Messages in this thread | | | Date | Sat, 20 Jun 2020 17:10:01 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH net-next v3 5/8] net: phy: mscc: 1588 block initialization |
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On Fri, Jun 19, 2020 at 02:22:57PM +0200, Antoine Tenart wrote: > From: Quentin Schulz <quentin.schulz@bootlin.com> > > This patch adds the first parts of the 1588 support in the MSCC PHY, > with registers definition and the 1588 block initialization. > > Those PHYs are distributed in hardware packages containing multiple > times the PHY. The VSC8584 for example is composed of 4 PHYs. With > hardware packages, parts of the logic is usually common and one of the > PHY has to be used for some parts of the initialization. Following this > logic, the 1588 blocks of those PHYs are shared between two PHYs and > accessing the registers has to be done using the "base" PHY of the > group. This is handled thanks to helpers in the PTP code (and locks). > We also need the MDIO bus lock while performing a single read or write > to the 1588 registers as the read/write are composed of multiple MDIO > transactions (and we don't want other threads updating the page).
Locking sounds complex. I assume LOCKDEP was your friend in getting this correct and deadlock free.
> + /* For multiple port PHYs; the MDIO address of the base PHY in the > + * pair of two PHYs that share a 1588 engine. PHY0 and PHY2 are coupled. > + * PHY1 and PHY3 as well. PHY0 and PHY1 are base PHYs for their > + * respective pair.
There are some evil hardware engineers out there :-(
It would be good it Richard gave this code a once over.
Andrew
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