Merge tag 'usb-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB/Thunderbolt updates from Greg KH:
 "Here is the large set of USB and Thunderbolt changes for 6.12-rc1.

  Nothing "major" in here, except for a new 9p network gadget that has
  been worked on for a long time (all of the needed acks are here)

  Other than that, it's the usual set of:

   - Thunderbolt / USB4 driver updates and additions for new hardware

   - dwc3 driver updates and new features added

   - xhci driver updates

   - typec driver updates

   - USB gadget updates and api additions to make some gadgets more
     configurable by userspace

   - dwc2 driver updates

   - usb phy driver updates

   - usbip feature additions

   - other minor USB driver updates

  All of these have been in linux-next for a long time with no reported
  issues"

* tag 'usb-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (145 commits)
  sub: cdns3: Use predefined PCI vendor ID constant
  sub: cdns2: Use predefined PCI vendor ID constant
  USB: misc: yurex: fix race between read and write
  USB: misc: cypress_cy7c63: check for short transfer
  USB: appledisplay: close race between probe and completion handler
  USB: class: CDC-ACM: fix race between get_serial and set_serial
  usb: r8a66597-hcd: make read-only const arrays static
  usb: typec: ucsi: Fix busy loop on ASUS VivoBooks
  usb: dwc3: rtk: Clean up error code in __get_dwc3_maximum_speed()
  usb: storage: ene_ub6250: Fix right shift warnings
  usb: roles: Improve the fix for a false positive recursive locking complaint
  locking/mutex: Introduce mutex_init_with_key()
  locking/mutex: Define mutex_init() once
  net/9p/usbg: fix CONFIG_USB_GADGET dependency
  usb: xhci: fix loss of data on Cadence xHC
  usb: xHCI: add XHCI_RESET_ON_RESUME quirk for Phytium xHCI host
  usb: dwc3: imx8mp: disable SS_CON and U3 wakeup for system sleep
  usb: dwc3: imx8mp: add 2 software managed quirk properties for host mode
  usb: host: xhci-plat: Parse xhci-missing_cas_quirk and apply quirk
  usb: misc: onboard_usb_dev: add Microchip usb5744 SMBus programming support
  ...

3 files changed, 966 insertions, 0 deletions

diff --git a/net/9p/Kconfig b/net/9p/Kconfig
index bcdab9c23b40..63f988f0c9e8 100644
--- a/net/9p/Kconfig
+++ b/net/9p/Kconfig
@@ -40,6 +40,12 @@ config NET_9P_XEN
 	  This builds support for a transport for 9pfs between
 	  two Xen domains.
 
+config NET_9P_USBG
+	bool "9P USB Gadget Transport"
+	depends on USB_GADGET=y || USB_GADGET=NET_9P
+	help
+	  This builds support for a transport for 9pfs over
+	  usb gadget.
 
 config NET_9P_RDMA
 	depends on INET && INFINIBAND && INFINIBAND_ADDR_TRANS
diff --git a/net/9p/Makefile b/net/9p/Makefile
index 1df9b344c30b..22794a451c3f 100644
--- a/net/9p/Makefile
+++ b/net/9p/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
 obj-$(CONFIG_NET_9P_XEN) += 9pnet_xen.o
 obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
+obj-$(CONFIG_NET_9P_USBG) += 9pnet_usbg.o
 
 9pnet-objs := \
 	mod.o \
@@ -23,3 +24,6 @@ obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
 
