netdev - RE: [PATCH net-next 04/13] ravb: Add ptp_cfg_active to struct ravb_hw

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Date:   Thu, 26 Aug 2021 10:34:46 +0000
From:   Biju Das <biju.das.jz@...renesas.com>
To:     Sergey Shtylyov <s.shtylyov@....ru>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
CC:     Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
        Andrew Lunn <andrew@...n.ch>,
        Sergei Shtylyov <sergei.shtylyov@...il.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Adam Ford <aford173@...il.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>
Subject: RE: [PATCH net-next 04/13] ravb: Add ptp_cfg_active to struct
 ravb_hw_info

Hi Sergei,

> Subject: Re: [PATCH net-next 04/13] ravb: Add ptp_cfg_active to struct
> ravb_hw_info
> 
> On 26.08.2021 9:20, Biju Das wrote:
> 
> [...]
> >>> There are some H/W differences for the gPTP feature between R-Car
> >>> Gen3, R-Car Gen2, and RZ/G2L as below.
> >>>
> >>> 1) On R-Car Gen3, gPTP support is active in config mode.
> >>> 2) On R-Car Gen2, gPTP support is not active in config mode.
> >>> 3) RZ/G2L does not support the gPTP feature.
> >>>
> >>> Add a ptp_cfg_active hw feature bit to struct ravb_hw_info for
> >>> supporting gPTP active in config mode for R-Car Gen3.
> >>
> >>     Wait, we've just done this ion the previous patch!
> >>
> >>> This patch also removes enum ravb_chip_id, chip_id from both struct
> >>> ravb_hw_info and struct ravb_private, as it is unused.
> >>>
> >>> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> >>> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> >>> ---
> >>>   drivers/net/ethernet/renesas/ravb.h      |  8 +-------
> >>>   drivers/net/ethernet/renesas/ravb_main.c | 12 +++++-------
> >>>   2 files changed, 6 insertions(+), 14 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ethernet/renesas/ravb.h
> >>> b/drivers/net/ethernet/renesas/ravb.h
> >>> index 9ecf1a8c3ca8..209e030935aa 100644
> >>> --- a/drivers/net/ethernet/renesas/ravb.h
> >>> +++ b/drivers/net/ethernet/renesas/ravb.h
> >>> @@ -979,17 +979,11 @@ struct ravb_ptp {
> >>>   	struct ravb_ptp_perout perout[N_PER_OUT];  };
> >>>
> >>> -enum ravb_chip_id {
> >>> -	RCAR_GEN2,
> >>> -	RCAR_GEN3,
> >>> -};
> >>> -
> >>>   struct ravb_hw_info {
> >>>   	const char (*gstrings_stats)[ETH_GSTRING_LEN];
> >>>   	size_t gstrings_size;
> >>>   	netdev_features_t net_hw_features;
> >>>   	netdev_features_t net_features;
> >>> -	enum ravb_chip_id chip_id;
> >>>   	int stats_len;
> >>>   	size_t max_rx_len;
> >>
> >>     I would put the above in a spearte patch...
> 
>     Separate. :-)
> 
> >>>   	unsigned aligned_tx: 1;
> >>> @@ -999,6 +993,7 @@ struct ravb_hw_info {
> >>>   	unsigned tx_counters:1;		/* E-MAC has TX counters */
> >>>   	unsigned multi_irqs:1;		/* AVB-DMAC and E-MAC has
> multiple
> >> irqs */
> >>>   	unsigned no_ptp_cfg_active:1;	/* AVB-DMAC does not support
> gPTP
> >> active in config mode */
> >>> +	unsigned ptp_cfg_active:1;	/* AVB-DMAC has gPTP support active in
> >> config mode */
> >>
> >>     Huh?
> >>
> >>>   };
> >>>
> >>>   struct ravb_private {
> >> [...]
> >>> @@ -2216,7 +2213,7 @@ static int ravb_probe(struct platform_device
> >> *pdev)
> >>>   	INIT_LIST_HEAD(&priv->ts_skb_list);
> >>>
> >>>   	/* Initialise PTP Clock driver */
> >>> -	if (info->chip_id != RCAR_GEN2)
> >>> +	if (info->ptp_cfg_active)
> >>>   		ravb_ptp_init(ndev, pdev);
> >>
> >>     What's that? Didn't you touch this lie in patch #3?
> >>
> >>     This seems lie a NAK bait... :-(
> >
> > Please refer the original patch[1] which introduced gPTP support active
> in config mode.
> > I am sure this will clear all your doubts.
> 
>     It hasn't. Why do we need 2 bit fields (1 "positive" and 1 "negative")
> for the same feature is beyond me.

The reason is mentioned in commit description, Do you agree 1, 2 and 3 mutually exclusive?

1) On R-Car Gen3, gPTP support is active in config mode.
2) On R-Car Gen2, gPTP support is not active in config mode.
3) RZ/G2L does not support the gPTP feature.

Regards,
Biju

> 
> > [1]
> > https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
> > kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fnext%2Flinux-next.git%
> > 2Fcommit%2Fdrivers%2Fnet%2Fethernet%2Frenesas%2Fravb_main.c%3Fh%3Dnext
> > -20210825%26id%3Df5d7837f96e53a8c9b6c49e1bc95cf0ae88b99e8&amp;data=04%
> > 7C01%7Cbiju.das.jz%40bp.renesas.com%7C142c7f172b4141617e7008d9687c7881
> > %7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C637655706082218315%7CUnk
> > nown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWw
> > iLCJXVCI6Mn0%3D%7C1000&amp;sdata=Miy2q4JGEZpwLHlkGxlEBK8P0XAPzuHUX6xib
> > FS8nDs%3D&amp;reserved=0
> >
> > Regards,
> > Biju
> 
> MBR, Sergey