Re: [PATCH v3 2/2] net: macb: Clean up macb_validate

On 10/13/21 4:29 AM, Antoine Tenart wrote:

Quoting Sean Anderson (2021-10-12 21:46:44)

quoted

+       /* There are three major types of interfaces we support:
+        * - (R)MII supporting 10/100 Mbit/s
+        * - GMII, RGMII, and SGMII supporting 10/100/1000 Mbit/s
+        * - 10GBASER supporting 10 Gbit/s only
+        * Because GMII and MII both support 10/100, GMII falls through to MII.
+        *
+        * If we can't support an interface mode, we just clear the supported
+        * mask and return. The major complication is that if we get
+        * PHY_INTERFACE_MODE_NA, we must return all modes we support.  Because
+        * of this, NA starts at the top of the switch and falls all the way to
+        * the bottom, and doesn't return early if we don't support a
+        * particular mode.
+        */
+       switch (state->interface) {
+       case PHY_INTERFACE_MODE_NA:
+       case PHY_INTERFACE_MODE_10GBASER:
+               if (bp->caps & MACB_CAPS_HIGH_SPEED &&
+                   bp->caps & MACB_CAPS_PCS &&
+                   bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) {
+                       phylink_set_10g_modes(mask);
+                       phylink_set(mask, 10000baseKR_Full);
+               } else if (one) {
+                       bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
+                       return;
+               }
+               if (one)
+                       break;

This can go in the first if block.

OK.

quoted

+               fallthrough;
+       case PHY_INTERFACE_MODE_GMII:
+       case PHY_INTERFACE_MODE_RGMII:
+       case PHY_INTERFACE_MODE_RGMII_ID:
+       case PHY_INTERFACE_MODE_RGMII_RXID:
+       case PHY_INTERFACE_MODE_RGMII_TXID:
+       case PHY_INTERFACE_MODE_SGMII:
+               if (macb_is_gem(bp)) {
+                       if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) {

Is not having MACB_CAPS_GIGABIT_MODE_AVAILABLE acceptable here, or
should the two above checks be merged?

As I understand it, macb_is_gem does not imply GIGABIT_MODE. I'm not
sure if GIGABIT_MODE implies macb_is_gem. The logic here is mostly to
match that in prepare()/config(). From what I can gather, all accesses
to GEM registers are protected by macb_is_gem.

--Sean

quoted

+                               phylink_set(mask, 1000baseT_Full);
+                               phylink_set(mask, 1000baseX_Full);
+                               if (!(bp->caps & MACB_CAPS_NO_GIGABIT_HALF))
+                                       phylink_set(mask, 1000baseT_Half);
+                       }
+               } else if (one) {
+                       bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
+                       return;
+               }
+               fallthrough;
+       case PHY_INTERFACE_MODE_MII:
+       case PHY_INTERFACE_MODE_RMII:
+               phylink_set(mask, 10baseT_Half);
+               phylink_set(mask, 10baseT_Full);
+               phylink_set(mask, 100baseT_Half);
+               phylink_set(mask, 100baseT_Full);
+               break;
+       default:
                bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
                return;
        }

(For readability, it's not for me to decide in the end).

Thanks,
Antoine