From: Johan Hovold <johan@kernel.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Johan Hovold <johan+linaro@kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Bjorn Andersson <andersson@kernel.org>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
Konrad Dybcio <konradybcio@kernel.org>,
Jonathan Marek <jonathan@marek.ca>,
linux-arm-msm@vger.kernel.org, linux-rtc@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] rtc: pm8xxx: add support for uefi offset
Date: Mon, 20 Jan 2025 16:15:54 +0100 [thread overview]
Message-ID: <Z45oqqnlMSNEYyil@hovoldconsulting.com> (raw)
In-Reply-To: <Z45nYEfq2IPsrRy7@bogus>
On Mon, Jan 20, 2025 at 03:10:24PM +0000, Sudeep Holla wrote:
> On Mon, Jan 20, 2025 at 03:41:48PM +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 can't the UEFI runtime services be used here ?
> In short, why is drivers/rtc/rtc-efi.c not working or no attempts are
> made to check if that works just fine ?
As I alluded to in the commit message, the Qualcomm UEFI implementation
is broken and the runtime services cannot be accessed during runtime...
That's why we can't use rtc-efi and why we have a dedicated efivars
implementation that talks directly to the firmware using a custom
protocol:
https://lore.kernel.org/all/20220723224949.1089973-1-luzmaximilian@gmail.com/
Johan
next prev parent reply other threads:[~2025-01-20 15:15 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-20 14:41 [PATCH 0/7] arm64: dts: qcom: x1e80100: enable rtc Johan Hovold
2025-01-20 14:41 ` [PATCH 1/7] dt-bindings: rtc: qcom-pm8xxx: add uefi-variable offset Johan Hovold
2025-01-20 14:41 ` [PATCH 2/7] dt-bindings: rtc: qcom-pm8xxx: document qcom,no-alarm flag Johan Hovold
2025-01-27 18:00 ` Rob Herring (Arm)
2025-01-20 14:41 ` [PATCH 3/7] rtc: pm8xxx: add support for uefi offset Johan Hovold
2025-01-20 15:10 ` Sudeep Holla
2025-01-20 15:15 ` Johan Hovold [this message]
2025-01-20 15:17 ` Johan Hovold
2025-01-20 17:13 ` Sudeep Holla
2025-01-24 12:56 ` Tobias Heider
2025-01-24 14:07 ` Johan Hovold
2025-01-20 14:41 ` [PATCH 4/7] rtc: pm8xxx: mitigate flash wear Johan Hovold
2025-01-23 11:39 ` Johan Hovold
2025-01-20 14:41 ` [PATCH 5/7] rtc: pm8xxx: implement qcom,no-alarm flag for non-HLOS owned alarm Johan Hovold
2025-01-20 14:41 ` [PATCH 6/7] arm64: dts: qcom: sc8280xp-x13s: switch to uefi rtc offset Johan Hovold
2025-01-20 18:08 ` Jens Glathe
2025-01-23 12:26 ` Konrad Dybcio
2025-01-20 14:41 ` [PATCH 7/7] arm64: dts: qcom: x1e80100: enable rtc Johan Hovold
2025-01-20 18:12 ` Jens Glathe
2025-01-21 10:06 ` Johan Hovold
2025-01-23 12:26 ` Konrad Dybcio
2025-01-20 21:19 ` [PATCH 0/7] " Steev Klimaszewski
2025-01-21 10:06 ` Johan Hovold
2025-01-21 3:48 ` Joel Stanley
2025-01-21 10:07 ` Johan Hovold
2025-01-23 12:28 ` Konrad Dybcio
2025-01-25 18:46 ` Sebastian Reichel
2025-01-27 0:20 ` Rob Herring
2025-02-19 13:37 ` Johan Hovold
2025-04-21 14:36 ` Rob Clark
2025-04-22 13:39 ` Johan Hovold
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