wusb: add the Wire Adapter (WA) core

Common code for supporting Host Wire Adapters and Device Wire Adapters.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 417 insertions, 0 deletions

diff --git a/drivers/usb/wusbcore/wa-hc.h b/drivers/usb/wusbcore/wa-hc.h
new file mode 100644
index 000000000000..586d350cdb4d
--- /dev/null
+++ b/drivers/usb/wusbcore/wa-hc.h
@@ -0,0 +1,417 @@
+/*
+ * 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 managent: 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 managment -- 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 khubd 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);
+
+/**
+ * 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;
+	atomic_t segs_available;
+	u8 buffer[1];	/* For reads/writes on USB */
+};
+
+
+/**
+ * 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 umodified 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
+ *        comonalities with WHCI), a wa layer (for sharing
+ *        comonalities 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 */
+	spinlock_t rpipe_bm_lock;	/* protect rpipe_bm */
+	struct mutex rpipe_mutex;	/* assigning resources to endpoints */
+
+	struct urb *dti_urb;		/* URB for reading xfer results */
+	struct urb *buf_in_urb;		/* URB for reading data in */
+	struct edc dti_edc;		/* DTI error density counter */
+	struct wa_xfer_result *xfer_result; /* real size = dti_ep maxpktsize */
+	size_t xfer_result_size;
+
+	s32 status;			/* For reading status */
+
+	struct list_head xfer_list;
+	struct list_head xfer_delayed_list;
+	spinlock_t xfer_list_lock;
+	struct work_struct xfer_work;
+	atomic_t xfer_id_count;
+};
+
+
+extern int wa_create(struct wahc *wa, struct usb_interface *iface);
+extern void __wa_destroy(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);
+}
+
+static inline void wa_nep_disarm(struct wahc *wa)
+{
+	usb_kill_urb(wa->nep_urb);
+}
+
+
+/* RPipes */
+static inline void wa_rpipe_init(struct wahc *wa)
+{
+	spin_lock_init(&wa->rpipe_bm_lock);
+	mutex_init(&wa->rpipe_mutex);
+}
+
+static inline void wa_init(struct wahc *wa)
+{
+	edc_init(&wa->nep_edc);
+	atomic_set(&wa->notifs_queued, 0);
+	wa_rpipe_init(wa);
+	edc_init(&wa->dti_edc);
+	INIT_LIST_HEAD(&wa->xfer_list);
+	INIT_LIST_HEAD(&wa->xfer_delayed_list);
+	spin_lock_init(&wa->xfer_list_lock);
+	INIT_WORK(&wa->xfer_work, wa_urb_enqueue_run);
+	atomic_set(&wa->xfer_id_count, 1);
+}
+
+/**
+ * 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);
+}
+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 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);
+}
+
+/**
+ * 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 *);
+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 an 'struct' hcd based sollution
+ */
+static inline struct wahc *wa_get(struct wahc *wa)
+{
+	usb_get_intf(wa->usb_iface);
+	return wa;
+}
+
+static inline void wa_put(struct wahc *wa)
+{
+	usb_put_intf(wa->usb_iface);
+}
+
+
+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, 1000 /* FIXME: arbitrary */);
+}
+
+
+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[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),
+		1000 /* FIXME: arbitrary */);
+	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 {
+		msleep(50);
+		result = __wa_get_status(wa);
+		if ((result & mask) == value)
+			break;
+		if (loops-- == 0) {
+			result = -ETIMEDOUT;
+			break;
+		}
+	} 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);
+out:
+	return 0;
+}
+
+
+#endif /* #ifndef __HWAHC_INTERNAL_H__ */