@@ -15,13 +15,21 @@
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/sched.h>
+#include <linux/workqueue.h>
#include <linux/usb/g_hid.h>
+#include <uapi/linux/usb/g_hid.h>
#include "u_f.h"
#include "u_hid.h"
#define HIDG_MINORS 4
+/*
+ * Most operating systems seem to allow for 5000ms timeout, we will allow
+ * userspace half that time to respond before we return an empty report.
+ */
+#define GET_REPORT_TIMEOUT_MS 2500
+
static int major, minors;
static const struct class hidg_class = {
@@ -31,6 +39,11 @@ static const struct class hidg_class = {
static DEFINE_IDA(hidg_ida);
static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
+struct report_entry {
+ struct usb_hidg_report report_data;
+ struct list_head node;
+};
+
/*-------------------------------------------------------------------------*/
/* HID gadget struct */
@@ -75,6 +88,19 @@ struct f_hidg {
wait_queue_head_t write_queue;
struct usb_request *req;
+ /* get report */
+ struct usb_request *get_req;
+ struct usb_hidg_report get_report;
+ bool get_report_returned;
+ int get_report_req_report_id;
+ int get_report_req_report_length;
+ spinlock_t get_report_spinlock;
+ wait_queue_head_t get_queue; /* Waiting for userspace response */
+ wait_queue_head_t get_id_queue; /* Get ID came in */
+ struct work_struct work;
+ struct workqueue_struct *workqueue;
+ struct list_head report_list;
+
struct device dev;
struct cdev cdev;
struct usb_function func;
@@ -524,6 +550,173 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
return status;
}
+static struct report_entry *f_hidg_search_for_report(struct f_hidg *hidg, u8 report_id)
+{
+ struct list_head *ptr;
+ struct report_entry *entry;
+
+ list_for_each(ptr, &hidg->report_list) {
+ entry = list_entry(ptr, struct report_entry, node);
+ if (entry->report_data.report_id == report_id)
+ return entry;
+ }
+
+ return NULL;
+}
+
+static void get_report_workqueue_handler(struct work_struct *work)
+{
+ struct f_hidg *hidg = container_of(work, struct f_hidg, work);
+ struct usb_composite_dev *cdev = hidg->func.config->cdev;
+ struct usb_request *req;
+ struct report_entry *ptr;
+ unsigned long flags;
+
+ int status = 0;
+
+ spin_lock_irqsave(&hidg->get_report_spinlock, flags);
+ req = hidg->get_req;
+ if (!req) {
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ return;
+ }
+
+ req->zero = 0;
+ req->length = min_t(unsigned int, min_t(unsigned int, hidg->get_report_req_report_length,
+ hidg->report_length),
+ MAX_REPORT_LENGTH);
+
+ /* Check if there is a response available for immediate response */
+ ptr = f_hidg_search_for_report(hidg, hidg->get_report_req_report_id);
+ if (ptr && !ptr->report_data.userspace_req) {
+ /* Report exists in list and it is to be used for immediate response */
+ req->buf = ptr->report_data.data;
+ status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+ hidg->get_report_returned = true;
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ } else {
+ /*
+ * Report does not exist in list or should not be immediately sent
+ * i.e. give userspace time to respond
+ */
+ hidg->get_report_returned = false;
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ wake_up(&hidg->get_id_queue);
+#define GET_REPORT_COND (!hidg->get_report_returned)
+ /* Wait until userspace has responded or timeout */
+ status = wait_event_interruptible_timeout(hidg->get_queue, !GET_REPORT_COND,
+ msecs_to_jiffies(GET_REPORT_TIMEOUT_MS));
+ spin_lock_irqsave(&hidg->get_report_spinlock, flags);
+ req = hidg->get_req;
+ if (!req) {
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ return;
+ }
+ if (status == 0 && !hidg->get_report_returned) {
+ /* GET_REPORT request was not serviced by userspace within timeout period */
+ VDBG(cdev, "get_report : userspace timeout.\n");
+ hidg->get_report_returned = true;
+ }
+
+ /* Search again for report ID in list and respond to GET_REPORT request */
+ ptr = f_hidg_search_for_report(hidg, hidg->get_report_req_report_id);
+ if (ptr) {
+ /*
+ * Either get an updated response just serviced by userspace
+ * or send the latest response in the list
+ */
+ req->buf = ptr->report_data.data;
