uwb: add the UWB stack (reservation manager)

DRP and reservation management.

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

1 files changed, 461 insertions, 0 deletions

diff --git a/drivers/uwb/drp.c b/drivers/uwb/drp.c
new file mode 100644
index 0000000..c0b1e5e
--- /dev/null
+++ b/drivers/uwb/drp.c
@@ -0,0 +1,461 @@
+/*
+ * Ultra Wide Band
+ * Dynamic Reservation Protocol handling
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@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/>.
+ */
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/delay.h>
+#include "uwb-internal.h"
+
+/**
+ * Construct and send the SET DRP IE
+ *
+ * @rc:         UWB Host controller
+ * @returns:    >= 0 number of bytes still available in the beacon
+ *              < 0 errno code on error.
+ *
+ * See WUSB[8.6.2.7]: The host must set all the DRP IEs that it wants the
+ * device to include in its beacon at the same time. We thus have to
+ * traverse all reservations and include the DRP IEs of all PENDING
+ * and NEGOTIATED reservations in a SET DRP command for transmission.
+ *
+ * A DRP Availability IE is appended.
+ *
+ * rc->uwb_dev.mutex is held
+ *
+ * FIXME We currently ignore the returned value indicating the remaining space
+ * in beacon. This could be used to deny reservation requests earlier if
+ * determined that they would cause the beacon space to be exceeded.
+ */
+static
+int uwb_rc_gen_send_drp_ie(struct uwb_rc *rc)
+{
+	int result;
+	struct device *dev = &rc->uwb_dev.dev;
+	struct uwb_rc_cmd_set_drp_ie *cmd;
+	struct uwb_rc_evt_set_drp_ie reply;
+	struct uwb_rsv *rsv;
+	int num_bytes = 0;
+	u8 *IEDataptr;
+
+	result = -ENOMEM;
+	/* First traverse all reservations to determine memory needed. */
+	list_for_each_entry(rsv, &rc->reservations, rc_node) {
+		if (rsv->drp_ie != NULL)
+			num_bytes += rsv->drp_ie->hdr.length + 2;
+	}
+	num_bytes += sizeof(rc->drp_avail.ie);
+	cmd = kzalloc(sizeof(*cmd) + num_bytes, GFP_KERNEL);
+	if (cmd == NULL)
+		goto error;
+	cmd->rccb.bCommandType = UWB_RC_CET_GENERAL;
+	cmd->rccb.wCommand = cpu_to_le16(UWB_RC_CMD_SET_DRP_IE);
+	cmd->wIELength = num_bytes;
+	IEDataptr = (u8 *)&cmd->IEData[0];
+
+	/* Next traverse all reservations to place IEs in allocated memory. */
+	list_for_each_entry(rsv, &rc->reservations, rc_node) {
+		if (rsv->drp_ie != NULL) {
+			memcpy(IEDataptr, rsv->drp_ie,
+			       rsv->drp_ie->hdr.length + 2);
+			IEDataptr += rsv->drp_ie->hdr.length + 2;
+		}
+	}
+	memcpy(IEDataptr, &rc->drp_avail.ie, sizeof(rc->drp_avail.ie));
+
+	reply.rceb.bEventType = UWB_RC_CET_GENERAL;
+	reply.rceb.wEvent = UWB_RC_CMD_SET_DRP_IE;
+	result = uwb_rc_cmd(rc, "SET-DRP-IE", &cmd->rccb,
+			sizeof(*cmd) + num_bytes, &reply.rceb,
+			sizeof(reply));
+	if (result < 0)
+		goto error_cmd;
+	result = le16_to_cpu(reply.wRemainingSpace);
+	if (reply.bResultCode != UWB_RC_RES_SUCCESS) {
+		dev_err(&rc->uwb_dev.dev, "SET-DRP-IE: command execution "
+				"failed: %s (%d). RemainingSpace in beacon "
+				"= %d\n", uwb_rc_strerror(reply.bResultCode),
+				reply.bResultCode, result);
+		result = -EIO;
+	} else {
+		dev_dbg(dev, "SET-DRP-IE sent. RemainingSpace in beacon "
+			     "= %d.\n", result);
+		result = 0;
+	}
+error_cmd:
+	kfree(cmd);
+error:
+	return result;
+
+}
+/**
+ * Send all DRP IEs associated with this host
+ *
+ * @returns:    >= 0 number of bytes still available in the beacon
+ *              < 0 errno code on error.
