Re: [PATCH 19/24] rtc: pm8xxx: add support for uefi offset

Johan Hovold
2023-01-27T15:26:22Z

On Fri, Jan 27, 2023 at 04:19:18PM +0100, Alexandre Belloni wrote:
> On 26/01/2023 15:20:52+0100, Johan Hovold wrote:
> > On many Qualcomm platforms the PMIC RTC control and time registers are
> > read-only so that the RTC time can not be updated. Instead an offset
> > needs be stored in some machine-specific non-volatile memory, which the
> > driver can take into account.
> >
> > Add support for storing a 32-bit offset from the GPS time epoch in a
> > UEFI variable so that the RTC time can be set on such platforms.
> >
>
> Why are you using the GPS epoch? This seems pretty random.

Tell that to the Qualcomm firmware team. ;)

Perhaps I could have made it more clear, but this is the format that the
firmware uses so Linux is not free to pick a different base here (or
time would differ ten years between UEFI/Windows and Linux).

> > The UEFI variable is
> >
> > 882f8c2b-9646-435f-8de5-f208ff80c1bd-RTCInfo
> >
> > and holds a 12-byte structure where the first four bytes is a GPS time
> > offset in little-endian byte order.

Johan