linux-stable.git/drivers/rtc/rtc-cmos.c, branch linux-4.8.y

rtc: simplify implementations of read_alarm

2016-07-09T08:24:45+00:00

Since commit d68778b80dd7 ("rtc: initialize output parameter for read
alarm to "uninitialized"") there is no need to explicitly set
unsupported members to -1. So drop the respective assignments from
drivers.

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Alexandre Belloni

mn10300: use RTC_DRV_CMOS instead of CONFIG_RTC

2016-06-25T23:20:08+00:00

nn10300 has a dependency on mc146818_get_time/mc146818_set_time,
which we want to move from the mc146818rtc.h header into the
rtc subsystem, which in turn is not usable on mn10300.

This changes mn10300 to use the modern rtc-cmos driver instead
of the old RTC driver, and that in turn lets us completely
remove the read_persistent_clock/update_persistent_clock callbacks.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Alexandre Belloni

rtc: cmos: move mc146818rtc code out of asm-generic/rtc.h

2016-06-03T22:20:00+00:00

Drivers should not really include stuff from asm-generic directly,
and the PC-style cmos rtc driver does this in order to reuse the
mc146818 implementation of get_rtc_time/set_rtc_time rather than
the architecture specific one for the architecture it gets built for.

To make it more obvious what is going on, this moves and renames the
two functions into include/linux/mc146818rtc.h, which holds the
other mc146818 specific code. Ideally it would be in a .c file,
but that would require extra infrastructure as the functions are
called by multiple drivers with conflicting dependencies.

With this change, the asm-generic/rtc.h header also becomes much
more generic, so it can be reused more easily across any architecture
that still relies on the genrtc driver.

The only caller of the internal __get_rtc_time/__set_rtc_time
functions is in arch/alpha/kernel/rtc.c, and we just change those
over to the new naming.

Signed-off-by: Arnd Bergmann 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Alexandre Belloni

rtc: Use IS_ENABLED() instead of checking for built-in or module

2016-05-20T10:33:51+00:00

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.

Signed-off-by: Javier Martinez Canillas 
Signed-off-by: Alexandre Belloni

rtc: cmos: prevent kernel warning on IRQ flags mismatch

2016-01-11T19:38:50+00:00

The Microsoft Surface 3 tablet shares interrupt line between RTC and one of SPI
controllers. However, the rtc_cmos driver doesn't allow shared interrupts and
user sees the following warning

genirq: Flags mismatch irq 8. 00000080 (8086228E:02) vs. 00000000 (rtc0)
...
[] pxa2xx_spi_probe+0x151/0x600 [spi_pxa2xx_platform]

Allow RTC driver to use shared interrupts.

Seems we are on the safe side to do just this simple change since
cmos_interrupt() handler checks for the actual hardware status anyway.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Alexandre Belloni

rtc: cmos: clean up cmos_nvram_read()/cmos_nvram_write()

2015-09-05T11:19:09+00:00

The change removes redundant sysfs binary file boundary checks, since
this task is already done on caller side in fs/sysfs/file.c

Signed-off-by: Vladimir Zapolskiy 
Signed-off-by: Alexandre Belloni

rtc: cmos: Revert "rtc-cmos: Add an alarm disable quirk"

2015-09-05T11:19:08+00:00

Commit d5a1c7e3fc38 ("rtc-cmos: Add an alarm disable quirk") that
added a special quirk is not needed because [PATCH 1/2] of this
patchset makes the kernel more robust:
rtc-cmos: Cancel alarm timer if alarm time is equal to now+1 seconds

Signed-off-by: Adrian Huang 
Tested-by: Egbert Eich 
Tested-by: Diego Ercolani 
Cc: Borislav Petkov 
Signed-off-by: Alexandre Belloni

rtc: cmos: Cancel alarm timer if alarm time is equal to now+1 seconds

2015-09-05T11:19:08+00:00

Steps to reproduce the problem:
	1) Enable RTC wake-up option in BIOS Setup
	2) Issue one of these commands in the OS: "poweroff"
	   or "shutdown -h now"
	3) System will shut down and then reboot automatically

Root-cause of the issue:
	1) During the shutdown process, the hwclock utility is used
	   to save the system clock to hardware clock (RTC).
	2) The hwclock utility invokes ioctl() with RTC_UIE_ON. The
	   kernel configures the RTC alarm for the periodic interrupt
	   (every 1 second).
	3) The hwclock uitlity closes the /dev/rtc0 device, and the
	   kernel disables the RTC alarm irq (AIE bit of Register B)
	   via ioctl() with RTC_UIE_OFF. But, the configured alarm
	   time is the current_time + 1.
	4) After the next 1 second is elapsed, the AF (alarm
	   interrupt flag) of Register C is set.
	5) The S5 handler in BIOS is invoked to configure alarm
	   registers (enable AIE bit and configure alarm date/time).
	   But, BIOS does not clear the previous interrupt status
	   during alarm configuration. Therefore, "AF=AIE=1" causes
	   the rtc device to trigger an interrupt.
	6) So, the machine reboots automatically right after shutdown.

This patch cancels the alarm timer if the following condictions are
met (suggested by Alexandre):
	1) The configured alarm time is equal to current_time + 1
	   seconds.
	2) The AIE timer is not in use.

The member 'alarm_expires' is introduced in struct cmos_rtc because
of the following reasons:
	1) The configured alarm time can be retrieved from
	   cmos_read_alarm(), but we need to take the 'wrapped
	   timestamp' and 'time rollover' into consideration. The
	   function __rtc_read_alarm() eliminates the concerns. To
	   avoid the duplicated code in the lower level RTC driver,
	   invoking __rtc_read_alarm from the lower level RTC driver
	   is not encouraged. Moreover, the compilation error 'the
	   undefined __rtc_read_alarm" is observed if the lower level
	   RTC driver is compiled as a kernel module.
	2) The uie_rtctimer.node.expires and aie_timer.node.expires can
	   be retrieved for the configured alarm time. But, the problem
	   is that either of them might configure the CMOS alarm time.
	   We cannot make sure UIE timer or AIE tiemr configured the
	   CMOS alarm time before. (uie_rtctimer or aie_timer is enabled
	   and then is disabled).
	3) The patch introduces the member 'alarm_expires' to keep the
	   newly configured alarm time, so the above-mentioned concerns
	   can be eliminated.

The issue goes away after 20-time shutdown tests.

Signed-off-by: Adrian Huang 
Tested-by: Egbert Eich 
Tested-by: Diego Ercolani 
Cc: Borislav Petkov 
Signed-off-by: Alexandre Belloni

rtc: use more standard kernel logging styles

2015-04-17T13:04:02+00:00

Neaten the logging a bit by adding #define pr_fmt

Miscellanea:

o Remove __FILE__/__func__ uses
o Coalesce formats adding missing spaces
o Align arguments
o (rtc-cmos) Integrated 2 consecutive messages

Signed-off-by: Joe Perches 
Acked-by: Alexandre Belloni 
Cc: Alessandro Zummo 
Cc: Joshua Kinard 
Cc: Chanwoo Choi 
Reviewed-by: Krzysztof Kozlowski 
Tested-by: Krzysztof Kozlowski 
Cc: Aaro Koskinen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: remove use of seq_printf return value

2015-04-15T23:35:24+00:00

The seq_printf return value, because it's frequently misused,
will eventually be converted to void.

See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to
     seq_has_overflowed() and make public")

Signed-off-by: Joe Perches 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds