[PATCH v6 0/5] mt76: channel switch support for USB devices

[PATCH v6 0/5] mt76: channel switch support for USB devices

[Markus Theil]

This patch series adds channel switch support for mt76 usb interfaces.
When testing, I noticed that between 5 or 7 consecutive beacons had the
identical channel switch count set. After some debugging I found out,
that beacon copying over usb took far too long (up to 700ms for one call
of mt76x02u_pre_tbtt_work).

Therefore the first four patches speed up beacon copying and the last
patch enables channel switch support also for usb interfaces.

v6:
* use min_t in mt76u_copy
* use round_up in mt76u_copy
* use additional copy for mmio beacon set again

v5 (thanks to Stanislaw):
* ommit empty mt76x2u_channel_switch_beacon
* copy txwi into beacon skb

v4:
* use multiple of 4 len for usb copy again

v3:
* fixed checkpatch errors

v2 (thanks for the comments Lorenzo):
* correctly track beacon data mask
* clean-ups
* make channel switch fn static (reported by kbuild test robot)

Markus Theil (5):
  mt76: mt76x02: ommit beacon slot clearing
  mt76: mt76x02: split beaconing
  mt76: mt76x02: remove a copy call for usb speedup
  mt76: speed up usb bulk copy
  mt76: mt76x02: add channel switch support for usb interfaces

 drivers/net/wireless/mediatek/mt76/mt76.h     |  2 +-
 .../wireless/mediatek/mt76/mt76x02_beacon.c   | 72 ++++++++-----------
 .../net/wireless/mediatek/mt76/mt76x02_mac.h  |  1 +
 .../net/wireless/mediatek/mt76/mt76x02_mmio.c |  5 ++
 .../wireless/mediatek/mt76/mt76x02_usb_core.c | 12 ++++
 .../net/wireless/mediatek/mt76/mt76x02_util.c |  2 +-
 drivers/net/wireless/mediatek/mt76/usb.c      | 24 +++++--
 7 files changed, 69 insertions(+), 49 deletions(-)

-- 
2.24.0

[PATCH v6 1/5] mt76: mt76x02: ommit beacon slot clearing

[Markus Theil]

mt76 hw does not send beacons from beacon slots, if the corresponding
bitmask is set accordingly. Therefore we can ommit clearing the beacon
memory. Clearing uses many usb calls, if usb drivers are used. These
calls unnecessarily slow down the beacon tasklet. Thanks to Stanislaw
Gruzska for pointing this out.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
index 4209209ac940..403866496640 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
@@ -58,8 +58,6 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
 			dev->beacon_data_mask |= BIT(bcn_idx);
 	} else {
 		dev->beacon_data_mask &= ~BIT(bcn_idx);
-		for (i = 0; i < beacon_len; i += 4)
-			mt76_wr(dev, beacon_addr + i, 0);
 	}
 
 	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
@@ -241,17 +239,11 @@ EXPORT_SYMBOL_GPL(mt76x02_enqueue_buffered_bc);
 
 void mt76x02_init_beacon_config(struct mt76x02_dev *dev)
 {
-	int i;
-
 	mt76_clear(dev, MT_BEACON_TIME_CFG, (MT_BEACON_TIME_CFG_TIMER_EN |
 					     MT_BEACON_TIME_CFG_TBTT_EN |
 					     MT_BEACON_TIME_CFG_BEACON_TX));
 	mt76_set(dev, MT_BEACON_TIME_CFG, MT_BEACON_TIME_CFG_SYNC_MODE);
 	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xffff);
-
-	for (i = 0; i < 8; i++)
-		mt76x02_mac_set_beacon(dev, i, NULL);
-
 	mt76x02_set_beacon_offsets(dev);
 }
 EXPORT_SYMBOL_GPL(mt76x02_init_beacon_config);
-- 
2.24.0

[PATCH v6 2/5] mt76: mt76x02: split beaconing

[Markus Theil]

Sending beacons to the hardware always happens in batches. In order to
speed up beacon processing on usb devices, this patch splits out common
code an calls it only once (mt76x02_mac_set_beacon_prepare,
mt76x02_mac_set_beacon_finish). Making this split breaks beacon
enabling/disabling per vif. This is fixed by adding a call to set the
bypass mask, if beaconing should be disabled for a vif. Otherwise the
beacon is send after the next beacon interval.

