Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

[Maxime Chevallier]

Hi Andrew,

On Tue, 28 Nov 2023 17:37:30 +0100
Andrew Lunn <andrew@xxxxxxx> wrote:

> On Tue, Nov 28, 2023 at 10:45:37AM +0100, Maxime Chevallier wrote:
> > The SGMII adapter isn't present on all dwmac-socfpga implementations.
> > Make sure we don't try to configure it if we don't have this adapter.  
> 
> If it does not exist, why even try to call socfpga_sgmii_config()?
> 
> It seems like this test needs moving up the call stack. socfpga_gen5_set_phy_mode():
> 
> 	if (phymode == PHY_INTERFACE_MODE_SGMII)
> 		if (dwmac->sgmii_adapter_base)
> 			socfpga_sgmii_config(dwmac, true);
> 		else
> 			return -EINVAL;

I don't have access to a platform with the SGMII adapter available, but
my understanding is that we shouldn't error-out when we don't have the
adapter, as some other component (like the lynx PCS) might be there to
handle that mode.

However you have a valid point in that we might want to check if we
have either an SGMII adapter or a PCS, and if we have none of these we
error-out. Thanks for the suggestion, I'll address that :)

Maxime