usb: gadget: move gadget API functions to udc-core

instead of defining all functions as static inlines,
let's move them to udc-core and export them with
EXPORT_SYMBOL_GPL, that way we can make sure that
only GPL drivers will use them.

As a side effect, it'll be nicer to add tracepoints
to the gadget API.

While at that, also fix Kconfig dependencies to
avoid randconfig build failures.

Acked-By: Sebastian Reichel <sre@kernel.org>
Acked-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 60 insertions, 525 deletions

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index fefe8b06a63d..c6e1149ddb0d 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -228,307 +228,49 @@ struct usb_ep {
 
 /*-------------------------------------------------------------------------*/
 
-/**
- * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
- * @ep:the endpoint being configured
- * @maxpacket_limit:value of maximum packet size limit
- *
- * This function should be used only in UDC drivers to initialize endpoint
- * (usually in probe function).
- */
+#if IS_ENABLED(CONFIG_USB_GADGET)
+void usb_ep_set_maxpacket_limit(struct usb_ep *ep, unsigned maxpacket_limit);
+int usb_ep_enable(struct usb_ep *ep);
+int usb_ep_disable(struct usb_ep *ep);
+struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, gfp_t gfp_flags);
+void usb_ep_free_request(struct usb_ep *ep, struct usb_request *req);
+int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags);
+int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req);
+int usb_ep_set_halt(struct usb_ep *ep);
+int usb_ep_clear_halt(struct usb_ep *ep);
+int usb_ep_set_wedge(struct usb_ep *ep);
+int usb_ep_fifo_status(struct usb_ep *ep);
+void usb_ep_fifo_flush(struct usb_ep *ep);
+#else
 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
-                                              unsigned maxpacket_limit)
-{
-        ep->maxpacket_limit = maxpacket_limit;
-        ep->maxpacket = maxpacket_limit;
-}
-
-/**
- * usb_ep_enable - configure endpoint, making it usable
- * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
- *      drivers discover endpoints through the ep_list of a usb_gadget.
- *
- * When configurations are set, or when interface settings change, the driver
- * will enable or disable the relevant endpoints.  while it is enabled, an
- * endpoint may be used for i/o until the driver receives a disconnect() from
- * the host or until the endpoint is disabled.
- *
- * the ep0 implementation (which calls this routine) must ensure that the
- * hardware capabilities of each endpoint match the descriptor provided
- * for it.  for example, an endpoint named "ep2in-bulk" would be usable
- * for interrupt transfers as well as bulk, but it likely couldn't be used
- * for iso transfers or for endpoint 14.  some endpoints are fully
- * configurable, with more generic names like "ep-a".  (remember that for
- * USB, "in" means "towards the USB master".)
- *
- * returns zero, or a negative error code.
- */
+                unsigned maxpacket_limit)
+{ }
 static inline int usb_ep_enable(struct usb_ep *ep)
-{
-        int ret;
-
-        if (ep->enabled)
-                return 0;
-
-        ret = ep->ops->enable(ep, ep->desc);
-        if (ret)
-                return ret;
-
-        ep->enabled = true;
-
-        return 0;
-}
-
-/**
- * usb_ep_disable - endpoint is no longer usable
- * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
- *
- * no other task may be using this endpoint when this is called.
- * any pending and uncompleted requests will complete with status
- * indicating disconnect (-ESHUTDOWN) before this call returns.
- * gadget drivers must call usb_ep_enable() again before queueing
- * requests to the endpoint.
- *
- * returns zero, or a negative error code.
- */
+{ return 0; }
 static inline int usb_ep_disable(struct usb_ep *ep)
-{
-        int ret;
-
-        if (!ep->enabled)
-                return 0;
-
-        ret = ep->ops->disable(ep);
-        if (ret)
-                return ret;
-
-        ep->enabled = false;
-
-        return 0;
-}
-
-/**
- * usb_ep_alloc_request - allocate a request object to use with this endpoint
- * @ep:the endpoint to be used with with the request
- * @gfp_flags:GFP_* flags to use
- *
- * Request objects must be allocated with this call, since they normally
- * need controller-specific setup and may even need endpoint-specific
