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// SPDX-License-Identifier: GPL-2.0
* HWA Host Controller Driver
* Wire Adapter Control/Data Streaming Iface (WUSB1.0[8])
* Copyright (C) 2005-2006 Intel Corporation
* Inaky Perez-Gonzalez <>
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
* This driver implements a USB Host Controller (struct usb_hcd) for a
* Wireless USB Host Controller based on the Wireless USB 1.0
* Host-Wire-Adapter specification (in layman terms, a USB-dongle that
* implements a Wireless USB host).
* Check out the Design-overview.txt file in the source documentation
* for other details on the implementation.
* Main blocks:
* driver glue with the driver API, workqueue daemon
* lc RC instance life cycle management (create, destroy...)
* hcd glue with the USB API Host Controller Interface API.
* nep Notification EndPoint management: collect notifications
* and queue them with the workqueue daemon.
* Handle notifications as coming from the NEP. Sends them
* off others to their respective modules (eg: connect,
* disconnect and reset go to devconnect).
* rpipe Remote Pipe management; rpipe is what we use to write
* to an endpoint on a WUSB device that is connected to a
* xfer Transfer management -- this is all the code that gets a
* buffer and pushes it to a device (or viceversa). *
* Some day a lot of this code will be shared between this driver and
* the drivers for DWA (xfer, rpipe).
* All starts at driver.c:hwahc_probe(), when one of this guys is
* connected. hwahc_disconnect() stops it.
* During operation, the main driver is devices connecting or
* disconnecting. They cause the HWA RC to send notifications into
* nep.c:hwahc_nep_cb() that will dispatch them to
* notif.c:wa_notif_dispatch(). From there they will fan to cause
* device connects, disconnects, etc.
* Note much of the activity is difficult to follow. For example a
* device connect goes to devconnect, which will cause the "fake" root
* hub port to show a connect and stop there. Then hub_wq will notice
* and call into the rh.c:hwahc_rc_port_reset() code to authenticate
* the device (and this might require user intervention) and enable
* the port.
* We also have a timer workqueue going from devconnect.c that
* schedules in hwahc_devconnect_create().
* The rest of the traffic is in the usual entry points of a USB HCD,
* which are hooked up in driver.c:hwahc_rc_driver, and defined in
* hcd.c.
#ifndef __HWAHC_INTERNAL_H__
#define __HWAHC_INTERNAL_H__
#include <linux/completion.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/uwb.h>
#include <linux/usb/wusb.h>
#include <linux/usb/wusb-wa.h>
struct wusbhc;
struct wahc;
extern void wa_urb_enqueue_run(struct work_struct *ws);
extern void wa_process_errored_transfers_run(struct work_struct *ws);
* RPipe instance
* @descr's fields are kept in LE, as we need to send it back and
* forth.
* @wa is referenced when set
* @segs_available is the number of requests segments that still can
* be submitted to the controller without overloading
* it. It is initialized to descr->wRequests when
* aiming.
* A rpipe supports a max of descr->wRequests at the same time; before
* submitting seg_lock has to be taken. If segs_avail > 0, then we can
* submit; if not, we have to queue them.
struct wa_rpipe {
struct kref refcnt;
struct usb_rpipe_descriptor descr;
struct usb_host_endpoint *ep;
struct wahc *wa;
spinlock_t seg_lock;
struct list_head seg_list;
struct list_head list_node;
atomic_t segs_available;
u8 buffer[1]; /* For reads/writes on USB */
enum wa_dti_state {
enum wa_quirks {
* The Alereon HWA expects the data frames in isochronous transfer
* requests to be concatenated and not sent as separate packets.
* The Alereon HWA can be instructed to not send transfer notifications
* as an optimization.
enum wa_vendor_specific_requests {
#define WA_MAX_BUF_IN_URBS 4
* Instance of a HWA Host Controller
* Except where a more specific lock/mutex applies or atomic, all
* fields protected by @mutex.
* @wa_descr Can be accessed without locking because it is in
* the same area where the device descriptors were
* read, so it is guaranteed to exist unmodified while
* the device exists.
* Endianess has been converted to CPU's.
* @nep_* can be accessed without locking as its processing is
* serialized; we submit a NEP URB and it comes to
* hwahc_nep_cb(), which won't issue another URB until it is
* done processing it.
