netdev - Re: [PATCH v2 2/3] net: stmmac: Add interconnect support

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Date: Wed, 26 Jun 2024 09:40:47 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Sagar Cheluvegowda <quic_scheluve@...cinc.com>,
 Vinod Koul <vkoul@...nel.org>,
 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>, Russell King <linux@...linux.org.uk>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Bhupesh Sharma <bhupesh.sharma@...aro.org>
Cc: kernel@...cinc.com, Andrew Halaney <ahalaney@...hat.com>,
 Andrew Lunn <andrew@...n.ch>, linux-arm-msm@...r.kernel.org,
 netdev@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org
Subject: Re: [PATCH v2 2/3] net: stmmac: Add interconnect support

On 26/06/2024 01:49, Sagar Cheluvegowda wrote:
> Add interconnect support to vote for bus bandwidth based
> on the current speed of the driver.This change adds support

Please do not use "This commit/patch/change", but imperative mood. See
longer explanation here:
https://elixir.bootlin.com/linux/v5.17.1/source/Documentation/process/submitting-patches.rst#L95

Also, space after full stop.

> for two different paths - one from ethernet to DDR and the
> other from Apps to ethernet.
> Vote from each interconnect client is aggregated and the on-chip
> interconnect hardware is configured to the most appropriate
> bandwidth profile.
> 
> Suggested-by: Andrew Halaney <ahalaney@...hat.com>
> Signed-off-by: Sagar Cheluvegowda <quic_scheluve@...cinc.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h          |  1 +
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c     |  8 ++++++++
>  drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 12 ++++++++++++
>  include/linux/stmmac.h                                |  2 ++
>  4 files changed, 23 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> index b23b920eedb1..56a282d2b8cd 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> @@ -21,6 +21,7 @@
>  #include <linux/ptp_clock_kernel.h>
>  #include <linux/net_tstamp.h>
>  #include <linux/reset.h>
> +#include <linux/interconnect.h>
>  #include <net/page_pool/types.h>
>  #include <net/xdp.h>
>  #include <uapi/linux/bpf.h>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index b3afc7cb7d72..ec7c61ee44d4 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -985,6 +985,12 @@ static void stmmac_fpe_link_state_handle(struct stmmac_priv *priv, bool is_up)
>  	}
>  }
>  
> +static void stmmac_set_icc_bw(struct stmmac_priv *priv, unsigned int speed)
> +{
> +	icc_set_bw(priv->plat->axi_icc_path, Mbps_to_icc(speed), Mbps_to_icc(speed));
> +	icc_set_bw(priv->plat->ahb_icc_path, Mbps_to_icc(speed), Mbps_to_icc(speed));
> +}
> +
>  static void stmmac_mac_link_down(struct phylink_config *config,
>  				 unsigned int mode, phy_interface_t interface)
>  {
> @@ -1080,6 +1086,8 @@ static void stmmac_mac_link_up(struct phylink_config *config,
>  	if (priv->plat->fix_mac_speed)
>  		priv->plat->fix_mac_speed(priv->plat->bsp_priv, speed, mode);
>  
> +	stmmac_set_icc_bw(priv, speed);
> +
>  	if (!duplex)
>  		ctrl &= ~priv->hw->link.duplex;
>  	else
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> index 54797edc9b38..e46c94b643a3 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> @@ -642,6 +642,18 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
>  		dev_dbg(&pdev->dev, "PTP rate %d\n", plat->clk_ptp_rate);
>  	}
>  
> +	plat->axi_icc_path = devm_of_icc_get(&pdev->dev, "axi");
> +	if (IS_ERR(plat->axi_icc_path)) {
> +		ret = (void *)plat->axi_icc_path;
> +		goto error_hw_init;

This sounds like an ABI break. Considering the interconnects are not
required by the binding, are you sure this behaves correctly without
interconnects in DTS?

Best regards,
Krzysztof