netdev - Re: [PATCH net v2] net: stmmac: thead: Enable TX clock before MAC initialization

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: <aJaqOHYU_eklj2BR@pie>
Date: Sat, 9 Aug 2025 01:54:00 +0000
From: Yao Zi <ziyao@...root.org>
To: Simon Horman <horms@...nel.org>
Cc: Drew Fustini <fustini@...nel.org>, Guo Ren <guoren@...nel.org>,
	Fu Wei <wefu@...hat.com>, 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>,
	Emil Renner Berthing <emil.renner.berthing@...onical.com>,
	Jisheng Zhang <jszhang@...nel.org>, nux-riscv@...ts.infradead.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net v2] net: stmmac: thead: Enable TX clock before MAC
 initialization

On Fri, Aug 08, 2025 at 02:39:00PM +0100, Simon Horman wrote:
> On Fri, Aug 08, 2025 at 10:34:48AM +0000, Yao Zi wrote:
> 
> ...
> 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > index f2946bea0bc2..50c1920bde6a 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > @@ -152,7 +152,7 @@ static int thead_set_clk_tx_rate(void *bsp_priv, struct clk *clk_tx_i,
> >  static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> >  {
> >  	struct thead_dwmac *dwmac = plat->bsp_priv;
> > -	u32 reg;
> > +	u32 reg, div;
> >  
> >  	switch (plat->mac_interface) {
> >  	case PHY_INTERFACE_MODE_MII:
> > @@ -164,6 +164,13 @@ static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> >  	case PHY_INTERFACE_MODE_RGMII_RXID:
> >  	case PHY_INTERFACE_MODE_RGMII_TXID:
> >  		/* use pll */
> > +		div = clk_get_rate(plat->stmmac_clk) / rgmii_clock(SPEED_1000);
> > +		reg = FIELD_PREP(GMAC_PLLCLK_DIV_EN, 1) |
> > +		      FIELD_PREP(GMAC_PLLCLK_DIV_NUM, div),
> 
> Sorry for not noticing this before sending my previous email.
> 
> Although the code above is correct. I think it would be clearer
> to use ';' rather than ',' at the end of the line above. Perhaps ','
> is a typo.(',' is next to ';' on my keyboard at least).

This is actually a typo that occasionally passes the compilation... yeah
thanks for catching it.

I'll add a comment about the requirement that PLLCLK_DIV_EN must be set
to zero before changing the rate, and fix this typo in v3 as well.

> Flagged by Clang 20.1.8 with -Wcomma

Best regards,
Yao Zi

> > +
> > +		writel(0, dwmac->apb_base + GMAC_PLLCLK_DIV);
> > +		writel(reg, dwmac->apb_base + GMAC_PLLCLK_DIV);
> > +
> >  		writel(GMAC_GTXCLK_SEL_PLL, dwmac->apb_base + GMAC_GTXCLK_SEL);
> >  		reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> >  		      GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
> 
> -- 
> pw-bot: changes-requested.