// SPDX-License-Identifier: GPL-2.0
/*
* drivers/usb/core/generic.c - generic driver for USB devices (not interfaces)
*
* (C) Copyright 2005 Greg Kroah-Hartman <[email protected]>
*
* based on drivers/usb/usb.c which had the following copyrights:
* (C) Copyright Linus Torvalds 1999
* (C) Copyright Johannes Erdfelt 1999-2001
* (C) Copyright Andreas Gal 1999
* (C) Copyright Gregory P. Smith 1999
* (C) Copyright Deti Fliegl 1999 (new USB architecture)
* (C) Copyright Randy Dunlap 2000
* (C) Copyright David Brownell 2000-2004
* (C) Copyright Yggdrasil Computing, Inc. 2000
* (usb_device_id matching changes by Adam J. Richter)
* (C) Copyright Greg Kroah-Hartman 2002-2003
*
* Released under the GPLv2 only.
*/
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <uapi/linux/usb/audio.h>
#include "usb.h"
static inline const char *plural(int n)
{
return (n == 1 ? "" : "s");
}
static int is_rndis(struct usb_interface_descriptor *desc)
{
return desc->bInterfaceClass == USB_CLASS_COMM
&& desc->bInterfaceSubClass == 2
&& desc->bInterfaceProtocol == 0xff;
}
static int is_activesync(struct usb_interface_descriptor *desc)
{
return desc->bInterfaceClass == USB_CLASS_MISC
&& desc->bInterfaceSubClass == 1
&& desc->bInterfaceProtocol == 1;
}
static bool is_audio(struct usb_interface_descriptor *desc)
{
return desc->bInterfaceClass == USB_CLASS_AUDIO;
}
static bool is_uac3_config(struct usb_interface_descriptor *desc)
{
return desc->bInterfaceProtocol == UAC_VERSION_3;
}
int usb_choose_configuration(struct usb_device *udev)
{
int i;
int num_configs;
int insufficient_power = 0;
struct usb_host_config *c, *best;
struct usb_device_driver *udriver;
/*
* If a USB device (not an interface) doesn't have a driver then the
* kernel has no business trying to select or install a configuration
* for it.
*/
if (!udev->dev.driver)
return -1;
udriver = to_usb_device_driver(udev->dev.driver);
if (usb_device_is_owned(udev))
return 0;
if (udriver->choose_configuration) {
i = udriver->choose_configuration(udev);
if (i >= 0)
return i;
}
best = NULL;
c = udev->config;
num_configs = udev->descriptor.bNumConfigurations;
for (i = 0; i < num_configs; (i++, c++)) {
struct usb_interface_descriptor *desc = NULL;
/* It's possible that a config has no interfaces! */
if (c->desc.bNumInterfaces > 0)
desc = &c->intf_cache[0]->altsetting->desc;
/*
* HP's USB bus-powered keyboard has only one configuration
* and it claims to be self-powered; other devices may have
* similar errors in their descriptors. If the next test
* were allowed to execute, such configurations would always
* be rejected and the devices would not work as expected.
* In the meantime, we run the risk of selecting a config
* that requires external power at a time when that power
* isn't available. It seems to be the lesser of two evils.
*
* Bugzilla #6448 reports a device that appears to crash
* when it receives a GET_DEVICE_STATUS request! We don't
* have any other way to tell whether a device is self-powered,
* but since we don't use that information anywhere but here,
* the call has been removed.
*
* Maybe the GET_DEVICE_STATUS call and the test below can
* be reinstated when device firmwares become more reliable.
* Don't hold your breath.
*/
#if 0
/* Rule out self-powered configs for a bus-powered device */
if (bus_powered && (c->desc.bmAttributes &
USB_CONFIG_ATT_SELFPOWER))
continue;
#endif
/*
* The next test may not be as effective as it should be.
* Some hubs have errors in their descriptor, claiming
* to be self-powered when they are really bus-powered.
* We will overestimate the amount of current such hubs
* make available for each port.
*
* This is a fairly benign sort of failure. It won't
* cause us to reject configurations that we should have
* accepted.
*/
/* Rule out configs that draw too much bus current */
if (usb_get_max_power(udev, c) > udev->bus_mA) {
insufficient_power++;
continue;
}
/*
* Select first configuration as default for audio so that
* devices that don't comply with UAC3 protocol are supported.
* But, still iterate through other configurations and
* select UAC3 compliant config if present.
*/
if (desc && is_audio(desc)) {
/* Always prefer the first found UAC3 config */
if (is_uac3_config(desc)) {
best = c;
break;
}
/* If there is no UAC3 config, prefer the first config */
else if (i == 0)
best = c;
/* Unconditional continue, because the rest of the code
* in the loop is irrelevant for audio devices, and
* because it can reassign best, which for audio devices
* we don't want.
