251 lines
8.1 KiB
C
251 lines
8.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
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*
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* Copyright (C) 2004 David Brownell
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/device.h>
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#include <linux/ctype.h>
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#include <linux/string.h>
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#include <linux/usb/ch9.h>
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#include <linux/usb/gadget.h>
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/**
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* usb_ep_autoconfig_ss() - choose an endpoint matching the ep
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* descriptor and ep companion descriptor
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* @gadget: The device to which the endpoint must belong.
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* @desc: Endpoint descriptor, with endpoint direction and transfer mode
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* initialized. For periodic transfers, the maximum packet
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* size must also be initialized. This is modified on
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* success.
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* @ep_comp: Endpoint companion descriptor, with the required
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* number of streams. Will be modified when the chosen EP
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* supports a different number of streams.
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*
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* This routine replaces the usb_ep_autoconfig when needed
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* superspeed enhancments. If such enhancemnets are required,
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* the FD should call usb_ep_autoconfig_ss directly and provide
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* the additional ep_comp parameter.
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*
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* By choosing an endpoint to use with the specified descriptor,
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* this routine simplifies writing gadget drivers that work with
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* multiple USB device controllers. The endpoint would be
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* passed later to usb_ep_enable(), along with some descriptor.
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*
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* That second descriptor won't always be the same as the first one.
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* For example, isochronous endpoints can be autoconfigured for high
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* bandwidth, and then used in several lower bandwidth altsettings.
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* Also, high and full speed descriptors will be different.
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*
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* Be sure to examine and test the results of autoconfiguration
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* on your hardware. This code may not make the best choices
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* about how to use the USB controller, and it can't know all
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* the restrictions that may apply. Some combinations of driver
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* and hardware won't be able to autoconfigure.
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*
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* On success, this returns an claimed usb_ep, and modifies the endpoint
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* descriptor bEndpointAddress. For bulk endpoints, the wMaxPacket value
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* is initialized as if the endpoint were used at full speed and
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* the bmAttribute field in the ep companion descriptor is
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* updated with the assigned number of streams if it is
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* different from the original value. To prevent the endpoint
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* from being returned by a later autoconfig call, claims it by
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* assigning ep->claimed to true.
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*
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* On failure, this returns a null endpoint descriptor.
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*/
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struct usb_ep *usb_ep_autoconfig_ss(
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struct usb_gadget *gadget,
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struct usb_endpoint_descriptor *desc,
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struct usb_ss_ep_comp_descriptor *ep_comp
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)
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{
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struct usb_ep *ep;
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u8 type;
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type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
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if (gadget->ops->match_ep) {
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ep = gadget->ops->match_ep(gadget, desc, ep_comp);
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if (ep)
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goto found_ep;
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}
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/* Second, look at endpoints until an unclaimed one looks usable */
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list_for_each_entry (ep, &gadget->ep_list, ep_list) {
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if (usb_gadget_ep_match_desc(gadget, ep, desc, ep_comp))
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goto found_ep;
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}
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/* Fail */
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return NULL;
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found_ep:
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/*
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* If the protocol driver hasn't yet decided on wMaxPacketSize
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* and wants to know the maximum possible, provide the info.
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*/
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if (desc->wMaxPacketSize == 0)
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desc->wMaxPacketSize = cpu_to_le16(ep->maxpacket_limit);
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/* report address */
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desc->bEndpointAddress &= USB_DIR_IN;
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if (isdigit(ep->name[2])) {
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u8 num = simple_strtoul(&ep->name[2], NULL, 10);
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desc->bEndpointAddress |= num;
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} else if (desc->bEndpointAddress & USB_DIR_IN) {
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if (++gadget->in_epnum > 15)
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return NULL;
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desc->bEndpointAddress = USB_DIR_IN | gadget->in_epnum;
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} else {
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if (++gadget->out_epnum > 15)
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return NULL;
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desc->bEndpointAddress |= gadget->out_epnum;
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}
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/* report (variable) full speed bulk maxpacket */
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if ((type == USB_ENDPOINT_XFER_BULK) && !ep_comp) {
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int size = ep->maxpacket_limit;
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/* min() doesn't work on bitfields with gcc-3.5 */
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if (size > 64)
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size = 64;
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desc->wMaxPacketSize = cpu_to_le16(size);
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}
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ep->address = desc->bEndpointAddress;
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ep->desc = NULL;
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ep->comp_desc = NULL;
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ep->claimed = true;
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return ep;
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}
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EXPORT_SYMBOL_GPL(usb_ep_autoconfig_ss);
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/**
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* usb_ep_autoconfig() - choose an endpoint matching the
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* descriptor
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* @gadget: The device to which the endpoint must belong.
