Re: [PATCH net-next v4 03/10] net: sparx5: add hostmode with phylink support

[Steen Hegelund <steen.hegelund@microchip.com>]

Hi Russell,

Thanks for your comments.

On Mon, 2021-06-21 at 15:26 +0100, Russell King (Oracle) wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Tue, Jun 15, 2021 at 10:50:27AM +0200, Steen Hegelund wrote:
> > This patch adds netdevs and phylink support for the ports in the switch.
> > It also adds register based injection and extraction for these ports.
> > 
> > Frame DMA support for injection and extraction will be added in a later
> > series.
> > 
> > Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
> > Signed-off-by: Bjarni Jonasson <bjarni.jonasson@microchip.com>
> > Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>
> 
> Hi,
> 
> While looking at this patch, I found sparx5_destroy_netdev() which seems
> to be unreferenced - it may be referenced in a future patch. However,
> this means that while sparx5_create_port() creates the phylink
> structure, there is nothing in this patch that cleans it up.

Yes the sparx5_destroy_netdev() is currently being added in a later patch. 
I will move it here instead. 

> 
> I'm puzzled by the call to phylink_disconnect_phy() in
> sparx5_destroy_netdev() too - surely if we get to the point of tearing
> down stuff that we've created at initialisation, the interface had
> better be down?

Yes the unregister_netdev is missing. I will add that before the phylink is destroyed.

> 
> > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_phylink.c
> > b/drivers/net/ethernet/microchip/sparx5/sparx5_phylink.c
> > new file mode 100644
> > index 000000000000..c17a3502645a
> > --- /dev/null
> > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_phylink.c
> > @@ -0,0 +1,185 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/* Microchip Sparx5 Switch driver
> > + *
> > + * Copyright (c) 2021 Microchip Technology Inc. and its subsidiaries.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/phylink.h>
> > +#include <linux/device.h>
> > +#include <linux/netdevice.h>
> > +#include <linux/sfp.h>
> > +
> > +#include "sparx5_main_regs.h"
> > +#include "sparx5_main.h"
> > +
> > +static void sparx5_phylink_validate(struct phylink_config *config,
> > +                                 unsigned long *supported,
> > +                                 struct phylink_link_state *state)
> > +{
> > +     struct sparx5_port *port = netdev_priv(to_net_dev(config->dev));
> > +     __ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
> > +
> > +     phylink_set(mask, Autoneg);
> > +     phylink_set_port_modes(mask);
> > +     phylink_set(mask, Pause);
> > +     phylink_set(mask, Asym_Pause);
> > +
> > +     switch (state->interface) {
> > +     case PHY_INTERFACE_MODE_5GBASER:
> > +     case PHY_INTERFACE_MODE_10GBASER:
> > +     case PHY_INTERFACE_MODE_25GBASER:
> > +     case PHY_INTERFACE_MODE_NA:
> > +             if (port->conf.bandwidth == SPEED_5000)
> > +                     phylink_set(mask, 5000baseT_Full);
> > +             if (port->conf.bandwidth == SPEED_10000) {
> > +                     phylink_set(mask, 5000baseT_Full);
> > +                     phylink_set(mask, 10000baseT_Full);
> > +                     phylink_set(mask, 10000baseCR_Full);
> > +                     phylink_set(mask, 10000baseSR_Full);
> > +                     phylink_set(mask, 10000baseLR_Full);
> > +                     phylink_set(mask, 10000baseLRM_Full);
> > +                     phylink_set(mask, 10000baseER_Full);
> > +             }
> > +             if (port->conf.bandwidth == SPEED_25000) {
> > +                     phylink_set(mask, 5000baseT_Full);
> > +                     phylink_set(mask, 10000baseT_Full);
> > +                     phylink_set(mask, 10000baseCR_Full);
> > +                     phylink_set(mask, 10000baseSR_Full);
> > +                     phylink_set(mask, 10000baseLR_Full);
> > +                     phylink_set(mask, 10000baseLRM_Full);
> > +                     phylink_set(mask, 10000baseER_Full);
> > +                     phylink_set(mask, 25000baseCR_Full);
> > +                     phylink_set(mask, 25000baseSR_Full);
> > +             }
> 
> I really need to fix phylink so we shouldn't be lying about which
> speeds are supported over a 10GBASER link... but that's something
> for the future.
> 
> > +static bool port_conf_has_changed(struct sparx5_port_config *a, struct sparx5_port_config *b)
> > +{
> > +     if (a->speed != b->speed ||
> > +         a->portmode != b->portmode ||
> > +         a->autoneg != b->autoneg ||
> > +         a->pause != b->pause ||
> > +         a->power_down != b->power_down ||
> > +         a->media != b->media)
> > +             return true;
> > +     return false;
> > +}
> 
> Should this be positioned somewhere else rather than in the middle of
> the sparx5 phylink functions (top of file maybe?)

I will move it to the top.

> 
> > +static void sparx5_phylink_mac_config(struct phylink_config *config,
> > +                                   unsigned int mode,
> > +                                   const struct phylink_link_state *state)
> > +{
> > +     struct sparx5_port *port = netdev_priv(to_net_dev(config->dev));
> > +
> > +     port->conf.autoneg = state->an_enabled;
> > +     port->conf.pause = state->pause;
> 
> What are you doing with state->pause? It looks to me like you're using
> both of these to carry configuration to pcs_config?

Hmm.  I have now removed that, and will the pcs_config() to collect the advertised pause mode.

> 
> Generally, an_enabled can be pulled out of the advertising mask, it
> should always reflect ETHTOOL_LINK_MODE_Autoneg_BIT. The "pause"
> interpretation of the pause bits here are somewhat hardware specific.
> It depends whether the MAC automatically receives state information
> from the PCS or not. If the hardware does, then MLO_PAUSE_AN indicates
> whether that should be permitted or not.
> 
> Otherwise, the advertising mask in pcs_config() indicates which pause
> modes should be advertised, and the tx_pause/rx_pause in the
> *_link_up() indicates what should actually be set.

OK. I will use the pcs_config() to collect the advertising mode and the .._link_up() to collect the
configuration value.

> 
> Thanks.
> 
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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-- 
BR
Steen

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steen.hegelund@microchip.com