Re: [PATCH v2 6/8] net: ethernet: renesas: rswitch: Add R-Car Gen4 gPTP support

[Richard Cochran <richardcochran@xxxxxxxxx>]

On Wed, Sep 21, 2022 at 05:47:43PM +0900, Yoshihiro Shimoda wrote:

> +static int rcar_gen4_ptp_gettime(struct ptp_clock_info *ptp,
> +				 struct timespec64 *ts)
> +{
> +	struct rcar_gen4_ptp_private *ptp_priv = ptp_to_priv(ptp);
> +
> +	ts->tv_nsec = ioread32(ptp_priv->addr + ptp_priv->offs->monitor_t0);
> +	ts->tv_sec = ioread32(ptp_priv->addr + ptp_priv->offs->monitor_t1) |
> +		     ((s64)ioread32(ptp_priv->addr + ptp_priv->offs->monitor_t2) << 32);

No locking here ...

> +	return 0;
> +}
> +
> +static int rcar_gen4_ptp_settime(struct ptp_clock_info *ptp,
> +				 const struct timespec64 *ts)
> +{
> +	struct rcar_gen4_ptp_private *ptp_priv = ptp_to_priv(ptp);
> +
> +	iowrite32(1, ptp_priv->addr + ptp_priv->offs->disable);
> +	iowrite32(0, ptp_priv->addr + ptp_priv->offs->config_t2);
> +	iowrite32(0, ptp_priv->addr + ptp_priv->offs->config_t1);
> +	iowrite32(0, ptp_priv->addr + ptp_priv->offs->config_t0);
> +	iowrite32(1, ptp_priv->addr + ptp_priv->offs->enable);
> +	iowrite32(ts->tv_sec >> 32, ptp_priv->addr + ptp_priv->offs->config_t2);
> +	iowrite32(ts->tv_sec, ptp_priv->addr + ptp_priv->offs->config_t1);
> +	iowrite32(ts->tv_nsec, ptp_priv->addr + ptp_priv->offs->config_t0);

... or here?

You need to protect multiple register access against concurrent callers.

Thanks,
Richard

> +	return 0;
> +}