Re: [RFC v2 PATCH 02/10] net: ti: prueth: Adds ICSSM Ethernet driver

[Basharath Hussain Khaja <basharath@couthit.com>]

> On Fri, Jan 24, 2025 at 05:53:45PM +0530, Basharath Hussain Khaja wrote:
>> From: Roger Quadros <rogerq@ti.com>
>> 
>> Updates Kernel configuration to enable PRUETH driver and its dependencies
>> along with makefile changes to add the new PRUETH driver.
>> 
>> Changes includes init and deinit of ICSSM PRU Ethernet driver including
>> net dev registration and firmware loading for DUAL-MAC mode running on
>> PRU-ICSS2 instance.
>> 
>> Changes also includes link handling, PRU booting, default firmware loading
>> and PRU stopping using existing remoteproc driver APIs.
>> 
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> Signed-off-by: Andrew F. Davis <afd@ti.com>
>> Signed-off-by: Parvathi Pudi <parvathi@couthit.com>
>> Signed-off-by: Basharath Hussain Khaja <basharath@couthit.com>
> 
> ...
> 
>> diff --git a/drivers/net/ethernet/ti/icssm/icssm_prueth.c
>> b/drivers/net/ethernet/ti/icssm/icssm_prueth.c
> 
> ...
> 
>> +static int icssm_emac_set_boot_pru(struct prueth_emac *emac,
>> +				   struct net_device *ndev)
>> +{
>> +	const struct prueth_firmware *pru_firmwares;
>> +	struct prueth *prueth = emac->prueth;
>> +	const char *fw_name;
>> +	int ret;
>> +
>> +	pru_firmwares = &prueth->fw_data->fw_pru[emac->port_id - 1];
>> +	fw_name = pru_firmwares->fw_name[prueth->eth_type];
>> +	if (!fw_name) {
>> +		netdev_err(ndev, "eth_type %d not supported\n",
>> +			   prueth->eth_type);
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = rproc_set_firmware(emac->pru, fw_name);
>> +	if (ret) {
>> +		netdev_err(ndev, "failed to set PRU0 firmware %s: %d\n",
>> +			   fw_name, ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = rproc_boot(emac->pru);
>> +	if (ret) {
>> +		netdev_err(ndev, "failed to boot PRU0: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +/**
>> + * icssm_emac_ndo_open - EMAC device open
>> + * @ndev: network adapter device
>> + *
>> + * Called when system wants to start the interface.
>> + *
>> + * Return: 0 for a successful open, or appropriate error code
>> + */
>> +static int icssm_emac_ndo_open(struct net_device *ndev)
>> +{
>> +	struct prueth_emac *emac = netdev_priv(ndev);
>> +	int ret;
>> +
>> +	ret = icssm_emac_set_boot_pru(emac, ndev);
>> +	if (ret)
>> +		netdev_err(ndev, "failed to boot PRU: %d\n", ret);
> 
> Hi Roger, Basharath, all,
> 
> icssm_emac_set_boot_pru() already logs errors, including the one above.
> So this log seems unnecessary to me.
> 
> Also, should an error be returned here?  If so, it looks like
> icssm_emac_set_boot_pru() should release resources allocated by
> rproc_set_firmware() if rproc_boot() fails.
> 

Agreed. We will remove the extra print and make sure allocated resources
are released appropriately in the next version.

>> +
>> +	/* start PHY */
>> +	phy_start(emac->phydev);
>> +
>> +	return 0;
>> +}
> 
> ...
> 
>> +static int icssm_prueth_netdev_init(struct prueth *prueth,
>> +				    struct device_node *eth_node)
>> +{
>> +	struct prueth_emac *emac;
>> +	struct net_device *ndev;
>> +	enum prueth_port port;
>> +	enum prueth_mac mac;
>> +	int ret;
>> +
>> +	port = icssm_prueth_node_port(eth_node);
>> +	if (port == PRUETH_PORT_INVALID)
>> +		return -EINVAL;
>> +
>> +	mac = icssm_prueth_node_mac(eth_node);
>> +	if (mac == PRUETH_MAC_INVALID)
>> +		return -EINVAL;
>> +
>> +	ndev = devm_alloc_etherdev(prueth->dev, sizeof(*emac));
>> +	if (!ndev)
>> +		return -ENOMEM;
>> +
>> +	SET_NETDEV_DEV(ndev, prueth->dev);
>> +	emac = netdev_priv(ndev);
>> +	prueth->emac[mac] = emac;
>> +	emac->prueth = prueth;
>> +	emac->ndev = ndev;
>> +	emac->port_id = port;
>> +
>> +	/* by default eth_type is EMAC */
>> +	switch (port) {
>> +	case PRUETH_PORT_MII0:
>> +		emac->pru = prueth->pru0;
>> +		break;
>> +	case PRUETH_PORT_MII1:
>> +		emac->pru = prueth->pru1;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +	/* get mac address from DT and set private and netdev addr */
>> +	ret = of_get_ethdev_address(eth_node, ndev);
>> +	if (!is_valid_ether_addr(ndev->dev_addr)) {
>> +		eth_hw_addr_random(ndev);
>> +		dev_warn(prueth->dev, "port %d: using random MAC addr: %pM\n",
>> +			 port, ndev->dev_addr);
>> +	}
>> +	ether_addr_copy(emac->mac_addr, ndev->dev_addr);
>> +
>> +	/* connect PHY */
>> +	emac->phydev = of_phy_get_and_connect(ndev, eth_node,
>> +					      icssm_emac_adjust_link);
>> +	if (!emac->phydev) {
>> +		dev_dbg(prueth->dev, "PHY connection failed\n");
>> +		ret = -EPROBE_DEFER;
> 
> Perhaps I misunderstand things, but if this occurs then
> presumably icssm_prueth_netdev_init() will be called again.
> And for each time this occirs another ndev will be allocated
> by devm_alloc_etherdev(), each of which will only be freed
> once the device is eventually torn-down.
> 
> I wonder if it would be better to free ndev here.
> Which I think would imply using a non-mdev allocation for symmetry.
> 
> Similarly for resources allocated in the caller icssm_prueth_probe().
> 

Agreed, we will address this error case and free the resources appropriately.

>> +		goto free;
>> +	}
>> +
>> +	/* remove unsupported modes */
>> +	phy_remove_link_mode(emac->phydev, ETHTOOL_LINK_MODE_10baseT_Full_BIT);
>> +
>> +	phy_remove_link_mode(emac->phydev, ETHTOOL_LINK_MODE_10baseT_Half_BIT);
>> +	phy_remove_link_mode(emac->phydev, ETHTOOL_LINK_MODE_100baseT_Half_BIT);
>> +
>> +	phy_remove_link_mode(emac->phydev, ETHTOOL_LINK_MODE_Pause_BIT);
>> +	phy_remove_link_mode(emac->phydev, ETHTOOL_LINK_MODE_Asym_Pause_BIT);
>> +
>> +	ndev->netdev_ops = &emac_netdev_ops;
>> +
>> +	return 0;
>> +free:
> 
> nit: This doesn't free anything.
> 

Sure. We will address in the next version.

>> +	prueth->emac[mac] = NULL;
>> +
>> +	return ret;
>> +}
> 
> ...

Thanks & Best Regards,
Basharath