RE: [PATCH/RFC 1/2] ravb: Preparation for supporting Gigabit Ethernet driver

[Biju Das <biju.das.jz@bp.renesas.com>]

Hello Sergei Shtylyov,

Thanks for the feedback.

> Subject: Re: [PATCH/RFC 1/2] ravb: Preparation for supporting Gigabit
> Ethernet driver
> 
> Hello!
> 
> On 7/14/21 5:54 PM, Biju Das wrote:
> 
> > The DMAC and EMAC blocks of Gigabit Ethernet IP is almost similar to
> > Ethernet AVB. With few canges in driver we can support both the IP.
> > This patch is in preparation for supporting the same.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> [...]
> > diff --git a/drivers/net/ethernet/renesas/ravb.h
> > b/drivers/net/ethernet/renesas/ravb.h
> > index 86a1eb0634e8..80e62ca2e3d3 100644
> > --- a/drivers/net/ethernet/renesas/ravb.h
> > +++ b/drivers/net/ethernet/renesas/ravb.h
> > @@ -864,7 +864,7 @@ enum GECMR_BIT {
> >
> >  /* The Ethernet AVB descriptor definitions. */  struct ravb_desc {
> > -	__le16 ds;		/* Descriptor size */
> > +	__le16 ds;	/* Descriptor size */
> 
>     Oops! But this should be a matter of the seperate patch if you want to
> fix whitespace...

OK. Will send as separate patch.

> 
> [...]
> > diff --git a/drivers/net/ethernet/renesas/ravb_main.c
> > b/drivers/net/ethernet/renesas/ravb_main.c
> > index 4afff320dfd0..7e6feda59f4a 100644
> > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > @@ -217,6 +217,29 @@ static int ravb_tx_free(struct net_device *ndev,
> > int q, bool free_txed_only)  }
> >
> >  /* Free skb's and DMA buffers for Ethernet AVB */
> > +static void ravb_ring_free_ex(struct net_device *ndev, int q)
> 
>    What does _ex() suffix mean (seems rather poor chice)? Perhaps rx would
> be better?

The rationale behind suffix "_ex" is "extend" the existing function to support both AVB and Gigabit ethernet IP.

> 
> > +{
> > +	struct ravb_private *priv = netdev_priv(ndev);
> > +	int ring_size;
> > +	int i;
> > +
> > +	for (i = 0; i < priv->num_rx_ring[q]; i++) {
> > +		struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
> > +
> > +		if (!dma_mapping_error(ndev->dev.parent,
> > +				       le32_to_cpu(desc->dptr)))
> > +			dma_unmap_single(ndev->dev.parent,
> > +					 le32_to_cpu(desc->dptr),
> > +					 RX_BUF_SZ,
> > +					 DMA_FROM_DEVICE);
> > +	}
> > +	ring_size = sizeof(struct ravb_ex_rx_desc) *
> > +		    (priv->num_rx_ring[q] + 1);
> > +	dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q],
> > +			  priv->rx_desc_dma[q]);
> > +	priv->rx_ring[q] = NULL;
> > +}
> > +
> >  static void ravb_ring_free(struct net_device *ndev, int q)  {
> >  	struct ravb_private *priv = netdev_priv(ndev);
> [...]
> > @@ -272,26 +281,15 @@ static void ravb_ring_free(struct net_device
> > *ndev, int q)  }
> >
> >  /* Format skb and descriptor buffer for Ethernet AVB */ -static void
> > ravb_ring_format(struct net_device *ndev, int q)
> > +static void ravb_ring_format_ex(struct net_device *ndev, int q)
> 
>    Again, what the _ex suffix mean?
> 
> [..]
> > @@ -396,7 +414,7 @@ static int ravb_ring_init(struct net_device *ndev,
> > int q)  }
> >
> >  /* E-MAC init function */
> > -static void ravb_emac_init(struct net_device *ndev)
> > +static void ravb_emac_init_ex(struct net_device *ndev)
> 
>    Same question for the 3rd time... :-)
> 
> [...]
> > @@ -422,29 +440,15 @@ static void ravb_emac_init(struct net_device
> *ndev)
> >  	ravb_write(ndev, ECSIPR_ICDIP | ECSIPR_MPDIP | ECSIPR_LCHNGIP,
> > ECSIPR);  }
> >
> > +static void ravb_emac_init(struct net_device *ndev) {
> > +	ravb_emac_init_ex(ndev);
> 
>    Hm, looks pretty useless...

