Date:   Mon, 28 Jan 2019 14:35:39 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To:     Stanislaw Gruszka <sgruszka@redhat.com>
Cc:     Felix Fietkau <nbd@nbd.name>, linux-wireless@vger.kernel.org
Subject: Re: [PATCH v2 1/7] mt76x02: use mask for vifs
Message-ID: <20190128133537.GB9257@localhost.localdomain>
References: <1548678108-9526-1-git-send-email-sgruszka@redhat.com>
 <1548678108-9526-2-git-send-email-sgruszka@redhat.com>
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> Use vif_mask to count interfaces to allow to set mac address in HW
> if there is only one interface and report error if we create
> interface with wrong BSSID resulting in already used index.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> ---
> v2:
> - do not change vif index calculation
> - return error for already used index
> 
>  drivers/net/wireless/mediatek/mt76/mt76x02.h      |  2 ++
>  drivers/net/wireless/mediatek/mt76/mt76x02_util.c | 12 +++++++++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02.h b/drivers/net/wireless/mediatek/mt76/mt76x02.h
> index 6d96766a6ed3..be077443bdb0 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02.h
> @@ -73,6 +73,8 @@ struct mt76x02_dev {
>  
>  	struct mutex phy_mutex;
>  
> +	u16 vif_mask;
> +
>  	u8 txdone_seq;
>  	DECLARE_KFIFO_PTR(txstatus_fifo, struct mt76x02_tx_status);
>  
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
> index 062614ad0d51..2e805d5493de 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c
> @@ -292,7 +292,6 @@ mt76x02_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>  
>  	if (vif->addr[0] & BIT(1))
>  		idx = 1 + (((dev->mt76.macaddr[0] ^ vif->addr[0]) >> 2) & 7);
> -
>  	/*
>  	 * Client mode typically only has one configurable BSSID register,
>  	 * which is used for bssidx=0. This is linked to the MAC address.
> @@ -309,6 +308,15 @@ mt76x02_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>  	if (vif->type == NL80211_IFTYPE_STATION)
>  		idx += 8;
>  

Maybe we shoud grub dev->mt76.mutex here, since we can have multiple processes trying
to add an interface

> +	if (dev->vif_mask & BIT(idx))
> +		return -EBUSY;
> + 
> +	/* Allow to change address in HW if we create first interface. */
> +	if (!dev->vif_mask && !ether_addr_equal(dev->mt76.macaddr, vif->addr))
> +                mt76x02_mac_setaddr(dev, vif->addr);
> +
> +	dev->vif_mask |= BIT(idx);
> +
>  	mt76x02_vif_init(dev, vif, idx);
>  	return 0;
>  }
> @@ -318,8 +326,10 @@ void mt76x02_remove_interface(struct ieee80211_hw *hw,
>  			      struct ieee80211_vif *vif)
>  {
>  	struct mt76x02_dev *dev = hw->priv;
> +	struct mt76x02_vif *mvif = (struct mt76x02_vif *)vif->drv_priv;
>  
>  	mt76_txq_remove(&dev->mt76, vif->txq);
> +	dev->vif_mask &= ~BIT(mvif->idx);

If we are removing the first configured interface, should we have to update
MT_MAC_ADDR_DW{0,1} regs?

Regards,
Lorenzo

>  }
>  EXPORT_SYMBOL_GPL(mt76x02_remove_interface);
>  
> -- 
> 2.19.2
>