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Commit 63c8ae77 authored by Hemant Kumar's avatar Hemant Kumar Committed by Elson Roy Serrao
Browse files

usb: core: Add usb_set_interface_timeout API 



Currently control transfer timeout is a fixed value of 5 sec.
Introduce generic api for customized timeout value which any
class driver can use.

Change-Id: I76730ad3d021f36ba9f97d91669a5c2f24c67942
Signed-off-by: default avatarHemant Kumar <hemantk@codeaurora.org>
Signed-off-by: default avatarElson Roy Serrao <eserrao@codeaurora.org>
parent 0fe1d128

drivers/usb/core/message.c

+169 −0
Original line number Diff line number Diff line
@@ -1493,6 +1493,175 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate) 
}

EXPORT_SYMBOL_GPL(usb_set_interface);



/**

 * usb_set_interface_timeout - Makes a particular alternate setting be current

 * and allows to set a timeout value for this control transfer.

 * @dev: the device whose interface is being updated

 * @interface: the interface being updated

 * @alternate: the setting being chosen.

 * @timeout: timeout value in ms (non-zero), before which this transfer should

 * complete.

 * Context: !in_interrupt ()

 *

 * This is used to enable data transfers on interfaces that may not

 * be enabled by default.  Not all devices support such configurability.

 * Only the driver bound to an interface may change its setting.

 *

 * Within any given configuration, each interface may have several

 * alternative settings.  These are often used to control levels of

 * bandwidth consumption.  For example, the default setting for a high

 * speed interrupt endpoint may not send more than 64 bytes per microframe,

 * while interrupt transfers of up to 3KBytes per microframe are legal.

 * Also, isochronous endpoints may never be part of an

 * interface's default setting.  To access such bandwidth, alternate

 * interface settings must be made current.

 *

 * Note that in the Linux USB subsystem, bandwidth associated with

 * an endpoint in a given alternate setting is not reserved until an URB

 * is submitted that needs that bandwidth.  Some other operating systems

 * allocate bandwidth early, when a configuration is chosen.

 *

 * This call is synchronous, and may not be used in an interrupt context.

 * Also, drivers must not change altsettings while urbs are scheduled for

 * endpoints in that interface; all such urbs must first be completed

 * (perhaps forced by unlinking).

 *

 * Return: Zero on success, or else the status code returned by the

 * underlying usb_control_msg() call.

 */

int usb_set_interface_timeout(struct usb_device *dev, int interface,

	int alternate, unsigned long timeout_ms)

{

	struct usb_interface *iface;

	struct usb_host_interface *alt;

	struct usb_hcd *hcd = bus_to_hcd(dev->bus);

	int i, ret, manual = 0;

	unsigned int epaddr;

	unsigned int pipe;



	if (dev->state == USB_STATE_SUSPENDED)

		return -EHOSTUNREACH;



	iface = usb_ifnum_to_if(dev, interface);

	if (!iface) {

		dev_dbg(&dev->dev, "selecting invalid interface %d\n",

			interface);

		return -EINVAL;

	}

	if (iface->unregistering)

		return -ENODEV;



	alt = usb_altnum_to_altsetting(iface, alternate);

	if (!alt) {

		dev_warn(&dev->dev, "selecting invalid altsetting %d\n",

			 alternate);

		return -EINVAL;

	}



	/* Make sure we have enough bandwidth for this alternate interface.

	 * Remove the current alt setting and add the new alt setting.

	 */

	mutex_lock(hcd->bandwidth_mutex);

	/* Disable LPM, and re-enable it once the new alt setting is installed,

	 * so that the xHCI driver can recalculate the U1/U2 timeouts.

