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a899575191
This patch fixes a race condition that caused the HWA_HC interface probe function to occasionally fail. The HWA_HC would attempt to register itself with the HWA_RC by searching for a uwb_rc class device with the same parent device ptr. If the probe function for the HWA_RC interface had yet to run, the uwb_rc class device would not have been created causing the look up to fail and the HWA_HC probe function to return an error causing the device to be unusable. The fix is for the HWA to delay registering with the HWA_RC until receiving the command from userspace to start the wireless channel. It is the responsibility of userspace to ensure that the uwb_rc class device has been created before starting the HWA channel. Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
122 lines
3.1 KiB
C
122 lines
3.1 KiB
C
/*
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* WUSB cluster reservation management
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*
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* Copyright (C) 2007 Cambridge Silicon Radio Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel.h>
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#include <linux/uwb.h>
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#include "wusbhc.h"
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/*
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* WUSB cluster reservations are multicast reservations with the
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* broadcast cluster ID (BCID) as the target DevAddr.
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*
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* FIXME: consider adjusting the reservation depending on what devices
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* are attached.
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*/
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static int wusbhc_bwa_set(struct wusbhc *wusbhc, u8 stream,
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const struct uwb_mas_bm *mas)
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{
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if (mas == NULL)
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mas = &uwb_mas_bm_zero;
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return wusbhc->bwa_set(wusbhc, stream, mas);
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}
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/**
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* wusbhc_rsv_complete_cb - WUSB HC reservation complete callback
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* @rsv: the reservation
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*
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* Either set or clear the HC's view of the reservation.
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*
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* FIXME: when a reservation is denied the HC should be stopped.
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*/
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static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv)
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{
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struct wusbhc *wusbhc = rsv->pal_priv;
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struct device *dev = wusbhc->dev;
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struct uwb_mas_bm mas;
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char buf[72];
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switch (rsv->state) {
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case UWB_RSV_STATE_O_ESTABLISHED:
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uwb_rsv_get_usable_mas(rsv, &mas);
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bitmap_scnprintf(buf, sizeof(buf), mas.bm, UWB_NUM_MAS);
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dev_dbg(dev, "established reservation: %s\n", buf);
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wusbhc_bwa_set(wusbhc, rsv->stream, &mas);
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break;
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case UWB_RSV_STATE_NONE:
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dev_dbg(dev, "removed reservation\n");
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wusbhc_bwa_set(wusbhc, 0, NULL);
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break;
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default:
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dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state);
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break;
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}
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}
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/**
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* wusbhc_rsv_establish - establish a reservation for the cluster
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* @wusbhc: the WUSB HC requesting a bandwidth reservation
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*/
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int wusbhc_rsv_establish(struct wusbhc *wusbhc)
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{
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struct uwb_rc *rc = wusbhc->uwb_rc;
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struct uwb_rsv *rsv;
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struct uwb_dev_addr bcid;
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int ret;
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if (rc == NULL)
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return -ENODEV;
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rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
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if (rsv == NULL)
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return -ENOMEM;
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bcid.data[0] = wusbhc->cluster_id;
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bcid.data[1] = 0;
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rsv->target.type = UWB_RSV_TARGET_DEVADDR;
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rsv->target.devaddr = bcid;
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rsv->type = UWB_DRP_TYPE_PRIVATE;
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rsv->max_mas = 256; /* try to get as much as possible */
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rsv->min_mas = 15; /* one MAS per zone */
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rsv->max_interval = 1; /* max latency is one zone */
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rsv->is_multicast = true;
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ret = uwb_rsv_establish(rsv);
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if (ret == 0)
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wusbhc->rsv = rsv;
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else
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uwb_rsv_destroy(rsv);
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return ret;
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}
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/**
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* wusbhc_rsv_terminate - terminate the cluster reservation
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* @wusbhc: the WUSB host whose reservation is to be terminated
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*/
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void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
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{
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if (wusbhc->rsv) {
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uwb_rsv_terminate(wusbhc->rsv);
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uwb_rsv_destroy(wusbhc->rsv);
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wusbhc->rsv = NULL;
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}
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}
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