+ *
+ * As per the protocol we obtain the host controller device lock to access
+ * bandwidth structures.
+ */
+int uwb_rc_send_all_drp_ie(struct uwb_rc *rc)
+{
+	int result;
+
+	mutex_lock(&rc->uwb_dev.mutex);
+	result = uwb_rc_gen_send_drp_ie(rc);
+	mutex_unlock(&rc->uwb_dev.mutex);
+	return result;
+}
+
+void uwb_drp_handle_timeout(struct uwb_rsv *rsv)
+{
+	struct device *dev = &rsv->rc->uwb_dev.dev;
+
+	dev_dbg(dev, "reservation timeout in state %s (%d)\n",
+		uwb_rsv_state_str(rsv->state), rsv->state);
+
+	switch (rsv->state) {
+	case UWB_RSV_STATE_O_INITIATED:
+		if (rsv->is_multicast) {
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_ESTABLISHED);
+			return;
+		}
+		break;
+	case UWB_RSV_STATE_O_ESTABLISHED:
+		if (rsv->is_multicast)
+			return;
+		break;
+	default:
+		break;
+	}
+	uwb_rsv_remove(rsv);
+}
+
+/*
+ * Based on the DRP IE, transition a target reservation to a new
+ * state.
+ */
+static void uwb_drp_process_target(struct uwb_rc *rc, struct uwb_rsv *rsv,
+				   struct uwb_ie_drp *drp_ie)
+{
+	struct device *dev = &rc->uwb_dev.dev;
+	int status;
+	enum uwb_drp_reason reason_code;
+
+	status = uwb_ie_drp_status(drp_ie);
+	reason_code = uwb_ie_drp_reason_code(drp_ie);
+
+	if (status) {
+		switch (reason_code) {
+		case UWB_DRP_REASON_ACCEPTED:
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_ACCEPTED);
+			break;
+		case UWB_DRP_REASON_MODIFIED:
+			dev_err(dev, "FIXME: unhandled reason code (%d/%d)\n",
+				reason_code, status);
+			break;
+		default:
+			dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
+				 reason_code, status);
+		}
+	} else {
+		switch (reason_code) {
+		case UWB_DRP_REASON_ACCEPTED:
+			/* New reservations are handled in uwb_rsv_find(). */
+			break;
+		case UWB_DRP_REASON_DENIED:
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
+			break;
+		case UWB_DRP_REASON_CONFLICT:
+		case UWB_DRP_REASON_MODIFIED:
+			dev_err(dev, "FIXME: unhandled reason code (%d/%d)\n",
+				reason_code, status);
+			break;
+		default:
+			dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
+				 reason_code, status);
+		}
+	}
+}
+
+/*
+ * Based on the DRP IE, transition an owner reservation to a new
+ * state.
+ */
+static void uwb_drp_process_owner(struct uwb_rc *rc, struct uwb_rsv *rsv,
+				  struct uwb_ie_drp *drp_ie)
+{
+	struct device *dev = &rc->uwb_dev.dev;
+	int status;
+	enum uwb_drp_reason reason_code;
+
+	status = uwb_ie_drp_status(drp_ie);
+	reason_code = uwb_ie_drp_reason_code(drp_ie);
+
+	if (status) {
+		switch (reason_code) {
+		case UWB_DRP_REASON_ACCEPTED:
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_ESTABLISHED);
+			break;
+		case UWB_DRP_REASON_MODIFIED:
+			dev_err(dev, "FIXME: unhandled reason code (%d/%d)\n",
+				reason_code, status);
+			break;
+		default:
+			dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
+				 reason_code, status);
+		}
+	} else {
+		switch (reason_code) {
+		case UWB_DRP_REASON_PENDING:
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_PENDING);
+			break;
+		case UWB_DRP_REASON_DENIED:
+			uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
+			break;
+		case UWB_DRP_REASON_CONFLICT:
+		case UWB_DRP_REASON_MODIFIED:
+			dev_err(dev, "FIXME: unhandled reason code (%d/%d)\n",
+				reason_code, status);
+			break;
+		default:
+			dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
+				 reason_code, status);
+		}
+	}
+}
+
+/*
+ * Process a received DRP IE, it's either for a reservation owned by
+ * the RC or targeted at it (or it's for a WUSB cluster reservation).
