From: Marc Zyngier <marc.zyngier@arm.com>
To: Linus Walleij <linus.ml.walleij@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
<linux-kernel@vger.kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Will Deacon <will.deacon@arm.com>,
Mike Turquette <mike.turquette@linaro.org>,
Marc Zyngier <maz@misterjones.org>
Subject: Re: [PATCH 33/36] AArch64: Generic timers support
Date: Thu, 12 Jul 2012 12:09:24 +0200 [thread overview]
Message-ID: <12a7f9b8e6d0b4dc3e3f6fcf91ad2a18@localhost> (raw)
In-Reply-To: <CAKnu2MrHibKWezjEK+6oOnamkjxWnWwKfoVYRDBURZ3VkaoxEQ@mail.gmail.com>
On Thu, 12 Jul 2012 02:18:42 +0200, Linus Walleij
<linus.ml.walleij@gmail.com> wrote:
Hi Linus,
> I'm reviewing the only patch I really understand...
>
> 2012/7/6 Catalin Marinas <catalin.marinas@arm.com>:
>
>> +/* This isn't really used any more */
>> +#define CLOCK_TICK_RATE 1000
>
> Is it still necessary to even have it there?
It is used as part of the LATCH/TICK_* computation in
include/linux/jiffies.h. It seems that any value could do, actually, and it
only seem to be used in kernel/time/ntp.c. Any guidance on this much
appreciated.
By the way, there is a very interesting comment about this in
arch/ia64/include/asm/timex.h.
>> + /* Try to determine the frequency from the device tree or
CNTFRQ
>> */
>> + if (!of_property_read_u32(np, "clock-frequency", &freq))
>> + arch_timer_rate = freq;
>
> Have you documented the bindings for this thing?
It has been documented as part of the architected timer patch that has
been merged for 3.5. See
Documentation/devicetree/bindings/arm/arch_timer.txt.
>> + arch_timer_calibrate();
>
> Why is the ability to get this from a clk not contemplated?
> I think this will be common. You could make it optional I think,
> just like in the SMP TWD.
_calibrate() is a misnomer here. It should really be _get_freq(). But your
point still stand, and we could indeed use a clk to obtain the frequency.
It should probably be selected in the following order: clock-frequency
(DT), clk, CNTFRQ.
>> diff --git a/include/clocksource/arm_generic.h
>> b/include/clocksource/arm_generic.h
>> new file mode 100644
>> index 0000000..6933f8e
> (...)
>> +#ifndef __ASM_ARCH_TIMER_H
>> +#define __ASM_ARCH_TIMER_H
>
> This #ifdef name looks confusing, what about
> #ifndef __CLKSOURCE_ARM_GENERIC_H?
>
> I noticed you already saw the problem with naming it "arch timers"
> and renamed it to "arm generic" so a leftover here :)
Thanks! :-)
M.
--
Fast, cheap, reliable. Pick two.
