kernel/linux.git/drivers/clocksource/arm_global_timer.c, branch v6.6.131

clocksource/drivers/arm_global_timer: Guard against division by zero

2024-08-29T15:33:35+00:00

[ Upstream commit e651f2fae33634175fae956d896277cf916f5d09 ] The result of the division of new_rate by gt_target_rate can be zero (if new_rate is smaller than gt_target_rate). Using that result as divisor without checking can result in a division by zero error. Guard against this by checking for a zero value earlier. While here, also change the psv variable to an unsigned long to make sure we don't overflow the datatype as all other types involved are also unsiged long. Signed-off-by: Martin Blumenstingl Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20240225151336.2728533-3-martin.blumenstingl@googlemail.com Signed-off-by: Sasha Levin

clocksource/drivers/arm_global_timer: Fix maximum prescaler value

2024-04-03T13:28:50+00:00

[ Upstream commit b34b9547cee41575a4fddf390f615570759dc999 ] The prescaler in the "Global Timer Control Register bit assignments" is documented to use bits [15:8], which means that the maximum prescaler register value is 0xff. Fixes: 171b45a4a70e ("clocksource/drivers/arm_global_timer: Implement rate compensation whenever source clock changes") Signed-off-by: Martin Blumenstingl Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20240218174138.1942418-2-martin.blumenstingl@googlemail.com Signed-off-by: Sasha Levin

clocksource/drivers/arm_global_timer: Remove duplicated argument in arm_global_timer

2021-06-16T15:33:04+00:00

Fix the following coccicheck warning: drivers/clocksource/arm_global_timer.c:107:4-23: duplicated argument to & or | Signed-off-by: Wan Jiabing Reviewed-by: Patrice Chotard Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20210615115440.8881-1-wanjiabing@vivo.com

clocksource/drivers/arm_global_timer: Make symbol 'gt_clk_rate_change_nb' static

2021-06-16T15:33:04+00:00

The sparse tool complains as follows: drivers/clocksource/arm_global_timer.c:54:23: warning: symbol 'gt_clk_rate_change_nb' was not declared. Should it be static? This symbol is not used outside of arm_global_timer.c, so mark it static. Reported-by: Hulk Robot Signed-off-by: Zou Wei Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/1623490046-37972-1-git-send-email-zou_wei@huawei.com

clocksource/drivers/arm_global_timer: Implement rate compensation whenever source clock changes

2021-06-16T15:33:04+00:00

This patch adds rate change notification support for the parent clock; should that clock change, then we try to adjust the our prescaler in order to compensate (i.e. we adjust to still get the same timer frequency). This is loosely based on what it's done in timer-cadence-ttc. timer-sun51, mips-gic-timer and smp_twd.c also seem to look at their parent clock rate and to perform some kind of adjustment whenever needed. In this particular case we have only one single counter and prescaler for all clocksource, clockevent and timer_delay, and we just update it for all (i.e. we don't let it go and call clockevents_update_freq() to notify to the kernel that our rate has changed). Note that, there is apparently no other way to fixup things, because once we call register_current_timer_delay(), specifying the timer rate, it seems that that rate is not supposed to change ever. In order for this mechanism to work, we have to make assumptions about how much the initial clock is supposed to eventually decrease from the initial one, and set our initial prescaler to a value that we can eventually decrease enough to compensate. We provide an option in KConfig for this. In case we end up in a situation in which we are not able to compensate the parent clock change, we fail returning NOTIFY_BAD. This fixes a real-world problem with Zynq arch not being able to use this driver and CPU_FREQ at the same time (because ARM global timer is fed by the CPU clock, which may keep changing when CPU_FREQ is enabled). Signed-off-by: Andrea Merello Cc: Patrice Chotard Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: Michal Simek Cc: Sören Brinkmann Reviewed-by: Patrice Chotard Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20210406130045.15491-2-andrea.merello@gmail.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 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 version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE

2017-06-14T09:58:45+00:00

The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the clocksource at early stage. However, this macro is also used to initialize the clockevent if any, or the clockevent only. It was originally suggested to declare another macro to initialize a clockevent, so in order to separate the two entities even they belong to the same IP. This was not accepted because of the impact on the DT where splitting a clocksource/clockevent definition does not make sense as it is a Linux concept not a hardware description. On the other side, the clocksource has not interrupt declared while the clockevent has, so it is easy from the driver to know if the description is for a clockevent or a clocksource, IOW it could be implemented at the driver level. So instead of dealing with a named clocksource macro, let's use a more generic one: TIMER_OF_DECLARE. The patch has not functional changes. Signed-off-by: Daniel Lezcano Acked-by: Heiko Stuebner Acked-by: Neil Armstrong Acked-by: Arnd Bergmann Acked-by: Matthias Brugger Reviewed-by: Linus Walleij

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-12-25T22:30:04+00:00

Pull timer type cleanups from Thomas Gleixner: "This series does a tree wide cleanup of types related to timers/timekeeping. - Get rid of cycles_t and use a plain u64. The type is not really helpful and caused more confusion than clarity - Get rid of the ktime union. The union has become useless as we use the scalar nanoseconds storage unconditionally now. The 32bit timespec alike storage got removed due to the Y2038 limitations some time ago. That leaves the odd union access around for no reason. Clean it up. Both changes have been done with coccinelle and a small amount of manual mopping up" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ktime: Get rid of ktime_equal() ktime: Cleanup ktime_set() usage ktime: Get rid of the union clocksource: Use a plain u64 instead of cycle_t

clocksource: Use a plain u64 instead of cycle_t

2016-12-25T10:04:12+00:00

There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz

cpu/hotplug: Cleanup state names

2016-12-25T09:47:44+00:00

When the state names got added a script was used to add the extra argument to the calls. The script basically converted the state constant to a string, but the cleanup to convert these strings into meaningful ones did not happen. Replace all the useless strings with 'subsys/xxx/yyy:state' strings which are used in all the other places already. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Sebastian Siewior Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de Signed-off-by: Thomas Gleixner