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Nicolai Stange 890f423b26 clocksource: sh_cmt: Compute rate before registration again
With the upcoming NTP correction related rate adjustments to be implemented
in the clockevents core, the latter needs to get informed about every rate
change of a clockevent device made after its registration.

Currently, sh_cmt violates this requirement in that it registers its
clockevent device with a dummy rate and sets its final ->mult and ->shift
values from its ->set_state_oneshot() and ->set_state_periodic() functions
respectively.

This patch moves the setting of the clockevent device's ->mult and ->shift
values to before its registration.

Note that there has been some back and forth regarding this question with
respect to the clocksource also provided by this driver:
  commit f4d7c3565c ("clocksource: sh_cmt: compute mult and shift before
                        registration")
moves the rate determination from the clocksource's ->enable() function to
before its registration. OTOH, the later
  commit 3593f5fe40 ("clocksource: sh_cmt: __clocksource_updatefreq_hz()
                        update")
basically reverts this, saying
  "Without this patch the old code uses clocksource_register() together
   with a hack that assumes a never changing clock rate."

However, I checked all current sh_cmt users in arch/sh as well as in
arch/arm/mach-shmobile carefully and right now, none of them changes any
rate in any clock tree relevant to sh_cmt after their respective
time_init(). Since all sh_cmt instances are created after time_init(), none
of them should ever observe any clock rate changes.

What's more, both, a clocksource as well as a clockevent device, can
immediately get selected for use at their registration and thus, enabled
at this point already. So it's probably safer to assume a "never changing
clock rate" here.

- Move the struct sh_cmt_channel's ->rate member to struct sh_cmt_device:
  it's a property of the underlying clock which is in turn specific to
  the sh_cmt_device.
- Determine the ->rate value in sh_cmt_setup() at device probing rather
  than at first usage.
- Set the clockevent device's ->mult and ->shift values right before its
  registration.
- Although not strictly necessary for the upcoming clockevent core changes,
  set the clocksource's rate at its registration for consistency.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2017-03-23 12:14:00 -07:00
arch powerpc fixes for 4.11 #5 2017-03-19 18:49:28 -07:00
block blk-mq-sched: don't run the queue async from blk_mq_try_issue_directly() 2017-03-14 11:51:59 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
drivers clocksource: sh_cmt: Compute rate before registration again 2017-03-23 12:14:00 -07:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs NFS client fixes for 4.11 2017-03-17 14:16:22 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-03-19 18:06:31 -07:00
init Change get_random_{int,log} to use the CRNG used by /dev/urandom and 2017-03-11 09:08:47 -08:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-18 08:33:44 -07:00
lib mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
mm mm/swap: don't BUG_ON() due to uninitialized swap slot cache 2017-03-19 19:00:47 -07:00
net NFS client fixes for 4.11 2017-03-17 14:16:22 -07:00
samples Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-03 11:38:56 -08:00
scripts Merge branch 'akpm' (patches from Andrew) 2017-03-10 08:34:42 -08:00
security Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
sound scripts/spelling.txt: add "disble(d)" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-17 13:59:52 -07:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled 2017-03-07 15:44:08 +00:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS MAINTAINERS: usb251xb: remove reference inexistent file 2017-03-09 10:34:16 +01:00
Makefile Linux 4.11-rc3 2017-03-19 19:09:39 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.