forked from Minki/linux
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>
315 lines
8.3 KiB
C
315 lines
8.3 KiB
C
/*
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* WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
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* MMC (Microscheduled Management Command) handling
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*
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* Copyright (C) 2005-2006 Intel Corporation
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* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
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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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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*
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* WUIEs and MMC IEs...well, they are almost the same at the end. MMC
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* IEs are Wireless USB IEs that go into the MMC period...[what is
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* that? look in Design-overview.txt].
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*
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*
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* This is a simple subsystem to keep track of which IEs are being
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* sent by the host in the MMC period.
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*
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* For each WUIE we ask to send, we keep it in an array, so we can
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* request its removal later, or replace the content. They are tracked
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* by pointer, so be sure to use the same pointer if you want to
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* remove it or update the contents.
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*
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* FIXME:
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* - add timers that autoremove intervalled IEs?
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*/
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#include <linux/usb/wusb.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include "wusbhc.h"
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/* Initialize the MMCIEs handling mechanism */
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int wusbhc_mmcie_create(struct wusbhc *wusbhc)
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{
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u8 mmcies = wusbhc->mmcies_max;
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wusbhc->mmcie = kcalloc(mmcies, sizeof(wusbhc->mmcie[0]), GFP_KERNEL);
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if (wusbhc->mmcie == NULL)
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return -ENOMEM;
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mutex_init(&wusbhc->mmcie_mutex);
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return 0;
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}
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/* Release resources used by the MMCIEs handling mechanism */
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void wusbhc_mmcie_destroy(struct wusbhc *wusbhc)
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{
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kfree(wusbhc->mmcie);
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}
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/*
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* Add or replace an MMC Wireless USB IE.
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*
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* @interval: See WUSB1.0[8.5.3.1]
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* @repeat_cnt: See WUSB1.0[8.5.3.1]
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* @handle: See WUSB1.0[8.5.3.1]
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* @wuie: Pointer to the header of the WUSB IE data to add.
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* MUST BE allocated in a kmalloc buffer (no stack or
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* vmalloc).
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* THE CALLER ALWAYS OWNS THE POINTER (we don't free it
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* on remove, we just forget about it).
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* @returns: 0 if ok, < 0 errno code on error.
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*
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* Goes over the *whole* @wusbhc->mmcie array looking for (a) the
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* first free spot and (b) if @wuie is already in the array (aka:
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* transmitted in the MMCs) the spot were it is.
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*
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* If present, we "overwrite it" (update).
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*
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*
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* NOTE: Need special ordering rules -- see below WUSB1.0 Table 7-38.
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* The host uses the handle as the 'sort' index. We
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* allocate the last one always for the WUIE_ID_HOST_INFO, and
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* the rest, first come first serve in inverse order.
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*
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* Host software must make sure that it adds the other IEs in
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* the right order... the host hardware is responsible for
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* placing the WCTA IEs in the right place with the other IEs
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* set by host software.
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*
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* NOTE: we can access wusbhc->wa_descr without locking because it is
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* read only.
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*/
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int wusbhc_mmcie_set(struct wusbhc *wusbhc, u8 interval, u8 repeat_cnt,
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struct wuie_hdr *wuie)
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{
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int result = -ENOBUFS;
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unsigned handle, itr;
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/* Search a handle, taking into account the ordering */
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mutex_lock(&wusbhc->mmcie_mutex);
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switch (wuie->bIEIdentifier) {
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case WUIE_ID_HOST_INFO:
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/* Always last */
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handle = wusbhc->mmcies_max - 1;
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break;
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case WUIE_ID_ISOCH_DISCARD:
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dev_err(wusbhc->dev, "Special ordering case for WUIE ID 0x%x "
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"unimplemented\n", wuie->bIEIdentifier);
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result = -ENOSYS;
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goto error_unlock;
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default:
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/* search for it or find the last empty slot */
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handle = ~0;
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for (itr = 0; itr < wusbhc->mmcies_max - 1; itr++) {
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if (wusbhc->mmcie[itr] == wuie) {
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handle = itr;
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break;
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}
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if (wusbhc->mmcie[itr] == NULL)
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handle = itr;
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}
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if (handle == ~0)
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goto error_unlock;
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}
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result = (wusbhc->mmcie_add)(wusbhc, interval, repeat_cnt, handle,
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wuie);
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if (result >= 0)
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wusbhc->mmcie[handle] = wuie;
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error_unlock:
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mutex_unlock(&wusbhc->mmcie_mutex);
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return result;
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}
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EXPORT_SYMBOL_GPL(wusbhc_mmcie_set);
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/*
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* Remove an MMC IE previously added with wusbhc_mmcie_set()
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*
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* @wuie Pointer used to add the WUIE
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*/
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void wusbhc_mmcie_rm(struct wusbhc *wusbhc, struct wuie_hdr *wuie)
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{
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int result;
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unsigned handle, itr;
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mutex_lock(&wusbhc->mmcie_mutex);
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for (itr = 0; itr < wusbhc->mmcies_max; itr++) {
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if (wusbhc->mmcie[itr] == wuie) {
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handle = itr;
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goto found;
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}
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}
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mutex_unlock(&wusbhc->mmcie_mutex);
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return;
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found:
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result = (wusbhc->mmcie_rm)(wusbhc, handle);
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if (result == 0)
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wusbhc->mmcie[itr] = NULL;
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mutex_unlock(&wusbhc->mmcie_mutex);
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}
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EXPORT_SYMBOL_GPL(wusbhc_mmcie_rm);
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static int wusbhc_mmc_start(struct wusbhc *wusbhc)
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{
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int ret;
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mutex_lock(&wusbhc->mutex);
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ret = wusbhc->start(wusbhc);
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if (ret >= 0)
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wusbhc->active = 1;
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mutex_unlock(&wusbhc->mutex);
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return ret;
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}
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static void wusbhc_mmc_stop(struct wusbhc *wusbhc)
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{
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mutex_lock(&wusbhc->mutex);
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wusbhc->active = 0;
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wusbhc->stop(wusbhc, WUSB_CHANNEL_STOP_DELAY_MS);
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mutex_unlock(&wusbhc->mutex);
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}
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/*
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* wusbhc_start - start transmitting MMCs and accepting connections
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* @wusbhc: the HC to start
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*
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* Establishes a cluster reservation, enables device connections, and
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* starts MMCs with appropriate DNTS parameters.