* @xfer_list:
* List of active transfers to verify existence from a xfer id
* gotten from the xfer result message. Can't use urb->list because
* it goes by endpoint, and we don't know the endpoint at the time
* when we get the xfer result message. We can't really rely on the
* pointer (will have to change for 64 bits) as the xfer id is 32 bits.
* @xfer_delayed_list: List of transfers that need to be started
* (with a workqueue, because they were
* submitted from an atomic context).
* FIXME: this needs to be layered up: a wusbhc layer (for sharing
* commonalities with WHCI), a wa layer (for sharing
* commonalities with DWA-RC).
struct wahc {
struct usb_device *usb_dev;
struct usb_interface *usb_iface;
/* HC to deliver notifications */
union {
struct wusbhc *wusb;
struct dwahc *dwa;
const struct usb_endpoint_descriptor *dto_epd, *dti_epd;
const struct usb_wa_descriptor *wa_descr;
struct urb *nep_urb; /* Notification EndPoint [lockless] */
struct edc nep_edc;
void *nep_buffer;
size_t nep_buffer_size;
atomic_t notifs_queued;
u16 rpipes;
unsigned long *rpipe_bm; /* rpipe usage bitmap */
struct list_head rpipe_delayed_list; /* delayed RPIPES. */
spinlock_t rpipe_lock; /* protect rpipe_bm and delayed list */
struct mutex rpipe_mutex; /* assigning resources to endpoints */
* dti_state is used to track the state of the dti_urb. When dti_state
* is WA_DTI_ISOC_PACKET_STATUS_PENDING, dti_isoc_xfer_in_progress and
* dti_isoc_xfer_seg identify which xfer the incoming isoc packet
* status refers to.
enum wa_dti_state dti_state;
u32 dti_isoc_xfer_in_progress;
u8 dti_isoc_xfer_seg;
struct urb *dti_urb; /* URB for reading xfer results */
/* URBs for reading data in */
struct urb buf_in_urbs[WA_MAX_BUF_IN_URBS];
int active_buf_in_urbs; /* number of buf_in_urbs active. */
struct edc dti_edc; /* DTI error density counter */
void *dti_buf;
size_t dti_buf_size;
unsigned long dto_in_use; /* protect dto endoint serialization */
s32 status; /* For reading status */
struct list_head xfer_list;
struct list_head xfer_delayed_list;
struct list_head xfer_errored_list;
* lock for the above xfer lists. Can be taken while a xfer->lock is
* held but not in the reverse order.
spinlock_t xfer_list_lock;
struct work_struct xfer_enqueue_work;
struct work_struct xfer_error_work;
atomic_t xfer_id_count;
kernel_ulong_t quirks;
extern int wa_create(struct wahc *wa, struct usb_interface *iface,
extern void __wa_destroy(struct wahc *wa);
extern int wa_dti_start(struct wahc *wa);
void wa_reset_all(struct wahc *wa);
/* Miscellaneous constants */
enum {
/** Max number of EPROTO errors we tolerate on the NEP in a
* period of time */
/** Period of time for EPROTO errors (in jiffies) */
/* Notification endpoint handling */
extern int wa_nep_create(struct wahc *, struct usb_interface *);
extern void wa_nep_destroy(struct wahc *);
static inline int wa_nep_arm(struct wahc *wa, gfp_t gfp_mask)
struct urb *urb = wa->nep_urb;
urb->transfer_buffer = wa->nep_buffer;
urb->transfer_buffer_length = wa->nep_buffer_size;
return usb_submit_urb(urb, gfp_mask);
static inline void wa_nep_disarm(struct wahc *wa)
/* RPipes */
static inline void wa_rpipe_init(struct wahc *wa)
static inline void wa_init(struct wahc *wa)
int index;
atomic_set(&wa->notifs_queued, 0);
INIT_WORK(&wa->xfer_enqueue_work, wa_urb_enqueue_run);
INIT_WORK(&wa->xfer_error_work, wa_process_errored_transfers_run);
wa->dto_in_use = 0;
atomic_set(&wa->xfer_id_count, 1);
/* init the buf in URBs */
for (index = 0; index < WA_MAX_BUF_IN_URBS; ++index)
wa->active_buf_in_urbs = 0;
* Destroy a pipe (when refcount drops to zero)
* Assumes it has been moved to the "QUIESCING" state.
