cregit-Linux how code gets into the kernel

Release 4.7 drivers/usb/wusbcore/wa-hc.h

/*
 * HWA Host Controller Driver
 * Wire Adapter Control/Data Streaming Iface (WUSB1.0[8])
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *
 * 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
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * 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
 *             HWA RC.
 *
 *  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 {
	
WA_DTI_TRANSFER_RESULT_PENDING,
	
WA_DTI_ISOC_PACKET_STATUS_PENDING,
	
WA_DTI_BUF_IN_DATA_PENDING
};


enum wa_quirks {
	/*
         * The Alereon HWA expects the data frames in isochronous transfer
         * requests to be concatenated and not sent as separate packets.
         */
	
WUSB_QUIRK_ALEREON_HWA_CONCAT_ISOC	= 0x01,
	/*
         * The Alereon HWA can be instructed to not send transfer notifications
         * as an optimization.
         */
	
WUSB_QUIRK_ALEREON_HWA_DISABLE_XFER_NOTIFICATIONS	= 0x02,
};


enum wa_vendor_specific_requests {
	
WA_REQ_ALEREON_DISABLE_XFER_NOTIFICATIONS = 0x4C,
	
WA_REQ_ALEREON_FEATURE_SET = 0x01,
	
WA_REQ_ALEREON_FEATURE_CLEAR = 0x00,
};


#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,
	kernel_ulong_t);
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 */
	
HWAHC_EPROTO_MAX = 16,
	/** Period of time for EPROTO errors (in jiffies) */
	
HWAHC_EPROTO_PERIOD = 4 * HZ,
};


/* 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); }

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static inline void wa_nep_disarm(struct wahc *wa) { usb_kill_urb(wa->nep_urb); }

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/* RPipes */
static inline void wa_rpipe_init(struct wahc *wa) { INIT_LIST_HEAD(&wa->rpipe_delayed_list); spin_lock_init(&wa->rpipe_lock); mutex_init(&wa->rpipe_mutex); }

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static inline void wa_init(struct wahc *wa) { int index; edc_init(&wa->nep_edc); atomic_set(&wa->notifs_queued, 0); wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING; wa_rpipe_init(wa); edc_init(&wa->dti_edc); INIT_LIST_HEAD(&wa->xfer_list); INIT_LIST_HEAD(&wa->xfer_delayed_list); INIT_LIST_HEAD(&wa->xfer_errored_list); spin_lock_init(&wa->xfer_list_lock); 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) usb_init_urb(&(wa->buf_in_urbs[index])); wa->active_buf_in_urbs = 0; }

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/** * 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) { kref_get(&rpipe->refcnt); }

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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); }

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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) { atomic_dec(&rpipe->segs_available); }

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/** * 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); }

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/* 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 * it...no 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) { usb_get_intf(wa->usb_iface); return wa; }

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static inline void wa_put(struct wahc *wa) { usb_put_intf(wa->usb_iface); }

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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), op ? USB_REQ_SET_FEATURE : USB_REQ_CLEAR_FEATURE, USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE, feature, wa->usb_iface->cur_altsetting->desc.bInterfaceNumber, NULL, 0, USB_CTRL_SET_TIMEOUT); }

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static inline int __wa_set_feature(struct wahc *wa, u16 feature) { return __wa_feature(wa, 1, feature); }

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static inline int __wa_clear_feature(struct wahc *wa, u16 feature) { return __wa_feature(wa, 0, feature); }

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/** * 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[8.3.1.6]. * * 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), USB_REQ_GET_STATUS, USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE, 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; }

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/** * 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 { msleep(50); result = __wa_get_status(wa); if ((result & mask) == value) break; if (loops-- == 0) { result = -ETIMEDOUT; break; } } while (result >= 0); return result; }

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/** 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); out: return 0; }

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#endif /* #ifndef __HWAHC_INTERNAL_H__ */

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