next prev parent reply other threads:[~2012-07-12 10:09 UTC|newest]
Thread overview: 182+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-06 21:05 [PATCH 00/36] AArch64 Linux kernel port Catalin Marinas
2012-07-06 21:05 ` [PATCH 01/36] atomic64_test: Simplify the #ifdef for atomic64_dec_if_positive() test Catalin Marinas
2012-07-18 4:33 ` Benjamin Herrenschmidt
2012-07-18 9:06 ` Catalin Marinas
2012-07-06 21:05 ` [PATCH 02/36] ipc: Add COMPAT_SHMLBA support Catalin Marinas
2012-07-18 5:53 ` Jon Masters
2012-07-18 9:03 ` Will Deacon
2012-07-06 21:05 ` [PATCH 03/36] ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC Catalin Marinas
2012-07-06 21:05 ` [PATCH 04/36] ipc: compat: use signed size_t types for msgsnd and msgrcv Catalin Marinas
2012-07-06 21:05 ` [PATCH 05/36] fs: Build sys_stat64() and friends if __ARCH_WANT_COMPAT_STAT64 Catalin Marinas
2012-07-06 21:05 ` [PATCH 06/36] fdt: Add generic dt_memblock_reserve() function Catalin Marinas
2012-07-07 21:18 ` Rob Herring
2012-07-08 9:43 ` Catalin Marinas
2012-07-06 21:05 ` [PATCH 07/36] AArch64: Assembly macros and definitions Catalin Marinas
2012-07-07 5:57 ` Greg KH
2012-07-08 9:23 ` Catalin Marinas
2012-07-20 14:22 ` [07/36] " Christopher Covington
2012-07-24 16:40 ` Catalin Marinas
2012-07-06 21:05 ` [PATCH 08/36] AArch64: Kernel booting and initialisation Catalin Marinas
2012-07-06 21:32 ` Stephen Warren
2012-07-08 9:18 ` Catalin Marinas
2012-07-23 17:48 ` Stephen Warren
2012-07-23 17:58 ` Catalin Marinas
2012-07-18 6:57 ` Jon Masters
2012-07-18 9:07 ` Will Deacon
2012-07-20 7:11 ` Jon Masters
2012-07-19 17:31 ` Christopher Covington
2012-07-20 7:10 ` Jon Masters
2012-07-20 8:28 ` Arnd Bergmann
2012-07-20 10:52 ` Catalin Marinas
2012-07-20 12:32 ` Geert Uytterhoeven
2012-07-20 13:16 ` Catalin Marinas
2012-07-20 13:47 ` Christopher Covington
2012-07-20 13:52 ` Catalin Marinas
2012-07-20 13:48 ` Catalin Marinas
2012-07-20 14:53 ` Christopher Covington
2012-07-23 20:52 ` [08/36] " Christopher Covington
2012-07-24 16:24 ` Catalin Marinas
2012-07-24 18:53 ` Arnd Bergmann
2012-07-24 23:20 ` Frank Rowand
2012-07-25 8:34 ` Catalin Marinas
2012-07-24 19:42 ` Christopher Covington
2012-07-25 8:47 ` Catalin Marinas
2012-07-25 13:39 ` Christopher Covington
2012-07-06 21:05 ` [PATCH 09/36] AArch64: Exception handling Catalin Marinas
2012-08-09 17:05 ` [09/36] " Christopher Covington
2012-08-09 17:23 ` Catalin Marinas
2012-08-09 19:19 ` Christopher Covington
2012-07-06 21:05 ` [PATCH 10/36] AArch64: MMU definitions Catalin Marinas
2012-10-02 0:43 ` Jon Masters
2012-10-02 15:39 ` Catalin Marinas
2012-07-06 21:05 ` [PATCH 11/36] AArch64: MMU initialisation Catalin Marinas
2012-07-06 21:05 ` [PATCH 12/36] AArch64: MMU fault handling and page table management Catalin Marinas