+ */
+static void uwb_drp_process(struct uwb_rc *rc, struct uwb_dev *src,
+		     struct uwb_ie_drp *drp_ie)
+{
+	struct uwb_rsv *rsv;
+
+	rsv = uwb_rsv_find(rc, src, drp_ie);
+	if (!rsv) {
+		/*
+		 * No reservation? It's either for a recently
+		 * terminated reservation; or the DRP IE couldn't be
+		 * processed (e.g., an invalid IE or out of memory).
+		 */
+		return;
+	}
+
+	/*
+	 * Do nothing with DRP IEs for reservations that have been
+	 * terminated.
+	 */
+	if (rsv->state == UWB_RSV_STATE_NONE) {
+		uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
+		return;
+	}
+
+	if (uwb_ie_drp_owner(drp_ie))
+		uwb_drp_process_target(rc, rsv, drp_ie);
+	else
+		uwb_drp_process_owner(rc, rsv, drp_ie);
+}
+
+
+/*
+ * Process all the DRP IEs (both DRP IEs and the DRP Availability IE)
+ * from a device.
+ */
+static
+void uwb_drp_process_all(struct uwb_rc *rc, struct uwb_rc_evt_drp *drp_evt,
+			 size_t ielen, struct uwb_dev *src_dev)
+{
+	struct device *dev = &rc->uwb_dev.dev;
+	struct uwb_ie_hdr *ie_hdr;
+	void *ptr;
+
+	ptr = drp_evt->ie_data;
+	for (;;) {
+		ie_hdr = uwb_ie_next(&ptr, &ielen);
+		if (!ie_hdr)
+			break;
+
+		switch (ie_hdr->element_id) {
+		case UWB_IE_DRP_AVAILABILITY:
+			/* FIXME: does something need to be done with this? */
+			break;
+		case UWB_IE_DRP:
+			uwb_drp_process(rc, src_dev, (struct uwb_ie_drp *)ie_hdr);
+			break;
+		default:
+			dev_warn(dev, "unexpected IE in DRP notification\n");
+			break;
+		}
+	}
+
+	if (ielen > 0)
+		dev_warn(dev, "%d octets remaining in DRP notification\n",
+			 (int)ielen);
+}
+
+
+/*
+ * Go through all the DRP IEs and find the ones that conflict with our
+ * reservations.
+ *
+ * FIXME: must resolve the conflict according the the rules in
+ * [ECMA-368].
+ */
+static
+void uwb_drp_process_conflict_all(struct uwb_rc *rc, struct uwb_rc_evt_drp *drp_evt,
+				  size_t ielen, struct uwb_dev *src_dev)
+{
+	struct device *dev = &rc->uwb_dev.dev;
+	struct uwb_ie_hdr *ie_hdr;
+	struct uwb_ie_drp *drp_ie;
+	void *ptr;
+
+	ptr = drp_evt->ie_data;
+	for (;;) {
+		ie_hdr = uwb_ie_next(&ptr, &ielen);
+		if (!ie_hdr)
+			break;
+
+		drp_ie = container_of(ie_hdr, struct uwb_ie_drp, hdr);
+
+		/* FIXME: check if this DRP IE conflicts. */
+	}
+
+	if (ielen > 0)
+		dev_warn(dev, "%d octets remaining in DRP notification\n",
+			 (int)ielen);
+}
+
+
+/*
+ * Terminate all reservations owned by, or targeted at, 'uwb_dev'.
+ */
+static void uwb_drp_terminate_all(struct uwb_rc *rc, struct uwb_dev *uwb_dev)
+{
+	struct uwb_rsv *rsv;
+
+	list_for_each_entry(rsv, &rc->reservations, rc_node) {
+		if (rsv->owner == uwb_dev
+		    || (rsv->target.type == UWB_RSV_TARGET_DEV && rsv->target.dev == uwb_dev))
+			uwb_rsv_remove(rsv);
+	}
+}
+
+
+/**
+ * uwbd_evt_handle_rc_drp - handle a DRP_IE event
+ * @evt: the DRP_IE event from the radio controller
+ *
+ * This processes DRP notifications from the radio controller, either
+ * initiating a new reservation or transitioning an existing
+ * reservation into a different state.