- * resources such as allocation of DMA descriptors.
- * Requests may be submitted with usb_ep_queue(), and receive a single
- * completion callback.  Free requests with usb_ep_free_request(), when
- * they are no longer needed.
- *
- * Returns the request, or null if one could not be allocated.
- */
+{ return 0; }
 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
-                                                       gfp_t gfp_flags)
-{
-        return ep->ops->alloc_request(ep, gfp_flags);
-}
-
-/**
- * usb_ep_free_request - frees a request object
- * @ep:the endpoint associated with the request
- * @req:the request being freed
- *
- * Reverses the effect of usb_ep_alloc_request().
- * Caller guarantees the request is not queued, and that it will
- * no longer be requeued (or otherwise used).
- */
+                gfp_t gfp_flags)
+{ return NULL; }
 static inline void usb_ep_free_request(struct usb_ep *ep,
-                                       struct usb_request *req)
-{
-        ep->ops->free_request(ep, req);
-}
-
-/**
- * usb_ep_queue - queues (submits) an I/O request to an endpoint.
- * @ep:the endpoint associated with the request
- * @req:the request being submitted
- * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
- *      pre-allocate all necessary memory with the request.
- *
- * This tells the device controller to perform the specified request through
- * that endpoint (reading or writing a buffer).  When the request completes,
- * including being canceled by usb_ep_dequeue(), the request's completion
- * routine is called to return the request to the driver.  Any endpoint
- * (except control endpoints like ep0) may have more than one transfer
- * request queued; they complete in FIFO order.  Once a gadget driver
- * submits a request, that request may not be examined or modified until it
- * is given back to that driver through the completion callback.
- *
- * Each request is turned into one or more packets.  The controller driver
- * never merges adjacent requests into the same packet.  OUT transfers
- * will sometimes use data that's already buffered in the hardware.
- * Drivers can rely on the fact that the first byte of the request's buffer
- * always corresponds to the first byte of some USB packet, for both
- * IN and OUT transfers.
- *
- * Bulk endpoints can queue any amount of data; the transfer is packetized
- * automatically.  The last packet will be short if the request doesn't fill it
- * out completely.  Zero length packets (ZLPs) should be avoided in portable
- * protocols since not all usb hardware can successfully handle zero length
- * packets.  (ZLPs may be explicitly written, and may be implicitly written if
- * the request 'zero' flag is set.)  Bulk endpoints may also be used
- * for interrupt transfers; but the reverse is not true, and some endpoints
- * won't support every interrupt transfer.  (Such as 768 byte packets.)
- *
- * Interrupt-only endpoints are less functional than bulk endpoints, for
- * example by not supporting queueing or not handling buffers that are
- * larger than the endpoint's maxpacket size.  They may also treat data
- * toggle differently.
- *
- * Control endpoints ... after getting a setup() callback, the driver queues
- * one response (even if it would be zero length).  That enables the
- * status ack, after transferring data as specified in the response.  Setup
- * functions may return negative error codes to generate protocol stalls.
- * (Note that some USB device controllers disallow protocol stall responses
- * in some cases.)  When control responses are deferred (the response is
- * written after the setup callback returns), then usb_ep_set_halt() may be
- * used on ep0 to trigger protocol stalls.  Depending on the controller,
- * it may not be possible to trigger a status-stage protocol stall when the
- * data stage is over, that is, from within the response's completion
- * routine.
- *
- * For periodic endpoints, like interrupt or isochronous ones, the usb host
- * arranges to poll once per interval, and the gadget driver usually will
- * have queued some data to transfer at that time.
- *
- * 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.
- */
-static inline int usb_ep_queue(struct usb_ep *ep,
-                               struct usb_request *req, gfp_t gfp_flags)
-{
-        if (WARN_ON_ONCE(!ep->enabled && ep->address))
-                return -ESHUTDOWN;
