Ronald Wahl 89356bee8e clocksource/drivers/timer-atmel-tcb: Fix initialization on SAM9 hardware ... [ Upstream commit 6d3bc4c02d ] On SAM9 hardware two cascaded 16 bit timers are used to form a 32 bit high resolution timer that is used as scheduler clock when the kernel has been configured that way (CONFIG_ATMEL_CLOCKSOURCE_TCB). The driver initially triggers a reset-to-zero of the two timers but this reset is only performed on the next rising clock. For the first timer this is ok - it will be in the next 60ns (16MHz clock). For the chained second timer this will only happen after the first timer overflows, i.e. after 2^16 clocks (~4ms with a 16MHz clock). So with other words the scheduler clock resets to 0 after the first 2^16 clock cycles. It looks like that the scheduler does not like this and behaves wrongly over its lifetime, e.g. some tasks are scheduled with a long delay. Why that is and if there are additional requirements for this behaviour has not been further analysed. There is a simple fix for resetting the second timer as well when the first timer is reset and this is to set the ATMEL_TC_ASWTRG_SET bit in the Channel Mode register (CMR) of the first timer. This will also rise the TIOA line (clock input of the second timer) when a software trigger respective SYNC is issued. Signed-off-by: Ronald Wahl <ronald.wahl@raritan.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20231007161803.31342-1-rwahl@gmx.de Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-11-28 16:54:49 +00:00
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acpi_pm.c	clocksource: acpi_pm: fix return value of __setup handler	2022-04-08 14:40:03 +02:00
arc_timer.c
arm_arch_timer.c
arm_global_timer.c
armv7m_systick.c
asm9260_timer.c
bcm2835_timer.c
bcm_kona_timer.c
clksrc-dbx500-prcmu.c
clksrc_st_lpc.c
clps711x-timer.c
dummy_timer.c
dw_apb_timer.c
dw_apb_timer_of.c
em_sti.c
exynos_mct.c	clocksource/drivers/exynos_mct: Handle DTS with higher number of interrupts	2022-04-08 14:40:02 +02:00
h8300_timer8.c
h8300_timer16.c
h8300_tpu.c
hyperv_timer.c	clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()	2022-06-22 14:13:16 +02:00
i8253.c
ingenic-ost.c
ingenic-sysost.c
ingenic-timer.c
jcore-pit.c
Kconfig	clocksource/drivers/timer-ti-dm: Select TIMER_OF	2021-11-18 14:04:09 +01:00
Makefile
mips-gic-timer.c
mmio.c
mps2-timer.c
mxs_timer.c
nomadik-mtu.c
numachip.c
renesas-ostm.c
samsung_pwm_timer.c
scx200_hrt.c
sh_cmt.c	clocksource/drivers/sh_cmt: Access registers according to spec	2023-01-14 10:15:20 +01:00
sh_mtu2.c
sh_tmu.c
timer-armada-370-xp.c
timer-atcpit100.c
timer-atlas7.c
timer-atmel-pit.c
timer-atmel-st.c
timer-atmel-tcb.c	clocksource/drivers/timer-atmel-tcb: Fix initialization on SAM9 hardware	2023-11-28 16:54:49 +00:00
timer-cadence-ttc.c	clocksource/drivers/cadence-ttc: Fix memory leak in ttc_timer_probe	2023-07-27 08:43:33 +02:00
timer-clint.c
timer-cs5535.c
timer-davinci.c	clocksource/drivers/davinci: Fix memory leak in davinci_timer_register when init fails	2023-05-17 11:48:03 +02:00
timer-digicolor.c
timer-efm32.c
timer-fsl-ftm.c
timer-fttmr010.c
timer-gx6605s.c
timer-imx-gpt.c	clocksource/drivers/timer-imx-gpt: Fix potential memory leak	2023-11-28 16:54:49 +00:00
timer-imx-sysctr.c
timer-imx-tpm.c
timer-integrator-ap.c
timer-ixp4xx.c	clocksource/drivers/ixp4xx: remove EXPORT_SYMBOL_GPL from ixp4xx_timer_setup()	2022-07-07 17:52:23 +02:00
timer-keystone.c
timer-lpc32xx.c
timer-mediatek.c
timer-meson6.c
timer-microchip-pit64b.c	clocksource/drivers/timer-microchip-pit64b: Use notrace	2022-04-08 14:40:02 +02:00
timer-milbeaut.c
timer-mp-csky.c
timer-npcm7xx.c
timer-nps.c
timer-of.c	clocksource/drivers/timer-of: Check return value of of_iomap in timer_of_base_init()	2022-04-08 14:40:02 +02:00
timer-of.h
timer-orion.c
timer-owl.c
timer-oxnas-rps.c	clocksource/drivers/oxnas-rps: Fix irq_of_parse_and_map() return value	2022-06-14 18:32:34 +02:00
timer-pistachio.c
timer-prima2.c
timer-probe.c
timer-pxa.c
timer-qcom.c
timer-rda.c
timer-riscv.c	Revert "clocksource/drivers/riscv: Events are stopped during CPU suspend"	2022-12-08 11:23:59 +01:00
timer-rockchip.c
timer-sp.h
timer-sp804.c	clocksource/drivers/sp804: Avoid error on multiple instances	2022-06-14 18:32:43 +02:00
timer-sprd.c
timer-stm32-lp.c
timer-stm32.c
timer-sun4i.c
timer-sun5i.c
timer-tango-xtal.c
timer-tegra.c
timer-ti-32k.c
timer-ti-dm-systimer.c	clocksource/drivers/timer-ti-dm: Fix missing clk_disable_unprepare in dmtimer_systimer_init_clock()	2023-01-14 10:15:20 +01:00
timer-ti-dm.c
timer-u300.c
timer-versatile.c
timer-vf-pit.c
timer-vt8500.c
timer-zevio.c