 9pnet_rdma-objs := \
 	trans_rdma.o \
+
+9pnet_usbg-objs := \
+	trans_usbg.o \
diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c
new file mode 100644
index 000000000000..975b76839dca
--- /dev/null
+++ b/net/9p/trans_usbg.c
@@ -0,0 +1,956 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * trans_usbg.c - USB peripheral usb9pfs configuration driver and transport.
+ *
+ * Copyright (C) 2024 Michael Grzeschik <m.grzeschik@pengutronix.de>
+ */
+
+/* Gadget usb9pfs only needs two bulk endpoints, and will use the usb9pfs
+ * transport to mount host exported filesystem via usb gadget.
+ */
+
+/*     +--------------------------+    |    +--------------------------+
+ *     |  9PFS mounting client    |    |    |  9PFS exporting server   |
+ *  SW |                          |    |    |                          |
+ *     |   (this:trans_usbg)      |    |    |(e.g. diod or nfs-ganesha)|
+ *     +-------------^------------+    |    +-------------^------------+
+ *                   |                 |                  |
+ * ------------------|------------------------------------|-------------
+ *                   |                 |                  |
+ *     +-------------v------------+    |    +-------------v------------+
+ *     |                          |    |    |                          |
+ *  HW |   USB Device Controller  <--------->   USB Host Controller    |
+ *     |                          |    |    |                          |
+ *     +--------------------------+    |    +--------------------------+
+ */
+
+#include <linux/cleanup.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/func_utils.h>
+
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <net/9p/transport.h>
+
+#define DEFAULT_BUFLEN        16384
+
+struct f_usb9pfs {
+	struct p9_client *client;
+
+	/* 9p request lock for en/dequeue */
+	spinlock_t lock;
+
+	struct usb_request *in_req;
+	struct usb_request *out_req;
+
+	struct usb_ep *in_ep;
+	struct usb_ep *out_ep;
+
+	struct completion send;
+	struct completion received;
+
+	unsigned int buflen;
+
+	struct usb_function function;
+};
+
+static inline struct f_usb9pfs *func_to_usb9pfs(struct usb_function *f)
+{
+	return container_of(f, struct f_usb9pfs, function);
+}
+
+struct f_usb9pfs_opts {
+	struct usb_function_instance func_inst;
+	unsigned int buflen;
+
+	struct f_usb9pfs_dev *dev;
+
+	/* Read/write access to configfs attributes is handled by configfs.
+	 *
+	 * This is to protect the data from concurrent access by read/write
+	 * and create symlink/remove symlink.
+	 */
+	struct mutex lock;
+	int refcnt;
+};
+
+struct f_usb9pfs_dev {
+	struct f_usb9pfs *usb9pfs;
+	struct f_usb9pfs_opts *opts;
+	char tag[41];
+	bool inuse;
+
+	struct list_head usb9pfs_instance;
+};
+
+static DEFINE_MUTEX(usb9pfs_lock);
+static struct list_head usbg_instance_list;
+
+static int usb9pfs_queue_tx(struct f_usb9pfs *usb9pfs, struct p9_req_t *p9_tx_req,
+			    gfp_t gfp_flags)
+{
+	struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
+	struct usb_request *req = usb9pfs->in_req;
+	int ret;
+
+	if (!(p9_tx_req->tc.size % usb9pfs->in_ep->maxpacket))
+		req->zero = 1;
+
+	req->buf = p9_tx_req->tc.sdata;
+	req->length = p9_tx_req->tc.size;