The code is also adapted for the mmio part of the driver, but should not
have any performance implication there.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 .../wireless/mediatek/mt76/mt76x02_beacon.c   | 44 +++++++------------
 .../net/wireless/mediatek/mt76/mt76x02_mac.h  |  1 +
 .../net/wireless/mediatek/mt76/mt76x02_mmio.c |  5 +++
 .../wireless/mediatek/mt76/mt76x02_usb_core.c |  5 +++
 4 files changed, 26 insertions(+), 29 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
index 403866496640..09013adae854 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
@@ -47,10 +47,6 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
 	int beacon_len = dev->beacon_ops->slot_size;
 	int beacon_addr = MT_BEACON_BASE + (beacon_len * bcn_idx);
 	int ret = 0;
-	int i;
-
-	/* Prevent corrupt transmissions during update */
-	mt76_set(dev, MT_BCN_BYPASS_MASK, BIT(bcn_idx));
 
 	if (skb) {
 		ret = mt76x02_write_beacon(dev, beacon_addr, skb);
@@ -60,41 +56,30 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
 		dev->beacon_data_mask &= ~BIT(bcn_idx);
 	}
 
-	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
-
 	return ret;
 }
 
-int mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 vif_idx,
-			   struct sk_buff *skb)
+void mt76x02_mac_set_beacon_finish(struct mt76x02_dev *dev)
 {
-	bool force_update = false;
-	int bcn_idx = 0;
 	int i;
+	int bcn_idx = 0;
 
-	for (i = 0; i < ARRAY_SIZE(dev->beacons); i++) {
-		if (vif_idx == i) {
-			force_update = !!dev->beacons[i] ^ !!skb;
-			dev_kfree_skb(dev->beacons[i]);
-			dev->beacons[i] = skb;
-			__mt76x02_mac_set_beacon(dev, bcn_idx, skb);
-		} else if (force_update && dev->beacons[i]) {
-			__mt76x02_mac_set_beacon(dev, bcn_idx,
-						 dev->beacons[i]);
-		}
-
+	for (i = 0; i < hweight8(dev->mt76.beacon_mask); ++i)
 		bcn_idx += !!dev->beacons[i];
-	}
-
-	for (i = bcn_idx; i < ARRAY_SIZE(dev->beacons); i++) {
-		if (!(dev->beacon_data_mask & BIT(i)))
-			break;
-
-		__mt76x02_mac_set_beacon(dev, i, NULL);
-	}
 
 	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N,
 		       bcn_idx - 1);
+
+	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
+}
+EXPORT_SYMBOL_GPL(mt76x02_mac_set_beacon_finish);
+
+int mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 vif_idx,
+			   struct sk_buff *skb)
+{
+	dev_kfree_skb(dev->beacons[vif_idx]);
+	dev->beacons[vif_idx] = skb;
+	__mt76x02_mac_set_beacon(dev, vif_idx, skb);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mt76x02_mac_set_beacon);
@@ -115,6 +100,7 @@ void mt76x02_mac_set_beacon_enable(struct mt76x02_dev *dev,
 	} else {
 		dev->mt76.beacon_mask &= ~BIT(mvif->idx);
 		mt76x02_mac_set_beacon(dev, mvif->idx, NULL);
+		mt76_set(dev, MT_BCN_BYPASS_MASK, BIT(mvif->idx));
 	}
 
 	if (!!old_mask == !!dev->mt76.beacon_mask)
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.h b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.h
index efa4ef945e35..e6e585c72f0d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.h
@@ -197,6 +197,7 @@ int mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 vif_idx,
 			   struct sk_buff *skb);
 void mt76x02_mac_set_beacon_enable(struct mt76x02_dev *dev,
 				   struct ieee80211_vif *vif, bool enable);
+void mt76x02_mac_set_beacon_finish(struct mt76x02_dev *dev);
 
 void mt76x02_edcca_init(struct mt76x02_dev *dev);
 #endif
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
index dc773070481d..73c39d03b7f8 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
@@ -24,10 +24,15 @@ static void mt76x02_pre_tbtt_tasklet(unsigned long arg)
 
 	mt76x02_resync_beacon_timer(dev);
 