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*/
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int wusbhc_start(struct wusbhc *wusbhc)
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{
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int result;
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struct device *dev = wusbhc->dev;
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WARN_ON(wusbhc->wuie_host_info != NULL);
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BUG_ON(wusbhc->uwb_rc == NULL);
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result = wusbhc_rsv_establish(wusbhc);
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if (result < 0) {
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dev_err(dev, "cannot establish cluster reservation: %d\n",
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result);
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goto error_rsv_establish;
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}
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result = wusbhc_devconnect_start(wusbhc);
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if (result < 0) {
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dev_err(dev, "error enabling device connections: %d\n", result);
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goto error_devconnect_start;
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}
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result = wusbhc_sec_start(wusbhc);
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if (result < 0) {
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dev_err(dev, "error starting security in the HC: %d\n", result);
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goto error_sec_start;
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}
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result = wusbhc->set_num_dnts(wusbhc, wusbhc->dnts_interval,
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wusbhc->dnts_num_slots);
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if (result < 0) {
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dev_err(dev, "Cannot set DNTS parameters: %d\n", result);
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goto error_set_num_dnts;
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}
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result = wusbhc_mmc_start(wusbhc);
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if (result < 0) {
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dev_err(dev, "error starting wusbch: %d\n", result);
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goto error_wusbhc_start;
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}
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return 0;
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error_wusbhc_start:
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wusbhc_sec_stop(wusbhc);
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error_set_num_dnts:
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error_sec_start:
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wusbhc_devconnect_stop(wusbhc);
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error_devconnect_start:
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wusbhc_rsv_terminate(wusbhc);
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error_rsv_establish:
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return result;
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}
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/*
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* wusbhc_stop - stop transmitting MMCs
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* @wusbhc: the HC to stop
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*
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* Stops the WUSB channel and removes the cluster reservation.
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*/
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void wusbhc_stop(struct wusbhc *wusbhc)
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{
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wusbhc_mmc_stop(wusbhc);
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wusbhc_sec_stop(wusbhc);
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wusbhc_devconnect_stop(wusbhc);
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wusbhc_rsv_terminate(wusbhc);
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}
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/*
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* Set/reset/update a new CHID
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*
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* Depending on the previous state of the MMCs, start, stop or change
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* the sent MMC. This effectively switches the host controller on and
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* off (radio wise).
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*/
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int wusbhc_chid_set(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid)
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{
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int result = 0;
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if (memcmp(chid, &wusb_ckhdid_zero, sizeof(*chid)) == 0)
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chid = NULL;
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mutex_lock(&wusbhc->mutex);
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if (chid) {
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if (wusbhc->active) {
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mutex_unlock(&wusbhc->mutex);
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return -EBUSY;
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}
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wusbhc->chid = *chid;
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}
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/* register with UWB if we haven't already since we are about to start
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the radio. */
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if ((chid) && (wusbhc->uwb_rc == NULL)) {
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wusbhc->uwb_rc = uwb_rc_get_by_grandpa(wusbhc->dev->parent);
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if (wusbhc->uwb_rc == NULL) {
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result = -ENODEV;
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dev_err(wusbhc->dev, "Cannot get associated UWB Host Controller\n");
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goto error_rc_get;
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}
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result = wusbhc_pal_register(wusbhc);
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if (result < 0) {
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dev_err(wusbhc->dev, "Cannot register as a UWB PAL\n");
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goto error_pal_register;
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}
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}
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mutex_unlock(&wusbhc->mutex);
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if (chid)
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result = uwb_radio_start(&wusbhc->pal);
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else
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uwb_radio_stop(&wusbhc->pal);
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return result;
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error_pal_register:
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uwb_rc_put(wusbhc->uwb_rc);
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wusbhc->uwb_rc = NULL;
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error_rc_get:
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mutex_unlock(&wusbhc->mutex);
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return result;
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}
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EXPORT_SYMBOL_GPL(wusbhc_chid_set);
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