+	req->context = p9_tx_req;
+
+	dev_dbg(&cdev->gadget->dev, "%s usb9pfs send --> %d/%d, zero: %d\n",
+		usb9pfs->in_ep->name, req->actual, req->length, req->zero);
+
+	ret = usb_ep_queue(usb9pfs->in_ep, req, gfp_flags);
+	if (ret)
+		req->context = NULL;
+
+	dev_dbg(&cdev->gadget->dev, "tx submit --> %d\n", ret);
+
+	return ret;
+}
+
+static int usb9pfs_queue_rx(struct f_usb9pfs *usb9pfs, struct usb_request *req,
+			    gfp_t gfp_flags)
+{
+	struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
+	int ret;
+
+	ret = usb_ep_queue(usb9pfs->out_ep, req, gfp_flags);
+
+	dev_dbg(&cdev->gadget->dev, "rx submit --> %d\n", ret);
+
+	return ret;
+}
+
+static int usb9pfs_transmit(struct f_usb9pfs *usb9pfs, struct p9_req_t *p9_req)
+{
+	int ret = 0;
+
+	guard(spinlock_irqsave)(&usb9pfs->lock);
+
+	ret = usb9pfs_queue_tx(usb9pfs, p9_req, GFP_ATOMIC);
+	if (ret)
+		return ret;
+
+	list_del(&p9_req->req_list);
+
+	p9_req_get(p9_req);
+
+	return ret;
+}
+
+static void usb9pfs_tx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct f_usb9pfs *usb9pfs = ep->driver_data;
+	struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
+	struct p9_req_t *p9_tx_req = req->context;
+	unsigned long flags;
+
+	/* reset zero packages */
+	req->zero = 0;
+
+	if (req->status) {
+		dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
+			ep->name, req->status, req->actual, req->length);
+		return;
+	}
+
+	dev_dbg(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
+		ep->name, req->status, req->actual, req->length);
+
+	spin_lock_irqsave(&usb9pfs->lock, flags);
+	WRITE_ONCE(p9_tx_req->status, REQ_STATUS_SENT);
+
+	p9_req_put(usb9pfs->client, p9_tx_req);
+
+	req->context = NULL;
+
+	spin_unlock_irqrestore(&usb9pfs->lock, flags);
+
+	complete(&usb9pfs->send);
+}
+
+static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf)
+{
+	struct p9_req_t *p9_rx_req;
+	struct p9_fcall	rc;
+	int ret;
+
+	/* start by reading header */
+	rc.sdata = buf;
+	rc.offset = 0;
+	rc.capacity = P9_HDRSZ;
+	rc.size = P9_HDRSZ;
+
+	p9_debug(P9_DEBUG_TRANS, "mux %p got %zu bytes\n", usb9pfs,
+		 rc.capacity - rc.offset);
+
+	ret = p9_parse_header(&rc, &rc.size, NULL, NULL, 0);
+	if (ret) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "error parsing header: %d\n", ret);
+		return NULL;
+	}
+
+	p9_debug(P9_DEBUG_TRANS,
+		 "mux %p pkt: size: %d bytes tag: %d\n",
+		 usb9pfs, rc.size, rc.tag);
+
+	p9_rx_req = p9_tag_lookup(usb9pfs->client, rc.tag);
+	if (!p9_rx_req || p9_rx_req->status != REQ_STATUS_SENT) {
+		p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", rc.tag);
+		return NULL;
+	}
+
+	if (rc.size > p9_rx_req->rc.capacity) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "requested packet size too big: %d for tag %d with capacity %zd\n",
+			 rc.size, rc.tag, p9_rx_req->rc.capacity);
+		p9_req_put(usb9pfs->client, p9_rx_req);
+		return NULL;
+	}
+
+	if (!p9_rx_req->rc.sdata) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "No recv fcall for tag %d (req %p), disconnecting!\n",
+			 rc.tag, p9_rx_req);
+		p9_req_put(usb9pfs->client, p9_rx_req);
+		return NULL;
+	}
+
+	return p9_rx_req;
+}
+
+static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct f_usb9pfs *usb9pfs = ep->driver_data;
