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Message-ID: <5e330c1e-3d5e-ad1b-1333-d7595cd47069@ti.com>
Date:   Thu, 12 Oct 2023 10:52:01 +0530
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Subject: Re: [PATCH] net: ti: icssg-prueth: Fix tx_total_bytes count
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To:     Ravi Gunasekaran <r-gunasekaran@ti.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>
CC:     <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
        <srk@ti.com>, Vignesh Raghavendra <vigneshr@ti.com>,
        Roger Quadros <rogerq@kernel.org>
References: <20231011063700.1824093-1-danishanwar@ti.com>
 <3bc32261-fdcf-2cea-cae2-f4dddc147d96@ti.com>
From:   MD Danish Anwar <danishanwar@ti.com>
In-Reply-To: <3bc32261-fdcf-2cea-cae2-f4dddc147d96@ti.com>
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On 11/10/23 15:16, Ravi Gunasekaran wrote:
> 
> 
> On 10/11/23 12:07 PM, MD Danish Anwar wrote:
>> ICSSG HW stats on TX side considers 8 preamble bytes as data bytes. Due
>> to this the tx_total_bytes of one interface doesn't match the
>> rx_total_bytes of other interface when two ICSSG interfaces are
> 
> The errata is on the ICSSG Tx side regardless of which interface it is
> connected to. Please rephrase this part of the message to something like,
> "rx_total_bytes of the link partner".
> 

Sure Ravi, I'll update the commit message.

>> connected with each other. There is no public errata available yet.
>>
>> As a workaround to fix this, decrease tx_total_bytes by 8 bytes for every
>> tx frame.
>>
>> Fixes: c1e10d5dc7a1 ("net: ti: icssg-prueth: Add ICSSG Stats")
>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>> ---
>>  drivers/net/ethernet/ti/icssg/icssg_stats.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/ti/icssg/icssg_stats.c b/drivers/net/ethernet/ti/icssg/icssg_stats.c
>> index bb0b33927e3b..dc12edcbac02 100644
>> --- a/drivers/net/ethernet/ti/icssg/icssg_stats.c
>> +++ b/drivers/net/ethernet/ti/icssg/icssg_stats.c
>> @@ -18,6 +18,7 @@ void emac_update_hardware_stats(struct prueth_emac *emac)
>>  	struct prueth *prueth = emac->prueth;
>>  	int slice = prueth_emac_slice(emac);
>>  	u32 base = stats_base[slice];
>> +	u32 tx_pkt_cnt = 0;
>>  	u32 val;
>>  	int i;
>>  
>> @@ -29,7 +30,12 @@ void emac_update_hardware_stats(struct prueth_emac *emac)
>>  			     base + icssg_all_stats[i].offset,
>>  			     val);
>>  
>> +		if (!strncmp(icssg_ethtool_stats[i].name, "tx_good_frames", ETH_GSTRING_LEN))
>> +			tx_pkt_cnt = val;
>> +
>>  		emac->stats[i] += val;
>> +		if (!strncmp(icssg_ethtool_stats[i].name, "tx_total_bytes", ETH_GSTRING_LEN))
>> +			emac->stats[i] -= tx_pkt_cnt * 8;
>>  	}
>>  }
>>  
> 

-- 
Thanks and Regards,
Danish