netdev - Re: [PATCH net-next v2] net: ngbe: Add ngbe mdio bus driver.

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Date:   Sat, 10 Dec 2022 11:47:29 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Mengyuan Lou <mengyuanlou@...-swift.com>
Cc:     netdev@...r.kernel.org, jiawenwu@...stnetic.com
Subject: Re: [PATCH net-next v2] net: ngbe: Add ngbe mdio bus driver.

>  int ngbe_reset_hw(struct ngbe_hw *hw)
>  {
>  	struct wx_hw *wxhw = &hw->wxhw;
> -	int status = 0;
> -	u32 reset = 0;
> +	u32 val = 0;
> +	int ret = 0;
>  
>  	/* Call adapter stop to disable tx/rx and clear interrupts */
> -	status = wx_stop_adapter(wxhw);
> -	if (status != 0)
> -		return status;
> -	reset = WX_MIS_RST_LAN_RST(wxhw->bus.func);
> -	wr32(wxhw, WX_MIS_RST, reset | rd32(wxhw, WX_MIS_RST));
> +	ret = wx_stop_adapter(wxhw);
> +	if (ret != 0)
> +		return ret;
> +
> +	if (hw->mac_type != ngbe_mac_type_mdi) {
> +		val = WX_MIS_RST_LAN_RST(wxhw->bus.func);
> +		wr32(wxhw, WX_MIS_RST, val | rd32(wxhw, WX_MIS_RST));
> +
> +		ret = read_poll_timeout(rd32, val,
> +					!(val & (BIT(9) << wxhw->bus.func)), 1000,
> +					100000, false, wxhw, 0x10028);
> +		if (ret)
> +			wx_dbg(wxhw, "Lan reset exceed s maximum times.\n");

This is a real error. Return it up the call stack so the user gets to
know. This should be netdev_err(), since it is an error.

> +static void ngbe_up(struct ngbe_adapter *adapter)
> +{
> +	struct ngbe_hw *hw = &adapter->hw;
> +
> +	pci_set_master(adapter->pdev);
> +	if (hw->gpio_ctrl)
> +		/* gpio0 is used to power on control*/
> +		wr32(&hw->wxhw, NGBE_GPIO_DR, 0);

Control of what?

> +static int ngbe_phy_read_reg_mdi(struct mii_bus *bus, int phy_addr, int regnum)
> +{
> +	u32 command = 0, device_type = 0;
> +	struct ngbe_hw *hw = bus->priv;
> +	struct wx_hw *wxhw = &hw->wxhw;
> +	u32 phy_data = 0;
> +	u32 val = 0;
> +	int ret = 0;
> +
> +	if (regnum & MII_ADDR_C45) {
> +		wr32(wxhw, NGBE_MDIO_CLAUSE_SELECT, 0x0);
> +		/* setup and write the address cycle command */
> +		command = NGBE_MSCA_RA(mdiobus_c45_regad(regnum)) |
> +			  NGBE_MSCA_PA(phy_addr) |
> +			  NGBE_MSCA_DA(mdiobus_c45_devad(regnum));
> +	} else {
> +		wr32(wxhw, NGBE_MDIO_CLAUSE_SELECT, 0xF);
> +		/* setup and write the address cycle command */
> +		command = NGBE_MSCA_RA(regnum) |
> +			  NGBE_MSCA_PA(phy_addr) |
> +			  NGBE_MSCA_DA(device_type);
> +	}
> +	wr32(wxhw, NGBE_MSCA, command);
> +	command = NGBE_MSCC_CMD(NGBE_MSCA_CMD_READ) |
> +		  NGBE_MSCC_BUSY |
> +		  NGBE_MDIO_CLK(6);
> +	wr32(wxhw, NGBE_MSCC, command);
> +
> +	/* wait to complete */
> +	ret = read_poll_timeout(rd32, val, !(val & NGBE_MSCC_BUSY), 1000,
> +				100000, false, wxhw, NGBE_MSCC);
> +
> +	if (ret)
> +		wx_dbg(wxhw, "PHY address command did not complete.\n");

netdev_err() and return the error code.

