Re: [PATCH iwl-next v5 1/9] net: ethtool: mm: extract stmmac verification logic into common library

[Furong Xu <0x1207@gmail.com>]

On Wed, 19 Feb 2025 21:53:41 -0500, Faizal Rahim <faizal.abdul.rahim@linux.intel.com> wrote:

> From: Vladimir Oltean <vladimir.oltean@nxp.com>
> 
> It appears that stmmac is not the only hardware which requires a
> software-driven verification state machine for the MAC Merge layer.
> 
> While on the one hand it's good to encourage hardware implementations,
> on the other hand it's quite difficult to tolerate multiple drivers
> implementing independently fairly non-trivial logic.
> 
> Extract the hardware-independent logic from stmmac into library code and
> put it in ethtool. Name the state structure "mmsv" for MAC Merge
> Software Verification. Let this expose an operations structure for
> executing the hardware stuff: sync hardware with the tx_active boolean
> (result of verification process), enable/disable the pMAC, send mPackets,
> notify library of external events (reception of mPackets), as well as
> link state changes.
> 
> Note that it is assumed that the external events are received in hardirq
> context. If they are not, it is probably a good idea to disable hardirqs
> when calling ethtool_mmsv_event_handle(), because the library does not
> do so.
> 
> Also, the MM software verification process has no business with the
> tx_min_frag_size, that is all the driver's to handle.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Co-developed-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
> Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
> Co-developed-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
> Tested-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  16 +-
>  .../ethernet/stmicro/stmmac/stmmac_ethtool.c  |  41 +---
>  .../net/ethernet/stmicro/stmmac/stmmac_fpe.c  | 174 +++-----------
>  .../net/ethernet/stmicro/stmmac/stmmac_fpe.h  |   5 -
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c |   8 +-
>  include/linux/ethtool.h                       | 131 ++++++++++
>  net/ethtool/mm.c                              | 225 +++++++++++++++++-
>  7 files changed, 399 insertions(+), 201 deletions(-)
> 
[...]
> +void ethtool_mmsv_link_state_handle(struct ethtool_mmsv *mmsv, bool up)
> +{
> +	unsigned long flags;
> +
> +	ethtool_mmsv_stop(mmsv);
> +
> +	spin_lock_irqsave(&mmsv->lock, flags);
> +
> +	if (up && mmsv->pmac_enabled) {
> +		/* VERIFY process requires pMAC enabled when NIC comes up */
> +		ethtool_mmsv_configure_pmac(mmsv, true);
> +
> +		/* New link => maybe new partner => new verification process */
> +		ethtool_mmsv_apply(mmsv);
> +	} else {
> +		mmsv->status = ETHTOOL_MM_VERIFY_STATUS_INITIAL;

Tested this patch on my side, everything works well, but the verify-status
is a little weird:

# kernel booted, check initial states:
ethtool --include-statistics --json --show-mm eth1
[ {
        "ifname": "eth1",
        "pmac-enabled": false,
        "tx-enabled": false,
        "tx-active": false,
        "tx-min-frag-size": 60,
        "rx-min-frag-size": 60,
        "verify-enabled": false,
        "verify-time": 128,
        "max-verify-time": 128,
        "verify-status": "INITIAL",
        "statistics": {
            "MACMergeFrameAssErrorCount": 0,
            "MACMergeFrameSmdErrorCount": 0,
            "MACMergeFrameAssOkCount": 0,
            "MACMergeFragCountRx": 0,
            "MACMergeFragCountTx": 0,
            "MACMergeHoldCount": 0
        }
    } ]

# Enable pMAC by: ethtool --set-mm eth1 pmac-enabled on
ethtool --include-statistics --json --show-mm eth1
[ {
        "ifname": "eth1",
        "pmac-enabled": true,
        "tx-enabled": false,
        "tx-active": false,
        "tx-min-frag-size": 60,
        "rx-min-frag-size": 60,
        "verify-enabled": false,
        "verify-time": 128,
        "max-verify-time": 128,
        "verify-status": "DISABLED",
        "statistics": {
            "MACMergeFrameAssErrorCount": 0,
            "MACMergeFrameSmdErrorCount": 0,
            "MACMergeFrameAssOkCount": 0,
            "MACMergeFragCountRx": 0,
            "MACMergeFragCountTx": 0,
            "MACMergeHoldCount": 0
        }
    } ]

# Disable pMAC by: ethtool --set-mm eth1 pmac-enabled off
ethtool --include-statistics --json --show-mm eth1
[ {
        "ifname": "eth1",
        "pmac-enabled": true,
        "tx-enabled": false,
        "tx-active": false,
        "tx-min-frag-size": 60,
        "rx-min-frag-size": 60,
        "verify-enabled": false,
        "verify-time": 128,
        "max-verify-time": 128,
        "verify-status": "DISABLED",
        "statistics": {
            "MACMergeFrameAssErrorCount": 0,
            "MACMergeFrameSmdErrorCount": 0,
            "MACMergeFrameAssOkCount": 0,
            "MACMergeFragCountRx": 0,
            "MACMergeFragCountTx": 0,
            "MACMergeHoldCount": 0
        }
    } ]

verify-status always normal on other cases.

@Vladimir, maybe we shouldn't update mmsv->status in ethtool_mmsv_link_state_handle()?
Or, update mmsv->status like below:
mmsv->status = mmsv->pmac_enabled ?
		ETHTOOL_MM_VERIFY_STATUS_INITIAL :
		ETHTOOL_MM_VERIFY_STATUS_DISABLED;

Anyway, this is too minor, so:

Tested-by: Furong Xu <0x1207@gmail.com>


> +		mmsv->verify_retries = ETHTOOL_MM_MAX_VERIFY_RETRIES;
> +
> +		/* No link or pMAC not enabled */
> +		ethtool_mmsv_configure_pmac(mmsv, false);
> +		ethtool_mmsv_configure_tx(mmsv, false);
> +	}
> +
> +	spin_unlock_irqrestore(&mmsv->lock, flags);
> +}
> +EXPORT_SYMBOL_GPL(ethtool_mmsv_link_state_handle);