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 | 19 ++++
include/uapi/linux/usb/gadget-ioctl.h | 3 +
3 files changed, 137 insertions(+), 6 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 3c8a9dd585c0..5a097ea718e8 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"
@@ -75,6 +76,13 @@ 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;
+
struct device dev;
struct cdev cdev;
struct usb_function func;
@@ -524,6 +532,64 @@ 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;
@@ -549,6 +615,7 @@ 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)
{
@@ -641,6 +708,10 @@ 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)
{
@@ -648,6 +719,8 @@ 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);
@@ -660,14 +733,29 @@ 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):
@@ -801,6 +889,14 @@ 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)
@@ -909,6 +1005,7 @@ 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,
};
@@ -919,6 +1016,14 @@ 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->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));
@@ -1004,8 +1109,10 @@ 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 */
@@ -1022,6 +1129,8 @@ 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..187224dcc0a1
--- /dev/null
+++ b/include/uapi/linux/usb/g_hid.h
@@ -0,0 +1,19 @@
+/* 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>
+
+#include <linux/usb/gadget-ioctl.h>
+
+/* This value is based on the maximum value of wMaxPacketSize for an endpoint,
+ * which in USB 3.2 is defined as 512 for control packets in section 9.6.6 */
+#define HIDG_REPORT_SIZE_MAX 512
+
+struct usb_hidg_report {
+ __u16 length;
+ __u8 data[HIDG_REPORT_SIZE_MAX];
+};
+
+#endif /* __UAPI_LINUX_USB_G_HID_H */
diff --git a/include/uapi/linux/usb/gadget-ioctl.h b/include/uapi/linux/usb/gadget-ioctl.h
index b5f8f7894db7..81f488643b53 100644
--- a/include/uapi/linux/usb/gadget-ioctl.h
+++ b/include/uapi/linux/usb/gadget-ioctl.h
@@ -25,6 +25,9 @@
*/
#define GADGETFS_CLEAR_HALT _IO('g', 3)
+/* g_hid ioctls */
+#define GADGET_HID_WRITE_GET_REPORT _IOW('g', 0x42, struct usb_hidg_report)
+
/* g_printer ioctls */
#define GADGET_GET_PRINTER_STATUS _IOR('g', 0x21, unsigned char)
#define GADGET_SET_PRINTER_STATUS _IOWR('g', 0x22, unsigned char)
--
2.43.0