-
-        return ep->ops->queue(ep, req, gfp_flags);
-}
-
-/**
- * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
- * @ep:the endpoint associated with the request
- * @req:the request being canceled
- *
- * If the request is still active on the endpoint, it is dequeued and its
- * completion routine is called (with status -ECONNRESET); else a negative
- * error code is returned. This is guaranteed to happen before the call to
- * usb_ep_dequeue() returns.
- *
- * Note that some hardware can't clear out write fifos (to unlink the request
- * 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).
- */
+                struct usb_request *req)
+{ }
+static inline int usb_ep_queue(struct usb_ep *ep, struct usb_request *req,
+                gfp_t gfp_flags)
+{ return 0; }
 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
-{
-        return ep->ops->dequeue(ep, req);
-}
-
-/**
- * usb_ep_set_halt - sets the endpoint halt feature.
- * @ep: the non-isochronous endpoint being stalled
- *
- * Use this to stall an endpoint, perhaps as an error report.
- * Except for control endpoints,
- * the endpoint stays halted (will not stream any data) until the host
- * clears this feature; drivers may need to empty the endpoint's request
- * queue first, to make sure no inappropriate transfers happen.
- *
- * Note that while an endpoint CLEAR_FEATURE will be invisible to the
- * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
- * 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.
- *
- * 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
- * transfer requests are still queued, or if the controller hardware
- * (usually a FIFO) still holds bytes that the host hasn't collected.
- */
+{ return 0; }
 static inline int usb_ep_set_halt(struct usb_ep *ep)
-{
-        return ep->ops->set_halt(ep, 1);
-}
-
-/**
- * usb_ep_clear_halt - clears endpoint halt, and resets toggle
- * @ep:the bulk or interrupt endpoint being reset
- *
- * Use this when responding to the standard usb "set interface" request,
- * for endpoints that aren't reconfigured, after clearing any other state
- * in the endpoint's i/o queue.
- *
- * 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),
- * and accordingly can't correctly implement interface altsettings.
- */
+{ return 0; }
 static inline int usb_ep_clear_halt(struct usb_ep *ep)
-{
-        return ep->ops->set_halt(ep, 0);
-}
-
-/**
- * usb_ep_set_wedge - sets the halt feature and ignores clear requests
- * @ep: the endpoint being wedged
- *
- * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
- * requests. If the gadget driver clears the halt status, it will
- * automatically unwedge the endpoint.
- *
- * Returns zero on success, else negative errno.
- */
-static inline int
-usb_ep_set_wedge(struct usb_ep *ep)
-{
-        if (ep->ops->set_wedge)
-                return ep->ops->set_wedge(ep);
-        else
-                return ep->ops->set_halt(ep, 1);
-}
-
-/**
- * usb_ep_fifo_status - returns number of bytes in fifo, or error
- * @ep: the endpoint whose fifo status is being checked.
- *
- * FIFO endpoints may have "unclaimed data" in them in certain cases,
- * such as after aborted transfers.  Hosts may not have collected all
- * the IN data written by the gadget driver (and reported by a request
- * completion).  The gadget driver may not have collected all the data
- * written OUT to it by the host.  Drivers that need precise handling for
- * fault reporting or recovery may need to use this call.
- *
- * 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.
- */
+{ return 0; }
+static inline int usb_ep_set_wedge(struct usb_ep *ep)
+{ return 0; }
 static inline int usb_ep_fifo_status(struct usb_ep *ep)
-{
-        if (ep->ops->fifo_status)
-                return ep->ops->fifo_status(ep);
-        else
-                return -EOPNOTSUPP;
-}
-
-/**
- * usb_ep_fifo_flush - flushes contents of a fifo
- * @ep: the endpoint whose fifo is being flushed.
- *
- * This call may be used to flush the "unclaimed data" that may exist in
- * an endpoint fifo after abnormal transaction terminations.  The call
- * must never be used except when endpoint is not being used for any
- * protocol translation.
- */
+{ return 0; }
 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
-{
-        if (ep->ops->fifo_flush)
-                ep->ops->fifo_flush(ep);
-}
-
+{ }
+#endif /* USB_GADGET */
 