+	struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
+	struct p9_req_t *p9_rx_req;
+
+	if (req->status) {
+		dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
+			ep->name, req->status, req->actual, req->length);
+		return;
+	}
+
+	p9_rx_req = usb9pfs_rx_header(usb9pfs, req->buf);
+	if (!p9_rx_req)
+		return;
+
+	memcpy(p9_rx_req->rc.sdata, req->buf, req->actual);
+
+	p9_rx_req->rc.size = req->actual;
+
+	p9_client_cb(usb9pfs->client, p9_rx_req, REQ_STATUS_RCVD);
+	p9_req_put(usb9pfs->client, p9_rx_req);
+
+	complete(&usb9pfs->received);
+}
+
+static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
+{
+	int value;
+
+	value = usb_ep_disable(ep);
+	if (value < 0)
+		dev_info(&cdev->gadget->dev,
+			 "disable %s --> %d\n", ep->name, value);
+}
+
+static void disable_usb9pfs(struct f_usb9pfs *usb9pfs)
+{
+	struct usb_composite_dev *cdev =
+		usb9pfs->function.config->cdev;
+
+	if (usb9pfs->in_req) {
+		usb_ep_free_request(usb9pfs->in_ep, usb9pfs->in_req);
+		usb9pfs->in_req = NULL;
+	}
+
+	if (usb9pfs->out_req) {
+		usb_ep_free_request(usb9pfs->out_ep, usb9pfs->out_req);
+		usb9pfs->out_req = NULL;
+	}
+
+	disable_ep(cdev, usb9pfs->in_ep);
+	disable_ep(cdev, usb9pfs->out_ep);
+	dev_dbg(&cdev->gadget->dev, "%s disabled\n",
+		usb9pfs->function.name);
+}
+
+static int alloc_requests(struct usb_composite_dev *cdev,
+			  struct f_usb9pfs *usb9pfs)
+{
+	int ret;
+
+	usb9pfs->in_req = usb_ep_alloc_request(usb9pfs->in_ep, GFP_ATOMIC);
+	if (!usb9pfs->in_req) {
+		ret = -ENOENT;
+		goto fail;
+	}
+
+	usb9pfs->out_req = alloc_ep_req(usb9pfs->out_ep, usb9pfs->buflen);
+	if (!usb9pfs->out_req) {
+		ret = -ENOENT;
+		goto fail_in;
+	}
+
+	usb9pfs->in_req->complete = usb9pfs_tx_complete;
+	usb9pfs->out_req->complete = usb9pfs_rx_complete;
+
+	/* length will be set in complete routine */
+	usb9pfs->in_req->context = usb9pfs;
+	usb9pfs->out_req->context = usb9pfs;
+
+	return 0;
+
+fail_in:
+	usb_ep_free_request(usb9pfs->in_ep, usb9pfs->in_req);
+fail:
+	return ret;
+}
+
+static int enable_endpoint(struct usb_composite_dev *cdev,
+			   struct f_usb9pfs *usb9pfs, struct usb_ep *ep)
+{
+	int ret;
+
+	ret = config_ep_by_speed(cdev->gadget, &usb9pfs->function, ep);
+	if (ret)
+		return ret;
+
+	ret = usb_ep_enable(ep);
+	if (ret < 0)
+		return ret;
+
+	ep->driver_data = usb9pfs;
+
+	return 0;
+}
+
+static int
+enable_usb9pfs(struct usb_composite_dev *cdev, struct f_usb9pfs *usb9pfs)
+{
+	struct p9_client *client;
+	int ret = 0;
+
+	ret = enable_endpoint(cdev, usb9pfs, usb9pfs->in_ep);
+	if (ret)
+		goto out;
+
+	ret = enable_endpoint(cdev, usb9pfs, usb9pfs->out_ep);
+	if (ret)
+		goto disable_in;
+
+	ret = alloc_requests(cdev, usb9pfs);
+	if (ret)
+		goto disable_out;
+
+	client = usb9pfs->client;
+	if (client)
+		client->status = Connected;
+
+	dev_dbg(&cdev->gadget->dev, "%s enabled\n", usb9pfs->function.name);
+	return 0;
+
+disable_out:
+	usb_ep_disable(usb9pfs->out_ep);
+disable_in:
+	usb_ep_disable(usb9pfs->in_ep);
+out:
+	return ret;
+}
+
+static int p9_usbg_create(struct p9_client *client, const char *devname, char *args)
+{
+	struct f_usb9pfs_dev *dev;
+	struct f_usb9pfs *usb9pfs;
+	int ret = -ENOENT;
+	int found = 0;
+
+	if (!devname)
+		return -EINVAL;
+
+	guard(mutex)(&usb9pfs_lock);
