Re: [PATCH net-next 08/13] net: dsa: hellcreek: deny tc-taprio changes to per-tc max SDU

Vladimir Oltean
2022-09-14T18:41:00Z

On Wed, Sep 14, 2022 at 08:13:53PM +0200, Kurt Kanzenbach wrote:
> I'd rather like to see that feature implemented :-). Something like below.
>
> From 3d44683979bf50960125fa3005b1142af61525c7 Mon Sep 17 00:00:00 2001
> From: Kurt Kanzenbach <kurt@linutronix.de>
> Date: Wed, 14 Sep 2022 19:51:40 +0200
> Subject: [PATCH] net: dsa: hellcreek: Offload per-tc max SDU from tc-taprio
>
> Add support for configuring the max SDU per priority and per port. If not
> specified, keep the default.
>
> Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---

Nice :) Do you also want the iproute2 patch, so you can test it?

> drivers/net/dsa/hirschmann/hellcreek.c | 61 +++++++++++++++++++++++---
> drivers/net/dsa/hirschmann/hellcreek.h | 7 +++
> 2 files changed, 61 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/dsa/hirschmann/hellcreek.c b/drivers/net/dsa/hirschmann/hellcreek.c
> index 5ceee71d9a25..1b22710e1641 100644
> --- a/drivers/net/dsa/hirschmann/hellcreek.c
> +++ b/drivers/net/dsa/hirschmann/hellcreek.c
> @@ -128,6 +128,16 @@ static void hellcreek_select_prio(struct hellcreek *hellcreek, int prio)
> hellcreek_write(hellcreek, val, HR_PSEL);
> }
>
> +static void hellcreek_select_port_prio(struct hellcreek *hellcreek, int port,
> + int prio)
> +{
> + u16 val = port << HR_PSEL_PTWSEL_SHIFT;
> +
> + val |= prio << HR_PSEL_PRTCWSEL_SHIFT;
> +
> + hellcreek_write(hellcreek, val, HR_PSEL);
> +}
> +
> static void hellcreek_select_counter(struct hellcreek *hellcreek, int counter)
> {
> u16 val = counter << HR_CSEL_SHIFT;
> @@ -1537,6 +1547,42 @@ hellcreek_port_prechangeupper(struct dsa_switch *ds, int port,
> return ret;
> }
>
> +static void hellcreek_setup_maxsdu(struct hellcreek *hellcreek, int port,
> + const struct tc_taprio_qopt_offload *schedule)
> +{
> + int tc;
> +
> + for (tc = 0; tc < 8; ++tc) {
> + u16 val;
> +
> + if (!schedule->max_sdu[tc])
> + continue;
> +
> + hellcreek_select_port_prio(hellcreek, port, tc);
> +
> + val = (schedule->max_sdu[tc] & HR_PTPRTCCFG_MAXSDU_MASK)
> + << HR_PTPRTCCFG_MAXSDU_SHIFT;
> +
> + hellcreek_write(hellcreek, val, HR_PTPRTCCFG);

So the maxSDU hardware register tracks exactly the L2 payload size, like
the software variable does, or does it include the Ethernet header size
and/or FCS?

> + }
> +}