Re: [Patch net-next v1 02/12] net: dsa: microchip: ptp: Initial hardware time stamping support

Arun.Ramadoss
2022-12-01T10:18:05Z

Hi Vladimir,

On Thu, 2022-12-01 at 02:39 +0200, Vladimir Oltean wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
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>
> On Mon, Nov 28, 2022 at 04:02:17PM +0530, Arun Ramadoss wrote:
> > diff --git a/drivers/net/dsa/microchip/ksz_common.h
> > b/drivers/net/dsa/microchip/ksz_common.h
> > index 5a6bfd42c6f9..cd20f39a565f 100644
> > --- a/drivers/net/dsa/microchip/ksz_common.h
> > +++ b/drivers/net/dsa/microchip/ksz_common.h
> > @@ -103,6 +103,10 @@ struct ksz_port {
> > struct ksz_device *ksz_dev;
> > struct ksz_irq pirq;
> > u8 num;
> > +#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ_PTP)
> > + u8 hwts_tx_en;
>
> Variable named "en" (enable) which takes the values 0 or 2? Not good.
> Also, why is the type not enum hwtstamp_tx_types, but u8? Can't you
> name
> this "enum hwtstamp_tx_types tx_type"?
>
> > + bool hwts_rx_en;
> > +#endif
> > };

I will rename variable.

> >
> > struct ksz_device {
> > diff --git a/drivers/net/dsa/microchip/ksz_ptp.c
> > b/drivers/net/dsa/microchip/ksz_ptp.c
> > index c737635ca266..a41418c6adf6 100644
> > --- a/drivers/net/dsa/microchip/ksz_ptp.c
> > +++ b/drivers/net/dsa/microchip/ksz_ptp.c
> > @@ -36,15 +36,88 @@ int ksz_get_ts_info(struct dsa_switch *ds, int
> > port, struct ethtool_ts_info *ts)
> > SOF_TIMESTAMPING_RX_HARDWARE |
> > SOF_TIMESTAMPING_RAW_HARDWARE;
> >
> > - ts->tx_types = BIT(HWTSTAMP_TX_OFF);
> > + ts->tx_types = BIT(HWTSTAMP_TX_OFF) |
> > BIT(HWTSTAMP_TX_ONESTEP_P2P);
> >
> > - ts->rx_filters = BIT(HWTSTAMP_FILTER_NONE);
> > + ts->rx_filters = BIT(HWTSTAMP_FILTER_NONE) |
> > BIT(HWTSTAMP_FILTER_ALL);
> >
> > ts->phc_index = ptp_clock_index(ptp_data->clock);
> >
> > return 0;
> > }
> >
> > +int ksz_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq
> > *ifr)
> > +{
> > + struct ksz_device *dev = ds->priv;
> > + struct hwtstamp_config config;
> > +
> > + config.flags = 0;
> > +
> > + config.tx_type = dev->ports[port].hwts_tx_en;
> > +
> > + if (dev->ports[port].hwts_rx_en)
> > + config.rx_filter = HWTSTAMP_FILTER_ALL;
> > + else
> > + config.rx_filter = HWTSTAMP_FILTER_NONE;
> > +
> > + return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
> > + -EFAULT : 0;
> > +}
> > +
> > +static int ksz_set_hwtstamp_config(struct ksz_device *dev, int
> > port,
> > + struct hwtstamp_config *config)
> > +{
> > + struct ksz_port *prt = &dev->ports[port];
> > +
> > + if (config->flags)
> > + return -EINVAL;
> > +
> > + switch (config->tx_type) {
> > + case HWTSTAMP_TX_OFF:
> > + case HWTSTAMP_TX_ONESTEP_P2P:
> > + prt->hwts_tx_en = config->tx_type;
> > + break;
> > + default:
> > + return -ERANGE;
> > + }
> > +
> > + switch (config->rx_filter) {
> > + case HWTSTAMP_FILTER_NONE:
> > + prt->hwts_rx_en = false;
> > + break;
> > + default:
> > + prt->hwts_rx_en = true;
> > + break;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int ksz_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq
> > *ifr)
> > +{
> > + struct ksz_device *dev = ds->priv;
> > + struct ksz_ptp_data *ptp_data;
> > + struct hwtstamp_config config;
> > + int ret;
> > +
> > + ptp_data = &dev->ptp_data;
> > +
> > + mutex_lock(&ptp_data->lock);
>
> I'm not sure that this mutex serves any purpose at all?
>
> One could have argued that concurrent calls to ksz_hwtstamp_get()
> shouldn't be able to see incoherent values of prt->hwts_tx_en and of
> prt->hwts_rx_en.
>
> But ksz_hwtstamp_get() doesn't acquire this mutex, so that is not
> true,
> this isn't why the mutex is acquired here. I don't know why it is.

Mutex is not needed. I will remove it.

>
> > +
> > + ret = copy_from_user(&config, ifr->ifr_data, sizeof(config));
> > + if (ret)
> > + goto error_return;
> > +
> > + ret = ksz_set_hwtstamp_config(dev, port, &config);
> > + if (ret)
> > + goto error_return;
> > +
> > + ret = copy_to_user(ifr->ifr_data, &config, sizeof(config));
> > +
> > +error_return:
> > + mutex_unlock(&ptp_data->lock);
> > + return ret;
> > +}