Will make this as a separate single factorisation patch supporting both IP's. So that
Reviewing will be easier.

> 
> > +}
> > +
> >  /* Device init function for Ethernet AVB */ -static int
> > ravb_dmac_init(struct net_device *ndev)
> > +static void ravb_dmac_init_ex(struct net_device *ndev)
> 
>    4th _ex...
> 
> [...]
> > @@ -532,7 +561,7 @@ static void ravb_rx_csum(struct sk_buff *skb)  }
> >
> >  /* Packet receive function for Ethernet AVB */ -static bool
> > ravb_rx(struct net_device *ndev, int *quota, int q)
> > +static bool ravb_rx_ex(struct net_device *ndev, int *quota, int q)
> >  {
> >  	struct ravb_private *priv = netdev_priv(ndev);
> >  	int entry = priv->cur_rx[q] % priv->num_rx_ring[q]; @@ -647,6
> > +676,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int
> q)
> >  	return boguscnt <= 0;
> >  }
> >
> > +static bool ravb_rx(struct net_device *ndev, int *quota, int q) {
> > +	return ravb_rx_ex(ndev, quota, q);
> > +}
> > +
> 
>    Looks pretty useless...

OK. Will make this as a separate single factorisation patch supporting both IP's. So that
Reviewing will be easier.

> 
> [...]
> > @@ -920,7 +954,7 @@ static int ravb_poll(struct napi_struct *napi, int
> budget)
> >  	if (ravb_rx(ndev, &quota, q))
> >  		goto out;
> >
> > -	/* Processing RX Descriptor Ring */
> > +	/* Processing TX Descriptor Ring */
> 
>     Hm, looka like a missing comment fix from the patch refactoring
> ravb_poll()...

OK. Will send this as separate patch.

> 
> [...]
> > @@ -2059,17 +2094,22 @@ static int ravb_probe(struct platform_device
> *pdev)
> >  	if (!ndev)
> >  		return -ENOMEM;
> >
> > +	/* The Ether-specific entries in the device structure. */
> > +	ndev->base_addr = res->start;
> > +
> > +	chip_id = (enum ravb_chip_id)of_device_get_match_data(&pdev->dev);
> > +
> > +	SET_NETDEV_DEV(ndev, &pdev->dev);
> > +
> > +	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);
> >
> > -	/* The Ether-specific entries in the device structure. */
> > -	ndev->base_addr = res->start;
> > -
> > -	chip_id = (enum ravb_chip_id)of_device_get_match_data(&pdev->dev);
> > -
> 
>    What does that hunk achieve?

RZ/G2L ethernet needs to de-assert the reset(in case bootloader didn't dessert). In that case
Clocks need to be turned on after that.

> 
> >  	if (chip_id == RCAR_GEN3)
> >  		irq = platform_get_irq_byname(pdev, "ch22");
> >  	else
> [...]
> > @@ -2257,7 +2292,7 @@ static int ravb_remove(struct platform_device
> *pdev)
> >  	struct ravb_private *priv = netdev_priv(ndev);
> >
> >  	/* Stop PTP Clock driver */
> > -	if (priv->chip_id != RCAR_GEN2)
> > +	if (priv->chip_id == RCAR_GEN3)
> >  		ravb_ptp_stop(ndev);
> >
> >  	clk_disable_unprepare(priv->refclk);
> > @@ -2362,7 +2397,7 @@ static int __maybe_unused ravb_resume(struct
> device *dev)
> >  	/* Request GTI loading */
> >  	ravb_modify(ndev, GCCR, GCCR_LTI, GCCR_LTI);
> >
> > -	if (priv->chip_id != RCAR_GEN2)
> > +	if (priv->chip_id == RCAR_GEN3)
> >  		ravb_set_delay_mode(ndev);
> 
>    Probably, all those chip_id check fixes deserve a patch of their own...

OK. Agreed, since the delays are specifics to GEN3.

Regards,
Biju

> 
> MBR, Sergei