rtc: efi: fixed typo in efi_procfs()

After the first check of the value of the "eft" variable
it does not change, it is obvious that a copy-paste
error was made here and the value of variable "alm"
should be checked here.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 501385f2a783 ("rtc: efi: add efi_procfs in efi_rtc_ops")
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
Link: https://lore.kernel.org/r/20231006090444.306729-1-korotkov.maxim.s@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: efi: Avoid spamming the log on RTC read failure

There are cases where the EFI runtime services may end up in a funny
state, e.g., due to a crash in the variable services, and this affects
other EFI runtime services as well.

That means that, even though GetTime() should not return an error, there
are cases where it might, and there is no point in logging such an
occurrence multiple times.

This works around an issue where user space -apparently- keeps hitting
on /dev/rtc if it fails to read the h/w clock, resulting in a tsunami of
log spam and a non-responsive system as a result.

Cc: Pierre Gondois <pierre.gondois@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/all/Y2o1hdZK9GGDVJsS@monolith.localdoman/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230217142338.1444509-1-ardb@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: efi: Enable SET/GET WAKEUP services as optional

The current implementation of rtc-efi is expecting all the 4
time services GET{SET}_TIME{WAKEUP} must be supported by UEFI
firmware. As per the EFI_RT_PROPERTIES_TABLE, the platform
specific implementations can choose to enable selective time
services based on the RTC device capabilities.

This patch does the following changes to provide GET/SET RTC
services on platforms that do not support the WAKEUP feature.

1) Relax time services cap check when creating a platform device.
2) Clear RTC_FEATURE_ALARM bit in the absence of WAKEUP services.
3) Conditional alarm entries in '/proc/driver/rtc'.

Cc: <stable@vger.kernel.org> # v6.0+
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230102230630.192911-1-sdonthineni@nvidia.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: efi: Add wakeup support

Add wakeup support for rtc-efi, so we can wakeup from S3/S4/S5 through
rtcwake.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
Link: https://lore.kernel.org/r/TYWP286MB260191455377CEBD2336557EB1659@TYWP286MB2601.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: efi: switch to RTC_FEATURE_UPDATE_INTERRUPT

Stop using uie_unsupported and clear RTC_FEATURE_UPDATE_INTERRUPT instead.
Also the driver doesn't supports UIE because it doesn't handle interrupts
so set RTC_FEATURE_ALARM_WAKEUP_ONLY,.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-24-alexandre.belloni@bootlin.com

rtc: efi: switch to devm_rtc_allocate_device

Switch to devm_rtc_allocate_device/devm_rtc_register_device, this allows
for further improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-23-alexandre.belloni@bootlin.com

rtc: efi: Remove the repeated module alias

'MODULE_ALIAS' is declared twice, cleanup one.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1621848834-20857-1-git-send-email-zhangshaokun@hisilicon.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: stop validating rtc_time in .read_time

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: efi: Fail probing if RTC reads don't work

While the EFI spec mandates an RTC, not every implementation actually adheres
to that rule (or can adhere to it - some systems just don't have an RTC).

For those, we really don't want to probe the EFI RTC driver at all, because if
we do we'd get a non-functional driver that does nothing useful but only spills
our kernel log with warnings.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: efi: add efi_procfs in efi_rtc_ops

Add efi_procfs in efi_rtc_ops to show rtc-efi info in /proc/driver/rtc.
Most of the code comes from efi_rtc_proc_show() in efirtc.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: efi: use correct EFI 'epoch'

The rtc-efi driver declares that the EFI 'epoch' is 1/1/1998, but
the UEFI spec does not define it at all. It does define a range of
[1900, 9999] for the 'Year' member of the EFI_TIME struct, so let's
use 1900 as the minimum year and not 1998.
Also, move the validation of the year to the convert_from_efi_time()
routine where all other EFI_TIME fields are validated as well.

This prevents rtc_read_time() failures when the RTC that backs the
EFI time services is set to a date before 1998, e.g., when it has
lost power.

This also optimizes the compute_wday() routine, by replacing the for
loop with a simple arithmetic expression, and by reusing the yearday
value that we need to compute anyway when populating the
rtc_time::tm_yday field.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: efi: Update author email address

I'm no longer employed by HP.

Signed-off-by: dann frazier <dannf@dannf.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

efi: rtc-efi: Mark UIE as unsupported

Tools like hwclock attempt to enable the RTC update interrupt (UIE) to
maximize the accuracy of the reported time value. The EFI rtc does not
have interrupt capability so this is a pointless exercise to begin with,
but the generic RTC framework ends up issuing a SetWakeupTime() Runtime
Services call before drawing that conclusion on its own.

Instead, we can mark UIE as unsupported at driver probe time. The net
result is the same, but without the spurious SetWakeupTime() call.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

rtc: drop owner assignment from platform_drivers

A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

efi: rtc-efi: Export platform:rtc-efi as module alias

When the rtc-efi driver is built as a module, we already register the
EFI rtc as a platform device if UEFI Runtime Services are enabled.
To wire it up to udev, and let the module be loaded automatically, we
need to export the 'platform:rtc-efi' alias from the module.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Mark Salter <msalter@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

drivers/rtc/rtc-efi.c: add missing module alias

Without proper alias kernel module is not loaded for rtc-efi driver.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Cc: dann frazier <dannf@dannf.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-efi.c: check for invalid data coming back from UEFI

In particular seeing zero in eft->month is problematic, as it results in
-1 (converted to unsigned int, i.e. yielding 0xffffffff) getting passed
to rtc_year_days(), where the value gets used as an array index
(normally resulting in a crash). This was observed with the driver
enabled on x86 on some Fujitsu system (with possibly not up to date
firmware, but anyway).

Perhaps efi_read_alarm() should not fail if neither enabled nor pending
are set, but the returned time is invalid?

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reported-by: Raymund Will <rw@suse.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-efi.c: avoid subtracting day twice when computing year days

Compared source code of rtc-lib.c::rtc_year_days() with
efirtc.c::rtc_year_days(), found the code in rtc-efi decreases value of
day twice when it computing year days. rtc-lib.c::rtc_year_days() has
already decrease days and return the year days from 0 to 365.

Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-efi.c: remove empty function

After the switch to devm_* functions and the removal of
rtc_device_unregister(), the 'remove' function does not do anything.
Delete it.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: dann frazier <dannf@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: rtc-efi: use devm_rtc_device_register()

devm_rtc_device_register() is device managed and makes cleanup paths
simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: rtc-efi: use module_platform_driver_probe()

Use module_platform_driver_probe() macro which makes the code smaller and
simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: rtc-efi: use dev_err()/dev_warn()/pr_err() instead of printk()

Fix the checkpatch warnings as below:

WARNING: Prefer netdev_err(netdev, ... then dev_err(dev, ... then pr_err(... to printk(KERN_ERR ...
WARNING: please, no space before tabs

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-efi.c: fix section mismatch warning

efi_rtc_init() uses platform_driver_probe(), so there's no need to also
set efi_rtc_driver's probe member (as it won't be used anyway). This
fixes a modpost section mismatch warning (as efi_rtc_probe() validly is
__init).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: add platform driver for EFI

Munge Stephane Eranian's efirtc.c code into an rtc platform driver

[akpm@linux-foundation.org: use is_leap_year()]
Signed-off-by: dann frazier <dannf@hp.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Cc: stephane eranian <eranian@googlemail.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>