Re: [PATCH net-next 5/8] net: ethernet: mtk_eth_soc: add MTK_NETSYS_V3 capability bit

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Daniel Golle <daniel@makrotopia.org>,
	netdev@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	Mark Lee <Mark-MC.Lee@mediatek.com>,
	Sean Wang <sean.wang@mediatek.com>,
	John Crispin <john@phrozen.org>, Felix Fietkau <nbd@nbd.name>,
	Conor Dooley <conor+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Sam Shih <Sam.Shih@mediatek.com>
Subject: Re: [PATCH net-next 5/8] net: ethernet: mtk_eth_soc: add MTK_NETSYS_V3 capability bit
Date: Tue, 13 Jun 2023 00:16:30 +0200	[thread overview]
Message-ID: <ZIeZPqFJqdf928f4@lore-desk> (raw)
In-Reply-To: <ZIb/WKKNlzjTIu2h@shell.armlinux.org.uk>

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> On Sun, Jun 11, 2023 at 01:38:23AM +0100, Daniel Golle wrote:
> > @@ -1333,8 +1354,13 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
> >  	mtk_tx_set_dma_desc(dev, itxd, &txd_info);
> >  
> >  	itx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
> > -	itx_buf->flags |= (!mac->id) ? MTK_TX_FLAGS_FPORT0 :
> > -			  MTK_TX_FLAGS_FPORT1;
> > +	if (mac->id == MTK_GMAC1_ID)
> > +		itx_buf->flags |= MTK_TX_FLAGS_FPORT0;
> > +	else if (mac->id == MTK_GMAC2_ID)
> > +		itx_buf->flags |= MTK_TX_FLAGS_FPORT1;
> > +	else
> > +		itx_buf->flags |= MTK_TX_FLAGS_FPORT2;
> 
> There appears to be two places that this code structure appears, and
> this is in the path for packet transmission. I wonder if it would be
> more efficient to instead do:
> 
> 	itx_buf->flags |= MTK_TX_FLAGS_SINGLE0 | mac->tx_flags;
> 
> with mac->tx_flags appropriately initialised?
> 
> > @@ -2170,7 +2214,9 @@ static int mtk_poll_tx_qdma(struct mtk_eth *eth, int budget,
> >  		tx_buf = mtk_desc_to_tx_buf(ring, desc,
> >  					    eth->soc->txrx.txd_size);
> >  		if (tx_buf->flags & MTK_TX_FLAGS_FPORT1)
> > -			mac = 1;
> > +			mac = MTK_GMAC2_ID;
> > +		else if (tx_buf->flags & MTK_TX_FLAGS_FPORT2)
> > +			mac = MTK_GMAC3_ID;
> 
> This has me wondering whether the flags are used for hardware or just
> for the driver's purposes. If it's the latter, can we instead store the
> MAC index in tx_buf, rather than having to decode a bitfield?
> 
> I suspect these are just for the driver given that the addition of
> MTK_TX_FLAGS_FPORT2 changes all subsequent bit numbers in this struct
> member.

ack, I agree. I will rework it.

Regards,
Lorenzo

> 
> >  
> >  		if (!tx_buf->data)
> >  			break;
> > @@ -3783,7 +3829,26 @@ static int mtk_hw_init(struct mtk_eth *eth, bool reset)
> >  	mtk_w32(eth, eth->soc->txrx.rx_irq_done_mask, reg_map->qdma.int_grp + 4);
> >  	mtk_w32(eth, 0x21021000, MTK_FE_INT_GRP);
> >  
> > -	if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V2)) {
> > +	if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V3)) {
> > +		/* PSE should not drop port1, port8 and port9 packets */
> > +		mtk_w32(eth, 0x00000302, PSE_DROP_CFG);
> > +
> > +		/* GDM and CDM Threshold */
> > +		mtk_w32(eth, 0x00000707, MTK_CDMW0_THRES);
> > +		mtk_w32(eth, 0x00000077, MTK_CDMW1_THRES);
> > +
> > +		/* Disable GDM1 RX CRC stripping */
> > +		val = mtk_r32(eth, MTK_GDMA_FWD_CFG(0));
> > +		val &= ~MTK_GDMA_STRP_CRC;
> > +		mtk_w32(eth, val, MTK_GDMA_FWD_CFG(0));
> 
> mtk_m32() ?
> 
> Thanks!
> 
> -- 
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
> 

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