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Subject[PATCH v3 02/18] wcn36xx: Pad TIM PVM if needed
Date
From: Pontus Fuchs <pontus.fuchs@gmail.com>

The wcn36xx FW expects a fixed size TIM PVM in the beacon template. If
supplied with a shorter than expected PVM it will overwrite the IE
following the TIM.

Squashed with fix from Jason Mobarak <jam@cozybit.com>:
Patch "wcn36xx: Pad TIM PVM if needed" has caused a regression in mesh
beaconing. The field tim_off is always 0 for mesh mode, and thus
pvm_len (referring to the TIM length field) and pad are both incorrectly
calculated. Thus, msg_body.beacon_length is incorrectly calculated for
mesh mode. Fix this.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: Jason Mobarak <jam@cozybit.com>
[bjorn: squashed in Jason's fixup]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v1:
- Merged in Jason's patch for skipping the padding in mesh mode.

drivers/net/wireless/ath/wcn36xx/hal.h | 3 +++
drivers/net/wireless/ath/wcn36xx/smd.c | 27 +++++++++++++++++++++++++--
2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/hal.h b/drivers/net/wireless/ath/wcn36xx/hal.h
index d713204f755d..3af16cba3d12 100644
--- a/drivers/net/wireless/ath/wcn36xx/hal.h
+++ b/drivers/net/wireless/ath/wcn36xx/hal.h
@@ -54,6 +54,9 @@
/* Default Beacon template size */
#define BEACON_TEMPLATE_SIZE 0x180

+/* Minimum PVM size that the FW expects. See comment in smd.c for details. */
+#define TIM_MIN_PVM_SIZE 6
+
/* Param Change Bitmap sent to HAL */
#define PARAM_BCN_INTERVAL_CHANGED (1 << 0)
#define PARAM_SHORT_PREAMBLE_CHANGED (1 << 1)
diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index ff3ed2461a69..089a7e445cd6 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -1375,12 +1375,19 @@ int wcn36xx_smd_send_beacon(struct wcn36xx *wcn, struct ieee80211_vif *vif,
u16 p2p_off)
{
struct wcn36xx_hal_send_beacon_req_msg msg_body;
- int ret = 0;
+ int ret = 0, pad, pvm_len;

mutex_lock(&wcn->hal_mutex);
INIT_HAL_MSG(msg_body, WCN36XX_HAL_SEND_BEACON_REQ);

- msg_body.beacon_length = skb_beacon->len;
+ pvm_len = skb_beacon->data[tim_off + 1] - 3;
+ pad = TIM_MIN_PVM_SIZE - pvm_len;
+
+ /* Padding is irrelevant to mesh mode since tim_off is always 0. */
+ if (vif->type == NL80211_IFTYPE_MESH_POINT)
+ pad = 0;
+
+ msg_body.beacon_length = skb_beacon->len + pad;
/* TODO need to find out why + 6 is needed */
msg_body.beacon_length6 = msg_body.beacon_length + 6;

@@ -1393,6 +1400,22 @@ int wcn36xx_smd_send_beacon(struct wcn36xx *wcn, struct ieee80211_vif *vif,
memcpy(msg_body.beacon, skb_beacon->data, skb_beacon->len);
memcpy(msg_body.bssid, vif->addr, ETH_ALEN);

+ if (pad > 0) {
+ /*
+ * The wcn36xx FW has a fixed size for the PVM in the TIM. If
+ * given the beacon template from mac80211 with a PVM shorter
+ * than the FW expectes it will overwrite the data after the
+ * TIM.
+ */
+ wcn36xx_dbg(WCN36XX_DBG_HAL, "Pad TIM PVM. %d bytes at %d\n",
+ pad, pvm_len);
+ memmove(&msg_body.beacon[tim_off + 5 + pvm_len + pad],
+ &msg_body.beacon[tim_off + 5 + pvm_len],
+ skb_beacon->len - (tim_off + 5 + pvm_len));
+ memset(&msg_body.beacon[tim_off + 5 + pvm_len], 0, pad);
+ msg_body.beacon[tim_off + 1] += pad;
+ }
+
/* TODO need to find out why this is needed? */
if (vif->type == NL80211_IFTYPE_MESH_POINT)
/* mesh beacon don't need this, so push further down */
--
2.5.0
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