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* @desc: Endpoint descriptor, with endpoint direction and transfer mode
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* initialized. For periodic transfers, the maximum packet
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* size must also be initialized. This is modified on success.
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*
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* By choosing an endpoint to use with the specified descriptor, this
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* routine simplifies writing gadget drivers that work with multiple
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* USB device controllers. The endpoint would be passed later to
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* usb_ep_enable(), along with some descriptor.
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*
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* That second descriptor won't always be the same as the first one.
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* For example, isochronous endpoints can be autoconfigured for high
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* bandwidth, and then used in several lower bandwidth altsettings.
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* Also, high and full speed descriptors will be different.
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*
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* Be sure to examine and test the results of autoconfiguration on your
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* hardware. This code may not make the best choices about how to use the
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* USB controller, and it can't know all the restrictions that may apply.
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* Some combinations of driver and hardware won't be able to autoconfigure.
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*
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* On success, this returns an claimed usb_ep, and modifies the endpoint
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* descriptor bEndpointAddress. For bulk endpoints, the wMaxPacket value
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* is initialized as if the endpoint were used at full speed. To prevent
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* the endpoint from being returned by a later autoconfig call, claims it
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* by assigning ep->claimed to true.
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*
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* On failure, this returns a null endpoint descriptor.
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*/
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struct usb_ep *usb_ep_autoconfig(
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struct usb_gadget *gadget,
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struct usb_endpoint_descriptor *desc
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)
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{
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return usb_ep_autoconfig_ss(gadget, desc, NULL);
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}
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EXPORT_SYMBOL_GPL(usb_ep_autoconfig);
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/**
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* usb_ep_autoconfig_release - releases endpoint and set it to initial state
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* @ep: endpoint which should be released
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*
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* This function can be used during function bind for endpoints obtained
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* from usb_ep_autoconfig(). It unclaims endpoint claimed by
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* usb_ep_autoconfig() to make it available for other functions. Endpoint
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* which was released is no longer invalid and shouldn't be used in
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* context of function which released it.
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*/
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void usb_ep_autoconfig_release(struct usb_ep *ep)
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{
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ep->claimed = false;
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ep->driver_data = NULL;
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}
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EXPORT_SYMBOL_GPL(usb_ep_autoconfig_release);
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/**
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* usb_ep_autoconfig_reset - reset endpoint autoconfig state
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* @gadget: device for which autoconfig state will be reset
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*
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* Use this for devices where one configuration may need to assign
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* endpoint resources very differently from the next one. It clears
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* state such as ep->claimed and the record of assigned endpoints
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* used by usb_ep_autoconfig().
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*/
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void usb_ep_autoconfig_reset (struct usb_gadget *gadget)
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{
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struct usb_ep *ep;
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list_for_each_entry (ep, &gadget->ep_list, ep_list) {
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ep->claimed = false;
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ep->driver_data = NULL;
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}
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gadget->in_epnum = 0;
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gadget->out_epnum = 0;
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}
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EXPORT_SYMBOL_GPL(usb_ep_autoconfig_reset);
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/**
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* usb_ep_autoconfig_by_name - Used to pick the endpoint by name. eg gsi-epin1
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* @gadget: The device to which the endpoint must belong.
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* @desc: Endpoint descriptor, with endpoint direction and transfer mode
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* initialized.
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* @ep_name: EP name that is to be searched.
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*
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*/
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struct usb_ep *usb_ep_autoconfig_by_name(
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struct usb_gadget *gadget,
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struct usb_endpoint_descriptor *desc,
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const char *ep_name
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)
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{
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struct usb_ep *ep;
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bool ep_found = false;
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if (!ep_name || !strlen(ep_name))
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goto err;
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list_for_each_entry(ep, &gadget->ep_list, ep_list)
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if (strncmp(ep->name, ep_name, strlen(ep_name)) == 0 &&
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!ep->driver_data) {
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ep_found = true;
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break;
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}
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if (ep_found) {
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desc->bEndpointAddress &= USB_DIR_IN;
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desc->bEndpointAddress |= ep->ep_num;
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ep->address = desc->bEndpointAddress;
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pr_debug("Allocating ep address:%x\n", ep->address);
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ep->desc = NULL;
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ep->comp_desc = NULL;
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return ep;
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}
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err:
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pr_err("%s:error finding ep %s\n", __func__, ep_name);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(usb_ep_autoconfig_by_name);
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