kernel_optimize_test/arch/arm
Benjamin Gaignard 022eb8ae8b ARM: 8938/1: kernel: initialize broadcast hrtimer based clock event device
On platforms implementing CPU power management, the CPUidle subsystem
can allow CPUs to enter idle states where local timers logic is lost on power
down. To keep the software timers functional the kernel relies on an
always-on broadcast timer to be present in the platform to relay the
interrupt signalling the timer expiries.

For platforms implementing CPU core gating that do not implement an always-on
HW timer or implement it in a broken way, this patch adds code to initialize
the kernel hrtimer based clock event device upon boot (which can be chosen as
tick broadcast device by the kernel).
It relies on a dynamically chosen CPU to be always powered-up. This CPU then
relays the timer interrupt to CPUs in deep-idle states through its HW local
timer device.

Having a CPU always-on has implications on power management platform
capabilities and makes CPUidle suboptimal, since at least a CPU is kept
always in a shallow idle state by the kernel to relay timer interrupts,
but at least leaves the kernel with a functional system with some working
power management capabilities.

The hrtimer based clock event device is unconditionally registered, but
has the lowest possible rating such that any broadcast-capable HW clock
event device present will be chosen in preference as the tick broadcast
device.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2019-11-16 10:51:24 +00:00
..
boot ARM: 8933/1: replace Sun/Solaris style flag on section directive 2019-11-15 22:21:19 +00:00
common ARM: scoop: Use the right include 2019-09-03 22:09:46 +02:00
configs ARM: SoC fixes 2019-10-25 16:00:47 -04:00
crypto crypto: arm/aes-ce - add dependency on AES library 2019-10-01 23:06:43 +10:00
include ARM: 8931/1: Add clock_getres entry point 2019-11-15 22:21:14 +00:00
kernel ARM: 8938/1: kernel: initialize broadcast hrtimer based clock event device 2019-11-16 10:51:24 +00:00
kvm kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj) 2019-09-04 23:12:50 +09:00
lib Merge branch 'misc' into fixes 2019-10-22 17:37:29 +01:00
mach-actions
mach-alpine
mach-artpec treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-asm9260
mach-aspeed ARM: SoC fixes 2019-09-30 10:04:28 -07:00
mach-at91 ARM: at91: move platform-specific asm-offset.h to arch/arm/mach-at91 2019-08-23 21:50:10 +02:00
mach-axxia treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-bcm ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-berlin
mach-clps711x
mach-cns3xxx
mach-davinci ARM: davinci: dm365: Fix McBSP dma_slave_map entry 2019-10-17 19:20:22 +05:30
mach-digicolor treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-dove ARM: orion/mvebu: unify debug-ll virtual addresses 2019-08-14 19:24:58 +02:00
mach-ebsa110 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-efm32
mach-ep93xx Merge branch 'spi-5.4' into spi-next 2019-09-15 10:32:06 +01:00
mach-exynos ARM: exynos: Enable support for ARM architected timers 2019-09-09 20:56:43 +02:00
mach-footbridge ARM: 8911/1: move pcibios_report_status to <asm/pci.h> 2019-10-27 21:14:40 +00:00
mach-gemini
mach-highbank ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-hisi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-imx ARM: imx: stop adjusting ar8031 phy tx delay 2019-08-24 20:30:22 +02:00
mach-integrator treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-iop32x ARM: iop32x: merge everything into mach-iop32x/ 2019-08-14 15:36:22 +02:00
mach-ixp4xx docs: arm: convert docs to ReST and rename to *.rst 2019-07-15 09:20:24 -03:00
mach-keystone ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-lpc18xx
mach-lpc32xx ARM: lpc32xx: allow multiplatform build 2019-08-15 21:34:08 +02:00
mach-mediatek
mach-meson
mach-milbeaut
mach-mmp irqchip/mmp: Mask off interrupts from other cores 2019-08-30 15:23:30 +01:00
mach-moxart
mach-mv78xx0 ARM: orion/mvebu: unify debug-ll virtual addresses 2019-08-14 19:24:58 +02:00
mach-mvebu
mach-mxs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-nomadik
mach-npcm
mach-nspire ARM: mach-nspire: Kill off CLCD auxdata 2019-08-13 15:48:23 +02:00
mach-omap1 Merge branch 'asoc-5.3' into asoc-linus 2019-09-09 14:55:18 +01:00
mach-omap2 ARM: OMAP2+: Add pdata for OMAP3 ISP IOMMU 2019-10-18 08:40:27 -07:00
mach-orion5x ARM: orion/mvebu: unify debug-ll virtual addresses 2019-08-14 19:24:58 +02:00
mach-oxnas treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-picoxcell treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-prima2
mach-pxa ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-qcom treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-rda
mach-realview treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-rockchip
mach-rpc ARM: riscpc: Mark expected switch fall-through 2019-08-20 19:42:48 -05:00
mach-s3c24xx docs: arm: convert docs to ReST and rename to *.rst 2019-07-15 09:20:24 -03:00
mach-s3c64xx ARM: s3c64xx: squash samsung_usb_phy.h into setup-usb-phy.c 2019-08-21 19:50:40 +02:00
mach-s5pv210
mach-sa1100 ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-shmobile
mach-socfpga treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-spear treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-sti treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-stm32 ARM: SoC platform updates 2019-07-19 17:05:08 -07:00
mach-sunxi
mach-tango ARM: use arch_extension directive instead of arch argument 2019-06-19 09:44:25 -07:00
mach-tegra ARM: tegra: Mark expected switch fall-through 2019-08-09 19:45:22 -05:00
mach-u300
mach-uniphier
mach-ux500 ARM: ux500: Stop populating the PRCMU devices early 2019-07-23 09:17:06 +02:00
mach-versatile
mach-vexpress ARM: vexpress: Cleanup cppcheck shifting warning 2019-07-31 16:36:58 +01:00
mach-vt8500
mach-zx treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
mach-zynq ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up 2019-08-14 09:40:43 +02:00
mm ARM: 8937/1: spectre-v2: remove Brahma-B53 from hardening 2019-11-16 10:51:23 +00:00
net
nwfpe
oprofile
plat-omap ARM: OMAP: dma: Mark expected switch fall-throughs 2019-08-13 04:53:37 -07:00
plat-orion
plat-pxa treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
plat-samsung ARM: samsung: Fix system restart on S3C6410 2019-09-09 20:54:35 +02:00
plat-versatile treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
probes treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tools docs: arm: convert docs to ReST and rename to *.rst 2019-07-15 09:20:24 -03:00
vdso ARM: 8932/1: Add clock_gettime64 entry point 2019-11-15 22:21:15 +00:00
vfp treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
xen xen: fixes and cleanups for 5.4-rc2 2019-10-04 11:13:09 -07:00
Kconfig ARM: 8928/1: ARM_ERRATA_775420: Spelling s/date/data/ 2019-10-31 16:58:57 +00:00
Kconfig-nommu
Kconfig.debug ARM updates for 5.4-rc1: 2019-09-22 09:39:09 -07:00
Makefile ARM updates for 5.4-rc1: 2019-09-22 09:39:09 -07:00