linux-kernel - Re: [PATCH v2 4/4] net: mdio: Add RTL9300 MDIO driver

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Message-ID: <20241216164814.GH780307@kernel.org>
Date: Mon, 16 Dec 2024 16:48:14 +0000
From: Simon Horman <horms@...nel.org>
To: Chris Packham <chris.packham@...iedtelesis.co.nz>
Cc: lee@...nel.org, robh@...nel.org, krzk+dt@...nel.org,
	conor+dt@...nel.org, andrew+netdev@...n.ch, davem@...emloft.net,
	edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
	tsbogend@...ha.franken.de, hkallweit1@...il.com,
	linux@...linux.org.uk, markus.stockhausen@....de,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, linux-mips@...r.kernel.org
Subject: Re: [PATCH v2 4/4] net: mdio: Add RTL9300 MDIO driver

On Mon, Dec 16, 2024 at 04:13:46PM +1300, Chris Packham wrote:
> Add a driver for the MDIO controller on the RTL9300 family of Ethernet
> switches with integrated SoC. There are 4 physical SMI interfaces on the
> RTL9300 but access is done using the switch ports so a single MDIO bus
> is presented to the rest of the system.
> 
> Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>

...

> diff --git a/drivers/net/mdio/mdio-realtek-rtl.c b/drivers/net/mdio/mdio-realtek-rtl.c

...

> +#define MAX_SMI_BUSSES  4
> +#define MAX_SMI_ADDR	0x1f
> +
> +struct realtek_mdio_priv {
> +	struct regmap *regmap;
> +	u8 smi_bus[MAX_PORTS];
> +	u8 smi_addr[MAX_PORTS];
> +	bool smi_bus_isc45[MAX_SMI_BUSSES];
> +	u32 reg_base;
> +};

...

> +static int realtek_mdiobus_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct realtek_mdio_priv *priv;
> +	struct fwnode_handle *child;
> +	struct mii_bus *bus;
> +	int err;
> +
> +	bus = devm_mdiobus_alloc_size(dev, sizeof(*priv));
> +	if (!bus)
> +		return -ENOMEM;
> +
> +	bus->name = "Reaktek Switch MDIO Bus";
> +	bus->read = realtek_mdio_read_c22;
> +	bus->write = realtek_mdio_write_c22;
> +	bus->read_c45 = realtek_mdio_read_c45;
> +	bus->write_c45 =  realtek_mdio_write_c45;
> +	bus->parent = dev;
> +	priv = bus->priv;
> +
> +	priv->regmap = syscon_node_to_regmap(dev->parent->of_node);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
> +
> +	err = device_property_read_u32(dev, "reg", &priv->reg_base);
> +	if (err)
> +		return err;
> +
> +	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
> +
> +	device_for_each_child_node(dev, child) {
> +		u32 pn, smi_addr[2];
> +
> +		err = fwnode_property_read_u32(child, "reg", &pn);
> +		if (err)
> +			return err;
> +
> +		if (pn >= MAX_PORTS)
> +			return dev_err_probe(dev, -EINVAL, "illegal port number %d\n", pn);
> +
> +		err = fwnode_property_read_u32_array(child, "realtek,smi-address", smi_addr, 2);
> +		if (err) {
> +			smi_addr[0] = 0;
> +			smi_addr[1] = pn;
> +		}
> +
> +		if (smi_addr[0] > MAX_SMI_BUSSES)

Hi Chris,

Should this condition be

		if (smi_addr[0] >= MAX_SMI_BUSSES)


> +			return dev_err_probe(dev, -EINVAL, "illegal smi bus number %d\n",
> +					     smi_addr[0]);
> +
> +		if (smi_addr[1] > MAX_SMI_ADDR)
> +			return dev_err_probe(dev, -EINVAL, "illegal smi addr %d\n", smi_addr[1]);
> +
> +		if (fwnode_device_is_compatible(child, "ethernet-phy-ieee802.3-c45"))
> +			priv->smi_bus_isc45[smi_addr[0]] = true;

Otherwise it seems that smi_bus_isc45 may overflow here.

Flagged by Smatch.

> +
> +		priv->smi_bus[pn] = smi_addr[0];
> +		priv->smi_addr[pn] = smi_addr[1];
> +	}
> +
> +	err = realtek_mdiobus_init(priv);
> +	if (err)
> +		return dev_err_probe(dev, err, "failed to initialise MDIO bus controller\n");
> +
> +	err = devm_of_mdiobus_register(dev, bus, dev->of_node);
> +	if (err)
> +		return dev_err_probe(dev, err, "cannot register MDIO bus\n");
> +
> +	return 0;
> +}

...

-- 
pw-bot: changes-requested