uwb: add the UWB stack (reservation manager)

DRP and reservation management.
Signed-off-by: David Vrabel <david.vrabel@csr.com>

drivers/uwb/drp-avail.c

+/*
+ * Ultra Wide Band
+ * DRP availability management
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Reinette Chatre <reinette.chatre@intel.com>
+ * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Manage DRP Availability (the MAS available for DRP
+ * reservations). Thus:
+ *
+ * - Handle DRP Availability Change notifications
+ *
+ * - Allow the reservation manager to indicate MAS reserved/released
+ *   by local (owned by/targeted at the radio controller)
+ *   reservations.
+ *
+ * - Based on the two sources above, generate a DRP Availability IE to
+ *   be included in the beacon.
+ *
+ * See also the documentation for struct uwb_drp_avail.
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/bitmap.h>
+#include "uwb-internal.h"
+
+/**
+ * uwb_drp_avail_init - initialize an RC's MAS availability
+ *
+ * All MAS are available initially.  The RC will inform use which
+ * slots are used for the BP (it may change in size).
+ */
+void uwb_drp_avail_init(struct uwb_rc *rc)
+{
+	bitmap_fill(rc->drp_avail.global, UWB_NUM_MAS);
+	bitmap_fill(rc->drp_avail.local, UWB_NUM_MAS);
+	bitmap_fill(rc->drp_avail.pending, UWB_NUM_MAS);
+}
+
+/*
+ * Determine MAS available for new local reservations.
+ *
+ * avail = global & local & pending
+ */
+static void uwb_drp_available(struct uwb_rc *rc, struct uwb_mas_bm *avail)
+{
+	bitmap_and(avail->bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS);
+	bitmap_and(avail->bm, avail->bm, rc->drp_avail.pending, UWB_NUM_MAS);
+}
+
+/**
+ * uwb_drp_avail_reserve_pending - reserve MAS for a new reservation
+ * @rc: the radio controller
+ * @mas: the MAS to reserve
+ *
+ * Returns 0 on success, or -EBUSY if the MAS requested aren't available.
+ */
+int uwb_drp_avail_reserve_pending(struct uwb_rc *rc, struct uwb_mas_bm *mas)
+{
+	struct uwb_mas_bm avail;
+
+	uwb_drp_available(rc, &avail);
+	if (!bitmap_subset(mas->bm, avail.bm, UWB_NUM_MAS))
+		return -EBUSY;
+
+	bitmap_andnot(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
+	return 0;
+}
+
+/**
+ * uwb_drp_avail_reserve - reserve MAS for an established reservation
+ * @rc: the radio controller
+ * @mas: the MAS to reserve
+ */
+void uwb_drp_avail_reserve(struct uwb_rc *rc, struct uwb_mas_bm *mas)
+{
+	bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
+	bitmap_andnot(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS);
+	rc->drp_avail.ie_valid = false;
+}
+
+/**
+ * uwb_drp_avail_release - release MAS from a pending or established reservation
+ * @rc: the radio controller
+ * @mas: the MAS to release
+ */
+void uwb_drp_avail_release(struct uwb_rc *rc, struct uwb_mas_bm *mas)
+{
+	bitmap_or(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS);
+	bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS);
+	rc->drp_avail.ie_valid = false;
+}
+
+/**
+ * uwb_drp_avail_ie_update - update the DRP Availability IE
+ * @rc: the radio controller
+ *
+ * avail = global & local
+ */
+void uwb_drp_avail_ie_update(struct uwb_rc *rc)
+{
+	struct uwb_mas_bm avail;
+
+	bitmap_and(avail.bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS);
+
+	rc->drp_avail.ie.hdr.element_id = UWB_IE_DRP_AVAILABILITY;
+	rc->drp_avail.ie.hdr.length = UWB_NUM_MAS / 8;
+	uwb_mas_bm_copy_le(rc->drp_avail.ie.bmp, &avail);
+	rc->drp_avail.ie_valid = true;
+}
+
+/**
+ * Create an unsigned long from a buffer containing a byte stream.
+ *
+ * @array: pointer to buffer
+ * @itr:   index of buffer from where we start
+ * @len:   the buffer's remaining size may not be exact multiple of
+ *         sizeof(unsigned long), @len is the length of buffer that needs
+ *         to be converted. This will be sizeof(unsigned long) or smaller
+ *         (BUG if not). If it is smaller then we will pad the remaining
+ *         space of the result with zeroes.
+ */
+static
+unsigned long get_val(u8 *array, size_t itr, size_t len)
+{
+	unsigned long val = 0;
+	size_t top = itr + len;
+
+	BUG_ON(len > sizeof(val));
+
+	while (itr < top) {
+		val <<= 8;
+		val |= array[top - 1];
+		top--;
+	}
+	val <<= 8 * (sizeof(val) - len); /* padding */
+	return val;
+}
+
+/**
+ * Initialize bitmap from data buffer.
