Re: [PATCH v3 RFC 4/4] net: dsa: hsr: Provide generic HSR ksz_hsr_{join|leave} functions

Lukasz Majewski
2023-09-05T16:51:02Z

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Hi Vladimir,

> On Mon, Sep 04, 2023 at 02:02:09PM +0200, Lukasz Majewski wrote:
> > This patch provides the common KSZ (i.e. Microchip) DSA code with
> > support for HSR aware devices.
> >
> > To be more specific - generic ksz_hsr_{join|leave} functions are
> > provided, now only supporting KSZ9477 IC.
> >
> > Signed-off-by: Lukasz Majewski <lukma@denx.de>
> > ---
> > Changes for v2:
> > - None
> >
> > Changes for v3:
> > - Do not return -EOPNOTSUPP for only PRP_V1 (as v2 will not be
> > caught)
>
> Should be squashed into patch 3/4. The split does not make the code
> easier to review for me.

So you recommend to have only one patch in which the hsr_join{leave}
function from ksz_common.c and ksz9477_hsr_join{leave} from ksz9477.c
are added?

>
> > ---
> > drivers/net/dsa/microchip/ksz_common.c | 69
> > ++++++++++++++++++++++++++ 1 file changed, 69 insertions(+)
> >
> > diff --git a/drivers/net/dsa/microchip/ksz_common.c
> > b/drivers/net/dsa/microchip/ksz_common.c index
> > 579fde54d1e1..91d1acaf4494 100644 ---
> > a/drivers/net/dsa/microchip/ksz_common.c +++
> > b/drivers/net/dsa/microchip/ksz_common.c @@ -16,6 +16,7 @@
> > #include <linux/etherdevice.h>
> > #include <linux/if_bridge.h>
> > #include <linux/if_vlan.h>
> > +#include <linux/if_hsr.h>
> > #include <linux/irq.h>
> > #include <linux/irqdomain.h>
> > #include <linux/of_mdio.h>
> > @@ -3433,6 +3434,72 @@ u16 ksz_hsr_get_ports(struct dsa_switch *ds)
> > return 0;
> > }
> >
> > +static int ksz_hsr_join(struct dsa_switch *ds, int port, struct
> > net_device *hsr) +{
> > + struct dsa_port *partner = NULL, *dp;
> > + struct ksz_device *dev = ds->priv;
> > + enum hsr_version ver;
> > + int ret;
> > +
> > + ret = hsr_get_version(hsr, &ver);
> > + if (ret)
> > + return ret;
> > +
> > + switch (dev->chip_id) {
> > + case KSZ9477_CHIP_ID:
> > + if (!(ver == HSR_V0 || ver == HSR_V1))
> > + return -EOPNOTSUPP;
>
> move the "default: return -EOPNOTSUPP" statement from below here.
>

Ok, I will add default statement with -EOPNOTSUPP.

> > + }
>
> I don't see any restriction to allow offloading a single HSR device.

As I've written in the other response - I've followed the xrs700x.c
convention.

Moreover, for me it seems more natural, that we only allow full HSR
support for 2 ports or none. Please be aware, that HSR supposed to
support only 2 ports, and having only one working is not recommended by
vendor.

> Looking at patch 3/4, that will obviously not work due to some
> hardware registers which are global and would be overwritten by the
> second HSR device.

I cannot guarantee that there will not be any "side effects" with this
approach. And to be honest - I would prefer to spent time on testing
recommended setups.

>
> For example, a5psw_port_bridge_join() has a similar restriction to
> offload a single bridge device.

HSR is IMHO a bit different than plain "bridge" offloading.

>
> If you return -EOPNOTSUPP, then DSA should fall back to an
> unoffloaded, 100% software-based HSR device, and that should work
> too.

And then we would have one port with SW HSR and another one with HW
HSR?

>It would be good if you could verify that the unoffloaded HSR
> works well after the changes too.

I've tested on KSZ9477-EVB the SW HSR operation with two ports (and two
or three boards) and HW HSR offloading. Results are presented in the
cover-letter.

>
> > +
> > + /* We can't enable redundancy on the switch until both
> > + * redundant ports have signed up.
> > + */
> > + dsa_hsr_foreach_port(dp, ds, hsr) {
> > + if (dp->index != port) {
> > + partner = dp;
> > + break;
> > + }
> > + }
> > +
> > + if (!partner)
> > + return 0;
> > +
> > + switch (dev->chip_id) {
> > + case KSZ9477_CHIP_ID:
> > + return ksz9477_hsr_join(ds, port, hsr, partner);
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int ksz_hsr_leave(struct dsa_switch *ds, int port,
> > + struct net_device *hsr)
> > +{
> > + struct dsa_port *partner = NULL, *dp;
> > + struct ksz_device *dev = ds->priv;
> > +
> > + dsa_hsr_foreach_port(dp, ds, hsr) {
> > + if (dp->index != port) {
> > + partner = dp;
> > + break;
> > + }
> > + }
> > +
> > + if (!partner)
> > + return 0;
> > +
> > + switch (dev->chip_id) {
> > + case KSZ9477_CHIP_ID:
> > + return ksz9477_hsr_leave(ds, port, hsr, partner);
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static const struct dsa_switch_ops ksz_switch_ops = {
> > .get_tag_protocol = ksz_get_tag_protocol,
> > .connect_tag_protocol = ksz_connect_tag_protocol,
> > @@ -3452,6 +3519,8 @@ static const struct dsa_switch_ops
> > ksz_switch_ops = { .get_sset_count = ksz_sset_count,
> > .port_bridge_join = ksz_port_bridge_join,
> > .port_bridge_leave = ksz_port_bridge_leave,
> > + .port_hsr_join = ksz_hsr_join,
> > + .port_hsr_leave = ksz_hsr_leave,
> > .port_stp_state_set = ksz_port_stp_state_set,
> > .port_pre_bridge_flags = ksz_port_pre_bridge_flags,
> > .port_bridge_flags = ksz_port_bridge_flags,
> > --
> > 2.20.1
> >
>

Best regards,

Lukasz Majewski

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