	 */

	if (usb_disable_lpm(dev)) {

		dev_err(&iface->dev, "%s Failed to disable LPM\n", __func__);

		mutex_unlock(hcd->bandwidth_mutex);

		return -ENOMEM;

	}

	/* Changing alt-setting also frees any allocated streams */

	for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)

		iface->cur_altsetting->endpoint[i].streams = 0;



	ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);

	if (ret < 0) {

		dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",

				alternate);

		usb_enable_lpm(dev);

		mutex_unlock(hcd->bandwidth_mutex);

		return ret;

	}



	if (dev->quirks & USB_QUIRK_NO_SET_INTF)

		ret = -EPIPE;

	else

		ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),

				   USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,

				   alternate, interface, NULL, 0, timeout_ms);



	/* 9.4.10 says devices don't need this and are free to STALL the

	 * request if the interface only has one alternate setting.

	 */

	if (ret == -EPIPE && iface->num_altsetting == 1) {

		dev_dbg(&dev->dev,

			"manual set_interface for iface %d, alt %d\n",

			interface, alternate);

		manual = 1;

	} else if (ret < 0) {

		/* Re-instate the old alt setting */

		usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);

		usb_enable_lpm(dev);

		mutex_unlock(hcd->bandwidth_mutex);

		return ret;

	}

	mutex_unlock(hcd->bandwidth_mutex);



	/* FIXME drivers shouldn't need to replicate/bugfix the logic here

	 * when they implement async or easily-killable versions of this or

	 * other "should-be-internal" functions (like clear_halt).

	 * should hcd+usbcore postprocess control requests?

	 */



	/* prevent submissions using previous endpoint settings */

	if (iface->cur_altsetting != alt) {

		remove_intf_ep_devs(iface);

		usb_remove_sysfs_intf_files(iface);

	}

	usb_disable_interface(dev, iface, true);



	iface->cur_altsetting = alt;



	/* Now that the interface is installed, re-enable LPM. */

	usb_unlocked_enable_lpm(dev);



	/* If the interface only has one altsetting and the device didn't

	 * accept the request, we attempt to carry out the equivalent action

	 * by manually clearing the HALT feature for each endpoint in the

	 * new altsetting.

	 */

	if (manual) {

		for (i = 0; i < alt->desc.bNumEndpoints; i++) {

			epaddr = alt->endpoint[i].desc.bEndpointAddress;

			pipe = __create_pipe(dev,

					USB_ENDPOINT_NUMBER_MASK & epaddr) |

					(usb_endpoint_out(epaddr) ?

					USB_DIR_OUT : USB_DIR_IN);



			usb_clear_halt(dev, pipe);

		}

	}



	/* 9.1.1.5: reset toggles for all endpoints in the new altsetting

	 *

	 * Note:

	 * Despite EP0 is always present in all interfaces/AS, the list of

	 * endpoints from the descriptor does not contain EP0. Due to its

	 * omnipresence one might expect EP0 being considered "affected" by

	 * any SetInterface request and hence assume toggles need to be reset.

	 * However, EP0 toggles are re-synced for every individual transfer

	 * during the SETUP stage - hence EP0 toggles are "don't care" here.

	 * (Likewise, EP0 never "halts" on well designed devices.)

	 */

	usb_enable_interface(dev, iface, true);

	if (device_is_registered(&iface->dev)) {

		usb_create_sysfs_intf_files(iface);

		create_intf_ep_devs(iface);

	}

	return 0;

}

EXPORT_SYMBOL(usb_set_interface_timeout);



/**

 * usb_reset_configuration - lightweight device reset

 * @dev: the device whose configuration is being reset

include/linux/usb.h

+2 −0
Original line number Diff line number Diff line
@@ -1832,6 +1832,8 @@ extern int usb_string(struct usb_device *dev, int index, 
extern int usb_clear_halt(struct usb_device *dev, int pipe);

extern int usb_reset_configuration(struct usb_device *dev);

extern int usb_set_interface(struct usb_device *dev, int ifnum, int alternate);

extern int usb_set_interface_timeout(struct usb_device *dev, int ifnum,

		int alternate, unsigned long timeout);

extern void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr);



/* this request isn't really synchronous, but it belongs with the others */