While the HID gadget implementation has been sufficient for devices that only
use INTERRUPT transfers, the USB HID standard includes provisions for Set- and
Get-Feature report CONTROL transfers that go over endpoint 0. These were
previously impossible with the existing implementation, and would either send
an empty reply, or stall out.
As the feature is a standard part of USB HID, it stands to reason that devices
would use it, and that the HID gadget should support it. This patch adds
support for (polled) device-to-host Get-Feature reports through a new ioctl
interface to the hidg class dev nodes.
Signed-off-by: Vicki Pfau <vi@xxxxxxxxxxx>
---
drivers/usb/gadget/function/f_hid.c | 121 ++++++++++++++++++++++++++--
include/uapi/linux/usb/g_hid.h | 38 +++++++++
include/uapi/linux/usb/gadgetfs.h | 2 +-
3 files changed, 154 insertions(+), 7 deletions(-)
create mode 100644 include/uapi/linux/usb/g_hid.h
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index ca0a7d9eaa34..7e70e4a168e6 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -16,6 +16,7 @@
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/usb/g_hid.h>
+#include <uapi/linux/usb/g_hid.h>
#include "u_f.h"
#include "u_hid.h"
@@ -71,6 +72,13 @@ 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;
+ spinlock_t get_spinlock;
+ bool get_pending;
+ wait_queue_head_t get_queue;
+
int minor;
struct cdev cdev;
struct usb_function func;
@@ -511,6 +519,64 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
return status;
}
+
+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;
+
+ int status = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hidg->get_spinlock, flags);
+
+#define GET_REPORT_COND (!hidg->get_pending)
+
+ while (!GET_REPORT_COND) {
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
+
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ if (wait_event_interruptible_exclusive(hidg->get_queue,
+ GET_REPORT_COND))
+ return -ERESTARTSYS;
+
+ spin_lock_irqsave(&hidg->get_spinlock, flags);
+ if (!hidg->get_pending) {
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
+ return -EINVAL;
+ }
+ }
+
+ hidg->get_pending = true;
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
+
+ status = copy_from_user(&hidg->get_report, buffer,
+ sizeof(struct usb_hidg_report));
+ if (status != 0) {
+ ERROR(cdev, "copy_from_user error\n");
+ status = -EINVAL;
+ }
+
+ spin_lock_irqsave(&hidg->get_spinlock, flags);
+ hidg->get_pending = false;
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
+
+ wake_up(&hidg->get_queue);
+ return status;
+}
+
+static long f_hidg_ioctl(struct file *file, unsigned int code, unsigned long arg)
+{
+ switch (code) {
+ 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;
@@ -536,6 +602,7 @@ static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
#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)
{
@@ -628,6 +695,10 @@ 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)
{
@@ -635,6 +706,8 @@ static int hidg_setup(struct usb_function *f,
struct usb_composite_dev *cdev = f->config->cdev;
struct usb_request *req = cdev->req;
int status = 0;
+ unsigned long flags;
+ bool do_wake = false;
__u16 value, length;
value = __le16_to_cpu(ctrl->wValue);
@@ -647,14 +720,29 @@ 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);
+ req = hidg->get_req;
+ req->zero = 0;
+ req->length = min_t(unsigned, length, hidg->report_length);
+ status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+ if (status < 0) {
+ ERROR(cdev, "usb_ep_queue error on get_report %d\n",
+ status);
- goto respond;
- break;
+ spin_lock_irqsave(&hidg->get_spinlock, flags);
+ if (hidg->get_pending) {
+ hidg->get_pending = false;
+ do_wake = true;
+ }
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
+
+ if (do_wake) {
+ wake_up(&hidg->get_queue);
+ }
+ }
+
+ return status;
case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
| HID_REQ_GET_PROTOCOL):
@@ -788,6 +876,14 @@ static void hidg_disable(struct usb_function *f)
hidg->req = NULL;
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
+
+ spin_lock_irqsave(&hidg->get_spinlock, flags);
+ if (!hidg->get_pending) {
+ usb_ep_free_request(f->config->cdev->gadget->ep0, hidg->get_req);
+ hidg->get_pending = true;
+ }
+ hidg->get_req = NULL;
+ spin_unlock_irqrestore(&hidg->get_spinlock, flags);
}
static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
@@ -896,6 +992,7 @@ 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,
.llseek = noop_llseek,
};
@@ -908,6 +1005,14 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
int status;
dev_t dev;
+ hidg->get_req = usb_ep_alloc_request(c->cdev->gadget->ep0, GFP_ATOMIC);
+ if (!hidg->get_req)
+ return -ENOMEM;
+ hidg->get_req->buf = hidg->get_report.data;
+ hidg->get_req->zero = 0;
+ hidg->get_req->complete = hidg_get_report_complete;
+ hidg->get_req->context = hidg;
+
/* maybe allocate device-global string IDs, and patch descriptors */
us = usb_gstrings_attach(c->cdev, ct_func_strings,
ARRAY_SIZE(ct_func_string_defs));
@@ -993,8 +1098,10 @@ 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_spinlock);
init_waitqueue_head(&hidg->write_queue);
init_waitqueue_head(&hidg->read_queue);
+ init_waitqueue_head(&hidg->get_queue);
INIT_LIST_HEAD(&hidg->completed_out_req);
/* create char device */
@@ -1021,6 +1128,8 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
if (hidg->req != NULL)
free_ep_req(hidg->in_ep, hidg->req);
+ usb_ep_free_request(c->cdev->gadget->ep0, hidg->get_req);
+
return status;
}
diff --git a/include/uapi/linux/usb/g_hid.h b/include/uapi/linux/usb/g_hid.h
new file mode 100644
index 000000000000..c6068b486354
--- /dev/null
+++ b/include/uapi/linux/usb/g_hid.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * g_hid.h -- Header file for USB HID gadget driver
+ *
+ * Copyright (C) 2022 Valve Software
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef __UAPI_LINUX_USB_G_HID_H
+#define __UAPI_LINUX_USB_G_HID_H
+
+#include <linux/types.h>
+
+struct usb_hidg_report {
+ __u16 length;
+ __u8 data[512];
+};
+
+/* The 'g' code is also used by gadgetfs and hid gadget ioctl requests.
+ * Don't add any colliding codes to either driver, and keep
+ * them in unique ranges (size 0x20 for now).
+ */
+#define GADGET_HID_WRITE_GET_REPORT _IOW('g', 0x42, struct usb_hidg_report)
+
+#endif /* __UAPI_LINUX_USB_G_HID_H */
diff --git a/include/uapi/linux/usb/gadgetfs.h b/include/uapi/linux/usb/gadgetfs.h
index 835473910a49..9754822b2a40 100644
--- a/include/uapi/linux/usb/gadgetfs.h
+++ b/include/uapi/linux/usb/gadgetfs.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).
*/
--
2.37.1