+ } else {
+ /* If there are no prevoiusly sent reports send empty report */
+ req->buf = hidg->get_report.data;
+ memset(req->buf, 0x0, req->length);
+ }
+
+ status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ }
+
+ if (status < 0)
+ VDBG(cdev, "usb_ep_queue error on ep0 responding to GET_REPORT\n");
+}
+
+static int f_hidg_get_report_id(struct file *file, __u8 __user *buffer)
+{
+ struct f_hidg *hidg = file->private_data;
+ int ret = 0;
+
+ ret = put_user(hidg->get_report_req_report_id, buffer);
+
+ return ret;
+}
+
+static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *buffer)
+{
+ struct f_hidg *hidg = file->private_data;
+ struct usb_composite_dev *cdev = hidg->func.config->cdev;
+ unsigned long flags;
+ struct report_entry *entry;
+ struct report_entry *ptr;
+ __u8 report_id;
+
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return -ENOMEM;
+
+ if (copy_from_user(&entry->report_data, buffer,
+ sizeof(struct usb_hidg_report))) {
+ ERROR(cdev, "copy_from_user error\n");
+ kfree(entry);
+ return -EINVAL;
+ }
+
+ report_id = entry->report_data.report_id;
+
+ spin_lock_irqsave(&hidg->get_report_spinlock, flags);
+ ptr = f_hidg_search_for_report(hidg, report_id);
+
+ if (ptr) {
+ /* Report already exists in list - update it */
+ if (copy_from_user(&ptr->report_data, buffer,
+ sizeof(struct usb_hidg_report))) {
+ ERROR(cdev, "copy_from_user error\n");
+ kfree(entry);
+ return -EINVAL;
+ }
+ kfree(entry);
+ } else {
+ /* Report does not exist in list - add it */
+ list_add_tail(&entry->node, &hidg->report_list);
+ }
+
+ /* If there is no response pending then do nothing further */
+ if (hidg->get_report_returned) {
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ return 0;
+ }
+
+ /* If this userspace response serves the current pending report */
+ if (hidg->get_report_req_report_id == report_id) {
+ hidg->get_report_returned = true;
+ wake_up(&hidg->get_queue);
+ }
+
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+ return 0;
+}
+
+static long f_hidg_ioctl(struct file *file, unsigned int code, unsigned long arg)
+{
+ switch (code) {
+ case GADGET_HID_READ_GET_REPORT_ID:
+ return f_hidg_get_report_id(file, (__u8 __user *)arg);
+ case GADGET_HID_WRITE_GET_REPORT:
+ return f_hidg_get_report(file, (struct usb_hidg_report __user *)arg);
+ default:
+ return -ENOTTY;
+ }
+}
+
static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
{
struct f_hidg *hidg = file->private_data;
@@ -531,6 +724,8 @@ static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
poll_wait(file, &hidg->read_queue, wait);
poll_wait(file, &hidg->write_queue, wait);
+ poll_wait(file, &hidg->get_queue, wait);
+ poll_wait(file, &hidg->get_id_queue, wait);
if (WRITE_COND)
ret |= EPOLLOUT | EPOLLWRNORM;
@@ -543,12 +738,16 @@ static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
ret |= EPOLLIN | EPOLLRDNORM;
}
+ if (GET_REPORT_COND)
+ ret |= EPOLLPRI;
+
return ret;
}
#undef WRITE_COND
#undef READ_COND_SSREPORT
#undef READ_COND_INTOUT
+#undef GET_REPORT_COND
static int f_hidg_release(struct inode *inode, struct file *fd)
{
@@ -641,6 +840,10 @@ static void hidg_ssreport_complete(struct usb_ep *ep, struct usb_request *req)
wake_up(&hidg->read_queue);
}
+static void hidg_get_report_complete(struct usb_ep *ep, struct usb_request *req)
+{
+}
+
static int hidg_setup(struct usb_function *f,
const struct usb_ctrlrequest *ctrl)
{
@@ -649,6 +852,7 @@ static int hidg_setup(struct usb_function *f,
struct usb_request *req = cdev->req;
int status = 0;
__u16 value, length;
+ unsigned long flags;
value = __le16_to_cpu(ctrl->wValue);
length = __le16_to_cpu(ctrl->wLength);
@@ -660,14 +864,20 @@ static int hidg_setup(struct usb_function *f,
switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
| HID_REQ_GET_REPORT):
- VDBG(cdev, "get_report\n");
+ VDBG(cdev, "get_report | wLength=%d\n", ctrl->wLength);
- /* send an empty report */
- length = min_t(unsigned, length, hidg->report_length);
- memset(req->buf, 0x0, length);
+ /*
+ * Update GET_REPORT ID so that an ioctl can be used to determine what
+ * GET_REPORT the request was actually for.