+
+	list_for_each_entry(dev, &usbg_instance_list, usb9pfs_instance) {
+		if (!strncmp(devname, dev->tag, strlen(devname))) {
+			if (!dev->inuse) {
+				dev->inuse = true;
+				found = 1;
+				break;
+			}
+			ret = -EBUSY;
+			break;
+		}
+	}
+
+	if (!found) {
+		pr_err("no channels available for device %s\n", devname);
+		return ret;
+	}
+
+	usb9pfs = dev->usb9pfs;
+	if (!usb9pfs)
+		return -EINVAL;
+
+	client->trans = (void *)usb9pfs;
+	if (!usb9pfs->in_req)
+		client->status = Disconnected;
+	else
+		client->status = Connected;
+	usb9pfs->client = client;
+
+	client->trans_mod->maxsize = usb9pfs->buflen;
+
+	complete(&usb9pfs->received);
+
+	return 0;
+}
+
+static void usb9pfs_clear_tx(struct f_usb9pfs *usb9pfs)
+{
+	struct p9_req_t *req;
+
+	guard(spinlock_irqsave)(&usb9pfs->lock);
+
+	req = usb9pfs->in_req->context;
+	if (!req)
+		return;
+
+	if (!req->t_err)
+		req->t_err = -ECONNRESET;
+
+	p9_client_cb(usb9pfs->client, req, REQ_STATUS_ERROR);
+}
+
+static void p9_usbg_close(struct p9_client *client)
+{
+	struct f_usb9pfs *usb9pfs;
+	struct f_usb9pfs_dev *dev;
+	struct f_usb9pfs_opts *opts;
+
+	if (!client)
+		return;
+
+	usb9pfs = client->trans;
+	if (!usb9pfs)
+		return;
+
+	client->status = Disconnected;
+
+	usb9pfs_clear_tx(usb9pfs);
+
+	opts = container_of(usb9pfs->function.fi,
+			    struct f_usb9pfs_opts, func_inst);
+
+	dev = opts->dev;
+
+	mutex_lock(&usb9pfs_lock);
+	dev->inuse = false;
+	mutex_unlock(&usb9pfs_lock);
+}
+
+static int p9_usbg_request(struct p9_client *client, struct p9_req_t *p9_req)
+{
+	struct f_usb9pfs *usb9pfs = client->trans;
+	int ret;
+
+	if (client->status != Connected)
+		return -EBUSY;
+
+	ret = wait_for_completion_killable(&usb9pfs->received);
+	if (ret)
+		return ret;
+
+	ret = usb9pfs_transmit(usb9pfs, p9_req);
+	if (ret)
+		return ret;
+
+	ret = wait_for_completion_killable(&usb9pfs->send);
+	if (ret)
+		return ret;
+
+	return usb9pfs_queue_rx(usb9pfs, usb9pfs->out_req, GFP_ATOMIC);
+}
+
+static int p9_usbg_cancel(struct p9_client *client, struct p9_req_t *req)
+{
+	struct f_usb9pfs *usb9pfs = client->trans;
+	int ret = 1;
+
+	p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
+
+	guard(spinlock_irqsave)(&usb9pfs->lock);
+
+	if (req->status == REQ_STATUS_UNSENT) {
+		list_del(&req->req_list);
+		WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
+		p9_req_put(client, req);
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static struct p9_trans_module p9_usbg_trans = {
+	.name = "usbg",
+	.create = p9_usbg_create,
+	.close = p9_usbg_close,
+	.request = p9_usbg_request,
+	.cancel = p9_usbg_cancel,
+	.owner = THIS_MODULE,
+};
+
+/*-------------------------------------------------------------------------*/
+
+#define USB_PROTOCOL_9PFS	0x09
+
+static struct usb_interface_descriptor usb9pfs_intf = {
+	.bLength =		sizeof(usb9pfs_intf),
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	.bInterfaceSubClass =	USB_SUBCLASS_VENDOR_SPEC,
+	.bInterfaceProtocol =   USB_PROTOCOL_9PFS,
+
+	/* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor fs_usb9pfs_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor fs_usb9pfs_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_usb9pfs_descs[] = {