> +static int ngbe_phy_write_reg_mdi(struct mii_bus *bus, int phy_addr, int regnum, u16 value)
> +{
> +	u32 command = 0, device_type = 0;
> +	struct ngbe_hw *hw = bus->priv;
> +	struct wx_hw *wxhw = &hw->wxhw;
> +	int ret = 0;
> +	u16 val = 0;
> +
> +	if (regnum & MII_ADDR_C45) {
> +		wr32(wxhw, NGBE_MDIO_CLAUSE_SELECT, 0x0);
> +		/* setup and write the address cycle command */
> +		command = NGBE_MSCA_RA(mdiobus_c45_regad(regnum)) |
> +			  NGBE_MSCA_PA(phy_addr) |
> +			  NGBE_MSCA_DA(mdiobus_c45_devad(regnum));
> +	} else {
> +		wr32(wxhw, NGBE_MDIO_CLAUSE_SELECT, 0xF);
> +		/* setup and write the address cycle command */
> +		command = NGBE_MSCA_RA(regnum) |
> +			  NGBE_MSCA_PA(phy_addr) |
> +			  NGBE_MSCA_DA(device_type);
> +	}
> +	wr32(wxhw, NGBE_MSCA, command);
> +	command = value |
> +		  NGBE_MSCC_CMD(NGBE_MSCA_CMD_WRITE) |
> +		  NGBE_MSCC_BUSY |
> +		  NGBE_MDIO_CLK(6);
> +	wr32(wxhw, NGBE_MSCC, command);
> +
> +	/* wait to complete */
> +	ret = read_poll_timeout(rd32, val, !(val & NGBE_MSCC_BUSY), 1000,
> +				100000, false, wxhw, NGBE_MSCC);
> +
> +	if (ret)
> +		wx_dbg(wxhw, "PHY address command did not complete.\n");

dev_error().

> +
> +	return ret;
> +}
> +
> +static int ngbe_phy_read_reg(struct mii_bus *bus, int phy_addr, int regnum)
> +{
> +	struct ngbe_hw *hw = bus->priv;
> +	u16 phy_data = 0;
> +
> +	if (hw->mac_type == ngbe_mac_type_mdi)
> +		phy_data = ngbe_phy_read_reg_internal(bus, phy_addr, regnum);
> +	else if (hw->mac_type == ngbe_mac_type_rgmii)
> +		phy_data = ngbe_phy_read_reg_mdi(bus, phy_addr, regnum);
> +
> +	return phy_data;

You return 0 if it is neither MDI or RGMII. It would be better to
either return -EINVAL, or 0xffff. A read on an MDIO bus for an address
without a device returns 0xffff due to the pull up resisters. That
will let Linux know there is no device there.

> +static void ngbe_handle_link_change(struct net_device *dev)
> +{
> +	struct ngbe_adapter *adapter = netdev_priv(dev);
> +	struct ngbe_hw *hw = &adapter->hw;
> +	struct wx_hw *wxhw = &hw->wxhw;
> +	u32 lan_speed = 2, reg;
> +	bool changed = false;
> +
> +	struct phy_device *phydev = hw->phydev;
> +
> +	if (hw->link != phydev->link ||
> +	    hw->speed != phydev->speed ||
> +	    hw->duplex != phydev->duplex) {
> +		changed = true;
> +		hw->link = phydev->link;
> +		hw->speed = phydev->speed;
> +		hw->duplex = phydev->duplex;
> +	}
> +
> +	if (!changed)
> +		return;
> +
> +	switch (phydev->speed) {
> +	case SPEED_1000:
> +		lan_speed = 2;
> +		break;
> +	case SPEED_100:
> +		lan_speed = 1;
> +		break;
> +	case SPEED_10:
> +		lan_speed = 0;
> +		break;
> +	default:
> +		break;
> +	}
> +	wr32m(wxhw, NGBE_CFG_LAN_SPEED, 0x3, lan_speed);
> +
> +	if (phydev->link) {
> +		if (phydev->speed & (SPEED_1000 | SPEED_100 | SPEED_10)) {

You logically OR 10, 100 and 1000? These SPEED_FOO macros are not
bits.

	Andrew