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[PATCH v2 0/4] clock: Get rid of clock_get_ns()
From: |
Peter Maydell |
Subject: |
[PATCH v2 0/4] clock: Get rid of clock_get_ns() |
Date: |
Tue, 15 Dec 2020 15:09:25 +0000 |
This patchseries makes some changes to the clock API:
* Remove clock_get_ns()
* Add clock_ticks_to_ns() to return number of nanoseconds
it will take the clock to tick N times
* clock_display_freq() to return prettily-formatted string
for showing humans the approximate clock frequency
This is based on discussions we had about these APIs a little while
back. The core driver here is that the clock objects internally
store the period in units of 2^-32 ns, so both clock_get_ns() and
clock_get_hz() are inherently returning a rounded-off result, which
can be badly inaccurate for fast clocks or if you want to multiply it
by a large tick count.
Ideally I'd like to get rid of clock_get_hz() as well, but
that looks trickier than handling clock_get_ns().
Patch 4 borrows a lot of the concept from one of Philippe's that he
sent out previously.
NB: tested with 'make check' and 'make check-acceptance' only.
Changes v1->v2:
* In patch 1, saturate return value to INT64_MAX (and update
docs to explain this and why)
Patches 2-4 have been reviewed, only patch 1 needs review.
thanks
-- PMM
Peter Maydell (4):
clock: Introduce clock_ticks_to_ns()
target/mips: Don't use clock_get_ns() in clock period calculation
clock: Remove clock_get_ns()
clock: Define and use new clock_display_freq()
docs/devel/clocks.rst | 51 ++++++++++++++++++++++++++++++++++++----
include/hw/clock.h | 53 +++++++++++++++++++++++++++++++++++++++---
hw/core/clock.c | 6 +++++
softmmu/qdev-monitor.c | 6 ++---
target/mips/cpu.c | 4 ++--
5 files changed, 108 insertions(+), 12 deletions(-)
--
2.20.1
- [PATCH v2 0/4] clock: Get rid of clock_get_ns(),
Peter Maydell <=
- [PATCH v2 1/4] clock: Introduce clock_ticks_to_ns(), Peter Maydell, 2020/12/15
- [PATCH v2 2/4] target/mips: Don't use clock_get_ns() in clock period calculation, Peter Maydell, 2020/12/15
- [PATCH v2 3/4] clock: Remove clock_get_ns(), Peter Maydell, 2020/12/15
- [PATCH v2 4/4] clock: Define and use new clock_display_freq(), Peter Maydell, 2020/12/15
- Re: [PATCH v2 0/4] clock: Get rid of clock_get_ns(), Philippe Mathieu-Daudé, 2020/12/15