+	/* Prevent corrupt transmissions during update */
+	mt76_set(dev, MT_BCN_BYPASS_MASK, 0xffff);
+
 	ieee80211_iterate_active_interfaces_atomic(mt76_hw(dev),
 		IEEE80211_IFACE_ITER_RESUME_ALL,
 		mt76x02_update_beacon_iter, dev);
 
+	mt76x02_mac_set_beacon_finish(dev);
+
 	mt76_csa_check(&dev->mt76);
 
 	if (dev->mt76.csa_complete)
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
index 78dfc1e7f27b..8a2a90fb5663 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
@@ -179,6 +179,9 @@ static void mt76x02u_pre_tbtt_work(struct work_struct *work)
 
 	mt76x02_resync_beacon_timer(dev);
 
+	/* Prevent corrupt transmissions during update */
+	mt76_set(dev, MT_BCN_BYPASS_MASK, 0xffff);
+
 	ieee80211_iterate_active_interfaces(mt76_hw(dev),
 		IEEE80211_IFACE_ITER_RESUME_ALL,
 		mt76x02_update_beacon_iter, dev);
@@ -191,6 +194,8 @@ static void mt76x02u_pre_tbtt_work(struct work_struct *work)
 		mt76x02_mac_set_beacon(dev, i, skb);
 	}
 
+	mt76x02_mac_set_beacon_finish(dev);
+
 	mt76x02u_restart_pre_tbtt_timer(dev);
 }
 
-- 
2.24.0

[PATCH v6 3/5] mt76: mt76x02: remove a copy call for usb speedup

[Markus Theil]

This patch removes a mt76_wr_copy call from the beacon path to hw.
The skb which is used in this place gets therefore build with txwi
inside its data. For mt76 usb drivers, this saves one synchronuous
copy call over usb, which lets the beacon work complete faster.

In mmio case, there is not enough headroom to put the txwi into the
skb, it is therefore using an additional mt76_wr_copy, which is fast
over mmio. Thanks Stanislaw for pointing this out.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 .../wireless/mediatek/mt76/mt76x02_beacon.c   | 20 +++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
index 09013adae854..422d53111229 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
@@ -26,15 +26,27 @@ static int
 mt76x02_write_beacon(struct mt76x02_dev *dev, int offset, struct sk_buff *skb)
 {
 	int beacon_len = dev->beacon_ops->slot_size;
-	struct mt76x02_txwi txwi;
 
 	if (WARN_ON_ONCE(beacon_len < skb->len + sizeof(struct mt76x02_txwi)))
 		return -ENOSPC;
 
-	mt76x02_mac_write_txwi(dev, &txwi, skb, NULL, NULL, skb->len);
+	/* USB devices already reserve enough skb headroom for txwi's. This
+	 * helps to save slow copies over USB.
+	 */
+	if (mt76_is_usb(dev)) {
+		struct mt76x02_txwi *txwi;
+
+		mt76_insert_hdr_pad(skb);
+		txwi = (struct mt76x02_txwi *)(skb->data - sizeof(*txwi));
+		mt76x02_mac_write_txwi(dev, txwi, skb, NULL, NULL, skb->len);
+		skb_push(skb, sizeof(*txwi));
+	} else {
+		struct mt76x02_txwi txwi;
 
-	mt76_wr_copy(dev, offset, &txwi, sizeof(txwi));
-	offset += sizeof(txwi);
+		mt76x02_mac_write_txwi(dev, &txwi, skb, NULL, NULL, skb->len);
+		mt76_wr_copy(dev, offset, &txwi, sizeof(txwi));
+		offset += sizeof(txwi);
+	}
 
 	mt76_wr_copy(dev, offset, skb->data, skb->len);
 	return 0;
-- 
2.24.0

[PATCH v6 4/5] mt76: speed up usb bulk copy

[Markus Theil]

