--- /dev/null
+/*
+ * f_loopback.c - USB peripheral loopback configuration driver
+ *
+ * Copyright (C) 2003-2008 David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/kernel.h>
+#include <linux/utsname.h>
+#include <linux/device.h>
+
+#include "g_zero.h"
+#include "gadget_chips.h"
+
+
+/*
+ * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
+ *
+ * This takes messages of various sizes written OUT to a device, and loops
+ * them back so they can be read IN from it. It has been used by certain
+ * test applications. It supports limited testing of data queueing logic.
+ *
+ *
+ * This is currently packaged as a configuration driver, which can't be
+ * combined with other functions to make composite devices. However, it
+ * can be combined with other independent configurations.
+ */
+struct f_loopback {
+ struct usb_function function;
+
+ struct usb_ep *in_ep;
+ struct usb_ep *out_ep;
+};
+
+static inline struct f_loopback *func_to_loop(struct usb_function *f)
+{
+ return container_of(f, struct f_loopback, function);
+}
+
+static unsigned qlen = 32;
+module_param(qlen, uint, 0);
+MODULE_PARM_DESC(qlenn, "depth of loopback queue");
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_interface_descriptor loopback_intf = {
+ .bLength = sizeof loopback_intf,
+ .bDescriptorType = USB_DT_INTERFACE,
+
+ .bNumEndpoints = 2,
+ .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
+ /* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor fs_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_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_loopback_descs[] = {
+ (struct usb_descriptor_header *) &loopback_intf,
+ (struct usb_descriptor_header *) &fs_sink_desc,
+ (struct usb_descriptor_header *) &fs_source_desc,
+ NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor hs_source_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor hs_sink_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = __constant_cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *hs_loopback_descs[] = {
+ (struct usb_descriptor_header *) &loopback_intf,
+ (struct usb_descriptor_header *) &hs_source_desc,
+ (struct usb_descriptor_header *) &hs_sink_desc,
+ NULL,
+};
+
+/* function-specific strings: */
+
+static struct usb_string strings_loopback[] = {
+ [0].s = "loop input to output",
+ { } /* end of list */
+};
+
+static struct usb_gadget_strings stringtab_loop = {
+ .language = 0x0409, /* en-us */
+ .strings = strings_loopback,
+};
+
+static struct usb_gadget_strings *loopback_strings[] = {
+ &stringtab_loop,
+ NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init
+loopback_bind(struct usb_configuration *c, struct usb_function *f)
+{
+ struct usb_composite_dev *cdev = c->cdev;
+ struct f_loopback *loop = func_to_loop(f);
+ int id;
+
+ /* allocate interface ID(s) */
+ id = usb_interface_id(c, f);
+ if (id < 0)
+ return id;
+ loopback_intf.bInterfaceNumber = id;
+
+ /* allocate endpoints */
+
+ loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_source_desc);
+ if (!loop->in_ep) {
+autoconf_fail:
+ ERROR(cdev, "%s: can't autoconfigure on %s\n",
+ f->name, cdev->gadget->name);
+ return -ENODEV;
+ }
+ loop->in_ep->driver_data = cdev; /* claim */
+
+ loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_sink_desc);
+ if (!loop->out_ep)
+ goto autoconf_fail;
+ loop->out_ep->driver_data = cdev; /* claim */
+
+ /* support high speed hardware */
+ if (gadget_is_dualspeed(c->cdev->gadget)) {
+ hs_source_desc.bEndpointAddress =
+ fs_source_desc.bEndpointAddress;
+ hs_sink_desc.bEndpointAddress =
+ fs_sink_desc.bEndpointAddress;
+ f->hs_descriptors = hs_loopback_descs;
+ }
+
+ DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
+ gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+ f->name, loop->in_ep->name, loop->out_ep->name);
+ return 0;
+}
+
+static void
+loopback_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+ kfree(func_to_loop(f));
+}
+
+static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct f_loopback *loop = ep->driver_data;
+ struct usb_composite_dev *cdev = loop->function.config->cdev;
+ int status = req->status;
+
+ switch (status) {
+
+ case 0: /* normal completion? */
+ if (ep == loop->out_ep) {
+ /* loop this OUT packet back IN to the host */
+ req->zero = (req->actual < req->length);
+ req->length = req->actual;
+ status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
+ if (status == 0)
+ return;
+
+ /* "should never get here" */
+ ERROR(cdev, "can't loop %s to %s: %d\n",
+ ep->name, loop->in_ep->name,
+ status);
+ }
+
+ /* queue the buffer for some later OUT packet */
+ req->length = buflen;
+ status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
+ if (status == 0)
+ return;
+
+ /* "should never get here" */
+ /* FALLTHROUGH */
+
+ default:
+ ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
+ status, req->actual, req->length);
+ /* FALLTHROUGH */
+
+ /* NOTE: since this driver doesn't maintain an explicit record
+ * of requests it submitted (just maintains qlen count), we
+ * rely on the hardware driver to clean up on disconnect or
+ * endpoint disable.
