netdev - RE: [PATCH] davinci_emac: Add cpu

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Date:	Tue, 10 Apr 2012 05:16:19 +0000
From:	"Manjunathappa, Prakash" <prakash.pm@...com>
To:	Sergei Shtylyov <sshtylyov@...sta.com>
CC:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"davinci-linux-open-source@...ux.davincidsp.com" 
	<davinci-linux-open-source@...ux.davincidsp.com>,
	"davem@...emloft.net" <davem@...emloft.net>
Subject: RE: [PATCH] davinci_emac: Add cpu_freq support

Hi Sergei,

On Mon, Apr 09, 2012 at 16:59:52, Sergei Shtylyov wrote:
> Hello.
> 
> On 09-04-2012 14:49, Manjunathappa, Prakash wrote:
> 
> > Reconfigure interrupt coalesce parameter for changed emac bus_freq
> > due to DVFS.
> 
> > Signed-off-by: Manjunathappa, Prakash<prakash.pm@...com>
> > ---
> >   drivers/net/ethernet/ti/davinci_emac.c |   60 ++++++++++++++++++++++++++++++++
> >   1 files changed, 60 insertions(+), 0 deletions(-)
> 
> > diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
> > index 174a334..11d3bd7 100644
> > --- a/drivers/net/ethernet/ti/davinci_emac.c
> > +++ b/drivers/net/ethernet/ti/davinci_emac.c
> [...]
> > @@ -1761,6 +1765,46 @@ static const struct net_device_ops emac_netdev_ops = {
> >   #endif
> >   };
> >
> > +#ifdef CONFIG_CPU_FREQ
> > +static int davinci_emac_cpufreq_transition(struct notifier_block *nb,
> > +				     unsigned long val, void *data)
> > +{
> > +	int ret = 0;
> > +	struct emac_priv *priv;
> > +
> > +	priv = container_of(nb, struct emac_priv, freq_transition);
> > +	if (priv->coal_intvl != 0) {
> > +		if (val == CPUFREQ_POSTCHANGE) {
> > +			if (emac_bus_frequency != clk_get_rate(emac_clk)) {
> 
>     These 3 *if*s could be collapsed into one, and so indentation level 
> lowered significantly.
> 

Ok I will tie them with "&&".

> > +				struct ethtool_coalesce coal;
> > +
> > +				emac_bus_frequency = clk_get_rate(emac_clk);
> > +
> > +				priv->bus_freq_mhz = (u32)(emac_bus_frequency /
> > +						1000000);
> > +				coal.rx_coalesce_usecs = (priv->coal_intvl
> > +						<<  4);
> > +				ret = emac_set_coalesce(priv->ndev,&coal);
> > +			}
> > +		}
> > +	}
> > +	return ret;
> > +}
> > +
> > +static inline int davinci_emac_cpufreq_register(struct emac_priv *priv)
> > +{
> > +	priv->freq_transition.notifier_call = davinci_emac_cpufreq_transition;
> > +	return cpufreq_register_notifier(&priv->freq_transition,
> > +					 CPUFREQ_TRANSITION_NOTIFIER);
> > +}
> > +
> > +static inline void davinci_emac_cpufreq_deregister(struct emac_priv *priv)
> > +{
> > +	cpufreq_unregister_notifier(&priv->freq_transition,
> > +				    CPUFREQ_TRANSITION_NOTIFIER);
> > +}
> > +#endif
> > +
> >   /**
> >    * davinci_emac_probe: EMAC device probe
> >    * @pdev: The DaVinci EMAC device that we are removing
> > @@ -1925,8 +1969,21 @@ static int __devinit davinci_emac_probe(struct platform_device *pdev)
> >   			   "(regs: %p, irq: %d)\n",
> >   			   (void *)priv->emac_base_phys, ndev->irq);
> >   	}
> > +
> > +#ifdef CONFIG_CPU_FREQ
> > +	rc = davinci_emac_cpufreq_register(priv);
> > +	if (rc) {
> > +		dev_err(&pdev->dev, "error in register_netdev\n");
> 
>     Really?
> 

Ahh, my bad... I will fix this.

> > +		rc = -ENODEV;
> > +		goto cpufreq_reg_err;
> > +	}
> > +#endif
> >   	return 0;
> >
> > +#ifdef CONFIG_CPU_FREQ
> > +cpufreq_reg_err:
> > +	unregister_netdev(ndev);
> > +#endif
> >   netdev_reg_err:
> >   	clk_disable(emac_clk);
> >   no_irq_res:
> > @@ -1973,6 +2030,9 @@ static int __devexit davinci_emac_remove(struct platform_device *pdev)
> >
> >   	release_mem_region(res->start, resource_size(res));
> >
> > +#ifdef CONFIG_CPU_FREQ
> > +	davinci_emac_cpufreq_deregister(priv);
> > +#endif
> 
>     This is considered a bad practice to use #ifdef in the body of function.
> Define the faunction you call here as empty inline in case CONFIG_CPU_FREQ is 
> not defined instead. The same about davinci_emac_cpufreq_register().
> 

Ok. I will correct this as you suggested.

Thanks,
Prakash

> WBR, Sergei
> 

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