diff options
Diffstat (limited to 'drivers/hid/uhid.c')
| -rw-r--r-- | drivers/hid/uhid.c | 572 |
1 files changed, 572 insertions, 0 deletions
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c new file mode 100644 index 00000000000..714cd8cc957 --- /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"); |