Subject: Re: [v5,net-next,1/9] net: stmmac: multiple queues dt configuration

From: Thierry Reding <[email-masked]>
Date: Tue, 21 Mar 2017 12:32:45 +0100

On Fri, Mar 10, 2017 at 06:24:51PM +0000, Joao Pinto wrote:
> This patch adds the multiple queues configuration in the Device Tree.
> It was also created a set of structures to keep the RX and TX queues
> configurations to be used in the driver.
> 
> Signed-off-by: Joao Pinto <jpinto-HKixBCOQz3hWk0Htik3J/[email-masked]>
> ---
> Changes v4->v5:
> - patch title update (stmicro replaced by stmmac)
> Changes v2->v4:
> - Just to keep up with patch-set version
> Changes v1->v2:
> - RX and TX queues child nodes had bad handle
> 
>  Documentation/devicetree/bindings/net/stmmac.txt   | 40 ++++++++++
>  .../net/ethernet/stmicro/stmmac/stmmac_platform.c  | 91 ++++++++++++++++++++++
>  include/linux/stmmac.h                             | 30 +++++++
>  3 files changed, 161 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt
> index d3bfc2b..4107e67 100644
> --- a/Documentation/devicetree/bindings/net/stmmac.txt
> +++ b/Documentation/devicetree/bindings/net/stmmac.txt
> @@ -72,6 +72,27 @@ Optional properties:
>  	- snps,mb: mixed-burst
>  	- snps,rb: rebuild INCRx Burst
>  - mdio: with compatible = "snps,dwmac-mdio", create and register mdio bus.
> +- Multiple RX Queues parameters: below the list of all the parameters to
> +				 configure the multiple RX queues:
> +	- snps,rx-queues-to-use: number of RX queues to be used in the driver
> +	- Choose one of these RX scheduling algorithms:
> +		- snps,rx-sched-sp: Strict priority
> +		- snps,rx-sched-wsp: Weighted Strict priority
> +	- For each RX queue
> +		- Choose one of these modes:
> +			- snps,dcb-algorithm: Queue to be enabled as DCB
> +			- snps,avb-algorithm: Queue to be enabled as AVB
> +		- snps,map-to-dma-channel: Channel to map
> +- Multiple TX Queues parameters: below the list of all the parameters to
> +				 configure the multiple TX queues:
> +	- snps,tx-queues-to-use: number of TX queues to be used in the driver
> +	- Choose one of these TX scheduling algorithms:
> +		- snps,tx-sched-wrr: Weighted Round Robin
> +		- snps,tx-sched-wfq: Weighted Fair Queuing
> +		- snps,tx-sched-dwrr: Deficit Weighted Round Robin
> +		- snps,tx-sched-sp: Strict priority
> +	- For each TX queue
> +		- snps,weight: TX queue weight (if using a weighted algorithm)
>  
>  Examples:
>  
> @@ -81,6 +102,23 @@ Examples:
>  		snps,blen = <256 128 64 32 0 0 0>;
>  	};
>  
> +	mtl_rx_setup: rx-queues-config {
> +		snps,rx-queues-to-use = <1>;
> +		snps,rx-sched-sp;
> +		queue0 {
> +			snps,dcb-algorithm;
> +			snps,map-to-dma-channel = <0x0>;
> +		};
> +	};
> +
> +	mtl_tx_setup: tx-queues-config {
> +		snps,tx-queues-to-use = <1>;
> +		snps,tx-sched-wrr;
> +		queue0 {
> +			snps,weight = <0x10>;
> +		};
> +	};
> +
>  	gmac0: ethernet@e0800000 {
>  		compatible = "st,spear600-gmac";
>  		reg = <0xe0800000 0x8000>;
> @@ -104,4 +142,6 @@ Examples:
>  			phy1: ethernet-phy@0 {
>  			};
>  		};
> +		snps,mtl-rx-config = <&mtl_rx_setup>;
> +		snps,mtl-tx-config = <&mtl_tx_setup>;
>  	};

That's kind of an odd placement for these nodes. Wouldn't they be better
located within the controller's device tree node, rather than referenced
by phandle? Making them children of the root node leaves them completely
without context.

Thierry