*/
continue;
}
/* When the first config's first interface is one of Microsoft's
* pet nonstandard Ethernet-over-USB protocols, ignore it unless
* this kernel has enabled the necessary host side driver.
* But: Don't ignore it if it's the only config.
*/
if (i == 0 && num_configs > 1 && desc &&
(is_rndis(desc) || is_activesync(desc))) {
#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
continue;
#else
best = c;
#endif
}
/* From the remaining configs, choose the first one whose
* first interface is for a non-vendor-specific class.
* Reason: Linux is more likely to have a class driver
* than a vendor-specific driver. */
else if (udev->descriptor.bDeviceClass !=
USB_CLASS_VENDOR_SPEC &&
(desc && desc->bInterfaceClass !=
USB_CLASS_VENDOR_SPEC)) {
best = c;
break;
}
/* If all the remaining configs are vendor-specific,
* choose the first one. */
else if (!best)
best = c;
}
if (insufficient_power > 0)
dev_info(&udev->dev, "rejected %d configuration%s "
"due to insufficient available bus power\n",
insufficient_power, plural(insufficient_power));
if (best) {
i = best->desc.bConfigurationValue;
dev_dbg(&udev->dev,
"configuration #%d chosen from %d choice%s\n",
i, num_configs, plural(num_configs));
} else {
i = -1;
dev_warn(&udev->dev,
"no configuration chosen from %d choice%s\n",
num_configs, plural(num_configs));
}
return i;
}
EXPORT_SYMBOL_GPL(usb_choose_configuration);
static int __check_for_non_generic_match(struct device_driver *drv, void *data)
{
struct usb_device *udev = data;
struct usb_device_driver *udrv;
if (!is_usb_device_driver(drv))
return 0;
udrv = to_usb_device_driver(drv);
if (udrv == &usb_generic_driver)
return 0;
return usb_driver_applicable(udev, udrv);
}
static bool usb_generic_driver_match(struct usb_device *udev)
{
if (udev->use_generic_driver)
return true;
/*
* If any other driver wants the device, leave the device to this other
* driver.
*/
if (bus_for_each_drv(&usb_bus_type, NULL, udev, __check_for_non_generic_match))
return false;
return true;
}
int usb_generic_driver_probe(struct usb_device *udev)
{
int err, c;
/* Choose and set the configuration. This registers the interfaces
* with the driver core and lets interface drivers bind to them.
*/
if (udev->authorized == 0)
dev_err(&udev->dev, "Device is not authorized for usage\n");
else {
c = usb_choose_configuration(udev);
if (c >= 0) {
err = usb_set_configuration(udev, c);
if (err && err != -ENODEV) {
dev_err(&udev->dev, "can't set config #%d, error %d\n",
c, err);
/* This need not be fatal. The user can try to
* set other configurations. */
}
}
}
/* USB device state == configured ... usable */
usb_notify_add_device(udev);
return 0;
}
void usb_generic_driver_disconnect(struct usb_device *udev)
{
usb_notify_remove_device(udev);
/* if this is only an unbind, not a physical disconnect, then
* unconfigure the device */
if (udev->actconfig)
usb_set_configuration(udev, -1);
}
#ifdef CONFIG_PM
int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg)
{
int rc;
/* Normal USB devices suspend through their upstream port.
* Root hubs don't have upstream ports to suspend,
* so we have to shut down their downstream HC-to-USB
* interfaces manually by doing a bus (or "global") suspend.
*/
if (!udev->parent)
rc = hcd_bus_suspend(udev, msg);
/*
* Non-root USB2 devices don't need to do anything for FREEZE
* or PRETHAW. USB3 devices don't support global suspend and
* needs to be selectively suspended.
*/
else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
&& (udev->speed < USB_SPEED_SUPER))
rc = 0;
else
rc = usb_port_suspend(udev, msg);
if (rc == 0)
usbfs_notify_suspend(udev);
return rc;
}
int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg)
{
int rc;
/* Normal USB devices resume/reset through their upstream port.
* Root hubs don't have upstream ports to resume or reset,
* so we have to start up their downstream HC-to-USB
* interfaces manually by doing a bus (or "global") resume.
*/
if (!udev->parent)
rc = hcd_bus_resume(udev, msg);
else
rc = usb_port_resume(udev, msg);
if (rc == 0)
usbfs_notify_resume(udev);
return rc;
}
#endif /* CONFIG_PM */
struct usb_device_driver usb_generic_driver = {
.name = "usb",
.match = usb_generic_driver_match,
.probe = usb_generic_driver_probe,
.disconnect = usb_generic_driver_disconnect,
#ifdef CONFIG_PM
.suspend = usb_generic_driver_suspend,
.resume = usb_generic_driver_resume,
#endif
.supports_autosuspend = 1,
};
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