+	(struct usb_descriptor_header *)&usb9pfs_intf,
+	(struct usb_descriptor_header *)&fs_usb9pfs_sink_desc,
+	(struct usb_descriptor_header *)&fs_usb9pfs_source_desc,
+	NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor hs_usb9pfs_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor hs_usb9pfs_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *hs_usb9pfs_descs[] = {
+	(struct usb_descriptor_header *)&usb9pfs_intf,
+	(struct usb_descriptor_header *)&hs_usb9pfs_source_desc,
+	(struct usb_descriptor_header *)&hs_usb9pfs_sink_desc,
+	NULL,
+};
+
+/* super speed support: */
+
+static struct usb_endpoint_descriptor ss_usb9pfs_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_usb9pfs_source_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	0,
+};
+
+static struct usb_endpoint_descriptor ss_usb9pfs_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_usb9pfs_sink_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	0,
+};
+
+static struct usb_descriptor_header *ss_usb9pfs_descs[] = {
+	(struct usb_descriptor_header *)&usb9pfs_intf,
+	(struct usb_descriptor_header *)&ss_usb9pfs_source_desc,
+	(struct usb_descriptor_header *)&ss_usb9pfs_source_comp_desc,
+	(struct usb_descriptor_header *)&ss_usb9pfs_sink_desc,
+	(struct usb_descriptor_header *)&ss_usb9pfs_sink_comp_desc,
+	NULL,
+};
+
+/* function-specific strings: */
+static struct usb_string strings_usb9pfs[] = {
+	[0].s = "usb9pfs input to output",
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings stringtab_usb9pfs = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_usb9pfs,
+};
+
+static struct usb_gadget_strings *usb9pfs_strings[] = {
+	&stringtab_usb9pfs,
+	NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int usb9pfs_func_bind(struct usb_configuration *c,
+			     struct usb_function *f)
+{
+	struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
+	struct f_usb9pfs_opts *opts;
+	struct usb_composite_dev *cdev = c->cdev;
+	int ret;
+	int id;
+
+	/* allocate interface ID(s) */
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	usb9pfs_intf.bInterfaceNumber = id;
+
+	id = usb_string_id(cdev);
+	if (id < 0)
+		return id;
+	strings_usb9pfs[0].id = id;
+	usb9pfs_intf.iInterface = id;
+
+	/* allocate endpoints */
+	usb9pfs->in_ep = usb_ep_autoconfig(cdev->gadget,
+					   &fs_usb9pfs_source_desc);
+	if (!usb9pfs->in_ep)
+		goto autoconf_fail;
+
+	usb9pfs->out_ep = usb_ep_autoconfig(cdev->gadget,
+					    &fs_usb9pfs_sink_desc);
+	if (!usb9pfs->out_ep)
+		goto autoconf_fail;
+
+	/* support high speed hardware */
+	hs_usb9pfs_source_desc.bEndpointAddress =
+		fs_usb9pfs_source_desc.bEndpointAddress;
+	hs_usb9pfs_sink_desc.bEndpointAddress =
+		fs_usb9pfs_sink_desc.bEndpointAddress;
+
+	/* support super speed hardware */
+	ss_usb9pfs_source_desc.bEndpointAddress =
+		fs_usb9pfs_source_desc.bEndpointAddress;
+	ss_usb9pfs_sink_desc.bEndpointAddress =
+		fs_usb9pfs_sink_desc.bEndpointAddress;
+
+	ret = usb_assign_descriptors(f, fs_usb9pfs_descs, hs_usb9pfs_descs,
+				     ss_usb9pfs_descs, ss_usb9pfs_descs);
+	if (ret)
+		return ret;
+
+	opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
+	opts->dev->usb9pfs = usb9pfs;
+
+	dev_dbg(&cdev->gadget->dev, "%s speed %s: IN/%s, OUT/%s\n",
