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Commit bf594c10 authored by Alan Stern's avatar Alan Stern Committed by Felipe Balbi
Browse files

USB: gadget: Document that certain ep operations can be called in interrupt context 



This documentation patch specifies that certain USB gadget endpoint
operations may be called in interrupt context:

	usb_ep_queue, usb_ep_dequeue, usb_ep_set_halt,
	usb_ep_clear_halt, usb_ep_set_wedge, usb_ep_fifo_status,
	and usb_ep_fifo_flush;

while others must be called in process context:

	usb_ep_enable and usb_ep_disable.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent ad22a666

drivers/usb/gadget/udc/core.c

+18 −0
Original line number Diff line number Diff line
@@ -87,6 +87,8 @@ EXPORT_SYMBOL_GPL(usb_ep_set_maxpacket_limit); 
 * configurable, with more generic names like "ep-a".  (remember that for

 * USB, "in" means "towards the USB master".)

 *

 * This routine must be called in process context.

 *

 * returns zero, or a negative error code.

 */

int usb_ep_enable(struct usb_ep *ep)
@@ -119,6 +121,8 @@ EXPORT_SYMBOL_GPL(usb_ep_enable); 
 * gadget drivers must call usb_ep_enable() again before queueing

 * requests to the endpoint.

 *

 * This routine must be called in process context.

 *

 * returns zero, or a negative error code.

 */

int usb_ep_disable(struct usb_ep *ep)
@@ -241,6 +245,8 @@ EXPORT_SYMBOL_GPL(usb_ep_free_request); 
 * Note that @req's ->complete() callback must never be called from

 * within usb_ep_queue() as that can create deadlock situations.

 *

 * This routine may be called in interrupt context.

 *

 * Returns zero, or a negative error code.  Endpoints that are not enabled

 * report errors; errors will also be

 * reported when the usb peripheral is disconnected.
@@ -284,6 +290,8 @@ EXPORT_SYMBOL_GPL(usb_ep_queue); 
 * at the head of the queue) except as part of disconnecting from usb. Such

 * restrictions prevent drivers from supporting configuration changes,

 * even to configuration zero (a "chapter 9" requirement).

 *

 * This routine may be called in interrupt context.

 */

int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)

{
@@ -311,6 +319,8 @@ EXPORT_SYMBOL_GPL(usb_ep_dequeue); 
 * current altsetting, see usb_ep_clear_halt().  When switching altsettings,

 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.

 *

 * This routine may be called in interrupt context.

 *

 * Returns zero, or a negative error code.  On success, this call sets

 * underlying hardware state that blocks data transfers.

 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
@@ -336,6 +346,8 @@ EXPORT_SYMBOL_GPL(usb_ep_set_halt); 
 * for endpoints that aren't reconfigured, after clearing any other state

 * in the endpoint's i/o queue.

 *

 * This routine may be called in interrupt context.

 *

 * Returns zero, or a negative error code.  On success, this call clears

 * the underlying hardware state reflecting endpoint halt and data toggle.

 * Note that some hardware can't support this request (like pxa2xx_udc),
@@ -360,6 +372,8 @@ EXPORT_SYMBOL_GPL(usb_ep_clear_halt); 
 * requests. If the gadget driver clears the halt status, it will

 * automatically unwedge the endpoint.

 *

 * This routine may be called in interrupt context.

 *

 * Returns zero on success, else negative errno.

 */

int usb_ep_set_wedge(struct usb_ep *ep)
@@ -388,6 +402,8 @@ EXPORT_SYMBOL_GPL(usb_ep_set_wedge); 
 * written OUT to it by the host.  Drivers that need precise handling for

 * fault reporting or recovery may need to use this call.

 *

 * This routine may be called in interrupt context.

 *

 * This returns the number of such bytes in the fifo, or a negative

 * errno if the endpoint doesn't use a FIFO or doesn't support such

 * precise handling.
@@ -415,6 +431,8 @@ EXPORT_SYMBOL_GPL(usb_ep_fifo_status); 
 * an endpoint fifo after abnormal transaction terminations.  The call

 * must never be used except when endpoint is not being used for any

 * protocol translation.

 *

 * This routine may be called in interrupt context.

 */

void usb_ep_fifo_flush(struct usb_ep *ep)

{