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-rw-r--r--drivers/uwb/neh.c620
1 files changed, 620 insertions, 0 deletions
diff --git a/drivers/uwb/neh.c b/drivers/uwb/neh.c
new file mode 100644
index 000000000..fbdca728b
--- /dev/null
+++ b/drivers/uwb/neh.c
@@ -0,0 +1,620 @@
+/*
+ * WUSB Wire Adapter: Radio Control Interface (WUSB[8])
+ * Notification and Event Handling
+ *
+ * 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.
+ *
+ *
+ * The RC interface of the Host Wire Adapter (USB dongle) or WHCI PCI
+ * card delivers a stream of notifications and events to the
+ * notification end event endpoint or area. This code takes care of
+ * getting a buffer with that data, breaking it up in separate
+ * notifications and events and then deliver those.
+ *
+ * Events are answers to commands and they carry a context ID that
+ * associates them to the command. Notifications are that,
+ * notifications, they come out of the blue and have a context ID of
+ * zero. Think of the context ID kind of like a handler. The
+ * uwb_rc_neh_* code deals with managing context IDs.
+ *
+ * This is why you require a handle to operate on a UWB host. When you
+ * open a handle a context ID is assigned to you.
+ *
+ * So, as it is done is:
+ *
+ * 1. Add an event handler [uwb_rc_neh_add()] (assigns a ctx id)
+ * 2. Issue command [rc->cmd(rc, ...)]
+ * 3. Arm the timeout timer [uwb_rc_neh_arm()]
+ * 4, Release the reference to the neh [uwb_rc_neh_put()]
+ * 5. Wait for the callback
+ * 6. Command result (RCEB) is passed to the callback
+ *
+ * If (2) fails, you should remove the handle [uwb_rc_neh_rm()]
+ * instead of arming the timer.
+ *
+ * Handles are for using in *serialized* code, single thread.
+ *
+ * When the notification/event comes, the IRQ handler/endpoint
+ * callback passes the data read to uwb_rc_neh_grok() which will break
+ * it up in a discrete series of events, look up who is listening for
+ * them and execute the pertinent callbacks.
+ *
+ * If the reader detects an error while reading the data stream, call
+ * uwb_rc_neh_error().
+ *
+ * CONSTRAINTS/ASSUMPTIONS:
+ *
+ * - Most notifications/events are small (less thank .5k), copying
+ * around is ok.
+ *
+ * - Notifications/events are ALWAYS smaller than PAGE_SIZE
+ *
+ * - Notifications/events always come in a single piece (ie: a buffer
+ * will always contain entire notifications/events).
+ *
+ * - we cannot know in advance how long each event is (because they
+ * lack a length field in their header--smart move by the standards
+ * body, btw). So we need a facility to get the event size given the
+ * header. This is what the EST code does (notif/Event Size
+ * Tables), check nest.c--as well, you can associate the size to
+ * the handle [w/ neh->extra_size()].
+ *
+ * - Most notifications/events are fixed size; only a few are variable
+ * size (NEST takes care of that).
+ *
+ * - Listeners of events expect them, so they usually provide a
+ * buffer, as they know the size. Listeners to notifications don't,
+ * so we allocate their buffers dynamically.
+ */
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/export.h>
+
+#include "uwb-internal.h"
+
+/*
+ * UWB Radio Controller Notification/Event Handle
+ *
+ * Represents an entity waiting for an event coming from the UWB Radio
+ * Controller with a given context id (context) and type (evt_type and
+ * evt). On reception of the notification/event, the callback (cb) is
+ * called with the event.
+ *
+ * If the timer expires before the event is received, the callback is
+ * called with -ETIMEDOUT as the event size.
