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Message-ID: <60ce1510-6f2f-dad0-005c-7bcb3880872a@linaro.org>
Date: Thu, 16 Mar 2023 09:08:02 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Serge Semin <Sergey.Semin@...kalelectronics.ru>,
Giuseppe Cavallaro <peppe.cavallaro@...com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>,
Jose Abreu <joabreu@...opsys.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc: Serge Semin <fancer.lancer@...il.com>,
Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
Christian Marangi <ansuelsmth@...il.com>,
Richard Cochran <richardcochran@...il.com>,
Biao Huang <biao.huang@...iatek.com>,
Yang Yingliang <yangyingliang@...wei.com>,
devicetree@...r.kernel.org, netdev@...r.kernel.org,
linux-stm32@...md-mailman.stormreply.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Alexandre Torgue <alexandre.torgue@...com>
Subject: Re: [PATCH net-next 12/16] dt-bindings: net: dwmac: Add MTL Tx Queue
properties constraints
On 13/03/2023 23:50, Serge Semin wrote:
> Currently none of the MTL Tx Queues QoS-related DT-properties have been
> equipped with the proper constraints meanwhile they can be specified at
> least based on the corresponding CSR field sizes or the DW (x|xG)MAC
> IP-core synthesize parameter constraints. Let's do that:
> + snps,tx-queues-to-use - number of Tx queues to utilise is limited with a
> number of available queues. DW MAC/GMAC: no queues, DW Eth QoS: <= 8, DW
> xGMAC: <= 16.
> + snps,weight - Tx Queue/Traffic Class quantum/weight utilised depending
> on enabled algorithm for the Data Center Bridging feature: DWRR (up to
> 0x1312D0 bytes to add to credit) or WFQ (up to 0x3FFF - least bandwidth)
> or WFQ (up to 0x64). DW MAC/GMAC: no queues, DW Eth QoS: <= 0x1312D0, DW
> xGMAC: <= 0x1312D0.
> + snps,send_slope - Tx Queue/Traffic Class Send-Slope credit value
> subtracted from the accumulated credit for the Audio/Video bridging
> feature (CBS algorithm, bits per cycle scaled up by 1,024). DW MAC/GMAC:
> no queues, DW Eth QoS: <= 0x2000, DW xGMAC: <= 0x3FFF.
> + snps,idle_slope - same meaning as snps,send_slope except it's determines
> the Idle-Slope credit of CBS algorithm. DW MAC/GMAC: no queues, DW Eth
> QoS: <= 0x2000, DW xGMAC: <= 0x8000.
> + snps,high_credit/snps,low_credit - maximum and minimum values
> accumulated in the credit for the Audio/Video bridging feature (CBS
> algorithm, bits scaled up by 1,024). DW MAC/GMAC: no queues, DW Eth
> QoS: <= 0x1FFFFFFF, DW xGMAC: <= 0x1FFFFFFF.
> + snps,priority - Tx Queue/Traffic Class priority (enabled by the
> PFC-packets) limits determined by the VLAN tag PRI field width (it's 7).
> DW MAC/GMAC: no queues, DW Eth QoS: 0xff, DW xGMAC: 0xff.
>
> Since the constraints vary for different IP-cores and the DT-schema is
> common for all of them the least restrictive values are chosen. The info
> above can be used for the IP-core specific DT-schemas if anybody ever is
> bothered with one to create.
>
> Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
> ---
> .../bindings/net/snps,dwmac-generic.yaml | 2 +-
> .../devicetree/bindings/net/snps,dwmac.yaml | 24 ++++++++++++++++++-
> 2 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/snps,dwmac-generic.yaml b/Documentation/devicetree/bindings/net/snps,dwmac-generic.yaml
> index ae740a1ab213..2974af79511d 100644
> --- a/Documentation/devicetree/bindings/net/snps,dwmac-generic.yaml
> +++ b/Documentation/devicetree/bindings/net/snps,dwmac-generic.yaml
> @@ -137,7 +137,7 @@ examples:
> snps,send_slope = <0x1000>;
> snps,idle_slope = <0x1000>;
> snps,high_credit = <0x3E800>;
> - snps,low_credit = <0xFFC18000>;
> + snps,low_credit = <0x1FC18000>;
> snps,priority = <0x1>;
> };
> };
> diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> index e5662b1498b7..2ebf7995426b 100644
> --- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> +++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> @@ -250,6 +250,10 @@ properties:
> snps,tx-queues-to-use:
> $ref: /schemas/types.yaml#/definitions/uint32
> description: number of TX queues to be used in the driver
> + default: 1
> + minimum: 1
> + maximum: 16
> +
> snps,tx-sched-wrr:
> type: boolean
> description: Weighted Round Robin
> @@ -296,13 +300,16 @@ properties:
> snps,tx-sched-wfq: false
> snps,tx-sched-dwrr: false
> patternProperties:
> - "^queue[0-9]$":
> + "^queue([0-9]|1[0-5])$":
> description: Each subnode represents a queue.
> type: object
> properties:
> snps,weight:
> $ref: /schemas/types.yaml#/definitions/uint32
> description: TX queue weight (if using a DCB weight algorithm)
> + minimum: 0
> + maximum: 0x1312D0
> +
> snps,dcb-algorithm:
> type: boolean
> description: TX queue will be working in DCB
> @@ -315,15 +322,27 @@ properties:
> snps,send_slope:
> $ref: /schemas/types.yaml#/definitions/uint32
> description: enable Low Power Interface
> + minimum: 0
> + maximum: 0x3FFF
lowercase hex everywhere.
Best regards,
Krzysztof
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