USB: HWA: fix device probe failure
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>
diff --git a/drivers/usb/wusbcore/mmc.c b/drivers/usb/wusbcore/mmc.c
index 021467f..b71760c 100644
--- a/drivers/usb/wusbcore/mmc.c
+++ b/drivers/usb/wusbcore/mmc.c
@@ -195,6 +195,7 @@
struct device *dev = wusbhc->dev;
WARN_ON(wusbhc->wuie_host_info != NULL);
+ BUG_ON(wusbhc->uwb_rc == NULL);
result = wusbhc_rsv_establish(wusbhc);
if (result < 0) {
@@ -276,12 +277,38 @@
}
wusbhc->chid = *chid;
}
+
+ /* register with UWB if we haven't already since we are about to start
+ the radio. */
+ if ((chid) && (wusbhc->uwb_rc == NULL)) {
+ wusbhc->uwb_rc = uwb_rc_get_by_grandpa(wusbhc->dev->parent);
+ if (wusbhc->uwb_rc == NULL) {
+ result = -ENODEV;
+ dev_err(wusbhc->dev, "Cannot get associated UWB Host Controller\n");
+ goto error_rc_get;
+ }
+
+ result = wusbhc_pal_register(wusbhc);
+ if (result < 0) {
+ dev_err(wusbhc->dev, "Cannot register as a UWB PAL\n");
+ goto error_pal_register;
+ }
+ }
mutex_unlock(&wusbhc->mutex);
if (chid)
result = uwb_radio_start(&wusbhc->pal);
else
uwb_radio_stop(&wusbhc->pal);
+
+ return result;
+
+error_pal_register:
+ uwb_rc_put(wusbhc->uwb_rc);
+ wusbhc->uwb_rc = NULL;
+error_rc_get:
+ mutex_unlock(&wusbhc->mutex);
+
return result;
}
EXPORT_SYMBOL_GPL(wusbhc_chid_set);