Re: [PATCH net-next 4/4] net: phy: mscc-miim: read poll when high resolution timers are disabled

From: Andrew Lunn <andrew@lunn.ch>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	davem@davemloft.net, hkallweit1@gmail.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	alexandre.belloni@bootlin.com, thomas.petazzoni@bootlin.com,
	allan.nielsen@microchip.com
Subject: Re: [PATCH net-next 4/4] net: phy: mscc-miim: read poll when high resolution timers are disabled
Date: Wed, 27 May 2020 00:01:27 +0200	[thread overview]
Message-ID: <20200526220127.GS768009@lunn.ch> (raw)
In-Reply-To: <e95bbdb6-a6db-be02-660e-7318b9bb5f01@gmail.com>

> > +/* When high resolution timers aren't built-in: we can't use usleep_range() as
> > + * we would sleep way too long. Use udelay() instead.
> > + */
> > +#define mscc_readl_poll_timeout(addr, val, cond, delay_us, timeout_us)	\
> > +({									\
> > +	if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS))			\
> > +		readl_poll_timeout_atomic(addr, val, cond, delay_us,	\
> > +					  timeout_us);			\
> > +	readl_poll_timeout(addr, val, cond, delay_us, timeout_us);	\
> > +})
> > +
> 
> I would make this a regular function which would not harm the compiler's
> ability to optimize it, but would give you type checking. With that fixed:

Hi Florian

cond makes that difficult, since it is not a parameter in the usual
sense, but an expression to evaluate if the polling should terminate.

readl_poll_timeout() and readl_poll_timeout_atomic() themselves are
#define's, and there are more levels of macros under them.

	   Andrew