75,19 @@ struct uhid_output_ev_req { __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; @@ -81,6 +96,8 @@ struct uhid_event { 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__)); From d99b8bad7663c8b920b366877a27b4176dece062 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:26 +0200 Subject: [PATCH 14/18] HID: uhid: add documentation This describes the protocol used by uhid for user-space applications. It describes the details like non-blocking I/O and readv/writev for multiple events per syscall. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- Documentation/hid/uhid.txt | 169 +++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 Documentation/hid/uhid.txt diff --git a/Documentation/hid/uhid.txt b/Documentation/hid/uhid.txt new file mode 100644 index 00000000000000..4627c4241ece69 --- /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 From 5148fa52a12fa1b97c730b2fe321f2aad7ea041c Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:27 +0200 Subject: [PATCH 15/18] HID: uhid: add example program This adds an example user-space program that emulates a 3 button mouse with wheel. It detects keyboard presses and moves the mouse accordingly. It register a fake HID device to feed the raw HID reports into the kernel. In this example, you could use uinput to get the same result, but this shows how to get the same behavior with uhid so you don't need HID parsers in user-space. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- samples/uhid/Makefile | 10 + samples/uhid/uhid-example.c | 381 ++++++++++++++++++++++++++++++++++++ 2 files changed, 391 insertions(+) create mode 100644 samples/uhid/Makefile create mode 100644 samples/uhid/uhid-example.c diff --git a/samples/uhid/Makefile b/samples/uhid/Makefile new file mode 100644 index 00000000000000..c95a696560a7de --- /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 00000000000000..03ce3c059a5e7b --- /dev/null +++ b/samples/uhid/uhid-example.c @@ -0,0 +1,381 @@ +/* + * UHID Example + * + * Copyright (c) 2012 David Herrmann + * + * 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 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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//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; +} From 0a09d3ab3780aad9e64f1e45e56acf5b20bb82bf Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 10 Jun 2012 15:16:28 +0200 Subject: [PATCH 16/18] MAINTAINERS: add UHID entry Add an UHID entry to the MAINTAINERS file. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- MAINTAINERS | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index aa067a95ce116e..4997519ea0ede7 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6886,6 +6886,13 @@ S: Maintained F: Documentation/filesystems/ufs.txt F: fs/ufs/ +UHID USERSPACE HID IO DRIVER: +M: David Herrmann +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 From 1a8b294ce6b0cdab438175eed45ebb088bdd659a Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Mon, 18 Jun 2012 17:08:08 +0200 Subject: [PATCH 17/18] HID: uhid: silence gcc warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gcc is giving me: drivers/hid/uhid.c: In function ‘uhid_hid_get_raw’: drivers/hid/uhid.c:157: warning: ‘len’ may be used uninitialized in this function which is clearly bogus, as - when used as memcpy() argument, it's initialized properly - the code is structured in a way that either 'ret' or 'len' is always initialized, so the return statement always has an initialized value. Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index ea560bfa033d2a..119b7e6405beeb 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -154,7 +154,7 @@ static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, struct uhid_event *ev; unsigned long flags; int ret; - size_t len; + size_t uninitialized_var(len); struct uhid_feature_answer_req *req; if (!uhid->running) From adefb69b1b94df29ea2df05cd838c0e032b2c473 Mon Sep 17 00:00:00 2001 From: Vinicius Costa Gomes Date: Sat, 14 Jul 2012 18:59:25 -0300 Subject: [PATCH 18/18] HID: uhid: Fix sending events with invalid data This was detected because events with invalid types were arriving to userspace. The code before this patch would only work for the first event in the queue (when uhid->tail is 0). Signed-off-by: Vinicius Costa Gomes Reviewed-by: David Herrmann Signed-off-by: Jiri Kosina --- drivers/hid/uhid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 119b7e6405beeb..714cd8cc9579b6 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -465,7 +465,7 @@ static ssize_t uhid_char_read(struct file *file, char __user *buffer, goto try_again; } else { len = min(count, sizeof(**uhid->outq)); - if (copy_to_user(buffer, &uhid->outq[uhid->tail], len)) { + if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { ret = -EFAULT; } else { kfree(uhid->outq[uhid->tail]);