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

[Simon Horman <horms@kernel.org>]

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@makrotopia.org>

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) ?
                                                                        ^
                           (

> +		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);

> +		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);
> +	}

...