From bf594c1070f5c34a2576a725eef69cba2686b98d Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 29 Jun 2018 13:52:20 -0400 Subject: [PATCH] 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: Alan Stern Signed-off-by: Felipe Balbi --- drivers/usb/gadget/udc/core.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index cab5e4f09924..af88b48c1cea 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -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) {