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References: <20220112173312.764660-1-miquel.raynal@bootlin.com> <20220112173312.764660-28-miquel.raynal@bootlin.com>
In-Reply-To: <20220112173312.764660-28-miquel.raynal@bootlin.com>
From:   Alexander Aring <alex.aring@gmail.com>
Date:   Wed, 12 Jan 2022 17:48:59 -0500
Message-ID: <CAB_54W5ojqi2obtNLihCMXsZkh+aN_cVbSTRptq3=PXkpknzJQ@mail.gmail.com>
Subject: Re: [wpan-next v2 27/27] net: ieee802154: ca8210: Refuse most of the
 scan operations
To:     Miquel Raynal <miquel.raynal@bootlin.com>
Cc:     Stefan Schmidt <stefan@datenfreihafen.org>,
        linux-wpan - ML <linux-wpan@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
        Michael Hennerich <michael.hennerich@analog.com>,
        Harry Morris <h.morris@cascoda.com>,
        Varka Bhadram <varkabhadram@gmail.com>,
        Xue Liu <liuxuenetmail@gmail.com>, Alan Ott <alan@signal11.us>,
        David Girault <david.girault@qorvo.com>,
        Romuald Despres <romuald.despres@qorvo.com>,
        Frederic Blain <frederic.blain@qorvo.com>,
        Nicolas Schodet <nico@ni.fr.eu.org>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        "linux-wireless@vger.kernel.org Wireless" 
        <linux-wireless@vger.kernel.org>
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Hi,

On Wed, 12 Jan 2022 at 12:34, Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>
> The Cascada 8210 hardware transceiver is kind of a hardMAC which
> interfaces with the softMAC and in practice does not support sending
> anything else than dataframes. This means we cannot send any BEACON_REQ
> during active scans nor any BEACON in general. Refuse these operations
> officially so that the user is aware of the limitation.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  drivers/net/ieee802154/ca8210.c | 25 ++++++++++++++++++++++++-
>  1 file changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
> index d3a9e4fe05f4..49c274280e3c 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -2385,6 +2385,25 @@ static int ca8210_set_promiscuous_mode(struct ieee802154_hw *hw, const bool on)
>         return link_to_linux_err(status);
>  }
>
> +static int ca8210_enter_scan_mode(struct ieee802154_hw *hw,
> +                                 struct cfg802154_scan_request *request)
> +{
> +       /* This xceiver can only send dataframes */
> +       if (request->type != NL802154_SCAN_PASSIVE)
> +               return -EOPNOTSUPP;
> +
> +       return 0;
> +}
> +
> +static int ca8210_enter_beacons_mode(struct ieee802154_hw *hw,
> +                                    struct cfg802154_beacons_request *request)
> +{
> +       /* This xceiver can only send dataframes */
> +       return -EOPNOTSUPP;
> +}
> +
> +static void ca8210_exit_scan_beacons_mode(struct ieee802154_hw *hw) { }
> +
>  static const struct ieee802154_ops ca8210_phy_ops = {
>         .start = ca8210_start,
>         .stop = ca8210_stop,
> @@ -2397,7 +2416,11 @@ static const struct ieee802154_ops ca8210_phy_ops = {
>         .set_cca_ed_level = ca8210_set_cca_ed_level,
>         .set_csma_params = ca8210_set_csma_params,
>         .set_frame_retries = ca8210_set_frame_retries,
> -       .set_promiscuous_mode = ca8210_set_promiscuous_mode
> +       .set_promiscuous_mode = ca8210_set_promiscuous_mode,
> +       .enter_scan_mode = ca8210_enter_scan_mode,
> +       .exit_scan_mode = ca8210_exit_scan_beacons_mode,
> +       .enter_beacons_mode = ca8210_enter_beacons_mode,
> +       .exit_beacons_mode = ca8210_exit_scan_beacons_mode,
>  };

so there is no flag that this driver can't support scanning currently
and it works now because the offload functionality will return
-ENOTSUPP? This is misleading because I would assume if it's not
supported we can do it by software which the driver can't do.

... I see that the offload functions now are getting used and have a
reason to be upstream, but the use of it is wrong.

- Alex