Use larger batches for usb copy to speed this operation up. Otherwise it
would be too slow for copying new beacons or broadcast frames over usb.
Assure, that always a multiple of 4 Bytes is copied, as outlined in
850e8f6fbd "mt76: round up length on mt76_wr_copy" from Felix Fietkau.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 drivers/net/wireless/mediatek/mt76/mt76.h |  2 +-
 drivers/net/wireless/mediatek/mt76/usb.c  | 24 +++++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 8aec7ccf2d79..7a6f5d097a3d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -383,7 +383,7 @@ enum mt76u_out_ep {
 struct mt76_usb {
 	struct mutex usb_ctrl_mtx;
 	union {
-		u8 data[32];
+		u8 data[128];
 		__le32 reg_val;
 	};
 
diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 20c6fe510e9d..0ad83fb5fd38 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -149,18 +149,30 @@ static void mt76u_copy(struct mt76_dev *dev, u32 offset,
 		       const void *data, int len)
 {
 	struct mt76_usb *usb = &dev->usb;
-	const u32 *val = data;
-	int i, ret;
+	const u8 *val = data;
+	int ret;
+	int current_batch_size;
+	int i = 0;
+
+	/* Assure that always a multiple of 4 bytes are copied,
+	 * otherwise beacons can be corrupted.
+	 * See: "mt76: round up length on mt76_wr_copy"
+	 * Commit 850e8f6fbd5d0003b0
+	 */
+	len = round_up(len, 4);
 
 	mutex_lock(&usb->usb_ctrl_mtx);
-	for (i = 0; i < DIV_ROUND_UP(len, 4); i++) {
-		put_unaligned(val[i], (u32 *)usb->data);
+	while (i < len) {
+		current_batch_size = min_t(int, sizeof(usb->data), len - i);
+		memcpy(usb->data, val + i, current_batch_size);
 		ret = __mt76u_vendor_request(dev, MT_VEND_MULTI_WRITE,
 					     USB_DIR_OUT | USB_TYPE_VENDOR,
-					     0, offset + i * 4, usb->data,
-					     sizeof(u32));
+					     0, offset + i, usb->data,
+					     current_batch_size);
 		if (ret < 0)
 			break;
+
+		i += current_batch_size;
 	}
 	mutex_unlock(&usb->usb_ctrl_mtx);
 }
-- 
2.24.0

[PATCH v6 5/5] mt76: mt76x02: add channel switch support for usb interfaces

[Markus Theil]

This patch enables channel switch support on mt76 usb interfaces.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
---
 drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c | 7 +++++++
 drivers/net/wireless/mediatek/mt76/mt76x02_util.c     | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
index 8a2a90fb5663..891825043117 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_usb_core.c
@@ -182,6 +182,12 @@ static void mt76x02u_pre_tbtt_work(struct work_struct *work)
 	/* Prevent corrupt transmissions during update */
 	mt76_set(dev, MT_BCN_BYPASS_MASK, 0xffff);
 
+	mt76_csa_check(&dev->mt76);
+	if (dev->mt76.csa_complete) {
+		mt76_csa_finish(&dev->mt76);
+		goto out;
+	}
+
 	ieee80211_iterate_active_interfaces(mt76_hw(dev),
 		IEEE80211_IFACE_ITER_RESUME_ALL,
 		mt76x02_update_beacon_iter, dev);
@@ -196,6 +202,7 @@ static void mt76x02u_pre_tbtt_work(struct work_struct *work)
 
 	mt76x02_mac_set_beacon_finish(dev);
 