+ */
+ spin_lock_irqsave(&hidg->get_report_spinlock, flags);
+ hidg->get_report_req_report_id = value & 0xff;
+ hidg->get_report_req_report_length = length;
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
- goto respond;
- break;
+ queue_work(hidg->workqueue, &hidg->work);
+
+ return status;
case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
| HID_REQ_GET_PROTOCOL):
@@ -793,6 +1003,14 @@ static void hidg_disable(struct usb_function *f)
spin_unlock_irqrestore(&hidg->read_spinlock, flags);
}
+ spin_lock_irqsave(&hidg->get_report_spinlock, flags);
+ if (!hidg->get_report_returned) {
+ usb_ep_free_request(f->config->cdev->gadget->ep0, hidg->get_req);
+ hidg->get_req = NULL;
+ hidg->get_report_returned = true;
+ }
+ spin_unlock_irqrestore(&hidg->get_report_spinlock, flags);
+
spin_lock_irqsave(&hidg->write_spinlock, flags);
if (!hidg->write_pending) {
free_ep_req(hidg->in_ep, hidg->req);
@@ -902,6 +1120,14 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
return status;
}
+#ifdef CONFIG_COMPAT
+static long f_hidg_compat_ioctl(struct file *file, unsigned int code,
+ unsigned long value)
+{
+ return f_hidg_ioctl(file, code, value);
+}
+#endif
+
static const struct file_operations f_hidg_fops = {
.owner = THIS_MODULE,
.open = f_hidg_open,
@@ -909,6 +1135,10 @@ static const struct file_operations f_hidg_fops = {
.write = f_hidg_write,
.read = f_hidg_read,
.poll = f_hidg_poll,
+ .unlocked_ioctl = f_hidg_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = f_hidg_compat_ioctl,
+#endif
.llseek = noop_llseek,
};
@@ -919,6 +1149,15 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
struct usb_string *us;
int status;
+ hidg->get_req = usb_ep_alloc_request(c->cdev->gadget->ep0, GFP_ATOMIC);
+ if (!hidg->get_req)
+ return -ENOMEM;
+
+ hidg->get_req->zero = 0;
+ hidg->get_req->complete = hidg_get_report_complete;
+ hidg->get_req->context = hidg;
+ hidg->get_report_returned = true;
+
/* maybe allocate device-global string IDs, and patch descriptors */
us = usb_gstrings_attach(c->cdev, ct_func_strings,
ARRAY_SIZE(ct_func_string_defs));
@@ -1004,9 +1243,24 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
hidg->write_pending = 1;
hidg->req = NULL;
spin_lock_init(&hidg->read_spinlock);
+ spin_lock_init(&hidg->get_report_spinlock);
init_waitqueue_head(&hidg->write_queue);
init_waitqueue_head(&hidg->read_queue);
+ init_waitqueue_head(&hidg->get_queue);
+ init_waitqueue_head(&hidg->get_id_queue);
INIT_LIST_HEAD(&hidg->completed_out_req);
+ INIT_LIST_HEAD(&hidg->report_list);
+
+ INIT_WORK(&hidg->work, get_report_workqueue_handler);
+ hidg->workqueue = alloc_workqueue("report_work",
+ WQ_FREEZABLE |
+ WQ_MEM_RECLAIM,
+ 1);
+
+ if (!hidg->workqueue) {
+ status = -ENOMEM;
+ goto fail;
+ }
/* create char device */
cdev_init(&hidg->cdev, &f_hidg_fops);
@@ -1016,12 +1270,16 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
return 0;
fail_free_descs:
+ destroy_workqueue(hidg->workqueue);
usb_free_all_descriptors(f);
fail:
ERROR(f->config->cdev, "hidg_bind FAILED\n");
if (hidg->req != NULL)
free_ep_req(hidg->in_ep, hidg->req);
+ usb_ep_free_request(c->cdev->gadget->ep0, hidg->get_req);
+ hidg->get_req = NULL;
+
return status;
}
@@ -1256,7 +1514,7 @@ static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
struct f_hidg *hidg = func_to_hidg(f);
cdev_device_del(&hidg->cdev, &hidg->dev);
-
+ destroy_workqueue(hidg->workqueue);
usb_free_all_descriptors(f);
}
new file mode 100644
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+
+#ifndef __UAPI_LINUX_USB_G_HID_H
+#define __UAPI_LINUX_USB_G_HID_H
+
+#include <linux/types.h>
+
+/* Maximum HID report length for High-Speed USB (i.e. USB 2.0) */
+#define MAX_REPORT_LENGTH 64
+
+/**
+ * struct usb_hidg_report - response to GET_REPORT
+ * @report_id: report ID that this is a response for
+ * @userspace_req:
+ * !0 this report is used for any pending GET_REPORT request
+ * but wait on userspace to issue a new report on future requests
+ * 0 this report is to be used for any future GET_REPORT requests
+ * @length: length of the report response
+ * @data: report response
+ * @padding: padding for 32/64 bit compatibility
+ *
+ * Structure used by GADGET_HID_WRITE_GET_REPORT ioctl on /dev/hidg*.
+ */
+struct usb_hidg_report {
+ __u8 report_id;
+ __u8 userspace_req;
+ __u16 length;
+ __u8 data[MAX_REPORT_LENGTH];
+ __u8 padding[4];
+};
+
+/* The 'g' code is used by gadgetfs and hid gadget ioctl requests.
+ * Don't add any colliding codes to either driver, and keep
+ * them in unique ranges.
+ */
+
+#define GADGET_HID_READ_GET_REPORT_ID _IOR('g', 0x41, __u8)
+#define GADGET_HID_WRITE_GET_REPORT _IOW('g', 0x42, struct usb_hidg_report)
+
+#endif /* __UAPI_LINUX_USB_G_HID_H */
@@ -62,7 +62,7 @@ struct usb_gadgetfs_event {
};
-/* The 'g' code is also used by printer gadget ioctl requests.
+/* The 'g' code is also used by printer and hid gadget ioctl requests.
* Don't add any colliding codes to either driver, and keep
* them in unique ranges (size 0x20 for now).
*/