kernel/linux.git/drivers/clocksource/dw_apb_timer.c, branch v6.6.132

clocksource: dw_apb_timer: Make CPU-affiliation being optional

2020-05-22T22:02:41+00:00

Currently the DW APB Timer driver binds each clockevent timers to a particular CPU. This isn't good for multiple reasons. First of all seeing the device is placed on APB bus (which makes it accessible from any CPU core), accessible over MMIO and having the DYNIRQ flag set we can be sure that manually binding the timer to any CPU just isn't correct. By doing so we just set an extra limitation on device usage. This also doesn't reflect the device actual capability, since by setting the IRQ affinity we can make it virtually local to any CPU. Secondly imagine if you had a real CPU-local timer with the same rating and the same CPU-affinity. In this case if DW APB timer was registered first, then due to the clockevent framework tick-timer selection procedure we'll end up with the real CPU-local timer being left unselected for clock-events tracking. But on most of the platforms (MIPS/ARM/etc) such timers are normally embedded into the CPU core and are accessible with much better performance then devices placed on APB. For instance in MIPS architectures there is r4k-timer, which is CPU-local, assigned with the same rating, and normally its clockevent device is registered after the platform-specific one. So in order to fix all of these issues let's make the DW APB Timer CPU affinity being optional and deactivated by passing a negative CPU id, which will effectively set the DW APB clockevent timer cpumask to 'cpu_possible_mask'. Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Paul Burton Cc: Ralf Baechle Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: Arnd Bergmann Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: linux-rtc@vger.kernel.org Cc: devicetree@vger.kernel.org Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20200521204818.25436-5-Sergey.Semin@baikalelectronics.ru

clocksource: Replace setup_irq() by request_irq()

2020-02-27T11:15:24+00:00

request_irq() is preferred over setup_irq(). The early boot setup_irq() invocations happen either via 'init_IRQ()' or 'time_init()', while memory allocators are ready by 'mm_init()'. Per tglx[1], setup_irq() existed in olden days when allocators were not ready by the time early interrupts were initialized. Hence replace setup_irq() by request_irq(). Seldom remove_irq() usage has been observed coupled with setup_irq(), wherever that has been found, it too has been replaced by free_irq(). A build error that was reported by kbuild test robot in the previous version of the patch also has been fixed. [1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos Signed-off-by: afzal mohammed Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/91961c77c1cf93d41523f5e1ac52043f32f97077.1582799709.git.afzal.mohd.ma@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

Merge branch 'clockevents/4.12' of https://git.linaro.org/people/daniel.lezcano/linux into timers/core

2017-04-17T08:55:14+00:00

Pull clockevents updates from Daniel Lezcano - Provide a framework to handle errata gracefuly for arm_arch_timer (Mark Zyngier) - Clarify the DT properties for the rockchip timer and add the clocksource as an alternative to the bogus architected timer (Alexander Kochetkov) - Rename the Gemini timer to Faraday timer fttmr010 and provide a specific initialization for Gemini (Linus Walleij) - Add missing newlines in the error message in the timers (Rafał Miłecki) - Read the clock once and implement the delay timer on Orion (Russell King)

clockevents/drivers/dw_apb: Set ->min_delta_ticks and ->max_delta_ticks

2017-04-14T20:11:13+00:00

In preparation for making the clockevents core NTP correction aware, all clockevent device drivers must set ->min_delta_ticks and ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a clockevent device's rate is going to change dynamically and thus, the ratio of ns to ticks ceases to stay invariant. Make the dw_apb clockevent driver initialize these fields properly. This patch alone doesn't introduce any change in functionality as the clockevents core still looks exclusively at the (untouched) ->min_delta_ns and ->max_delta_ns. As soon as this has changed, a followup patch will purge the initialization of ->min_delta_ns and ->max_delta_ns from this driver. Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Daniel Lezcano Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Acked-by: Daniel Lezcano Signed-off-by: Nicolai Stange Signed-off-by: John Stultz

clocksource: Add missing line break to error messages

2017-04-07T14:23:04+00:00

Printing with pr_* functions requires adding line break manually. Signed-off-by: Rafał Miłecki Acked-by: Thierry Reding Signed-off-by: Daniel Lezcano

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

clockevents/drivers/dw_apb_timer: Implement ->set_state_oneshot_stopped()

2016-04-28T13:09:03+00:00

The dw_apb_timer only "supports PERIODIC mode and their drivers emulate ONESHOT over that" as described in commit 8fff52fd5093 ("clockevents: Introduce CLOCK_EVT_STATE_ONESHOT_STOPPED state"). Inspired by Viresh, I think the dw_apb_timer also needs to implement the set_state_oneshot_stopped() which is called by the clkevt core, when the next event is required at an expiry time of 'KTIME_MAX'. This normally happens with NO_HZ_{IDLE|FULL} in both LOWRES/HIGHRES modes. This patch makes the clockevent device to stop on such an event, to avoid spurious interrupts, as explained by the above commit. Signed-off-by: Jisheng Zhang Signed-off-by: Daniel Lezcano Reviewed-by: Viresh Kumar

clocksource/drivers/dw_apb_timer: Inline apbt_readl and apbt_writel

2015-12-15T20:41:28+00:00

It seems gcc can automatically inline apbt_writel() for us, but apbt_real isn't inlined. This patch makes them inline to get a trivial performance improvement: 4096 rounds of __apbt_read_clocksource() call spend time on Marvell BG4CT platform: before the patch 1275240ns on average after the patch 1263240ns on average so we get 1% performance improvement. Signed-off-by: Jisheng Zhang Signed-off-by: Daniel Lezcano

clocksource/drivers/dw_apb_timer: Use {readl|writel}_relaxed in critical path

2015-12-15T20:41:28+00:00

It's safe to use the relaxed version. From another side, the relaxed io accessor macros are available on all architectures now, so we can use the relaxed versions to get a trivial system performance improvement, we measured time the following functions spent on Marvell BG4CT: 4096 rounds of __apbt_read_clocksource() call: before the patch: 1263240ns on average after the patch: 1250080ns on average improved by 1% 4096 rounds of apbt_eoi() call: before the patch: 1290960ns on average after the patch: 1248240ns on average 4096 rounds of apbt_next_event() call: before the patch: 3333660ns on average after the patch: 1322040ns on average improved by 60%! Signed-off-by: Jisheng Zhang Signed-off-by: Daniel Lezcano