+out:
 	mt76x02u_restart_pre_tbtt_timer(dev);
 }
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
index 414b22399d93..3f95e5b24e1d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
@@ -174,7 +174,6 @@ void mt76x02_init_device(struct mt76x02_dev *dev)
 		wiphy->reg_notifier = mt76x02_regd_notifier;
 		wiphy->iface_combinations = mt76x02_if_comb;
 		wiphy->n_iface_combinations = ARRAY_SIZE(mt76x02_if_comb);
-		wiphy->flags |= WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 
 		/* init led callbacks */
 		if (IS_ENABLED(CONFIG_MT76_LEDS)) {
@@ -184,6 +183,7 @@ void mt76x02_init_device(struct mt76x02_dev *dev)
 		}
 	}
 
+	wiphy->flags |= WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_VHT_IBSS);
 
 	hw->sta_data_size = sizeof(struct mt76x02_sta);
-- 
2.24.0

Re: [PATCH v6 2/5] mt76: mt76x02: split beaconing

[Stanislaw Gruszka]

On Tue, Nov 19, 2019 at 04:47:43PM +0100, Markus Theil wrote:
> Sending beacons to the hardware always happens in batches. In order to
> speed up beacon processing on usb devices, this patch splits out common
> code an calls it only once (mt76x02_mac_set_beacon_prepare,
> mt76x02_mac_set_beacon_finish). Making this split breaks beacon
> enabling/disabling per vif. This is fixed by adding a call to set the
> bypass mask, if beaconing should be disabled for a vif. Otherwise the
> beacon is send after the next beacon interval.
> 
> The code is also adapted for the mmio part of the driver, but should not
> have any performance implication there.
> 
> Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
> ---
>  .../wireless/mediatek/mt76/mt76x02_beacon.c   | 44 +++++++------------
>  .../net/wireless/mediatek/mt76/mt76x02_mac.h  |  1 +
>  .../net/wireless/mediatek/mt76/mt76x02_mmio.c |  5 +++
>  .../wireless/mediatek/mt76/mt76x02_usb_core.c |  5 +++
>  4 files changed, 26 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> index 403866496640..09013adae854 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
> @@ -47,10 +47,6 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
>  	int beacon_len = dev->beacon_ops->slot_size;
>  	int beacon_addr = MT_BEACON_BASE + (beacon_len * bcn_idx);
>  	int ret = 0;
> -	int i;
> -
> -	/* Prevent corrupt transmissions during update */
> -	mt76_set(dev, MT_BCN_BYPASS_MASK, BIT(bcn_idx));
>  
>  	if (skb) {
>  		ret = mt76x02_write_beacon(dev, beacon_addr, skb);
> @@ -60,41 +56,30 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
>  		dev->beacon_data_mask &= ~BIT(bcn_idx);
>  	}
>  
> -	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
> -
>  	return ret;
>  }
>  
> -int mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 vif_idx,
> -			   struct sk_buff *skb)
> +void mt76x02_mac_set_beacon_finish(struct mt76x02_dev *dev)
>  {
> -	bool force_update = false;
> -	int bcn_idx = 0;
>  	int i;
> +	int bcn_idx = 0;
>  
> -	for (i = 0; i < ARRAY_SIZE(dev->beacons); i++) {
> -		if (vif_idx == i) {
> -			force_update = !!dev->beacons[i] ^ !!skb;
> -			dev_kfree_skb(dev->beacons[i]);
> -			dev->beacons[i] = skb;
> -			__mt76x02_mac_set_beacon(dev, bcn_idx, skb);
> -		} else if (force_update && dev->beacons[i]) {
> -			__mt76x02_mac_set_beacon(dev, bcn_idx,
> -						 dev->beacons[i]);
> -		}
> -
> +	for (i = 0; i < hweight8(dev->mt76.beacon_mask); ++i)
>  		bcn_idx += !!dev->beacons[i];

This looks wrong since we do not calculate all beacons, only 
up to hweight8(dev->mt76.beacon_mask).

But since we need to calculate number of all beacons we can just
use hweight8(dev->mt76.beacon_mask) directly.