+ */
+struct uwb_rc_neh {
+ struct kref kref;
+
+ struct uwb_rc *rc;
+ u8 evt_type;
+ __le16 evt;
+ u8 context;
+ u8 completed;
+ uwb_rc_cmd_cb_f cb;
+ void *arg;
+
+ struct timer_list timer;
+ struct list_head list_node;
+};
+
+static void uwb_rc_neh_timer(struct timer_list *t);
+
+static void uwb_rc_neh_release(struct kref *kref)
+{
+ struct uwb_rc_neh *neh = container_of(kref, struct uwb_rc_neh, kref);
+
+ kfree(neh);
+}
+
+static void uwb_rc_neh_get(struct uwb_rc_neh *neh)
+{
+ kref_get(&neh->kref);
+}
+
+/**
+ * uwb_rc_neh_put - release reference to a neh
+ * @neh: the neh
+ */
+void uwb_rc_neh_put(struct uwb_rc_neh *neh)
+{
+ kref_put(&neh->kref, uwb_rc_neh_release);
+}
+
+
+/**
+ * Assigns @neh a context id from @rc's pool
+ *
+ * @rc: UWB Radio Controller descriptor; @rc->neh_lock taken
+ * @neh: Notification/Event Handle
+ * @returns 0 if context id was assigned ok; < 0 errno on error (if
+ * all the context IDs are taken).
+ *
+ * (assumes @wa is locked).
+ *
+ * NOTE: WUSB spec reserves context ids 0x00 for notifications and
+ * 0xff is invalid, so they must not be used. Initialization
+ * fills up those two in the bitmap so they are not allocated.
+ *
+ * We spread the allocation around to reduce the possibility of two
+ * consecutive opened @neh's getting the same context ID assigned (to
+ * avoid surprises with late events that timed out long time ago). So
+ * first we search from where @rc->ctx_roll is, if not found, we
+ * search from zero.
+ */
+static
+int __uwb_rc_ctx_get(struct uwb_rc *rc, struct uwb_rc_neh *neh)
+{
+ int result;
+ result = find_next_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX,
+ rc->ctx_roll++);
+ if (result < UWB_RC_CTX_MAX)
+ goto found;
+ result = find_first_zero_bit(rc->ctx_bm, UWB_RC_CTX_MAX);
+ if (result < UWB_RC_CTX_MAX)
+ goto found;
+ return -ENFILE;
+found:
+ set_bit(result, rc->ctx_bm);
+ neh->context = result;
+ return 0;
+}
+
+
+/** Releases @neh's context ID back to @rc (@rc->neh_lock is locked). */
+static
+void __uwb_rc_ctx_put(struct uwb_rc *rc, struct uwb_rc_neh *neh)
+{
+ struct device *dev = &rc->uwb_dev.dev;
+ if (neh->context == 0)
+ return;
+ if (test_bit(neh->context, rc->ctx_bm) == 0) {
+ dev_err(dev, "context %u not set in bitmap\n",
+ neh->context);
+ WARN_ON(1);
+ }
+ clear_bit(neh->context, rc->ctx_bm);
+ neh->context = 0;
+}
+
+/**
+ * uwb_rc_neh_add - add a neh for a radio controller command
+ * @rc: the radio controller
+ * @cmd: the radio controller command
+ * @expected_type: the type of the expected response event
+ * @expected_event: the expected event ID
+ * @cb: callback for when the event is received
+ * @arg: argument for the callback
+ *
+ * Creates a neh and adds it to the list of those waiting for an
+ * event. A context ID will be assigned to the command.
+ */
+struct uwb_rc_neh *uwb_rc_neh_add(struct uwb_rc *rc, struct uwb_rccb *cmd,
+ u8 expected_type, u16 expected_event,
+ uwb_rc_cmd_cb_f cb, void *arg)
+{
+ int result;
+ unsigned long flags;
+ struct device *dev = &rc->uwb_dev.dev;
+ struct uwb_rc_neh *neh;
+
+ neh = kzalloc(sizeof(*neh), GFP_KERNEL);
+ if (neh == NULL) {
+ result = -ENOMEM;
+ goto error_kzalloc;
+ }
+
+ kref_init(&neh->kref);
+ INIT_LIST_HEAD(&neh->list_node);
+ timer_setup(&neh->timer, uwb_rc_neh_timer, 0);
+
+ neh->rc = rc;
+ neh->evt_type = expected_type;
+ neh->evt = cpu_to_le16(expected_event);
+ neh->cb = cb;
+ neh->arg = arg;
+
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ result = __uwb_rc_ctx_get(rc, neh);
+ if (result >= 0) {
+ cmd->bCommandContext = neh->context;
+ list_add_tail(&neh->list_node, &rc->neh_list);
+ uwb_rc_neh_get(neh);
+ }
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+ if (result < 0)
+ goto error_ctx_get;
+
+ return neh;
+
+error_ctx_get:
+ kfree(neh);
+error_kzalloc:
+ dev_err(dev, "cannot open handle to radio controller: %d\n", result);
+ return ERR_PTR(result);
+}
+
+static void __uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
+{
+ __uwb_rc_ctx_put(rc, neh);
+ list_del(&neh->list_node);
+}
+
+/**
+ * uwb_rc_neh_rm - remove a neh.
