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9115df89d1
linux/drivers/clocksource
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Jisheng Zhang 9115df89d1 clocksource/drivers/dw_apb_timer_of: Implement ARM delay timer 
Implement an ARM delay timer to be used for udelay(). This allows us to
skip the delay loop calibration at boot on Marvell BG2, BG2Q, BG2CD
platforms. And after this patch, udelay() will be unaffected by CPU
frequency changes.

Note: Although in case there are several possible delay timers, we may
not select the "best" delay timer. Take one Marvell Berlin platform for
example: we have arch timer and dw-apb timer. The arch timer freq is
25MHZ while the dw-apb timer freq is 100MHZ, current selection would
choose the dw-apb timer. But the dw apb timer is on the APB bus while
arch timer sits in CPU, the cost of accessing the apb timer is higher
than the arch timer. We could introduce "rating" concept to delay
timer, but this approach "brings a lot of complexity and workarounds
in the code for a small benefit" as pointed out by Daniel.

Later, Arnd pointed out "However, we could argue that this actually
doesn't matter at all, because the entire point of the ndelay()/
udelay()/mdelay() functions is to waste CPU cycles doing not much at
all, so we can just as well waste them reading the timer register
than spinning on the CPU reading the arch timer more often.", so we
just simply register the dw apb base delay timer.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2015-12-15 09:42:00 +01:00
..
acpi_pm.c treewide: Fix printks with 0x%# 2013-08-27 10:49:38 +02:00
arm_arch_timer.c clocksource / arm_arch_timer: Convert to ACPI probing 2015-10-01 02:18:39 +02:00
arm_global_timer.c clocksource/drivers/arm_global_timer: Prevent ftrace recursion 2015-10-27 01:32:33 +01:00
armv7m_systick.c clocksource/drivers/armv7m_systick: Add ARM System timer driver 2015-06-02 12:10:14 +02:00
asm9260_timer.c clockevents/drivers/asm9260: Migrate to new 'set-state' interface 2015-08-10 11:40:25 +02:00
bcm2835_timer.c clockevents/drivers/bcm2835: Migrate to new 'set-state' interface 2015-08-06 12:16:41 +02:00
bcm_kona_timer.c clockevents/drivers/bcm_kona: Migrate to new 'set-state' interface 2015-08-06 12:16:42 +02:00
cadence_ttc_timer.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 14:04:50 -07:00
clksrc_st_lpc.c clocksource: sti: Provide 'use timer as sched clock' capability 2015-07-23 17:07:26 +01:00
clksrc-dbx500-prcmu.c clocksource: dbx500-prcmu: Switch to sched_clock_register() 2013-07-30 11:24:52 -07:00
clksrc-probe.c clocksource: cosmetic: Drop OF 'dependency' from symbols 2015-10-01 02:18:39 +02:00
clps711x-timer.c clockevents/drivers/clps711x: Migrate to new 'set-state' interface 2015-08-10 11:40:27 +02:00
cs5535-clockevt.c clockevents/drivers/cs5535: Migrate to new 'set-state' interface 2015-08-06 12:16:42 +02:00
dummy_timer.c clockevents/drivers/dummy_timer: Migrate to new 'set-state' interface 2015-08-10 11:40:28 +02:00
dw_apb_timer_of.c clocksource/drivers/dw_apb_timer_of: Implement ARM delay timer 2015-12-15 09:42:00 +01:00
dw_apb_timer.c clockevents/drivers/dw_apb_timer: Add dynamic irq flag to the timer 2015-08-10 11:40:53 +02:00
em_sti.c clocksource/drivers/em_sti: Remove unneeded memset()s 2015-10-15 17:41:59 +02:00
exynos_mct.c clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr() 2015-10-15 17:42:03 +02:00
fsl_ftm_timer.c clocksource/fsl: Avoid harmless 64-bit warnings 2015-11-16 19:07:08 +01:00
h8300_timer8.c clocksource/drivers/h8300_*: Remove unneeded memset()s 2015-10-15 17:42:02 +02:00
h8300_timer16.c clocksource/drivers/h8300_*: Remove unneeded memset()s 2015-10-15 17:42:02 +02:00
h8300_tpu.c clocksource/drivers/h8300_*: Remove unneeded memset()s 2015-10-15 17:42:02 +02:00
i8253.c clockevents/drivers/i8253: Migrate to new 'set-state' interface 2015-08-10 11:40:30 +02:00
Kconfig clocksource/drivers/Kconfig: Add missing GENERIC_CLOCKEVENTS dependency 2015-12-15 09:41:58 +01:00
Makefile ARM: SoC cleanups for v4.4 2015-11-10 14:48:36 -08:00
meson6_timer.c clockevents/drivers/meson6: Migrate to new 'set-state' interface 2015-08-10 11:40:30 +02:00
metag_generic.c clockevents/drivers/metag_generic: Migrate to new 'set-state' interface 2015-08-10 11:40:31 +02:00
