linux-kernel - Re: [PATCH net-next 3/3] net: stmmac: Add glue layer for Spacemit K3 SoC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <f8e4c5ec-94b1-4da0-8a40-976770514828@lunn.ch>
Date: Tue, 20 Jan 2026 14:56:26 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Inochi Amaoto <inochiama@...il.com>
Cc: Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Yixun Lan <dlan@...too.org>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Richard Cochran <richardcochran@...il.com>,
	Paul Walmsley <pjw@...nel.org>, Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>, Alexandre Ghiti <alex@...ti.fr>,
	"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
	Yanteng Si <siyanteng@...oftware.com.cn>,
	Yao Zi <ziyao@...root.org>,
	Vladimir Oltean <vladimir.oltean@....com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
	Choong Yong Liang <yong.liang.choong@...ux.intel.com>,
	Maxime Chevallier <maxime.chevallier@...tlin.com>,
	Chen-Yu Tsai <wens@...nel.org>,
	Shangjuan Wei <weishangjuan@...incomputing.com>,
	Boon Khai Ng <boon.khai.ng@...era.com>,
	Quentin Schulz <quentin.schulz@...rry.de>,
	Giuseppe Cavallaro <peppe.cavallaro@...com>,
	Jose Abreu <joabreu@...opsys.com>, netdev@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-riscv@...ts.infradead.org, spacemit@...ts.linux.dev,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org,
	Longbin Li <looong.bin@...il.com>
Subject: Re: [PATCH net-next 3/3] net: stmmac: Add glue layer for Spacemit K3
 SoC

> +/* Note: the delay step value is at 0.1ps */
> +static const unsigned int k3_delay_step_10x[4] = {
> +	367, 493, 559, 685
> +};

Am i reading it correctly that RGMII delays are limited to these four
values?

If so, please add this list to the DT binding.

> +static int spacemit_dwmac_detected_delay_value(unsigned int delay,
> +					       unsigned int *config)
> +{
> +	int i;
> +	int code, best_code = 0;
> +	unsigned int best_delay = 0;
> +	unsigned int best_config = 0;
> +
> +	if (delay == 0)
> +		return 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
> +		unsigned int step = k3_delay_step_10x[i];
> +
> +		for (code = 1; code <= MAX_DLINE_DELAY_CODE; code++) {
> +			/*
> +			 * Note K3 require a specific factor for calculate
> +			 * the delay, in this scenario it is 0.9. So the
> +			 * formula is code * step / 10 * 0.9
> +			 */
> +			unsigned int tmp = code * step * 9 / 10 / 10;
> +
> +			if (abs(tmp - delay) < abs(best_delay - delay)) {
> +				best_code = code;
> +				best_delay = tmp;
> +				best_config = i;
> +			}
> +		}
> +	}

With the four values listed in DT, i would make this a straight match,
not the nearest, and return -EINVAL otherwise.

    Andrew