2012-07-06 21:05 ` [PATCH 13/36] AArch64: Process management Catalin Marinas
2012-07-06 21:05 ` [PATCH 14/36] AArch64: CPU support Catalin Marinas
2012-07-06 21:05 ` [PATCH 15/36] AArch64: Cache maintenance routines Catalin Marinas
2012-07-06 21:05 ` [PATCH 16/36] AArch64: TLB maintenance functionality Catalin Marinas
2012-07-06 21:05 ` [PATCH 17/36] AArch64: IRQ handling Catalin Marinas
2012-07-06 21:05 ` [PATCH 18/36] AArch64: Atomic operations Catalin Marinas
2012-07-06 21:06 ` [PATCH 19/36] AArch64: Device specific operations Catalin Marinas
2012-07-06 21:06 ` [PATCH 20/36] AArch64: DMA mapping API Catalin Marinas
2012-07-06 21:06 ` [PATCH 21/36] AArch64: SMP support Catalin Marinas
2012-07-06 21:06 ` [PATCH 22/36] AArch64: ELF definitions Catalin Marinas
2012-07-06 21:06 ` [PATCH 23/36] AArch64: System calls handling Catalin Marinas
2012-07-06 21:06 ` [PATCH 24/36] AArch64: VDSO support Catalin Marinas
2012-07-06 21:06 ` [PATCH 25/36] AArch64: Signal handling support Catalin Marinas
2012-07-06 21:06 ` [PATCH 26/36] AArch64: User access library functions Catalin Marinas
2012-07-06 21:06 ` [PATCH 27/36] AArch64: 32-bit (compat) applications support Catalin Marinas
2012-07-06 21:06 ` [PATCH 28/36] AArch64: Floating point and SIMD Catalin Marinas
2012-07-06 21:06 ` [PATCH 29/36] AArch64: Debugging support Catalin Marinas
2012-07-06 21:06 ` [PATCH 30/36] AArch64: Performance counters support Catalin Marinas
2012-07-06 21:06 ` [PATCH 31/36] AArch64: Miscellaneous library functions Catalin Marinas
2012-07-06 21:06 ` [PATCH 32/36] AArch64: Loadable modules Catalin Marinas
2012-07-06 21:06 ` [PATCH 33/36] AArch64: Generic timers support Catalin Marinas
2012-07-12 0:18 ` Linus Walleij
2012-07-12 10:09 ` Marc Zyngier [this message]
2012-07-12 10:56 ` Linus Walleij
2012-07-12 16:57 ` John Stultz
2012-07-12 17:31 ` Marc Zyngier
2012-07-12 17:39 ` John Stultz
2012-07-13 12:40 ` Arnd Bergmann
2012-07-13 16:02 ` Catalin Marinas
2012-07-13 16:32 ` Arnd Bergmann
2012-07-13 18:30 ` John Stultz
2012-07-06 21:06 ` [PATCH 34/36] AArch64: Miscellaneous header files Catalin Marinas
2012-07-06 21:06 ` [PATCH 35/36] AArch64: Build infrastructure Catalin Marinas
2012-07-06 21:06 ` [PATCH 36/36] AArch64: MAINTAINERS update Catalin Marinas
2012-08-10 16:24 ` [36/36] " Christopher Covington
2012-07-06 22:58 ` [PATCH 00/36] AArch64 Linux kernel port Alan Cox
2012-07-07 21:30 ` Arnd Bergmann
2012-07-07 23:14 ` Catalin Marinas
2012-07-07 23:29 ` Alan Cox
2012-07-09 11:35 ` Catalin Marinas
2012-07-09 13:51 ` Alan Cox
2012-07-09 15:32 ` Arnd Bergmann
2012-07-09 15:49 ` Alan Cox
2012-07-09 16:02 ` Catalin Marinas
2012-07-09 16:33 ` Arnd Bergmann
2012-07-07 3:29 ` Matthew Garrett
2012-07-09 12:32 ` Mark Brown
2012-07-09 13:06 ` Matthew Garrett
2012-07-09 13:56 ` Mark Brown
2012-07-09 14:02 ` Matthew Garrett
