Re: [PATCH v2 6/8] net: ti: icssg-ethtool: Adjust channel count for SR1.0

[Roger Quadros <rogerq@kernel.org>]

On 17/01/2024 18:15, Diogo Ivo wrote:
> SR1.0 uses the highest priority channel to transmit control
> messages to the firmware. Take this into account when computing
> channels.
> 
> Based on the work of Roger Quadros in TI's 5.10 SDK [1].
> 
> [1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/?h=ti-linux-5.10.y
> 
> Co-developed-by: Jan Kiszka <jan.kiszka@siemens.com>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
> ---
>  drivers/net/ethernet/ti/icssg/icssg_ethtool.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
> index a27ec1dcc8d5..29e67526fa22 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
> +++ b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
> @@ -141,6 +141,9 @@ static int emac_set_channels(struct net_device *ndev,
>  		return -EBUSY;
>  
>  	emac->tx_ch_num = ch->tx_count;
> +	/* highest channel number for management messaging on SR1 */
> +	if (emac->is_sr1)
> +		emac->tx_ch_num++;

I don't recollect now but is management channel always pinned to the highest priority
channel?

Wouldn't it be better if we don't mix up management channel details here
in emac_get/set_channels(). So this patch is not required and we only need
to set ch->max_tx to PRUETH_MAX_TX_QUEUES-1 for sr1?

>  
>  	return 0;
>  }
> @@ -151,9 +154,12 @@ static void emac_get_channels(struct net_device *ndev,
>  	struct prueth_emac *emac = netdev_priv(ndev);
>  
>  	ch->max_rx = 1;
> -	ch->max_tx = PRUETH_MAX_TX_QUEUES;

Leave the above intact and add
	if (emac->is_sr1)
		ch->max_tx--;

> +	/* SR1 use high priority channel for management messages */
> +	ch->max_tx = emac->is_sr1 ? PRUETH_MAX_TX_QUEUES - 1 :
> +				    PRUETH_MAX_TX_QUEUES;
>  	ch->rx_count = 1;
> -	ch->tx_count = emac->tx_ch_num;
> +	ch->tx_count = emac->is_sr1 ? emac->tx_ch_num - 1 :
> +				      emac->tx_ch_num;
>  }
>  
>  static const struct ethtool_rmon_hist_range emac_rmon_ranges[] = {

-- 
cheers,
-roger