1 files changed, 214 insertions, 0 deletions
diff --git a/drivers/usb/gadget/epautoconf.c b/drivers/usb/gadget/epautoconf.c
new file mode 100644
index 0000000000..ed5a92c474
--- /dev/null
+++ b/drivers/usb/gadget/epautoconf.c
@@ -0,0 +1,214 @@
+// 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;
+
+	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;
+	}
+
+	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. Because of
+ * that the users must consider adjusting the autoconfigured descriptor.
+ * 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
+)
+{
+	struct usb_ep	*ep;
+	u8		type;
+
+	ep = usb_ep_autoconfig_ss(gadget, desc, NULL);
+	if (!ep)
+		return NULL;
+
+	type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
+
+	/* report (variable) full speed bulk maxpacket */
+	if (type == USB_ENDPOINT_XFER_BULK) {
+		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);
+	}
+
+	return ep;
+}
+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 valid 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);