+ *
+ * The bitmap to be converted could come from a IE, for example a
+ * DRP Availability IE.
+ * From ECMA-368 1.0 [16.8.7]: "
+ * octets: 1            1               N * (0 to 32)
+ *         Element ID   Length (=N)     DRP Availability Bitmap
+ *
+ * The DRP Availability Bitmap field is up to 256 bits long, one
+ * bit for each MAS in the superframe, where the least-significant
+ * bit of the field corresponds to the first MAS in the superframe
+ * and successive bits correspond to successive MASs."
+ *
+ * The DRP Availability bitmap is in octets from 0 to 32, so octet
+ * 32 contains bits for MAS 1-8, etc. If the bitmap is smaller than 32
+ * octets, the bits in octets not included at the end of the bitmap are
+ * treated as zero. In this case (when the bitmap is smaller than 32
+ * octets) the MAS represented range from MAS 1 to MAS (size of bitmap)
+ * with the last octet still containing bits for MAS 1-8, etc.
+ *
+ * For example:
+ * F00F0102 03040506 0708090A 0B0C0D0E 0F010203
+ * ^^^^
+ * ||||
+ * ||||
+ * |||\LSB of byte is MAS 9
+ * ||\MSB of byte is MAS 16
+ * |\LSB of first byte is MAS 1
+ * \ MSB of byte is MAS 8
+ *
+ * An example of this encoding can be found in ECMA-368 Annex-D [Table D.11]
+ *
+ * The resulting bitmap will have the following mapping:
+ *	bit position 0 == MAS 1
+ *	bit position 1 == MAS 2
+ *	...
+ *	bit position (UWB_NUM_MAS - 1) == MAS UWB_NUM_MAS
+ *
+ * @bmp_itr:	pointer to bitmap (can be declared with DECLARE_BITMAP)
+ * @buffer:	pointer to buffer containing bitmap data in big endian
+ *              format (MSB first)
+ * @buffer_size:number of bytes with which bitmap should be initialized
+ */
+static
+void buffer_to_bmp(unsigned long *bmp_itr, void *_buffer,
+		   size_t buffer_size)
+{
+	u8 *buffer = _buffer;
+	size_t itr, len;
+	unsigned long val;
+
+	itr = 0;
+	while (itr < buffer_size) {
+		len = buffer_size - itr >= sizeof(val) ?
+			sizeof(val) : buffer_size - itr;
+		val = get_val(buffer, itr, len);
+		bmp_itr[itr / sizeof(val)] = val;
+		itr += sizeof(val);
+	}
+}
+
+
+/**
+ * Extract DRP Availability bitmap from the notification.
+ *
+ * The notification that comes in contains a bitmap of (UWB_NUM_MAS / 8) bytes
+ * We convert that to our internal representation.
+ */
+static
+int uwbd_evt_get_drp_avail(struct uwb_event *evt, unsigned long *bmp)
+{
+	struct device *dev = &evt->rc->uwb_dev.dev;
+	struct uwb_rc_evt_drp_avail *drp_evt;
+	int result = -EINVAL;
+
+	/* Is there enough data to decode the event? */
+	if (evt->notif.size < sizeof(*drp_evt)) {
+		dev_err(dev, "DRP Availability Change: Not enough "
+			"data to decode event [%zu bytes, %zu "
+			"needed]\n", evt->notif.size, sizeof(*drp_evt));
+		goto error;
+	}
+	drp_evt = container_of(evt->notif.rceb, struct uwb_rc_evt_drp_avail, rceb);
+	buffer_to_bmp(bmp, drp_evt->bmp, UWB_NUM_MAS/8);
+	result = 0;
+error:
+	return result;
+}
+
+
+/**
+ * Process an incoming DRP Availability notification.
+ *
+ * @evt:	Event information (packs the actual event data, which
+ *              radio controller it came to, etc).
+ *
+ * @returns:    0 on success (so uwbd() frees the event buffer), < 0
+ *              on error.
+ *
+ * According to ECMA-368 1.0 [16.8.7], bits set to ONE indicate that
+ * the MAS slot is available, bits set to ZERO indicate that the slot
+ * is busy.
+ *
+ * So we clear available slots, we set used slots :)
+ *
+ * The notification only marks non-availability based on the BP and
+ * received DRP IEs that are not for this radio controller.  A copy of
+ * this bitmap is needed to generate the real availability (which
+ * includes local and pending reservations).
+ *
+ * The DRP Availability IE that this radio controller emits will need
+ * to be updated.
