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

Vladimir Oltean
2023-09-05T17:08:11Z

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.

> ---
> 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.

> + }

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

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

If you return -EOPNOTSUPP, then DSA should fall back to an unoffloaded,
100% software-based HSR device, and that should work too. It would be
good if you could verify that the unoffloaded HSR works well after the
changes too.

> +
> + /* 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
>