2012-07-09 15:46 ` Mark Brown
2012-07-07 3:53 ` Olof Johansson
2012-07-07 19:27 ` Arnd Bergmann
2012-07-07 23:45 ` Jan Engelhardt
2012-07-08 5:05 ` Henrique de Moraes Holschuh
2012-07-08 20:28 ` Jan Engelhardt
2012-07-08 7:54 ` Jon Masters
2012-07-08 11:17 ` Dr. David Alan Gilbert
2012-07-08 18:13 ` Jon Masters
2012-07-08 18:31 ` Jon Masters
2012-07-08 22:24 ` Dennis Gilmore
2012-07-09 2:01 ` Jon Masters
2012-07-09 8:57 ` Catalin Marinas
2012-07-09 13:33 ` Geert Uytterhoeven
2012-07-08 20:31 ` Jan Engelhardt
2012-07-08 23:32 ` Jon Masters
2012-07-10 7:10 ` Ingo Molnar
2012-07-10 10:10 ` Catalin Marinas
2012-07-10 15:33 ` Alan Cox
2012-07-10 16:52 ` Arnd Bergmann
2012-07-10 20:35 ` Ingo Molnar
2012-07-10 21:19 ` Arnd Bergmann
2012-07-10 21:48 ` Catalin Marinas
2012-07-11 8:20 ` Ingo Molnar
2012-07-11 11:30 ` Alan Cox
2012-07-10 21:44 ` Catalin Marinas
2012-07-11 8:55 ` Catalin Marinas
2012-07-11 5:26 ` Rusty Russell
2012-07-11 10:53 ` Catalin Marinas
2012-07-12 2:08 ` Rusty Russell
2012-07-10 16:57 ` Catalin Marinas
2012-07-10 16:52 ` Dennis Gilmore
2012-07-10 17:14 ` Joe Perches
2012-07-10 18:01 ` Jan Ceuleers
2012-07-10 18:05 ` richard -rw- weinberger
2012-07-10 20:16 ` Alexander Holler
2012-07-14 22:16 ` Jon Masters
2012-07-10 22:08 ` Chris Adams
2012-07-14 9:30 ` Pavel Machek
2012-07-15 12:16 ` Catalin Marinas
2012-07-15 19:43 ` Arnd Bergmann
2012-07-15 21:33 ` Catalin Marinas
2012-07-16 12:16 ` Pavel Machek
2012-07-17 7:05 ` Jon Masters
2012-07-17 8:02 ` Arnd Bergmann
2012-07-17 9:50 ` Alan Cox
2012-07-18 2:36 ` Jon Masters
2012-07-17 10:45 ` Catalin Marinas
2012-07-16 9:26 ` Geert Uytterhoeven
2012-07-17 6:53 ` Christoph Hellwig
2012-07-17 8:07 ` Arnd Bergmann
2012-07-16 8:24 ` Avi Kivity
2012-07-17 7:09 ` Jon Masters
2012-07-17 8:37 ` Catalin Marinas
2012-07-15 23:21 ` Måns Rullgård
2012-07-15 23:53 ` Linus Torvalds
2012-07-17 22:18 ` Catalin Marinas
2012-07-17 22:35 ` Joe Perches
2012-07-18 2:33 ` Jon Masters
2012-07-18 15:27 ` Dennis Gilmore
2012-07-18 17:14 ` Catalin Marinas
2012-07-18 17:25 ` Måns Rullgård
2012-07-18 19:35 ` Jon Masters
2012-07-18 19:55 ` Linus Torvalds
2012-07-19 14:16 ` Guillem Jover
2012-07-07 23:42 ` Jan Engelhardt
2012-07-08 10:18 ` Catalin Marinas
2012-07-09 12:31 ` Jan Engelhardt
2012-07-07 9:30 ` Mikael Pettersson
2012-07-07 19:21 ` Kirill A. Shutemov
2012-07-10 10:12 ` Catalin Marinas
2012-07-14 9:35 ` Pavel Machek
2012-07-15 11:36 ` Catalin Marinas
2012-07-16 16:19 ` Pavel Machek
2012-07-16 19:45 ` Arnd Bergmann
2012-07-16 19:47 ` Måns Rullgård
2012-07-18 5:35 ` Jon Masters
2012-07-18 9:13 ` Catalin Marinas
2012-07-26 11:59 ` Catalin Marinas
[not found] <jknWN-4WG-3@gated-at.bofh.it>
[not found] ` <jkulA-O3-3@gated-at.bofh.it>
[not found] ` <jkIRz-2Hu-11@gated-at.bofh.it>
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