 /*-------------------------------------------------------------------------*/
 
@@ -760,251 +502,44 @@ static inline int gadget_is_otg(struct usb_gadget *g)
 #endif
 }
 
-/**
- * usb_gadget_frame_number - returns the current frame number
- * @gadget: controller that reports the frame number
- *
- * Returns the usb frame number, normally eleven bits from a SOF packet,
- * or negative errno if this device doesn't support this capability.
- */
-static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
-{
-        return gadget->ops->get_frame(gadget);
-}
+/*-------------------------------------------------------------------------*/
 
-/**
- * usb_gadget_wakeup - tries to wake up the host connected to this gadget
- * @gadget: controller used to wake up the host
- *
- * Returns zero on success, else negative error code if the hardware
- * doesn't support such attempts, or its support has not been enabled
- * by the usb host.  Drivers must return device descriptors that report
- * their ability to support this, or hosts won't enable it.
- *
- * This may also try to use SRP to wake the host and start enumeration,
- * even if OTG isn't otherwise in use.  OTG devices may also start
- * remote wakeup even when hosts don't explicitly enable it.
- */
+#if IS_ENABLED(CONFIG_USB_GADGET)
+int usb_gadget_frame_number(struct usb_gadget *gadget);
+int usb_gadget_wakeup(struct usb_gadget *gadget);
+int usb_gadget_set_selfpowered(struct usb_gadget *gadget);
+int usb_gadget_clear_selfpowered(struct usb_gadget *gadget);
+int usb_gadget_vbus_connect(struct usb_gadget *gadget);
+int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA);
+int usb_gadget_vbus_disconnect(struct usb_gadget *gadget);
+int usb_gadget_connect(struct usb_gadget *gadget);
+int usb_gadget_disconnect(struct usb_gadget *gadget);
+int usb_gadget_deactivate(struct usb_gadget *gadget);
+int usb_gadget_activate(struct usb_gadget *gadget);
+#else
+static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
+{ return 0; }
 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
-{
-        if (!gadget->ops->wakeup)
-                return -EOPNOTSUPP;
-        return gadget->ops->wakeup(gadget);
-}
-
-/**
- * usb_gadget_set_selfpowered - sets the device selfpowered feature.
- * @gadget:the device being declared as self-powered
- *
- * this affects the device status reported by the hardware driver
- * to reflect that it now has a local power supply.
- *
- * returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
-{
-        if (!gadget->ops->set_selfpowered)
-                return -EOPNOTSUPP;
-        return gadget->ops->set_selfpowered(gadget, 1);
-}
-
-/**
- * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
- * @gadget:the device being declared as bus-powered
- *
- * this affects the device status reported by the hardware driver.
- * some hardware may not support bus-powered operation, in which
- * case this feature's value can never change.
- *
- * returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
-{
-        if (!gadget->ops->set_selfpowered)
-                return -EOPNOTSUPP;
-        return gadget->ops->set_selfpowered(gadget, 0);
-}
-
-/**
- * usb_gadget_vbus_connect - Notify controller that VBUS is powered
- * @gadget:The device which now has VBUS power.
- * Context: can sleep
- *
- * This call is used by a driver for an external transceiver (or GPIO)
- * that detects a VBUS power session starting.  Common responses include
- * resuming the controller, activating the D+ (or D-) pullup to let the
- * host detect that a USB device is attached, and starting to draw power
- * (8mA or possibly more, especially after SET_CONFIGURATION).
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
-{
-        if (!gadget->ops->vbus_session)
-                return -EOPNOTSUPP;
-        return gadget->ops->vbus_session(gadget, 1);
-}
-
-/**
- * usb_gadget_vbus_draw - constrain controller's VBUS power usage
- * @gadget:The device whose VBUS usage is being described
- * @mA:How much current to draw, in milliAmperes.  This should be twice
- *      the value listed in the configuration descriptor bMaxPower field.
- *
- * This call is used by gadget drivers during SET_CONFIGURATION calls,
- * reporting how much power the device may consume.  For example, this
- * could affect how quickly batteries are recharged.
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
-{
-        if (!gadget->ops->vbus_draw)
-                return -EOPNOTSUPP;