+ */
+int uwbd_evt_handle_rc_drp_avail(struct uwb_event *evt)
+{
+	int result;
+	struct uwb_rc *rc = evt->rc;
+	DECLARE_BITMAP(bmp, UWB_NUM_MAS);
+
+	result = uwbd_evt_get_drp_avail(evt, bmp);
+	if (result < 0)
+		return result;
+
+	mutex_lock(&rc->rsvs_mutex);
+	bitmap_copy(rc->drp_avail.global, bmp, UWB_NUM_MAS);
+	rc->drp_avail.ie_valid = false;
+	mutex_unlock(&rc->rsvs_mutex);
+
+	uwb_rsv_sched_update(rc);
+
+	return 0;
+}

drivers/uwb/drp-ie.c

+/*
+ * UWB DRP IE management.
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/random.h>
+#include <linux/uwb.h>
+
+#include "uwb-internal.h"
+
+/*
+ * Allocate a DRP IE.
+ *
+ * To save having to free/allocate a DRP IE when its MAS changes,
+ * enough memory is allocated for the maxiumum number of DRP
+ * allocation fields.  This gives an overhead per reservation of up to
+ * (UWB_NUM_ZONES - 1) * 4 = 60 octets.
+ */
+static struct uwb_ie_drp *uwb_drp_ie_alloc(void)
+{
+	struct uwb_ie_drp *drp_ie;
+	unsigned tiebreaker;
+
+	drp_ie = kzalloc(sizeof(struct uwb_ie_drp) +
+			UWB_NUM_ZONES * sizeof(struct uwb_drp_alloc),
+			GFP_KERNEL);
+	if (drp_ie) {
+		drp_ie->hdr.element_id = UWB_IE_DRP;
+
+		get_random_bytes(&tiebreaker, sizeof(unsigned));
+		uwb_ie_drp_set_tiebreaker(drp_ie, tiebreaker & 1);
+	}
+	return drp_ie;
+}
+
+
+/*
+ * Fill a DRP IE's allocation fields from a MAS bitmap.
+ */
+static void uwb_drp_ie_from_bm(struct uwb_ie_drp *drp_ie,
+			       struct uwb_mas_bm *mas)
+{
+	int z, i, num_fields = 0, next = 0;
+	struct uwb_drp_alloc *zones;
+	__le16 current_bmp;
+	DECLARE_BITMAP(tmp_bmp, UWB_NUM_MAS);
+	DECLARE_BITMAP(tmp_mas_bm, UWB_MAS_PER_ZONE);
+
+	zones = drp_ie->allocs;
+
+	bitmap_copy(tmp_bmp, mas->bm, UWB_NUM_MAS);
+
+	/* Determine unique MAS bitmaps in zones from bitmap. */
+	for (z = 0; z < UWB_NUM_ZONES; z++) {
+		bitmap_copy(tmp_mas_bm, tmp_bmp, UWB_MAS_PER_ZONE);
+		if (bitmap_weight(tmp_mas_bm, UWB_MAS_PER_ZONE) > 0) {
+			bool found = false;
+			current_bmp = (__le16) *tmp_mas_bm;
+			for (i = 0; i < next; i++) {
+				if (current_bmp == zones[i].mas_bm) {
+					zones[i].zone_bm |= 1 << z;
+					found = true;
+					break;
+				}
+			}
+			if (!found)  {
+				num_fields++;
+				zones[next].zone_bm = 1 << z;
+				zones[next].mas_bm = current_bmp;
+				next++;
+			}
+		}
+		bitmap_shift_right(tmp_bmp, tmp_bmp, UWB_MAS_PER_ZONE, UWB_NUM_MAS);
+	}
+
+	/* Store in format ready for transmission (le16). */
+	for (i = 0; i < num_fields; i++) {
+		drp_ie->allocs[i].zone_bm = cpu_to_le16(zones[i].zone_bm);
+		drp_ie->allocs[i].mas_bm = cpu_to_le16(zones[i].mas_bm);
+	}
+
+	drp_ie->hdr.length = sizeof(struct uwb_ie_drp) - sizeof(struct uwb_ie_hdr)
+		+ num_fields * sizeof(struct uwb_drp_alloc);
+}
+
+/**
+ * uwb_drp_ie_update - update a reservation's DRP IE
+ * @rsv: the reservation
+ */
+int uwb_drp_ie_update(struct uwb_rsv *rsv)
+{
+	struct device *dev = &rsv->rc->uwb_dev.dev;
+	struct uwb_ie_drp *drp_ie;
+	int reason_code, status;
+
+	switch (rsv->state) {
+	case UWB_RSV_STATE_NONE:
+		kfree(rsv->drp_ie);
+		rsv->drp_ie = NULL;
+		return 0;
+	case UWB_RSV_STATE_O_INITIATED:
+		reason_code = UWB_DRP_REASON_ACCEPTED;
+		status = 0;
+		break;
+	case UWB_RSV_STATE_O_PENDING:
+		reason_code = UWB_DRP_REASON_ACCEPTED;
+		status = 0;
