Re: [PATCH v6 2/2] clocksource: Ingenic: Add support for the Ingenic X1000 OST.
From: Paul Cercueil
Date: Sat Jul 18 2020 - 12:11:24 EST
Le sam. 18 juil. 2020 Ã 23:55, Zhou Yanjie <zhouyanjie@xxxxxxxxxxxxxx>
a Ãcrit :
Hi Paul,
å 2020/7/18 äå11:44, Paul Cercueil åé:
Hi Zhou,
Le sam. 18 juil. 2020 Ã 21:42, Zhou Yanjie
<zhouyanjie@xxxxxxxxxxxxxx> a Ãcrit :
Hello Paul and Daniel,
å 2020/7/18 äå9:12, Paul Cercueil åé:
Hi Daniel,
Le ven. 17 juil. 2020 Ã 10:02, Daniel Lezcano
<daniel.lezcano@xxxxxxxxxx> a Ãcrit :
On 17/07/2020 08:13, Zhou Yanjie wrote:
Hi Daniel,
å 2020/7/17 äå12:20, Daniel Lezcano åé:
On 10/07/2020 19:02, åçæ (Zhou Yanjie) wrote:
X1000 and SoCs after X1000 (such as X1500 and X1830) had a
separate
OST, it no longer belongs to TCU. This driver will register
both a
clocksource and a sched_clock to the system.
Tested-by: åæ (Zhou Zheng) <sernia.zhou@xxxxxxxxxxx>
Co-developed-by: æéæ (Qi Pengzhen)
<aric.pzqi@xxxxxxxxxxx>
Signed-off-by: æéæ (Qi Pengzhen) <aric.pzqi@xxxxxxxxxxx>
Signed-off-by: åçæ (Zhou Yanjie)
<zhouyanjie@xxxxxxxxxxxxxx>
Reviewed-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
Notes:
v1->v2:
Fix compile warnings.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
v2->v3:
No change.
v3->v4:
1.Rename "ost" to "sysost"
1.Remove unrelated changes.
2.Remove ost_clock_parent enum.
3.Remove
ost->percpu_timer_channel/ost->global_timer_channel.
4.Set up independent .recalc_rate/.set_rate for
percpu/global
timer.
5.No longer call functions in variable declarations.
v4->v5:
Use "of_io_request_and_map()" instead "of_iomap()".
Suggested-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
v5->v6:
No change.
drivers/clocksource/Kconfig | 11 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/ingenic-sysost.c | 539
+++++++++++++++++++++++++++++++++++
3 files changed, 551 insertions(+)
create mode 100644 drivers/clocksource/ingenic-sysost.c
diff --git a/drivers/clocksource/Kconfig
b/drivers/clocksource/Kconfig
index 91418381fcd4..1bca8b8fb30f 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -696,6 +696,17 @@ config INGENIC_TIMER
help
Support for the timer/counter unit of the Ingenic JZ
SoCs.
+config INGENIC_SYSOST
+ bool "Clocksource/timer using the SYSOST in Ingenic X
SoCs"
We usually use silent options and let the platform's Kconfig
enable it.
We show up the option only when COMPILE_TEST is enabled.
Is there a reason to do it differently?
Do you mean
bool "Clocksource/timer using the SYSOST in Ingenic X SoCs"
or
default MACH_INGENIC ?
Both, no default here.
eg.
bool "Clocksource/timer using the SYSOST in Ingenic X SoCs" if
COMPILE_TEST
and
in arch/mips/Kconfig in the config MACH_INGENIC section :
...
select INGENIC_SYSOST
...
Disagreed. That's not how we do things on MIPS. Selecting
MACH_INGENIC means "this kernel will support Ingenic SoCs",
but not that it will only support these. Hence the depends on
MIPS / default MACH_INGENIC.
As for the select INGENIC_SYSOST, this driver only applies to a
few SoCs, I certainly don't want it to be force-enabled. I
don't even wait it to be force-enabled on X1000, since it is
optional there too.
Cheers,
-Paul
If we still need to keep the "default MACH_INGENIC", then Daniel
can directly apply the v6 version.
If we need to use the silent options, maybe we can enable them
separately according to
MACH_JZ4740/MACH_JZ4770/MACH_JZ4780/MACH_X1000/MACH_X1830.
In fact, I think X1000 and X1830 need to enable this driver in most
cases, because the current test has found that use TCU to provide
clocksource and clockevent will cause data loss/error when
transmitting data through spi or ethernet. And these errors no
longer appear after using OST.
This is likely because the clock is too fast, try to reduce it by a
factor 2 or 4, it should behave better.
Yes, it is indeed because the clock is too fast, especially the TCU
only has 16-bit, which makes this problem more serious. I even
reduced the timing clock to the lowest possible 23kHz (divided by
1024). The problem has been alleviated, but it cannot completely
solved, and finally there is no problem after opening the OST.
If it turns out OST is really needed, then it should be selected
from MACH_X1000/X1830, not MACH_INGENIC.
Sure, I will do it in v8.
Thanks and best regards!
Please do it in a separate patch then (but in the same patchset).
Cheers,
-Paul
Cheers,
-Paul
Thanks and best regards!
This driver has some origins from "INGENIC_TIMER" driver and
"INGENIC_OST" driver.
Early Ingenic processors used TCU (timer/counter unit, has 6 or
8
generic timer channels) to provide clocksource and clockevent
(both with
only 16bit precision). This part of the processor can only use
"INGENIC_TIMER" driver.
Later processors provide an independent 32bit or 64bit timer
channel
(still under TCU, known as ost channel, this channel can not
generate
interrupt) to provid higher precision clocksource. The
"INGENIC_OST"
driver is for this channel. These processors can use
"INGENIC_TIMER"
driver, but using "INGENIC_OST" driver to provide higher
precision
clocksource would be a better choice (clockevent still needs to
be
provided by generic timer channel of TCU, and still 16bit
precision).
And the recent processors provide a SYSOST components, it is
independent
from TCU, including a 64bit timer channel for clocksource and a
32bit
timer channel for clockevent. Although these processors can
also use
"INGENIC_TIMER" driver, but the better choice is completely
independent
use of "INGENIC_SYSOST" driver to provide higher precision
clocksource
and clockevent.
Ok, the rating should do the job then.
Thanks for the explanation.
You may have already noticed that this independent SYSOST
component is
like an upgraded and streamlined TCU, which only retains one
generic
timer channel that can generate interrupts, upgrade it from
16bit to
32bit, and then retain the 64bit ost channel. so the driver
code and
Kconfig code of this patch is largely referenced
"INGENIC_TIMER" driver and "INGENIC_OST" driver.
Thanks and best regards!
+ default MACH_INGENIC
+ depends on MIPS || COMPILE_TEST
+ depends on COMMON_CLK
+ select MFD_SYSCON
+ select TIMER_OF
+ select IRQ_DOMAIN
+ help
+ Support for the SYSOST of the Ingenic X Series SoCs.
+
[ ... ]
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