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 000000000000..c0b1e5e2bd08
--- /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;
+}