Re: [PATCH net-next v6 4/7] stmmac: intel: configure SerDes according to the interface mode

[Simon Horman <horms@kernel.org>]

On Tue, Feb 04, 2025 at 02:10:17PM +0800, Choong Yong Liang wrote:
> Intel platform will configure the SerDes through PMC api based on the
> provided interface mode.
> 
> This patch adds several new functions below:-
> - intel_tsn_lane_is_available(): This new function reads FIA lane
>   ownership registers and common lane registers through IPC commands
>   to know which lane the mGbE port is assigned to.
> - intel_config_serdes(): To configure the SerDes based on the assigned
>   lane and latest interface mode, it sends IPC command to the PMC through
>   PMC driver/API. The PMC acts as a proxy for R/W on behalf of the driver.
> - intel_set_reg_access(): Set the register access to the available TSN
>   interface.
> 
> Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>

...

> +static int intel_config_serdes(struct net_device *ndev,
> +			       void *intel_data,
> +			       phy_interface_t interface)
> +{
> +	struct intel_priv_data *intel_priv = intel_data;
> +	struct stmmac_priv *priv = netdev_priv(ndev);
> +	int ret = 0;
> +
> +	if (!intel_tsn_lane_is_available(ndev, intel_priv)) {
> +		netdev_info(priv->dev,
> +			    "No TSN lane available to set the registers.\n");
> +		goto pmc_read_error;
> +	}
> +
> +	if (intel_priv->pid_modphy == PID_MODPHY1) {
> +		if (interface == PHY_INTERFACE_MODE_2500BASEX) {
> +			ret = intel_set_reg_access(pid_modphy1_2p5g_regs,
> +						   ARRAY_SIZE(pid_modphy1_2p5g_regs));
> +		} else {
> +			ret = intel_set_reg_access(pid_modphy1_1g_regs,
> +						   ARRAY_SIZE(pid_modphy1_1g_regs));
> +		}
> +	} else {
> +		if (interface == PHY_INTERFACE_MODE_2500BASEX) {
> +			ret = intel_set_reg_access(pid_modphy3_2p5g_regs,
> +						   ARRAY_SIZE(pid_modphy3_2p5g_regs));
> +		} else {
> +			ret = intel_set_reg_access(pid_modphy3_1g_regs,
> +						   ARRAY_SIZE(pid_modphy3_1g_regs));
> +		}
> +	}
> +
> +	priv->plat->phy_interface = interface;
> +
> +	if (ret < 0)
> +		goto pmc_read_error;

Perhaps this is an artifact of earlier refactoring,
but the condition above seems to be without meaning
as in either case the code goes directly to pmc_read_error.

> +
> +pmc_read_error:
> +	intel_serdes_powerdown(ndev, intel_priv);
> +	intel_serdes_powerup(ndev, intel_priv);
> +
> +	return ret;
> +}
> +
>  static void common_default_data(struct plat_stmmacenet_data *plat)
>  {
>  	plat->clk_csr = 2;	/* clk_csr_i = 20-35MHz & MDC = clk_csr_i/16 */

...