+ */
+ case -ECONNABORTED: /* hardware forced ep reset */
+ case -ECONNRESET: /* request dequeued */
+ case -ESHUTDOWN: /* disconnect from host */
+ free_ep_req(ep, req);
+ return;
+ }
+}
+
+static void disable_loopback(struct f_loopback *loop)
+{
+ struct usb_composite_dev *cdev;
+
+ cdev = loop->function.config->cdev;
+ disable_endpoints(cdev, loop->in_ep, loop->out_ep);
+ VDBG(cdev, "%s disabled\n", loop->function.name);
+}
+
+static int
+enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
+{
+ int result = 0;
+ const struct usb_endpoint_descriptor *src, *sink;
+ struct usb_ep *ep;
+ struct usb_request *req;
+ unsigned i;
+
+ src = ep_choose(cdev->gadget, &hs_source_desc, &fs_source_desc);
+ sink = ep_choose(cdev->gadget, &hs_sink_desc, &fs_sink_desc);
+
+ /* one endpoint writes data back IN to the host */
+ ep = loop->in_ep;
+ result = usb_ep_enable(ep, src);
+ if (result < 0)
+ return result;
+ ep->driver_data = loop;
+
+ /* one endpoint just reads OUT packets */
+ ep = loop->out_ep;
+ result = usb_ep_enable(ep, sink);
+ if (result < 0) {
+fail0:
+ ep = loop->in_ep;
+ usb_ep_disable(ep);
+ ep->driver_data = NULL;
+ return result;
+ }
+ ep->driver_data = loop;
+
+ /* allocate a bunch of read buffers and queue them all at once.
+ * we buffer at most 'qlen' transfers; fewer if any need more
+ * than 'buflen' bytes each.
+ */
+ for (i = 0; i < qlen && result == 0; i++) {
+ req = alloc_ep_req(ep);
+ if (req) {
+ req->complete = loopback_complete;
+ result = usb_ep_queue(ep, req, GFP_ATOMIC);
+ if (result)
+ ERROR(cdev, "%s queue req --> %d\n",
+ ep->name, result);
+ } else {
+ usb_ep_disable(ep);
+ ep->driver_data = NULL;
+ result = -ENOMEM;
+ goto fail0;
+ }
+ }
+
+ DBG(cdev, "%s enabled\n", loop->function.name);
+ return result;
+}
+
+static int loopback_set_alt(struct usb_function *f,
+ unsigned intf, unsigned alt)
+{
+ struct f_loopback *loop = func_to_loop(f);
+ struct usb_composite_dev *cdev = f->config->cdev;
+
+ /* we know alt is zero */
+ if (loop->in_ep->driver_data)
+ disable_loopback(loop);
+ return enable_loopback(cdev, loop);
+}
+
+static void loopback_disable(struct usb_function *f)
+{
+ struct f_loopback *loop = func_to_loop(f);
+
+ disable_loopback(loop);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int __init loopback_bind_config(struct usb_configuration *c)
+{
+ struct f_loopback *loop;
+ int status;
+
+ loop = kzalloc(sizeof *loop, GFP_KERNEL);
+ if (!loop)
+ return -ENOMEM;
+
+ loop->function.name = "loopback";
+ loop->function.descriptors = fs_loopback_descs;
+ loop->function.bind = loopback_bind;
+ loop->function.unbind = loopback_unbind;
+ loop->function.set_alt = loopback_set_alt;
+ loop->function.disable = loopback_disable;
+
+ status = usb_add_function(c, &loop->function);
+ if (status)
+ kfree(loop);
+ return status;
+}
+
+static struct usb_configuration loopback_driver = {
+ .label = "loopback",
+ .strings = loopback_strings,
+ .bind = loopback_bind_config,
+ .bConfigurationValue = 2,
+ .bmAttributes = USB_CONFIG_ATT_SELFPOWER,
+ .bMaxPower = 1, /* 2 mA, minimal */
+ /* .iConfiguration = DYNAMIC */
+};
+
+/**
+ * loopback_add - add a loopback testing configuration to a device
+ * @cdev: the device to support the loopback configuration
+ */
+int __init loopback_add(struct usb_composite_dev *cdev)
+{
+ int id;
+
+ /* allocate string ID(s) */
+ id = usb_string_id(cdev);
+ if (id < 0)
+ return id;
+ strings_loopback[0].id = id;
+
+ loopback_intf.iInterface = id;
+ loopback_driver.iConfiguration = id;
+
+ /* support OTG systems */
+ if (gadget_is_otg(cdev->gadget)) {
+ loopback_driver.descriptors = otg_desc;
+ loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+ }
+
+ return usb_add_config(cdev, &loopback_driver);
+}
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