Re: [PATCH net-next v2 1/1] net: stmmac: Add support for external trigger timestamping

From: Jakub Kicinski <kuba@kernel.org>
To: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S . Miller" <davem@davemloft.net>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Voon Weifeng <weifeng.voon@intel.com>,
	Ong Boon Leong <boon.leong.ong@intel.com>,
	netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org,
	Richard Cochran <richardcochran@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v2 1/1] net: stmmac: Add support for external trigger timestamping
Date: Fri, 9 Apr 2021 17:50:04 -0700	[thread overview]
Message-ID: <20210409175004.2fceacdd@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20210407170442.1641-1-vee.khee.wong@linux.intel.com>

Other than the minor nit below LGTM. Let's give Richard one more day.

On Thu,  8 Apr 2021 01:04:42 +0800 Wong Vee Khee wrote:
> +static void timestamp_interrupt(struct stmmac_priv *priv)
> +{
> +	struct ptp_clock_event event;
> +	unsigned long flags;
> +	u32 num_snapshot;
> +	u32 ts_status;
> +	u32 tsync_int;
> +	u64 ptp_time;
> +	int i;
> +
> +	tsync_int = readl(priv->ioaddr + GMAC_INT_STATUS) & GMAC_INT_TSIE;
> +
> +	if (!tsync_int)
> +		return;
> +
> +	/* Read timestamp status to clear interrupt from either external
> +	 * timestamp or start/end of PPS.
> +	 */
> +	ts_status = readl(priv->ioaddr + GMAC_TIMESTAMP_STATUS);
> +
> +	if (priv->plat->ext_snapshot_en) {

Are you intending to add more code after this if? Otherwise you could
flip the condition and return early instead of having the extra level
of indentation.

> +		num_snapshot = (ts_status & GMAC_TIMESTAMP_ATSNS_MASK) >>
> +			       GMAC_TIMESTAMP_ATSNS_SHIFT;
> +
> +		for (i = 0; i < num_snapshot; i++) {
> +			spin_lock_irqsave(&priv->ptp_lock, flags);
> +			get_ptptime(priv->ptpaddr, &ptp_time);
> +			spin_unlock_irqrestore(&priv->ptp_lock, flags);
> +			event.type = PTP_CLOCK_EXTTS;
> +			event.index = 0;
> +			event.timestamp = ptp_time;
> +			ptp_clock_event(priv->ptp_clock, &event);
> +		}
> +	}
> +}

Not really related to this patch but how does stmmac set IRQF_SHARED
and yet not track if it indeed generated the interrupt? Isn't that
against the rules?