From: Stefan Roese <sr@denx.de>
To: Simon Glass <sjg@chromium.org>
Cc: "Michael Walle" <michael@walle.cc>,
"U-Boot Mailing List" <u-boot@lists.denx.de>,
"Pali Rohár" <pali@kernel.org>, "Tony Dinh" <mibodhi@gmail.com>
Subject: Re: [PATCH 2/6] timer: orion-timer: Add timer_get_boot_us() for BOOTSTAGE support
Date: Wed, 31 Aug 2022 07:57:01 +0200 [thread overview]
Message-ID: <65546e81-1287-3994-6e83-38fea3d1fa6c@denx.de> (raw)
In-Reply-To: <CAPnjgZ0et2ZankP+=C37z7z9PYBF2BkO2JxWo_XDe1ZLRXup3A@mail.gmail.com>
Hi Simon,
On 30.08.22 17:56, Simon Glass wrote:
> Hi Stefan,
>
> On Tue, 30 Aug 2022 at 06:08, Stefan Roese <sr@denx.de> wrote:
>>
>> Adding Simon to Cc...
>>
>> On 30.08.22 14:00, Michael Walle wrote:
>>> Am 2022-08-30 13:53, schrieb Stefan Roese:
>>>> Add timer_get_boot_us() to support boards, that have CONFIG_BOOTSTAGE
>>>> enabled, like pogo_v4.
>>>>
>>>> Signed-off-by: Stefan Roese <sr@denx.de>
>>>> ---
>>>> drivers/timer/orion-timer.c | 22 ++++++++++++++++++++++
>>>> 1 file changed, 22 insertions(+)
>>>>
>>>> diff --git a/drivers/timer/orion-timer.c b/drivers/timer/orion-timer.c
>>>> index 02ed138642b8..7e920eaeaa40 100644
>>>> --- a/drivers/timer/orion-timer.c
>>>> +++ b/drivers/timer/orion-timer.c
>>>> @@ -41,6 +41,28 @@ u64 notrace timer_early_get_count(void)
>>>> }
>>>> #endif
>>>>
>>>> +#if CONFIG_IS_ENABLED(BOOTSTAGE)
>>>> +ulong timer_get_boot_us(void)
>>>> +{
>>>> + u64 ticks = 0;
>>>> + u32 rate = 1;
>>>> + u64 us;
>>>> + int ret;
>>>> +
>>>> + ret = dm_timer_init();
>>>> + if (!ret) {
>>>> + /* The timer is available */
>>>> + rate = timer_get_rate(gd->timer);
>>>> + timer_get_count(gd->timer, &ticks);
>>>> + } else {
>>>> + return 0;
>>>> + }
>>>> +
>>>> + us = (ticks * 1000) / rate;
>>>> + return us;
>>>> +}
>>>> +#endif
>>>
>>> This is duplicate code in almost all the timer drivers, shouldn't
>>> this be a (weak) default implementation in timer-uclass.c?
>>
>> Yes. I was lazy and just copied this function and did not notice, that
>> even more timer drivers have this function. Of course it makes sense
>> to not duplicate code here, but have a common function for this. Frankly
>> I don't even know why exactly this function is needed, as I did not
>> look into BOOTSTAGE yet.
>>
>> Simon, do we really need this function? Can't bootstage just use the
>> "normal" timer functionality instead?
>
> It is needed because bootstage is called before driver model is ready.
> In fact it can be used to time driver model things.
I see, makes sense. This brings up my next questions though, why isn't
CONFIG_TIMER_EARLY enough in this case? AFAICT it's targeted exactly
for this early (pre DM) bootstage. From drivers/timer/Kconfig:
config TIMER_EARLY
bool "Allow timer to be used early in U-Boot"
depends on TIMER
# initr_bootstage() requires a timer and is called before initr_dm()
# so only the early timer is available
default y if X86 && BOOTSTAGE
help
In some cases the timer must be accessible before driver model is
active. Examples include when using CONFIG_TRACE to trace U-Boot's
execution before driver model is set up. Enable this option to
use an early timer. These functions must be supported by your timer
driver: timer_early_get_count() and timer_early_get_rate().
So again, do we really need timer_get_boot_us() or isn't it enough
to select TIMER_EARLY when BOOTSTAGE is enabled?
Thanks,
Stefan
> The function here isn't that useful, since we cannot call
> dm_timer_init() before driver model is set up.
>
> The timer_get_boot_us() function can by in a timer driver, but must
> exist outside the driver infrastructure. It must init the hard and
> then return the correct time. One driver model probes the timer
> driver, it must then continue on in that way.
>
> Actually it looks like all the timers do this wrong. See
> arch/arm/mach-imx/syscounter.c or arch/arm/cpu/armv8/generic_timer.c
> for some ideas.
Thanks,
Stefan
next prev parent reply other threads:[~2022-08-31 5:57 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 11:53 [PATCH 0/6] Enable CONFIG_TIMER for all Kirwood / MVEBU boards Stefan Roese
2022-08-30 11:53 ` [PATCH 1/6] timer: orion-timer: Add support for other Armada SoC's Stefan Roese
2022-08-30 11:53 ` [PATCH 2/6] timer: orion-timer: Add timer_get_boot_us() for BOOTSTAGE support Stefan Roese
2022-08-30 12:00 ` Michael Walle
2022-08-30 12:08 ` Stefan Roese
2022-08-30 15:56 ` Simon Glass
2022-08-31 5:57 ` Stefan Roese [this message]
2022-08-31 17:44 ` Simon Glass
2022-09-01 5:33 ` Stefan Roese
2022-08-30 11:53 ` [PATCH 3/6] arm: mvebu: Use CONFIG_TIMER on all MVEBU & KIRKWOOD platforms Stefan Roese
2022-08-30 12:04 ` Michael Walle
2022-08-30 12:11 ` Stefan Roese
2022-08-30 11:53 ` [PATCH 4/6] arm: mvebu: dts: Makefile: Compile Armada 375 dtb in a separate step Stefan Roese
2022-08-30 11:53 ` [PATCH 5/6] arm: mvebu: dts: armada-375.dtsi: Add timer0 & timer1 Stefan Roese
2022-08-30 11:53 ` [PATCH 6/6] arm: mvebu: dts: mvebu-u-boot.dtsi: Add "u-boot, dm-pre-reloc" to timer DT node Stefan Roese
2022-08-30 22:15 ` [PATCH 0/6] Enable CONFIG_TIMER for all Kirwood / MVEBU boards Tony Dinh
2022-08-31 5:02 ` Stefan Roese
2022-08-31 5:08 ` Stefan Roese
2022-08-31 6:12 ` Stefan Roese
2022-08-31 6:45 ` Tony Dinh
2022-08-31 6:30 ` Tony Dinh
2022-08-31 7:22 ` Stefan Roese
2022-08-31 15:08 ` Tony Dinh
2022-08-31 21:53 ` Tony Dinh
2022-09-01 1:38 ` Tony Dinh
2022-09-01 2:27 ` Simon Glass
2022-09-01 7:39 ` Tony Dinh
2022-09-01 9:27 ` Stefan Roese
2022-09-01 11:52 ` Stefan Herbrechtsmeier
2022-09-02 5:38 ` Stefan Roese
2022-09-01 14:34 ` Simon Glass
2022-09-01 23:46 ` Tony Dinh
2022-09-02 2:51 ` Tony Dinh
2022-09-02 3:49 ` Tony Dinh
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