diff options
Diffstat (limited to 'drivers/usb/gadget/epautoconf.c')
| -rw-r--r-- | drivers/usb/gadget/epautoconf.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/drivers/usb/gadget/epautoconf.c b/drivers/usb/gadget/epautoconf.c new file mode 100644 index 000000000..71b15c65b --- /dev/null +++ b/drivers/usb/gadget/epautoconf.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers + * + * Copyright (C) 2004 David Brownell + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/device.h> + +#include <linux/ctype.h> +#include <linux/string.h> + +#include <linux/usb/ch9.h> +#include <linux/usb/gadget.h> + +/** + * 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); |