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From: Biju Das <biju.das.jz@bp.renesas.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Sergei Shtylyov <sergei.shtylyov@gmail.com>,
	Sergey Shtylyov <s.shtylyov@omprussia.ru>,
	Adam Ford <aford173@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Andrew Gabbasov <andrew_gabbasov@mentor.com>,
	Yuusuke Ashizuka <ashiduka@fujitsu.com>,
	netdev <netdev@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: RE: [PATCH/RFC 2/2] ravb: Add GbEthernet driver support
Date: Thu, 15 Jul 2021 10:31:24 +0000	[thread overview]
Message-ID: <OS0PR01MB59222DC66DFF9A363A60E40586129@OS0PR01MB5922.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdW-NeDqiNDzQzzqnmQB2qL0Bc1-m+NQu9v8bK+_+7HxWQ@mail.gmail.com>

Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH/RFC 2/2] ravb: Add GbEthernet driver support
> 
> Hi Biju,
> 
> On Wed, Jul 14, 2021 at 4:54 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > Add Gigabit Ethernet driver support.
> >
> > The Gigabit Etherner IP consists of Ethernet controller (E-MAC),
> > Internal TCP/IP Offload Engine (TOE) and Dedicated Direct memory
> > access controller (DMAC).
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/net/ethernet/renesas/ravb.h
> > +++ b/drivers/net/ethernet/renesas/ravb.h
> 
> > @@ -986,6 +1068,7 @@ struct ravb_ptp {  enum ravb_chip_id {
> >         RCAR_GEN2,
> >         RCAR_GEN3,
> > +       RZ_G2L,
> >  };
> 
> Instead of adding another chip type, it may be better to replace the chip
> type by a structure with feature bits, values, and function pointers (see
> examples below).
 
> BTW given the ravb driver is based on the sh_eth driver ("Ethernet AVB
> includes an Gigabit Ethernet controller (E-MAC) that is basically
> compatible with SuperH Gigabit Ethernet E-MAC"), and seeing the amount of
> changes, I'm wondering if rgeth is closer to sh_eth? ;-)

With sh_eth driver,We can reuse only E-MAC IP. But with RAVB we can reuse both DMAC and E-MAC.
Hence I believe it is closer to AVB.

> 
> > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> 
> > @@ -247,8 +288,12 @@ static void ravb_ring_free(struct net_device *ndev,
> int q)
> >         int ring_size;
> >         int i;
> >
> > -       if (priv->rx_ring[q]) {
> > -               ravb_ring_free_ex(ndev, q);
> > +       if (priv->chip_id == RZ_G2L) {
> > +               if (priv->rgeth_rx_ring[q])
> > +                       rgeth_ring_free_ex(ndev, q);
> > +       } else {
> > +               if (priv->rx_ring[q])
> > +                       ravb_ring_free_ex(ndev, q);
> >         }
> 
> Could be called through a function pointer instead.

OK.
> 
> > @@ -356,7 +434,7 @@ static void ravb_ring_format(struct net_device
> > *ndev, int q)  static int ravb_ring_init(struct net_device *ndev, int
> > q)  {
> >         struct ravb_private *priv = netdev_priv(ndev);
> > -       size_t skb_sz = RX_BUF_SZ;
> > +       size_t skb_sz = (priv->chip_id == RZ_G2L) ? RGETH_RCV_BUFF_MAX
> > + : RX_BUF_SZ;
> 
> Could use a value in the structure.
OK.
> 
> > @@ -730,7 +1054,7 @@ static void ravb_emac_interrupt_unlocked(struct
> net_device *ndev)
> >         ecsr = ravb_read(ndev, ECSR);
> >         ravb_write(ndev, ecsr, ECSR);   /* clear interrupt */
> >
> > -       if (ecsr & ECSR_MPD)
> > +       if (priv->chip_id != RZ_G2L && (ecsr & ECSR_MPD))
> 
> Could use a feature bit.

OK.

> 
> > @@ -2104,11 +2578,19 @@ static int ravb_probe(struct platform_device
> *pdev)
> >         priv = netdev_priv(ndev);
> >         priv->chip_id = chip_id;
> >
> > -       ndev->features = NETIF_F_RXCSUM;
> > -       ndev->hw_features = NETIF_F_RXCSUM;
> > -
> > -       pm_runtime_enable(&pdev->dev);
> > -       pm_runtime_get_sync(&pdev->dev);
> > +       if (chip_id == RZ_G2L) {
> > +               ndev->hw_features |= (NETIF_F_HW_CSUM | NETIF_F_RXCSUM);
> > +               priv->rstc = devm_reset_control_get(&pdev->dev, NULL);
> 
> R-Car Gen2 and Gen3 describe a reset in DT, too.
> Does it hurt to always use the reset?

OK will use reset.


> 
> > +               if (IS_ERR(priv->rstc)) {
> > +                       dev_err(&pdev->dev, "failed to get cpg
> > + reset\n");
> 
> dev_err_probe(), to avoid printing an error on -EPROBE_DEFER.

OK.


Regards,
Biju

> 
> > +                       free_netdev(ndev);
> > +                       return PTR_ERR(priv->rstc);
> > +               }
> > +               reset_control_deassert(priv->rstc);
> > +       } else {
> > +               ndev->features = NETIF_F_RXCSUM;
> > +               ndev->hw_features = NETIF_F_RXCSUM;
> > +       }
> 
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-
> m68k.org
> 
> In personal conversations with technical people, I call myself a hacker.
> But when I'm talking to journalists I just say "programmer" or something
> like that.
>                                 -- Linus Torvalds

  reply	other threads:[~2021-07-15 10:31 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 14:54 [PATCH/RFC 0/2] Add Gigabit Ethernet " Biju Das
2021-07-14 14:54 ` [PATCH/RFC 1/2] ravb: Preparation for supporting Gigabit Ethernet driver Biju Das
2021-07-14 15:39   ` Andrew Lunn
2021-07-14 16:24     ` Biju Das
2021-07-14 18:20   ` Sergei Shtylyov
2021-07-15  6:49     ` Biju Das
2021-07-14 14:54 ` [PATCH/RFC 2/2] ravb: Add GbEthernet driver support Biju Das
2021-07-14 16:02   ` Andrew Lunn
2021-07-14 17:01     ` Biju Das
2021-07-14 17:25       ` Andrew Lunn
2021-07-14 17:56         ` Biju Das
2021-07-15 10:13   ` Geert Uytterhoeven
2021-07-15 10:31     ` Biju Das [this message]
2021-07-19 20:41   ` Sergei Shtylyov
2021-07-20  6:32     ` Biju Das
2021-07-14 19:26 ` [PATCH/RFC 0/2] Add Gigabit Ethernet " Sergei Shtylyov

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