> -	}
> -
> -	for (i = bcn_idx; i < ARRAY_SIZE(dev->beacons); i++) {
> -		if (!(dev->beacon_data_mask & BIT(i)))
> -			break;
> -
> -		__mt76x02_mac_set_beacon(dev, i, NULL);
> -	}
>  
>  	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N,
>  		       bcn_idx - 1);
> +
> +	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);

I'm not sure if this is correct for multi bss.

In MT7620 manual BCM_BAYPASS_MASK is described as below:

"
Directly bypasses the Tx Beacon frame with the  specified 
Beacon number. Bit0=Nth Beacon, bit1=(N- 1)th Beacon,... etc.
N is the number of  Beacons defined in the  MULTI_BCN_NUM field in the 
MAC_BSSID_DW1(offset: 0x1014) register.
0: Disable
1: Enable
"

Assuming manual is correct (it could be wrong) bypass mask should be
calculated differently.

Stanislaw

Re: [PATCH v6 2/5] mt76: mt76x02: split beaconing

[Markus Theil]

On 11/20/19 10:28 AM, Stanislaw Gruszka wrote:
> On Tue, Nov 19, 2019 at 04:47:43PM +0100, Markus Theil wrote:
>> Sending beacons to the hardware always happens in batches. In order to
>> speed up beacon processing on usb devices, this patch splits out common
>> code an calls it only once (mt76x02_mac_set_beacon_prepare,
>> mt76x02_mac_set_beacon_finish). Making this split breaks beacon
>> enabling/disabling per vif. This is fixed by adding a call to set the
>> bypass mask, if beaconing should be disabled for a vif. Otherwise the
>> beacon is send after the next beacon interval.
>>
>> The code is also adapted for the mmio part of the driver, but should not
>> have any performance implication there.
>>
>> Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
>> ---
>>  .../wireless/mediatek/mt76/mt76x02_beacon.c   | 44 +++++++------------
>>  .../net/wireless/mediatek/mt76/mt76x02_mac.h  |  1 +
>>  .../net/wireless/mediatek/mt76/mt76x02_mmio.c |  5 +++
>>  .../wireless/mediatek/mt76/mt76x02_usb_core.c |  5 +++
>>  4 files changed, 26 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
>> index 403866496640..09013adae854 100644
>> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
>> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_beacon.c
>> @@ -47,10 +47,6 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
>>  	int beacon_len = dev->beacon_ops->slot_size;
>>  	int beacon_addr = MT_BEACON_BASE + (beacon_len * bcn_idx);
>>  	int ret = 0;
>> -	int i;
>> -
>> -	/* Prevent corrupt transmissions during update */
>> -	mt76_set(dev, MT_BCN_BYPASS_MASK, BIT(bcn_idx));
>>  
>>  	if (skb) {
>>  		ret = mt76x02_write_beacon(dev, beacon_addr, skb);
>> @@ -60,41 +56,30 @@ __mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 bcn_idx,
>>  		dev->beacon_data_mask &= ~BIT(bcn_idx);
>>  	}
>>  
>> -	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
>> -
>>  	return ret;
>>  }
>>  
>> -int mt76x02_mac_set_beacon(struct mt76x02_dev *dev, u8 vif_idx,
>> -			   struct sk_buff *skb)
>> +void mt76x02_mac_set_beacon_finish(struct mt76x02_dev *dev)
>>  {
>> -	bool force_update = false;
>> -	int bcn_idx = 0;
>>  	int i;
>> +	int bcn_idx = 0;
>>  
>> -	for (i = 0; i < ARRAY_SIZE(dev->beacons); i++) {
>> -		if (vif_idx == i) {
>> -			force_update = !!dev->beacons[i] ^ !!skb;
>> -			dev_kfree_skb(dev->beacons[i]);
>> -			dev->beacons[i] = skb;
>> -			__mt76x02_mac_set_beacon(dev, bcn_idx, skb);
>> -		} else if (force_update && dev->beacons[i]) {
>> -			__mt76x02_mac_set_beacon(dev, bcn_idx,
>> -						 dev->beacons[i]);
>> -		}
>> -
>> +	for (i = 0; i < hweight8(dev->mt76.beacon_mask); ++i)
>>  		bcn_idx += !!dev->beacons[i];
> This looks wrong since we do not calculate all beacons, only 
> up to hweight8(dev->mt76.beacon_mask).
>
> But since we need to calculate number of all beacons we can just
> use hweight8(dev->mt76.beacon_mask) directly.

