Re: [PATCH net-next 3/3] net: dpaa2-mac: add backplane link mode support

[Ioana Ciornei <ioana.ciornei@nxp.com>]

On Thu, Feb 04, 2021 at 02:51:24PM +0000, Russell King - ARM Linux admin wrote:
> On Wed, Jan 20, 2021 at 10:19:01PM +0000, Ioana Ciornei wrote:
> > On Tue, Jan 19, 2021 at 03:36:09PM +0000, Russell King wrote:
> > > Add support for backplane link mode, which is, according to discussions
> > > with NXP earlier in the year, is a mode where the OS (Linux) is able to
> > > manage the PCS and Serdes itself.
> > 
> > Indeed, DPMACs in TYPE_BACKPLANE can have both their PCS and SerDes managed
> > by Linux (since the firmware is not touching these).
> > That being said, DPMACs in TYPE_PHY (the type that is already supported
> > in dpaa2-mac) can also have their PCS managed by Linux (no interraction
> > from the firmware's part with the PCS, just the SerDes).
> > 
> > All in all, this patch is not needed for this particular usecase, where
> > the switch between 1000Base-X and SGMII is done by just a minor
> > reconfiguration in the PCS, without the need for SerDes changes.
> > 
> > Also, with just the changes from this patch, a interface connected to a
> > DPMAC in TYPE_BACKPLANE is not even creating a phylink instance. It's
> > mainly because of this check from dpaa2-eth:
> > 
> > 	if (dpaa2_eth_is_type_phy(priv)) {
> > 		err = dpaa2_mac_connect(mac);
> > 
> > 
> > I would suggest just dropping this patch.
> 
> Hi Ioana,
> 
> So what is happening with this series given our discussions off-list?
> 

Let's also accept TYPE_BACKPLANE as you suggested.

> Do I resend it as-is?
> 

For the net-next, you would also need the following diff on top of your changes in patch 3/3:

--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
@@ -695,7 +695,9 @@ static inline unsigned int dpaa2_eth_rx_head_room(struct dpaa2_eth_priv *priv)

 static inline bool dpaa2_eth_is_type_phy(struct dpaa2_eth_priv *priv)
 {
-       if (priv->mac && priv->mac->attr.link_type == DPMAC_LINK_TYPE_PHY)
+       if (priv->mac &&
+           (priv->mac->attr.link_type == DPMAC_LINK_TYPE_PHY ||
+            priv->mac->attr.link_type == DPMAC_LINK_TYPE_BACKPLANE))
                return true;

        return false;

Would you mind amending your commit with this and resending the series?

Thanks,
Ioana