+		(gadget_is_superspeed(c->cdev->gadget) ? "super" :
+		(gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
+			f->name, usb9pfs->in_ep->name, usb9pfs->out_ep->name);
+
+	return 0;
+
+autoconf_fail:
+	ERROR(cdev, "%s: can't autoconfigure on %s\n",
+	      f->name, cdev->gadget->name);
+	return -ENODEV;
+}
+
+static void usb9pfs_func_unbind(struct usb_configuration *c,
+				struct usb_function *f)
+{
+	struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
+
+	disable_usb9pfs(usb9pfs);
+}
+
+static void usb9pfs_free_func(struct usb_function *f)
+{
+	struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
+	struct f_usb9pfs_opts *opts;
+
+	kfree(usb9pfs);
+
+	opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	opts->refcnt--;
+	mutex_unlock(&opts->lock);
+
+	usb_free_all_descriptors(f);
+}
+
+static int usb9pfs_set_alt(struct usb_function *f,
+			   unsigned int intf, unsigned int alt)
+{
+	struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	return enable_usb9pfs(cdev, usb9pfs);
+}
+
+static void usb9pfs_disable(struct usb_function *f)
+{
+	struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
+
+	usb9pfs_clear_tx(usb9pfs);
+}
+
+static struct usb_function *usb9pfs_alloc(struct usb_function_instance *fi)
+{
+	struct f_usb9pfs_opts *usb9pfs_opts;
+	struct f_usb9pfs *usb9pfs;
+
+	usb9pfs = kzalloc(sizeof(*usb9pfs), GFP_KERNEL);
+	if (!usb9pfs)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&usb9pfs->lock);
+
+	init_completion(&usb9pfs->send);
+	init_completion(&usb9pfs->received);
+
+	usb9pfs_opts = container_of(fi, struct f_usb9pfs_opts, func_inst);
+
+	mutex_lock(&usb9pfs_opts->lock);
+	usb9pfs_opts->refcnt++;
+	mutex_unlock(&usb9pfs_opts->lock);
+
+	usb9pfs->buflen = usb9pfs_opts->buflen;
+
+	usb9pfs->function.name = "usb9pfs";
+	usb9pfs->function.bind = usb9pfs_func_bind;
+	usb9pfs->function.unbind = usb9pfs_func_unbind;
+	usb9pfs->function.set_alt = usb9pfs_set_alt;
+	usb9pfs->function.disable = usb9pfs_disable;
+	usb9pfs->function.strings = usb9pfs_strings;
+
+	usb9pfs->function.free_func = usb9pfs_free_func;
+
+	return &usb9pfs->function;
+}
+
+static inline struct f_usb9pfs_opts *to_f_usb9pfs_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_usb9pfs_opts,
+			    func_inst.group);
+}
+
+static inline struct f_usb9pfs_opts *fi_to_f_usb9pfs_opts(struct usb_function_instance *fi)
+{
+	return container_of(fi, struct f_usb9pfs_opts, func_inst);
+}
+
+static void usb9pfs_attr_release(struct config_item *item)
+{
+	struct f_usb9pfs_opts *usb9pfs_opts = to_f_usb9pfs_opts(item);
+
+	usb_put_function_instance(&usb9pfs_opts->func_inst);
+}
+
+static struct configfs_item_operations usb9pfs_item_ops = {
+	.release		= usb9pfs_attr_release,
+};
+
+static ssize_t f_usb9pfs_opts_buflen_show(struct config_item *item, char *page)
+{
+	struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
+	int ret;
+
+	mutex_lock(&opts->lock);
+	ret = sysfs_emit(page, "%d\n", opts->buflen);
+	mutex_unlock(&opts->lock);
+
+	return ret;
+}
+
+static ssize_t f_usb9pfs_opts_buflen_store(struct config_item *item,
+					   const char *page, size_t len)
+{
+	struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
+	int ret;
+	u32 num;
+
+	guard(mutex)(&opts->lock);
+