-        return gadget->ops->vbus_draw(gadget, mA);
-}
-
-/**
- * usb_gadget_vbus_disconnect - notify controller about VBUS session end
- * @gadget:the device whose VBUS supply is being described
- * Context: can sleep
- *
- * This call is used by a driver for an external transceiver (or GPIO)
- * that detects a VBUS power session ending.  Common responses include
- * reversing everything done in usb_gadget_vbus_connect().
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
-{
-        if (!gadget->ops->vbus_session)
-                return -EOPNOTSUPP;
-        return gadget->ops->vbus_session(gadget, 0);
-}
-
-/**
- * usb_gadget_connect - software-controlled connect to USB host
- * @gadget:the peripheral being connected
- *
- * Enables the D+ (or potentially D-) pullup.  The host will start
- * enumerating this gadget when the pullup is active and a VBUS session
- * is active (the link is powered).  This pullup is always enabled unless
- * usb_gadget_disconnect() has been used to disable it.
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_connect(struct usb_gadget *gadget)
-{
-        int ret;
-
-        if (!gadget->ops->pullup)
-                return -EOPNOTSUPP;
-
-        if (gadget->deactivated) {
-                /*
-                 * If gadget is deactivated we only save new state.
-                 * Gadget will be connected automatically after activation.
-                 */
-                gadget->connected = true;
-                return 0;
-        }
-
-        ret = gadget->ops->pullup(gadget, 1);
-        if (!ret)
-                gadget->connected = 1;
-        return ret;
-}
-
-/**
- * usb_gadget_disconnect - software-controlled disconnect from USB host
- * @gadget:the peripheral being disconnected
- *
- * Disables the D+ (or potentially D-) pullup, which the host may see
- * as a disconnect (when a VBUS session is active).  Not all systems
- * support software pullup controls.
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
-{
-        int ret;
-
-        if (!gadget->ops->pullup)
-                return -EOPNOTSUPP;
-
-        if (gadget->deactivated) {
-                /*
-                 * If gadget is deactivated we only save new state.
-                 * Gadget will stay disconnected after activation.
-                 */
-                gadget->connected = false;
-                return 0;
-        }
-
-        ret = gadget->ops->pullup(gadget, 0);
-        if (!ret)
-                gadget->connected = 0;
-        return ret;
-}
-
-/**
- * usb_gadget_deactivate - deactivate function which is not ready to work
- * @gadget: the peripheral being deactivated
- *
- * This routine may be used during the gadget driver bind() call to prevent
- * the peripheral from ever being visible to the USB host, unless later
- * usb_gadget_activate() is called.  For example, user mode components may
- * need to be activated before the system can talk to hosts.
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_deactivate(struct usb_gadget *gadget)
-{
-        int ret;
-
-        if (gadget->deactivated)
-                return 0;
-
-        if (gadget->connected) {
-                ret = usb_gadget_disconnect(gadget);
-                if (ret)
-                        return ret;
-                /*
-                 * If gadget was being connected before deactivation, we want
-                 * to reconnect it in usb_gadget_activate().
-                 */
-                gadget->connected = true;
-        }
-        gadget->deactivated = true;
-
-        return 0;
-}
-
-/**
- * usb_gadget_activate - activate function which is not ready to work
- * @gadget: the peripheral being activated
- *
- * This routine activates gadget which was previously deactivated with
- * usb_gadget_deactivate() call. It calls usb_gadget_connect() if needed.
- *
- * Returns zero on success, else negative errno.
- */
+{ return 0; }
 static inline int usb_gadget_activate(struct usb_gadget *gadget)
-{
-        if (!gadget->deactivated)
-                return 0;
-
-        gadget->deactivated = false;
-
-        /*
-         * If gadget has been connected before deactivation, or became connected
-         * while it was being deactivated, we call usb_gadget_connect().
-         */
-        if (gadget->connected)
-                return usb_gadget_connect(gadget);
-
-        return 0;
-}
+{ return 0; }
+#endif /* CONFIG_USB_GADGET */
 
 /*-------------------------------------------------------------------------*/