From: Rohan G Thomas <rohan.g.thomas@intel.com>
To: fancer.lancer@gmail.com
Cc: alexandre.torgue@foss.st.com, conor+dt@kernel.org,
conor.dooley@microchip.com, davem@davemloft.net,
devicetree@vger.kernel.org, edumazet@google.com,
joabreu@synopsys.com, krzysztof.kozlowski+dt@linaro.org,
kuba@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
mcoquelin.stm32@gmail.com, netdev@vger.kernel.org,
pabeni@redhat.com, peppe.cavallaro@st.com, robh+dt@kernel.org,
rohan.g.thomas@intel.com
Subject: Re: [PATCH net-next v5 1/2] dt-bindings: net: snps,dwmac: Tx queues with coe
Date: Thu, 24 Aug 2023 01:10:04 +0800 [thread overview]
Message-ID: <20230823171004.6825-1-rohan.g.thomas@intel.com> (raw)
In-Reply-To: <l7yajzhpuotn62pjkxk43qtcn3u4zltpyqcvo224737bjg3eab@bzu6pirxbvh2>
>On Tue, Aug 22, 2023 at 05:15:25PM -0700, Jakub Kicinski wrote:
>> On Sat, 19 Aug 2023 10:31:31 +0800 Rohan G Thomas wrote:
>> > + snps,tx-queues-with-coe:
>> > + $ref: /schemas/types.yaml#/definitions/uint32
>> > + description: number of TX queues that support TX checksum offloading
>>
>
>> Is it going to be obvious that if not present all queues support
>> checksum offload? I think we should document the default.
>
>This question is debatable:
>1. By default the DW xGMAC and DW QoS Eth IP-cores are
>synthesized with only the very first Tx queue having Tx COE enabled.
>2. If TSO is disabled then the Tx COE can be individually enabled
>for each queue available on DW QoS Eth controller and for the very
>first N queues on DW xGMAC controller.
>3. If TSO is enabled then the Tx COE will be automatically and always
>enabled for as many first queues as there are TSO-capable
>DMA-channels.
>4. At the current state the STMMAC driver assumes that all Tx Queues
>support Tx COE.
>
>The entry 4 can't be changed since we'll risk to catch regressions on
>the platforms with no property specified. On the other hand it partly
>contradicts to the rest of the entries. I don't know what would be a
>correct way to specify the default value in this case. Most likely
>just keep the entry 4 and be done with it.
>
>BTW I just noticed that but the suggested "snps,tx-queues-with-coe"
>property semantic will only cover a DW XGMAC-part of the case 2. DW
>QoS Eth can be synthesized with Tx COE individually enabled for a
>particular queue if TSO is unavailable.
Hi Serge,
Didn't know about a different IP configuration supported by DW QoS Eth IP. If
this is the case, I think we can have a flag 'coe-unsupported' for any TX
queue subnode as below.
+ snps,coe-unsupported:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description:
+ TX checksum offload is unsupported by the TX queue. If TX checksum
+ offload is requested for a packet to be transmitted through this
+ TX queue then have a software fallback in the driver for checksum
+ calculation.
If this is okay, I can rework the patch based on this. Covers both DW QoS Eth IP
and DW XGMAC IP cases.
>
>-Serge(y)
>
>> --
>> pw-bot: cr
BR,
Rohan
next prev parent reply other threads:[~2023-08-23 17:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-19 2:31 [PATCH net-next v5 0/2] net: stmmac: Tx coe sw fallback Rohan G Thomas
2023-08-19 2:31 ` [PATCH net-next v5 1/2] dt-bindings: net: snps,dwmac: Tx queues with coe Rohan G Thomas
2023-08-21 12:15 ` Serge Semin
2023-08-23 0:15 ` Jakub Kicinski
2023-08-23 5:45 ` Rohan G Thomas
2023-08-23 10:00 ` Serge Semin
2023-08-23 17:10 ` Rohan G Thomas [this message]
2023-08-27 0:18 ` Serge Semin
2023-08-19 2:31 ` [PATCH net-next v5 2/2] net: stmmac: Tx coe sw fallback Rohan G Thomas
2023-08-21 12:15 ` Serge Semin
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