+ * @rc: the radio controller
+ * @neh: the neh to remove
+ *
+ * Remove an active neh immediately instead of waiting for the event
+ * (or a time out).
+ */
+void uwb_rc_neh_rm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ __uwb_rc_neh_rm(rc, neh);
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+
+ del_timer_sync(&neh->timer);
+ uwb_rc_neh_put(neh);
+}
+
+/**
+ * uwb_rc_neh_arm - arm an event handler timeout timer
+ *
+ * @rc: UWB Radio Controller
+ * @neh: Notification/event handler for @rc
+ *
+ * The timer is only armed if the neh is active.
+ */
+void uwb_rc_neh_arm(struct uwb_rc *rc, struct uwb_rc_neh *neh)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ if (neh->context)
+ mod_timer(&neh->timer,
+ jiffies + msecs_to_jiffies(UWB_RC_CMD_TIMEOUT_MS));
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+}
+
+static void uwb_rc_neh_cb(struct uwb_rc_neh *neh, struct uwb_rceb *rceb, size_t size)
+{
+ (*neh->cb)(neh->rc, neh->arg, rceb, size);
+ uwb_rc_neh_put(neh);
+}
+
+static bool uwb_rc_neh_match(struct uwb_rc_neh *neh, const struct uwb_rceb *rceb)
+{
+ return neh->evt_type == rceb->bEventType
+ && neh->evt == rceb->wEvent
+ && neh->context == rceb->bEventContext;
+}
+
+/**
+ * Find the handle waiting for a RC Radio Control Event
+ *
+ * @rc: UWB Radio Controller
+ * @rceb: Pointer to the RCEB buffer
+ * @event_size: Pointer to the size of the RCEB buffer. Might be
+ * adjusted to take into account the @neh->extra_size
+ * settings.
+ *
+ * If the listener has no buffer (NULL buffer), one is allocated for
+ * the right size (the amount of data received). @neh->ptr will point
+ * to the event payload, which always starts with a 'struct
+ * uwb_rceb'. kfree() it when done.
+ */
+static
+struct uwb_rc_neh *uwb_rc_neh_lookup(struct uwb_rc *rc,
+ const struct uwb_rceb *rceb)
+{
+ struct uwb_rc_neh *neh = NULL, *h;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rc->neh_lock, flags);
+
+ list_for_each_entry(h, &rc->neh_list, list_node) {
+ if (uwb_rc_neh_match(h, rceb)) {
+ neh = h;
+ break;
+ }
+ }
+
+ if (neh)
+ __uwb_rc_neh_rm(rc, neh);
+
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+
+ return neh;
+}
+
+
+/*
+ * Process notifications coming from the radio control interface
+ *
+ * @rc: UWB Radio Control Interface descriptor
+ * @neh: Notification/Event Handler @neh->ptr points to
+ * @uwb_evt->buffer.
+ *
+ * This function is called by the event/notif handling subsystem when
+ * notifications arrive (hwarc_probe() arms a notification/event handle
+ * that calls back this function for every received notification; this
+ * function then will rearm itself).
+ *
+ * Notification data buffers are dynamically allocated by the NEH
+ * handling code in neh.c [uwb_rc_neh_lookup()]. What is actually
+ * allocated is space to contain the notification data.
+ *
+ * Buffers are prefixed with a Radio Control Event Block (RCEB) as
+ * defined by the WUSB Wired-Adapter Radio Control interface. We
+ * just use it for the notification code.