You're right that I made a mistake here. Using
hweight8(dev->mt76.beacon_mask) would be wrong
for usb devices, which may setup buffered broadcast or multicast frames
as additional beacons.
My updated patch therefore uses hweight8(dev->mt76.beacon_data_mask)
directly.

>> -	}
>> -
>> -	for (i = bcn_idx; i < ARRAY_SIZE(dev->beacons); i++) {
>> -		if (!(dev->beacon_data_mask & BIT(i)))
>> -			break;
>> -
>> -		__mt76x02_mac_set_beacon(dev, i, NULL);
>> -	}
>>  
>>  	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N,
>>  		       bcn_idx - 1);
>> +
>> +	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
> I'm not sure if this is correct for multi bss.
>
> In MT7620 manual BCM_BAYPASS_MASK is described as below:
>
> "
> Directly bypasses the Tx Beacon frame with the  specified 
> Beacon number. Bit0=Nth Beacon, bit1=(N- 1)th Beacon,... etc.
> N is the number of  Beacons defined in the  MULTI_BCN_NUM field in the 
> MAC_BSSID_DW1(offset: 0x1014) register.
> 0: Disable
> 1: Enable
> "
>
> Assuming manual is correct (it could be wrong) bypass mask should be
> calculated differently.
>
> Stanislaw
>
I tested the updated code with my usb nic and an mbss with 2 ap vifs.
Both beacons were transmitted. Maybe the manual is wrong in this place.

Markus  

Re: [PATCH v6 2/5] mt76: mt76x02: split beaconing

[Stanislaw Gruszka]

On Wed, Nov 20, 2019 at 11:27:55PM +0100, Markus Theil wrote:
> >> -	}
> >> -
> >> -	for (i = bcn_idx; i < ARRAY_SIZE(dev->beacons); i++) {
> >> -		if (!(dev->beacon_data_mask & BIT(i)))
> >> -			break;
> >> -
> >> -		__mt76x02_mac_set_beacon(dev, i, NULL);
> >> -	}
> >>  
> >>  	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N,
> >>  		       bcn_idx - 1);
> >> +
> >> +	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
> > I'm not sure if this is correct for multi bss.
> >
> > In MT7620 manual BCM_BAYPASS_MASK is described as below:
> >
> > "
> > Directly bypasses the Tx Beacon frame with the  specified 
> > Beacon number. Bit0=Nth Beacon, bit1=(N- 1)th Beacon,... etc.
> > N is the number of  Beacons defined in the  MULTI_BCN_NUM field in the 
> > MAC_BSSID_DW1(offset: 0x1014) register.
> > 0: Disable
> > 1: Enable
> > "
> >
> > Assuming manual is correct (it could be wrong) bypass mask should be
> > calculated differently.
> >
> > Stanislaw
> >
> I tested the updated code with my usb nic and an mbss with 2 ap vifs.
> Both beacons were transmitted. Maybe the manual is wrong in this place.

If MAC_BSSID_DW1_MBEACON_N is set to 1 (2 beacons) according to manual
bit0 is for second beacon slot and bit1 is for first beacon slot.
Those bits are both marked at once, so no problem will happen.

Problem may happen when you remove first vif/beacon. Then you will
have bit1 marked in ->beacon_data_mask . But bit0 will be expect
in BCM_BAYPASS_MASK by hardware (when MAC_BSSID_DW1_MBEACON_N=0)

This scenarios can be extended to more vifs. So if you no longer 
use bcn_idx and use vif_idx directly to point beacon slot/address.
(ie. before for vif_idx 0,4,6, bcn_idx were 0,1,2 now there
will be 0,4,6). You need to specify 7 (8 beacons) in
MT_MAC_BSSID_DW1_MBEACON_N, and set bypass mask accordingly.
For example:

	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N, 7);
	mask = 0;
	for (i = 0; i < 8; i++)
		if (dev->beacons[i])
			mask |= BIT(7 - i);

	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~mask);

But again, this have to be tested. Ideally on mmio hardware which
support more bssid's or on usb hardware with temporally increased
num of bss limitation.

