Re: [PATCH v5 1/2] net: stmmac: add support for platform specific reset

From: Simon Horman <simon.horman@corigine.com>
To: Shenwei Wang <shenwei.wang@nxp.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Wong Vee Khee <veekhee@apple.com>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Mohammad Athari Bin Ismail <mohammad.athari.ismail@intel.com>,
	Andrey Konovalov <andrey.konovalov@linaro.org>,
	Jochen Henneberg <jh@henneberg-systemdesign.com>,
	Tan Tee Min <tee.min.tan@linux.intel.com>,
	netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-stm32@st-md-mailman.stormreply.com, imx@lists.linux.dev
Subject: Re: [PATCH v5 1/2] net: stmmac: add support for platform specific reset
Date: Mon, 3 Apr 2023 21:49:52 +0200	[thread overview]
Message-ID: <ZCst4PvQ+dlZEbgl@corigine.com> (raw)
In-Reply-To: <20230403152408.238530-1-shenwei.wang@nxp.com>

On Mon, Apr 03, 2023 at 10:24:07AM -0500, Shenwei Wang wrote:
> This patch adds support for platform-specific reset logic in the
> stmmac driver. Some SoCs require a different reset mechanism than
> the standard dwmac IP reset. To support these platforms, a new function
> pointer 'fix_soc_reset' is added to the plat_stmmacenet_data structure.
> The stmmac_reset in hwif.h is modified to call the 'fix_soc_reset'
> function if it exists. This enables the driver to use the platform-specific
> reset logic when necessary.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> ---
>  v5:
>   - add the missing __iomem tag in the stmmac_reset definition.
> 
>  drivers/net/ethernet/stmicro/stmmac/hwif.c | 10 ++++++++++
>  drivers/net/ethernet/stmicro/stmmac/hwif.h |  3 +--
>  include/linux/stmmac.h                     |  1 +
>  3 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.c b/drivers/net/ethernet/stmicro/stmmac/hwif.c
> index bb7114f970f8..0eefa697ffe8 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/hwif.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/hwif.c
> @@ -87,6 +87,16 @@ static int stmmac_dwxlgmac_quirks(struct stmmac_priv *priv)
>  	return 0;
>  }
> 
> +int stmmac_reset(struct stmmac_priv *priv, void __iomem *ioaddr)
> +{
> +	struct plat_stmmacenet_data *plat = priv ? priv->plat : NULL;

Here the case where priv is NULL is handled.

> +
> +	if (plat && plat->fix_soc_reset)
> +		return plat->fix_soc_reset(plat, ioaddr);
> +
> +	return stmmac_do_callback(priv, dma, reset, ioaddr);

But this will dereference priv unconditionally.

I think perhaps this is code that I suggested.
If so, sorry about not noticing this then.

> +}
> +
>  static const struct stmmac_hwif_entry {
>  	bool gmac;
>  	bool gmac4;

...