+ *
+ * On each case statement we just transcode endianess of the different
+ * fields. We declare a pointer to a RCI definition of an event, and
+ * then to a UWB definition of the same event (which are the same,
+ * remember). Event if we use different pointers
+ */
+static
+void uwb_rc_notif(struct uwb_rc *rc, struct uwb_rceb *rceb, ssize_t size)
+{
+ struct device *dev = &rc->uwb_dev.dev;
+ struct uwb_event *uwb_evt;
+
+ if (size == -ESHUTDOWN)
+ return;
+ if (size < 0) {
+ dev_err(dev, "ignoring event with error code %zu\n",
+ size);
+ return;
+ }
+
+ uwb_evt = kzalloc(sizeof(*uwb_evt), GFP_ATOMIC);
+ if (unlikely(uwb_evt == NULL)) {
+ dev_err(dev, "no memory to queue event 0x%02x/%04x/%02x\n",
+ rceb->bEventType, le16_to_cpu(rceb->wEvent),
+ rceb->bEventContext);
+ return;
+ }
+ uwb_evt->rc = __uwb_rc_get(rc); /* will be put by uwbd's uwbd_event_handle() */
+ uwb_evt->ts_jiffies = jiffies;
+ uwb_evt->type = UWB_EVT_TYPE_NOTIF;
+ uwb_evt->notif.size = size;
+ uwb_evt->notif.rceb = rceb;
+
+ uwbd_event_queue(uwb_evt);
+}
+
+static void uwb_rc_neh_grok_event(struct uwb_rc *rc, struct uwb_rceb *rceb, size_t size)
+{
+ struct device *dev = &rc->uwb_dev.dev;
+ struct uwb_rc_neh *neh;
+ struct uwb_rceb *notif;
+ unsigned long flags;
+
+ if (rceb->bEventContext == 0) {
+ notif = kmalloc(size, GFP_ATOMIC);
+ if (notif) {
+ memcpy(notif, rceb, size);
+ uwb_rc_notif(rc, notif, size);
+ } else
+ dev_err(dev, "event 0x%02x/%04x/%02x (%zu bytes): no memory\n",
+ rceb->bEventType, le16_to_cpu(rceb->wEvent),
+ rceb->bEventContext, size);
+ } else {
+ neh = uwb_rc_neh_lookup(rc, rceb);
+ if (neh) {
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ /* to guard against a timeout */
+ neh->completed = 1;
+ del_timer(&neh->timer);
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+ uwb_rc_neh_cb(neh, rceb, size);
+ } else
+ dev_warn(dev, "event 0x%02x/%04x/%02x (%zu bytes): nobody cared\n",
+ rceb->bEventType, le16_to_cpu(rceb->wEvent),
+ rceb->bEventContext, size);
+ }
+}
+
+/**
+ * Given a buffer with one or more UWB RC events/notifications, break
+ * them up and dispatch them.
+ *
+ * @rc: UWB Radio Controller
+ * @buf: Buffer with the stream of notifications/events
+ * @buf_size: Amount of data in the buffer
+ *
+ * Note each notification/event starts always with a 'struct
+ * uwb_rceb', so the minimum size if 4 bytes.
+ *
+ * The device may pass us events formatted differently than expected.
+ * These are first filtered, potentially creating a new event in a new
+ * memory location. If a new event is created by the filter it is also
+ * freed here.
+ *
+ * For each notif/event, tries to guess the size looking at the EST
+ * tables, then looks for a neh that is waiting for that event and if
+ * found, copies the payload to the neh's buffer and calls it back. If
+ * not, the data is ignored.
+ *
+ * Note that if we can't find a size description in the EST tables, we
+ * still might find a size in the 'neh' handle in uwb_rc_neh_lookup().
+ *
+ * Assumptions:
+ *
+ * @rc->neh_lock is NOT taken
+ *
+ * We keep track of various sizes here:
+ * size: contains the size of the buffer that is processed for the
+ * incoming event. this buffer may contain events that are not
+ * formatted as WHCI.
+ * real_size: the actual space taken by this event in the buffer.
+ * We need to keep track of the real size of an event to be able to
+ * advance the buffer correctly.
