Re: [PATCH net-next] net: ethernet: mtk_eth_soc: add paths and SerDes modes for MT7988

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Daniel Golle <daniel@makrotopia.org>
Cc: Felix Fietkau <nbd@nbd.name>, John Crispin <john@phrozen.org>,
	Sean Wang <sean.wang@mediatek.com>,
	Mark Lee <Mark-MC.Lee@mediatek.com>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, llvm@lists.linux.dev,
	ndesaulniers@google.com, nathan@kernel.org, trix@redhat.com
Subject: Re: [PATCH net-next] net: ethernet: mtk_eth_soc: add paths and SerDes modes for MT7988
Date: Sat, 16 Sep 2023 19:24:38 +0100	[thread overview]
Message-ID: <ZQXy5pxPRN1QXQkq@shell.armlinux.org.uk> (raw)
In-Reply-To: <675b5abd8b40a71c177e9e4e4c92d2d6b1413b9b.1694527316.git.daniel@makrotopia.org>

On Tue, Sep 12, 2023 at 03:54:40PM +0100, Daniel Golle wrote:
> +static void mtk_usxgmii_pcs_get_state(struct phylink_pcs *pcs,
> +				      struct phylink_link_state *state)
> +{
> +	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
> +	struct mtk_eth *eth = mpcs->eth;
> +	struct mtk_mac *mac = eth->mac[mtk_xgmii2mac_id(eth, mpcs->id)];
> +	u32 val = 0;
> +
> +	regmap_read(mpcs->regmap, RG_PCS_AN_CTRL0, &val);
> +	if (FIELD_GET(USXGMII_AN_ENABLE, val)) {
> +		/* Refresh LPA by inverting LPA_LATCH */
> +		regmap_read(mpcs->regmap, RG_PCS_AN_STS0, &val);
> +		regmap_update_bits(mpcs->regmap, RG_PCS_AN_STS0,
> +				   USXGMII_LPA_LATCH,
> +				   !(val & USXGMII_LPA_LATCH));
> +
> +		regmap_read(mpcs->regmap, RG_PCS_AN_STS0, &val);
> +
> +		phylink_decode_usxgmii_word(state, FIELD_GET(USXGMII_PCS_AN_WORD,
> +							     val));
> +
> +		state->interface = mpcs->interface;

Why are you assigning state->interface?

> +	} else {
> +		val = mtk_r32(mac->hw, MTK_XGMAC_STS(mac->id));
> +
> +		if (mac->id == MTK_GMAC2_ID)
> +			val >>= 16;
> +
> +		switch (FIELD_GET(MTK_USXGMII_PCS_MODE, val)) {
> +		case 0:
> +			state->speed = SPEED_10000;
> +			break;
> +		case 1:
> +			state->speed = SPEED_5000;
> +			break;
> +		case 2:
> +			state->speed = SPEED_2500;
> +			break;
> +		case 3:
> +			state->speed = SPEED_1000;
> +			break;
> +		}
> +
> +		state->interface = mpcs->interface;
> +		state->link = FIELD_GET(MTK_USXGMII_PCS_LINK, val);
> +		state->duplex = DUPLEX_FULL;
> +	}
> +
> +	/* Refresh USXGMII link status by toggling RG_PCS_RX_STATUS_UPDATE */
> +	regmap_set_bits(mpcs->regmap, RG_PCS_RX_STATUS0, RG_PCS_RX_STATUS_UPDATE);
> +	ndelay(1020);
> +	regmap_clear_bits(mpcs->regmap, RG_PCS_RX_STATUS0, RG_PCS_RX_STATUS_UPDATE);
> +	ndelay(1020);
> +
> +	/* Read USXGMII link status */
> +	regmap_read(mpcs->regmap, RG_PCS_RX_STATUS0, &val);
> +	state->link = state->link && FIELD_GET(RG_PCS_RX_LINK_STATUS, val);

Doesn't this make the assignment to state->link above irrelevant?

I need to spend a bit longer looking through this - it looks like there
are three levels of indirection in this now?

-- 
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