struct wa_xfer;
extern void rpipe_destroy(struct kref *_rpipe);
static inline
void __rpipe_get(struct wa_rpipe *rpipe)
extern int rpipe_get_by_ep(struct wahc *, struct usb_host_endpoint *,
struct urb *, gfp_t);
static inline void rpipe_put(struct wa_rpipe *rpipe)
kref_put(&rpipe->refcnt, rpipe_destroy);
extern void rpipe_ep_disable(struct wahc *, struct usb_host_endpoint *);
extern void rpipe_clear_feature_stalled(struct wahc *,
struct usb_host_endpoint *);
extern int wa_rpipes_create(struct wahc *);
extern void wa_rpipes_destroy(struct wahc *);
static inline void rpipe_avail_dec(struct wa_rpipe *rpipe)
* Returns true if the rpipe is ready to submit more segments.
static inline int rpipe_avail_inc(struct wa_rpipe *rpipe)
return atomic_inc_return(&rpipe->segs_available) > 0
&& !list_empty(&rpipe->seg_list);
/* Transferring data */
extern int wa_urb_enqueue(struct wahc *, struct usb_host_endpoint *,
struct urb *, gfp_t);
extern int wa_urb_dequeue(struct wahc *, struct urb *, int);
extern void wa_handle_notif_xfer(struct wahc *, struct wa_notif_hdr *);
/* Misc
* FIXME: Refcounting for the actual @hwahc object is not correct; I
* mean, this should be refcounting on the HCD underneath, but
* it is not. In any case, the semantics for HCD refcounting
* are *weird*...on refcount reaching zero it just frees
* RC specific function is called...unless I miss
* something.
* FIXME: has to go away in favour of a 'struct' hcd based solution
static inline struct wahc *wa_get(struct wahc *wa)
return wa;
static inline void wa_put(struct wahc *wa)
static inline int __wa_feature(struct wahc *wa, unsigned op, u16 feature)
return usb_control_msg(wa->usb_dev, usb_sndctrlpipe(wa->usb_dev, 0),
static inline int __wa_set_feature(struct wahc *wa, u16 feature)
return __wa_feature(wa, 1, feature);
static inline int __wa_clear_feature(struct wahc *wa, u16 feature)
return __wa_feature(wa, 0, feature);
* Return the status of a Wire Adapter
* @wa: Wire Adapter instance
* @returns < 0 errno code on error, or status bitmap as described
* in WUSB1.0[].
* NOTE: need malloc, some arches don't take USB from the stack
static inline
s32 __wa_get_status(struct wahc *wa)
s32 result;
result = usb_control_msg(
wa->usb_dev, usb_rcvctrlpipe(wa->usb_dev, 0),
0, wa->usb_iface->cur_altsetting->desc.bInterfaceNumber,
&wa->status, sizeof(wa->status), USB_CTRL_GET_TIMEOUT);
if (result >= 0)
result = wa->status;
return result;
* Waits until the Wire Adapter's status matches @mask/@value
* @wa: Wire Adapter instance.
* @returns < 0 errno code on error, otherwise status.
* Loop until the WAs status matches the mask and value (status & mask
* == value). Timeout if it doesn't happen.
* FIXME: is there an official specification on how long status
* changes can take?
static inline s32 __wa_wait_status(struct wahc *wa, u32 mask, u32 value)
s32 result;
unsigned loops = 10;
do {
result = __wa_get_status(wa);
if ((result & mask) == value)
if (loops-- == 0) {
result = -ETIMEDOUT;
} while (result >= 0);
return result;
/** Command @hwahc to stop, @returns 0 if ok, < 0 errno code on error */
static inline int __wa_stop(struct wahc *wa)
int result;
struct device *dev = &wa->usb_iface->dev;
result = __wa_clear_feature(wa, WA_ENABLE);
if (result < 0 && result != -ENODEV) {
dev_err(dev, "error commanding HC to stop: %d\n", result);
goto out;
result = __wa_wait_status(wa, WA_ENABLE, 0);
if (result < 0 && result != -ENODEV)
dev_err(dev, "error waiting for HC to stop: %d\n", result);
return 0;
#endif /* #ifndef __HWAHC_INTERNAL_H__ */