/*
* 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_loop_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_loop_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_loop_sink_desc,
(struct usb_descriptor_header *) &fs_loop_source_desc,
NULL,
};
/* high speed support: */
static struct usb_endpoint_descriptor hs_loop_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_loop_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_loop_source_desc,
(struct usb_descriptor_header *) &hs_loop_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_loop_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_loop_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_loop_source_desc.bEndpointAddress =
fs_loop_source_desc.bEndpointAddress;
hs_loop_sink_desc.bEndpointAddress =
fs_loop_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_loop_source_desc, &fs_loop_source_desc);
sink = ep_choose(cdev->gadget,
&hs_loop_sink_desc, &fs_loop_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,
/* .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);
}
