Re: [PATCH RFC net-next v2] net: ethernet: mtk_eth_soc: add paths and SerDes modes for MT7988

[Daniel Golle]

Hi Simon,

thank you for reviewing!

On Sun, Aug 27, 2023 at 05:35:23PM +0200, Simon Horman wrote:
> On Thu, Aug 24, 2023 at 09:24:48PM +0100, Daniel Golle wrote:
> > MT7988 comes with a built-in 2.5G PHY as well as SerDes lanes to
> > connect external PHYs or transceivers in USXGMII, 10GBase-R, 5GBase-R,
> > 2500Base-X, 1000Base-X and Cisco SGMII interface modes.
> > 
> > Implement support for configuring for the new paths to SerDes interfaces
> > and the internal 2.5G PHY.
> > 
> > Add USXGMII PCS driver for 10GBase-R, 5GBase-R and USXGMII mode, and
> > setup the new PHYA on MT7988 to access the also still existing old
> > LynxI PCS for 1000Base-X, 2500Base-X and Cisco SGMII PCS interface
> > modes.
> > 
> > Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
> 
> Hi Daniel,
> 
> some minor feedback from my side.
> 
> ...
> 
> > diff --git a/drivers/net/ethernet/mediatek/mtk_usxgmii.c b/drivers/net/ethernet/mediatek/mtk_usxgmii.c
> 
> ...
> 
> > +static int mtk_usxgmii_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
> > +				  phy_interface_t interface,
> > +				  const unsigned long *advertising,
> > +				  bool permit_pause_to_mac)
> > +{
> > +	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
> > +	struct mtk_eth *eth = mpcs->eth;
> > +	struct regmap *pextp = eth->regmap_pextp[mpcs->id];
> > +	unsigned int an_ctrl = 0, link_timer = 0, xfi_mode = 0, adapt_mode = 0;
> > +	bool mode_changed = false;
> > +
> > +	if (!pextp)
> > +		return -ENODEV;
> > +
> > +	if (interface == PHY_INTERFACE_MODE_USXGMII) {
> > +		an_ctrl = FIELD_PREP(USXGMII_AN_SYNC_CNT, 0x1FF) |
> > +			  (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) ?
> > +			  USXGMII_AN_ENABLE : 0;
> 
> clang-16 W=1 suggests using parentheses here:
> 
>  drivers/net/ethernet/mediatek/mtk_usxgmii.c:468:51: warning: operator '?:' has lower precedence than '|'; '|' will be evaluated first [-Wbitwise-conditional-parentheses]
>                            (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) ?
>                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
>  drivers/net/ethernet/mediatek/mtk_usxgmii.c:468:51: note: place parentheses around the '|' expression to silence this warning
>                            (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) ?
>                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
>  drivers/net/ethernet/mediatek/mtk_usxgmii.c:468:51: note: place parentheses around the '?:' expression to evaluate it first
>                            (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) ?
>                                                                         ^
>                            (

Yeah, I've seen that one coming up on patchwork as well, fixed it already in my
local tree.

> 
> > +		link_timer = FIELD_PREP(USXGMII_LINK_TIMER_IDLE_DETECT, 0x7B) |
> > +			     FIELD_PREP(USXGMII_LINK_TIMER_COMP_ACK_DETECT, 0x7B) |
> > +			     FIELD_PREP(USXGMII_LINK_TIMER_AN_RESTART, 0x7B);
> > +		xfi_mode = FIELD_PREP(USXGMII_XFI_RX_MODE, USXGMII_XFI_RX_MODE_10G) |
> > +			   FIELD_PREP(USXGMII_XFI_TX_MODE, USXGMII_XFI_TX_MODE_10G);
> 
> ...
> 
> > +int mtk_usxgmii_init(struct mtk_eth *eth)
> > +{
> > +	struct device_node *r = eth->dev->of_node;
> > +	struct device *dev = eth->dev;
> > +	struct device_node *np;
> > +	int i, ret;
> > +
> > +	for (i = 0; i < MTK_MAX_DEVS; i++) {
> > +		np = of_parse_phandle(r, "mediatek,usxgmiisys", i);
> > +		if (!np)
> > +			break;
> > +
> > +		eth->usxgmii_pcs[i] = devm_kzalloc(dev, sizeof(*eth->usxgmii_pcs), GFP_KERNEL);
> 
> Smatch warns that only 8 bytes are allocated, whereas 64 are needed.
> I think one more defference of the parameter to sizeof().
> 
> e.g.:
> 
> 		eth->usxgmii_pcs[i] = devm_kzalloc(dev,
> 						   sizeof(*eth->usxgmii_pcs[i]),
> 						   GFP_KERNEL);

Good catch, thank you! I will fix it.


> 
> > +		if (!eth->usxgmii_pcs[i])
> > +			return -ENOMEM;
> > +
> > +		eth->usxgmii_pcs[i]->id = i;
> > +		eth->usxgmii_pcs[i]->eth = eth;
> > +		eth->usxgmii_pcs[i]->regmap = syscon_node_to_regmap(np);
> > +		if (IS_ERR(eth->usxgmii_pcs[i]->regmap))
> > +			return PTR_ERR(eth->usxgmii_pcs[i]->regmap);
> > +
> > +		eth->usxgmii_pcs[i]->pcs.ops = &mtk_usxgmii_pcs_ops;
> > +		eth->usxgmii_pcs[i]->pcs.poll = true;
> > +		eth->usxgmii_pcs[i]->pcs.neg_mode = true;
> > +		eth->usxgmii_pcs[i]->interface = PHY_INTERFACE_MODE_NA;
> > +		eth->usxgmii_pcs[i]->neg_mode = -1;
> > +
> > +		of_node_put(np);
> > +	}
> 
> ...
>