On Sat, Sep 05, 2020 at 10:02:58AM -0700, Richard Cochran wrote:
> On Fri, Sep 04, 2020 at 08:29:27AM +0100, Russell King wrote:
> > Add support for the TAI block in the mvpp2.2 hardware.
> >
> > Signed-off-by: Russell King <rmk+ker...@armlinux.org.uk>
>
> Acked-by: Richard Cochran <richardcoch...@gmail.com>
>
> A few minor questions/comments follow...
>
> > diff --git a/drivers/net/ethernet/marvell/Kconfig
> > b/drivers/net/ethernet/marvell/Kconfig
> > index ef4f35ba077d..a599e44a36a8 100644
> > --- a/drivers/net/ethernet/marvell/Kconfig
> > +++ b/drivers/net/ethernet/marvell/Kconfig
> > @@ -92,6 +92,12 @@ config MVPP2
> > This driver supports the network interface units in the
> > Marvell ARMADA 375, 7K and 8K SoCs.
> >
> > +config MVPP2_PTP
> > + bool "Marvell Armada 8K Enable PTP support"
> > + depends on NETWORK_PHY_TIMESTAMPING
> > + depends on (PTP_1588_CLOCK = y && MVPP2 = y) || \
> > + (PTP_1588_CLOCK && MVPP2 = m)
>
> So I guess this incantation obviates the need for checking whether
> ptp_clock_register() returns null?
There's no point offering the option if the result isn't going to be
functional.
> > +static long mvpp22_tai_aux_work(struct ptp_clock_info *ptp)
> > +{
> > + return 0;
> > +}
>
> Since this is a noop, you can leave
> tai->caps.do_aux_work = mvpp22_tai_aux_work;
> as null.
Ok.
> > +static void mvpp22_tai_set_step(struct mvpp2_tai *tai)
> > +{
> > + void __iomem *base = tai->base;
> > + u32 nano, frac;
> > +
> > + nano = upper_32_bits(tai->period);
> > + frac = lower_32_bits(tai->period);
> > +
> > + /* As the fractional nanosecond is a signed offset, if the MSB (sign)
> > + * bit is set, we have to increment the whole nanoseconds.
> > + */
> > + if (frac >= 0x80000000)
> > + nano += 1;
> > +
> > + mvpp2_tai_write(nano, base + MVPP22_TAI_TOD_STEP_NANO_CR);
> > + mvpp2_tai_write(frac >> 16, base + MVPP22_TAI_TOD_STEP_FRAC_HIGH);
> > + mvpp2_tai_write(frac, base + MVPP22_TAI_TOD_STEP_FRAC_LOW);
> > +}
> > +
> > +static void mvpp22_tai_set_tod(struct mvpp2_tai *tai)
> > +{
> > + struct timespec64 now;
> > +
> > + ktime_get_real_ts64(&now);
> > + mvpp22_tai_settime64(&tai->caps, &now);
> > +}
> > +
> > +static void mvpp22_tai_init(struct mvpp2_tai *tai)
> > +{
> > + void __iomem *base = tai->base;
> > +
> > + mvpp22_tai_set_step(tai);
> > +
> > + /* Release the TAI reset */
> > + mvpp2_tai_modify(base + MVPP22_TAI_CR0, CR0_SW_NRESET, CR0_SW_NRESET);
> > +
> > + mvpp22_tai_set_tod(tai);
>
> The consensus on the list seems to be that new PHCs should start
> ticking from time zero (1970), although some older drivers do use
> ktime. For new clocks, I'd prefer using zero.
Ok.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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