+ *
+ * DRP notifications can occur for three different reasons:
+ *
+ * - UWB_DRP_NOTIF_DRP_IE_RECVD: one or more DRP IEs with the RC as
+ *   the target or source have been recieved.
+ *
+ *   These DRP IEs could be new or for an existing reservation.
+ *
+ *   If the DRP IE for an existing reservation ceases to be to
+ *   recieved for at least mMaxLostBeacons, the reservation should be
+ *   considered to be terminated.  Note that the TERMINATE reason (see
+ *   below) may not always be signalled (e.g., the remote device has
+ *   two or more reservations established with the RC).
+ *
+ * - UWB_DRP_NOTIF_CONFLICT: DRP IEs from any device in the beacon
+ *   group conflict with the RC's reservations.
+ *
+ * - UWB_DRP_NOTIF_TERMINATE: DRP IEs are no longer being received
+ *   from a device (i.e., it's terminated all reservations).
+ *
+ * Only the software state of the reservations is changed; the setting
+ * of the radio controller's DRP IEs is done after all the events in
+ * an event buffer are processed.  This saves waiting multiple times
+ * for the SET_DRP_IE command to complete.
+ */
+int uwbd_evt_handle_rc_drp(struct uwb_event *evt)
+{
+	struct device *dev = &evt->rc->uwb_dev.dev;
+	struct uwb_rc *rc = evt->rc;
+	struct uwb_rc_evt_drp *drp_evt;
+	size_t ielength, bytes_left;
+	struct uwb_dev_addr src_addr;
+	struct uwb_dev *src_dev;
+	int reason;
+
+	/* Is there enough data to decode the event (and any IEs in
+	   its payload)? */
+	if (evt->notif.size < sizeof(*drp_evt)) {
+		dev_err(dev, "DRP event: Not enough data to decode event "
+			"[%zu bytes left, %zu needed]\n",
+			evt->notif.size, sizeof(*drp_evt));
+		return 0;
+	}
+	bytes_left = evt->notif.size - sizeof(*drp_evt);
+	drp_evt = container_of(evt->notif.rceb, struct uwb_rc_evt_drp, rceb);
+	ielength = le16_to_cpu(drp_evt->ie_length);
+	if (bytes_left != ielength) {
+		dev_err(dev, "DRP event: Not enough data in payload [%zu"
+			"bytes left, %zu declared in the event]\n",
+			bytes_left, ielength);
+		return 0;
+	}
+
+	memcpy(src_addr.data, &drp_evt->src_addr, sizeof(src_addr));
+	src_dev = uwb_dev_get_by_devaddr(rc, &src_addr);
+	if (!src_dev) {
+		/*
+		 * A DRP notification from an unrecognized device.
+		 *
+		 * This is probably from a WUSB device that doesn't
+		 * have an EUI-48 and therefore doesn't show up in the
+		 * UWB device database.  It's safe to simply ignore
+		 * these.
+		 */
+		return 0;
+	}
+
+	mutex_lock(&rc->rsvs_mutex);
+
+	reason = uwb_rc_evt_drp_reason(drp_evt);
+
+	switch (reason) {
+	case UWB_DRP_NOTIF_DRP_IE_RCVD:
+		uwb_drp_process_all(rc, drp_evt, ielength, src_dev);
+		break;
+	case UWB_DRP_NOTIF_CONFLICT:
+		uwb_drp_process_conflict_all(rc, drp_evt, ielength, src_dev);
+		break;
+	case UWB_DRP_NOTIF_TERMINATE:
+		uwb_drp_terminate_all(rc, src_dev);
+		break;
+	default:
+		dev_warn(dev, "ignored DRP event with reason code: %d\n", reason);
+		break;
+	}
+
+	mutex_unlock(&rc->rsvs_mutex);
+
+	uwb_dev_put(src_dev);
+	return 0;
+}