mips-gic-timer.c MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime() 2015-11-11 08:36:41 +01:00
mmio.c clocksource: Fix clocksource_mmio_readX_down 2014-05-23 09:19:40 +02:00
moxart_timer.c clockevents/drivers/moxart: Migrate to new 'set-state' interface 2015-08-10 11:40:32 +02:00
mtk_timer.c clocksource/drivers/mtk_timer: Fix memleak in mtk_timer_init() 2015-12-15 09:41:04 +01:00
mxs_timer.c clockevents/drivers/mxs: Migrate to new 'set-state' interface 2015-08-10 11:40:34 +02:00
nomadik-mtu.c clockevents/drivers/nomadik-mtu: Migrate to new 'set-state' interface 2015-08-10 11:40:34 +02:00
numachip.c x86/numachip: Fix timer build conflict 2015-09-23 05:39:20 +02:00
pxa_timer.c clockevents/drivers/pxa: Migrate to new 'set-state' interface 2015-08-10 11:40:35 +02:00
qcom-timer.c clockevents/drivers/qcom: Migrate to new 'set-state' interface 2015-08-10 11:40:36 +02:00
rockchip_timer.c clocksource/drivers/rockchip: Remove dsb() usage 2015-12-15 09:41:11 +01:00
samsung_pwm_timer.c clocksource/drivers/samsung_pwm_timer: Prevent ftrace recursion 2015-10-27 01:33:41 +01:00
scx200_hrt.c clocksource: scx200_hrt: Fix the build 2012-02-22 13:25:16 +01:00
sh_cmt.c clocksource/drivers/sh_cmt: Remove unneeded memset() in sh_cmt_setup() 2015-10-15 17:42:00 +02:00
sh_mtu2.c clocksource/drivers/sh_mtu2: Fix multiple shutdown call issue 2015-10-28 15:22:56 +01:00
sh_tmu.c clocksource/drivers/sh_tmu: Fix traceback spotted in -next 2015-08-10 11:40:57 +02:00
sun4i_timer.c clockevents/drivers/sun4i: Migrate to new 'set-state' interface 2015-08-10 11:40:40 +02:00
tango_xtal.c clocksource/drivers/tango_xtal: Add new timer for Tango SoCs 2015-10-16 14:09:57 +02:00
tcb_clksrc.c misc: atmel_tclib: get and use slow clock 2015-10-06 12:33:14 +02:00
tegra20_timer.c clocksource/drivers/tegra: Allow timer irq affinity change 2015-12-15 09:41:06 +01:00
time-armada-370-xp.c clocksource/drivers/armada-370-xp: Implement ARM delay timer 2015-10-19 22:42:14 +02:00
time-efm32.c clockevents/drivers/efm32: Migrate to new 'set-state' interface 2015-08-10 11:40:42 +02:00
time-lpc32xx.c clocksource/drivers/lpc32xx: Add the lpc32xx timer driver 2015-06-02 12:10:10 +02:00
time-orion.c clockevents/drivers/orion: Migrate to new 'set-state' interface 2015-08-10 11:40:42 +02:00
time-pistachio.c clocksource/drivers/pistachio: Prevent ftrace recursion 2015-10-27 01:33:18 +01:00
timer-atlas7.c clockevents/drivers/atlas7: Migrate to new 'set-state' interface 2015-08-10 11:40:43 +02:00
timer-atmel-pit.c clockevents/drivers/timer-atmel-pit: Fix typo in structure initialization 2015-08-10 11:40:56 +02:00
timer-atmel-st.c clocksource: atmel-st: get and use slow clock 2015-10-06 12:25:11 +02:00
timer-digicolor.c clocksource/drivers/digicolor: Prevent ftrace recursion 2015-10-27 01:34:17 +01:00
timer-imx-gpt.c clocksource/drivers/imx: Allow timer irq affinity change 2015-10-15 17:42:05 +02:00
timer-integrator-ap.c clockevents/drivers/integrator: Migrate to new 'set-state' interface 2015-08-10 11:40:46 +02:00
timer-keystone.c clocksource/drivers/keystone: Fix bad NO_IRQ usage 2015-09-29 14:33:51 +02:00
timer-prima2.c clocksource/drivers/prima2: Prevent ftrace recursion 2015-10-27 01:33:50 +01:00
timer-sp804.c clockevents/drivers/timer-sp804: Migrate to new 'set-state' interface 2015-08-10 11:40:55 +02:00
timer-sp.h ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource 2015-06-02 09:58:18 +01:00
timer-stm32.c clockevents/drivers/stm32: Migrate to new 'set-state' interface 2015-08-10 11:40:48 +02:00
timer-sun5i.c clockevents/drivers/sun5i: Migrate to new 'set-state' interface 2015-08-10 11:40:49 +02:00
timer-ti-32k.c clocksource: add TI 32.768 Hz counter driver 2015-10-16 11:06:24 -05:00
timer-u300.c clockevents/drivers/u300: Migrate to new 'set-state' interface 2015-08-10 11:40:49 +02:00
versatile.c clocksource: versatile: Adapt for Versatile AB and PB boards 2015-01-29 14:02:16 +01:00
vf_pit_timer.c clocksource/drivers/vf_pit_timer: Prevent ftrace recursion 2015-10-27 01:33:58 +01:00
vt8500_timer.c clocksource/drivers/vt8500: Remove unneeded header 2015-12-15 09:41:40 +01:00
zevio-timer.c clockevents/drivers/zevio: Migrate to new 'set-state' interface 2015-08-10 11:40:51 +02:00