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