+	if (opts->refcnt)
+		return -EBUSY;
+
+	ret = kstrtou32(page, 0, &num);
+	if (ret)
+		return ret;
+
+	opts->buflen = num;
+
+	return len;
+}
+
+CONFIGFS_ATTR(f_usb9pfs_opts_, buflen);
+
+static struct configfs_attribute *usb9pfs_attrs[] = {
+	&f_usb9pfs_opts_attr_buflen,
+	NULL,
+};
+
+static const struct config_item_type usb9pfs_func_type = {
+	.ct_item_ops	= &usb9pfs_item_ops,
+	.ct_attrs	= usb9pfs_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct f_usb9pfs_dev *_usb9pfs_do_find_dev(const char *tag)
+{
+	struct f_usb9pfs_dev *usb9pfs_dev;
+
+	if (!tag)
+		return NULL;
+
+	list_for_each_entry(usb9pfs_dev, &usbg_instance_list, usb9pfs_instance) {
+		if (strcmp(usb9pfs_dev->tag, tag) == 0)
+			return usb9pfs_dev;
+	}
+
+	return NULL;
+}
+
+static int usb9pfs_tag_instance(struct f_usb9pfs_dev *dev, const char *tag)
+{
+	struct f_usb9pfs_dev *existing;
+	int ret = 0;
+
+	guard(mutex)(&usb9pfs_lock);
+
+	existing = _usb9pfs_do_find_dev(tag);
+	if (!existing)
+		strscpy(dev->tag, tag, ARRAY_SIZE(dev->tag));
+	else if (existing != dev)
+		ret = -EBUSY;
+
+	return ret;
+}
+
+static int usb9pfs_set_inst_tag(struct usb_function_instance *fi, const char *tag)
+{
+	if (strlen(tag) >= sizeof_field(struct f_usb9pfs_dev, tag))
+		return -ENAMETOOLONG;
+	return usb9pfs_tag_instance(fi_to_f_usb9pfs_opts(fi)->dev, tag);
+}
+
+static void usb9pfs_free_instance(struct usb_function_instance *fi)
+{
+	struct f_usb9pfs_opts *usb9pfs_opts =
+		container_of(fi, struct f_usb9pfs_opts, func_inst);
+	struct f_usb9pfs_dev *dev = usb9pfs_opts->dev;
+
+	mutex_lock(&usb9pfs_lock);
+	list_del(&dev->usb9pfs_instance);
+	mutex_unlock(&usb9pfs_lock);
+
+	kfree(usb9pfs_opts);
+}
+
+static struct usb_function_instance *usb9pfs_alloc_instance(void)
+{
+	struct f_usb9pfs_opts *usb9pfs_opts;
+	struct f_usb9pfs_dev *dev;
+
+	usb9pfs_opts = kzalloc(sizeof(*usb9pfs_opts), GFP_KERNEL);
+	if (!usb9pfs_opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&usb9pfs_opts->lock);
+
+	usb9pfs_opts->func_inst.set_inst_name = usb9pfs_set_inst_tag;
+	usb9pfs_opts->func_inst.free_func_inst = usb9pfs_free_instance;
+
+	usb9pfs_opts->buflen = DEFAULT_BUFLEN;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (IS_ERR(dev)) {
+		kfree(usb9pfs_opts);
+		return ERR_CAST(dev);
+	}
+
+	usb9pfs_opts->dev = dev;
+	dev->opts = usb9pfs_opts;
+
+	config_group_init_type_name(&usb9pfs_opts->func_inst.group, "",
+				    &usb9pfs_func_type);
+
+	mutex_lock(&usb9pfs_lock);
+	list_add_tail(&dev->usb9pfs_instance, &usbg_instance_list);
+	mutex_unlock(&usb9pfs_lock);
+
+	return &usb9pfs_opts->func_inst;
+}
+DECLARE_USB_FUNCTION(usb9pfs, usb9pfs_alloc_instance, usb9pfs_alloc);
+
+static int __init usb9pfs_modinit(void)
+{
+	int ret;
+
+	INIT_LIST_HEAD(&usbg_instance_list);
+
+	ret = usb_function_register(&usb9pfsusb_func);
+	if (!ret)
+		v9fs_register_trans(&p9_usbg_trans);
+
+	return ret;
+}
+
+static void __exit usb9pfs_modexit(void)
+{
+	usb_function_unregister(&usb9pfsusb_func);
+	v9fs_unregister_trans(&p9_usbg_trans);
+}
+
+module_init(usb9pfs_modinit);
+module_exit(usb9pfs_modexit);
+
+MODULE_ALIAS_9P("usbg");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("USB gadget 9pfs transport");
+MODULE_AUTHOR("Michael Grzeschik");