Stanislaw

Re: [PATCH v6 2/5] mt76: mt76x02: split beaconing

[Markus Theil]

On 21.11.19 13:58, Stanislaw Gruszka wrote:
> On Wed, Nov 20, 2019 at 11:27:55PM +0100, Markus Theil wrote:
>>>> -	}
>>>> -
>>>> -	for (i = bcn_idx; i < ARRAY_SIZE(dev->beacons); i++) {
>>>> -		if (!(dev->beacon_data_mask & BIT(i)))
>>>> -			break;
>>>> -
>>>> -		__mt76x02_mac_set_beacon(dev, i, NULL);
>>>> -	}
>>>>  
>>>>  	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N,
>>>>  		       bcn_idx - 1);
>>>> +
>>>> +	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~dev->beacon_data_mask);
>>> I'm not sure if this is correct for multi bss.
>>>
>>> In MT7620 manual BCM_BAYPASS_MASK is described as below:
>>>
>>> "
>>> Directly bypasses the Tx Beacon frame with the  specified 
>>> Beacon number. Bit0=Nth Beacon, bit1=(N- 1)th Beacon,... etc.
>>> N is the number of  Beacons defined in the  MULTI_BCN_NUM field in the 
>>> MAC_BSSID_DW1(offset: 0x1014) register.
>>> 0: Disable
>>> 1: Enable
>>> "
>>>
>>> Assuming manual is correct (it could be wrong) bypass mask should be
>>> calculated differently.
>>>
>>> Stanislaw
>>>
>> I tested the updated code with my usb nic and an mbss with 2 ap vifs.
>> Both beacons were transmitted. Maybe the manual is wrong in this place.
> If MAC_BSSID_DW1_MBEACON_N is set to 1 (2 beacons) according to manual
> bit0 is for second beacon slot and bit1 is for first beacon slot.
> Those bits are both marked at once, so no problem will happen.
>
> Problem may happen when you remove first vif/beacon. Then you will
> have bit1 marked in ->beacon_data_mask . But bit0 will be expect
> in BCM_BAYPASS_MASK by hardware (when MAC_BSSID_DW1_MBEACON_N=0)
>
> This scenarios can be extended to more vifs. So if you no longer 
> use bcn_idx and use vif_idx directly to point beacon slot/address.
> (ie. before for vif_idx 0,4,6, bcn_idx were 0,1,2 now there
> will be 0,4,6). You need to specify 7 (8 beacons) in
> MT_MAC_BSSID_DW1_MBEACON_N, and set bypass mask accordingly.
> For example:
>
> 	mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N, 7);
> 	mask = 0;
> 	for (i = 0; i < 8; i++)
> 		if (dev->beacons[i])
> 			mask |= BIT(7 - i);
>
> 	mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~mask);
>
> But again, this have to be tested. Ideally on mmio hardware which
> support more bssid's or on usb hardware with temporally increased
> num of bss limitation.
>
> Stanislaw
>
I'm currently fixing this. My next version will include the following for this aspect:
- clear beacon_data_mask before each round of setting beacons
- use ffz(dev->beacon_data_mask) to find next position and put next beacon in the corresponding slot
- as usb and mmio always copy the beacon, free_skb directly afterwards and drop the beacons array (the current code could leak memory for beacons in this array)

- permanently set the number of additional beacons to 7: mt76_rmw_field(dev, MT_MAC_BSSID_DW1, MT_MAC_BSSID_DW1_MBEACON_N, 7)
- updating the beacon bypass mask then becomes: mt76_wr(dev, MT_BCN_BYPASS_MASK, 0xff00 | ~bitrev8(dev->beacon_data_mask))

When I've tested this, I'll send an updated version.

Markus