+		break;
+	case UWB_RSV_STATE_O_MODIFIED:
+		reason_code = UWB_DRP_REASON_MODIFIED;
+		status = 1;
+		break;
+	case UWB_RSV_STATE_O_ESTABLISHED:
+		reason_code = UWB_DRP_REASON_ACCEPTED;
+		status = 1;
+		break;
+	case UWB_RSV_STATE_T_ACCEPTED:
+		reason_code = UWB_DRP_REASON_ACCEPTED;
+		status = 1;
+		break;
+	case UWB_RSV_STATE_T_DENIED:
+		reason_code = UWB_DRP_REASON_DENIED;
+		status = 0;
+		break;
+	default:
+		dev_dbg(dev, "rsv with unhandled state (%d)\n", rsv->state);
+		return -EINVAL;
+	}
+
+	if (rsv->drp_ie == NULL) {
+		rsv->drp_ie = uwb_drp_ie_alloc();
+		if (rsv->drp_ie == NULL)
+			return -ENOMEM;
+	}
+	drp_ie = rsv->drp_ie;
+
+	uwb_ie_drp_set_owner(drp_ie,        uwb_rsv_is_owner(rsv));
+	uwb_ie_drp_set_status(drp_ie,       status);
+	uwb_ie_drp_set_reason_code(drp_ie,  reason_code);
+	uwb_ie_drp_set_stream_index(drp_ie, rsv->stream);
+	uwb_ie_drp_set_type(drp_ie,         rsv->type);
+
+	if (uwb_rsv_is_owner(rsv)) {
+		switch (rsv->target.type) {
+		case UWB_RSV_TARGET_DEV:
+			drp_ie->dev_addr = rsv->target.dev->dev_addr;
+			break;
+		case UWB_RSV_TARGET_DEVADDR:
+			drp_ie->dev_addr = rsv->target.devaddr;
+			break;
+		}
+	} else
+		drp_ie->dev_addr = rsv->owner->dev_addr;
+
+	uwb_drp_ie_from_bm(drp_ie, &rsv->mas);
+
+	rsv->ie_valid = true;
+	return 0;
+}
+
+/*
+ * Set MAS bits from given MAS bitmap in a single zone of large bitmap.
+ *
+ * We are given a zone id and the MAS bitmap of bits that need to be set in
+ * this zone. Note that this zone may already have bits set and this only
+ * adds settings - we cannot simply assign the MAS bitmap contents to the
+ * zone contents. We iterate over the the bits (MAS) in the zone and set the
+ * bits that are set in the given MAS bitmap.
+ */
+static
+void uwb_drp_ie_single_zone_to_bm(struct uwb_mas_bm *bm, u8 zone, u16 mas_bm)
+{
+	int mas;
+	u16 mas_mask;
+
+	for (mas = 0; mas < UWB_MAS_PER_ZONE; mas++) {
+		mas_mask = 1 << mas;
+		if (mas_bm & mas_mask)
+			set_bit(zone * UWB_NUM_ZONES + mas, bm->bm);
+	}
+}
+
+/**
+ * uwb_drp_ie_zones_to_bm - convert DRP allocation fields to a bitmap
+ * @mas:    MAS bitmap that will be populated to correspond to the
+ *          allocation fields in the DRP IE
+ * @drp_ie: the DRP IE that contains the allocation fields.
+ *
+ * The input format is an array of MAS allocation fields (16 bit Zone
+ * bitmap, 16 bit MAS bitmap) as described in [ECMA-368] section
+ * 16.8.6. The output is a full 256 bit MAS bitmap.
+ *
+ * We go over all the allocation fields, for each allocation field we
+ * know which zones are impacted. We iterate over all the zones
+ * impacted and call a function that will set the correct MAS bits in
+ * each zone.
+ */
+void uwb_drp_ie_to_bm(struct uwb_mas_bm *bm, const struct uwb_ie_drp *drp_ie)
+{
+	int numallocs = (drp_ie->hdr.length - 4) / 4;
+	const struct uwb_drp_alloc *alloc;
+	int cnt;
+	u16 zone_bm, mas_bm;
+	u8 zone;
+	u16 zone_mask;
+
+	for (cnt = 0; cnt < numallocs; cnt++) {
+		alloc = &drp_ie->allocs[cnt];
+		zone_bm = le16_to_cpu(alloc->zone_bm);
+		mas_bm = le16_to_cpu(alloc->mas_bm);
+		for (zone = 0; zone < UWB_NUM_ZONES; zone++)   {
+			zone_mask = 1 << zone;
+			if (zone_bm & zone_mask)
+				uwb_drp_ie_single_zone_to_bm(bm, zone, mas_bm);
+		}
+	}
+}