+ * event_size: the size of the event as expected by the core layer
+ * [OR] the size of the event after filtering. if the filtering
+ * created a new event in a new memory location then this is
+ * effectively the size of a new event buffer
+ */
+void uwb_rc_neh_grok(struct uwb_rc *rc, void *buf, size_t buf_size)
+{
+ struct device *dev = &rc->uwb_dev.dev;
+ void *itr;
+ struct uwb_rceb *rceb;
+ size_t size, real_size, event_size;
+ int needtofree;
+
+ itr = buf;
+ size = buf_size;
+ while (size > 0) {
+ if (size < sizeof(*rceb)) {
+ dev_err(dev, "not enough data in event buffer to "
+ "process incoming events (%zu left, minimum is "
+ "%zu)\n", size, sizeof(*rceb));
+ break;
+ }
+
+ rceb = itr;
+ if (rc->filter_event) {
+ needtofree = rc->filter_event(rc, &rceb, size,
+ &real_size, &event_size);
+ if (needtofree < 0 && needtofree != -ENOANO) {
+ dev_err(dev, "BUG: Unable to filter event "
+ "(0x%02x/%04x/%02x) from "
+ "device. \n", rceb->bEventType,
+ le16_to_cpu(rceb->wEvent),
+ rceb->bEventContext);
+ break;
+ }
+ } else
+ needtofree = -ENOANO;
+ /* do real processing if there was no filtering or the
+ * filtering didn't act */
+ if (needtofree == -ENOANO) {
+ ssize_t ret = uwb_est_find_size(rc, rceb, size);
+ if (ret < 0)
+ break;
+ if (ret > size) {
+ dev_err(dev, "BUG: hw sent incomplete event "
+ "0x%02x/%04x/%02x (%zd bytes), only got "
+ "%zu bytes. We don't handle that.\n",
+ rceb->bEventType, le16_to_cpu(rceb->wEvent),
+ rceb->bEventContext, ret, size);
+ break;
+ }
+ real_size = event_size = ret;
+ }
+ uwb_rc_neh_grok_event(rc, rceb, event_size);
+
+ if (needtofree == 1)
+ kfree(rceb);
+
+ itr += real_size;
+ size -= real_size;
+ }
+}
+EXPORT_SYMBOL_GPL(uwb_rc_neh_grok);
+
+
+/**
+ * The entity that reads from the device notification/event channel has
+ * detected an error.
+ *
+ * @rc: UWB Radio Controller
+ * @error: Errno error code
+ *
+ */
+void uwb_rc_neh_error(struct uwb_rc *rc, int error)
+{
+ struct uwb_rc_neh *neh;
+ unsigned long flags;
+
+ for (;;) {
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ if (list_empty(&rc->neh_list)) {
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+ break;
+ }
+ neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node);
+ __uwb_rc_neh_rm(rc, neh);
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+
+ del_timer_sync(&neh->timer);
+ uwb_rc_neh_cb(neh, NULL, error);
+ }
+}
+EXPORT_SYMBOL_GPL(uwb_rc_neh_error);
+
+
+static void uwb_rc_neh_timer(struct timer_list *t)
+{
+ struct uwb_rc_neh *neh = from_timer(neh, t, timer);
+ struct uwb_rc *rc = neh->rc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ if (neh->completed) {
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+ return;
+ }
+ if (neh->context)
+ __uwb_rc_neh_rm(rc, neh);
+ else
+ neh = NULL;
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+
+ if (neh)
+ uwb_rc_neh_cb(neh, NULL, -ETIMEDOUT);
+}
+
+/** Initializes the @rc's neh subsystem
+ */
+void uwb_rc_neh_create(struct uwb_rc *rc)
+{
+ spin_lock_init(&rc->neh_lock);
+ INIT_LIST_HEAD(&rc->neh_list);
+ set_bit(0, rc->ctx_bm); /* 0 is reserved (see [WUSB] table 8-65) */
+ set_bit(0xff, rc->ctx_bm); /* and 0xff is invalid */
+ rc->ctx_roll = 1;
+}
+
+
+/** Release's the @rc's neh subsystem */
+void uwb_rc_neh_destroy(struct uwb_rc *rc)
+{
+ unsigned long flags;
+ struct uwb_rc_neh *neh;
+
+ for (;;) {
+ spin_lock_irqsave(&rc->neh_lock, flags);
+ if (list_empty(&rc->neh_list)) {
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+ break;
+ }
+ neh = list_first_entry(&rc->neh_list, struct uwb_rc_neh, list_node);
+ __uwb_rc_neh_rm(rc, neh);
+ spin_unlock_irqrestore(&rc->neh_lock, flags);
+
+ del_timer_sync(&neh->timer);
+ uwb_rc_neh_put(neh);
+ }
+}
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