From: Will Deacon <will.deacon@arm.com>
To: Doug Anderson <dianders@chromium.org>
Cc: Christopher Covington <cov@codeaurora.org>,
Olof Johansson <olof@lixom.net>,
Mark Rutland <Mark.Rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Pawel Moll <Pawel.Moll@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Marc Zyngier <Marc.Zyngier@arm.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Sudeep Holla <Sudeep.Holla@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Kumar Gala <galak@codeaurora.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sonny Rao <sonnyrao@chromium.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Nathan Lynch <Nathan_Lynch@mentor.com>
Subject: Re: [PATCH] clocksource: arch_timer: Allow the device tree to specify the physical timer
Date: Thu, 11 Sep 2014 17:09:08 +0100 [thread overview]
Message-ID: <20140911160908.GT6158@arm.com> (raw)
In-Reply-To: <CAD=FV=XPqma5sYbn65NLEAipZFq96t_HcX96ym_cEQrqTKddOQ@mail.gmail.com>
On Thu, Sep 11, 2014 at 05:04:11PM +0100, Doug Anderson wrote:
> On Thu, Sep 11, 2014 at 8:58 AM, Christopher Covington
> <cov@codeaurora.org> wrote:
> > On 09/11/2014 11:52 AM, Doug Anderson wrote:
> >> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> >> index 5163ec1..8ca07a9 100644
> >> --- a/drivers/clocksource/arm_arch_timer.c
> >> +++ b/drivers/clocksource/arm_arch_timer.c
> >> @@ -649,6 +649,9 @@ static void __init arch_timer_init(struct device_node *np)
> >> arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
> >> arch_timer_detect_rate(NULL, np);
> >>
> >> + if (of_property_read_bool(np, "arm,use-physical-timer"))
> >> + arch_timer_use_virtual = false;
Can you #ifdef CONFIG_ARM here please?
> >> /*
> >> * If HYP mode is available, we know that the physical timer
> >> * has been configured to be accessible from PL1. Use it, so
> >>
> >
> > How's the VDSO supposed to deal with this? It currently does:
> >
> > cycle_now = arch_counter_get_cntvct()
>
> I don't see that line of code anywhere when I do a "git grep" on linux
> or linuxnext. Can you give me a clearer pointer?
It's in the actual vdso code (arch/arm64/kernel/vdso/gettimeofday.S):
/* Read the virtual counter. */
isb
mrs x15, cntvct_el0
Will
next prev parent reply other threads:[~2014-09-11 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-11 15:52 [PATCH] clocksource: arch_timer: Allow the device tree to specify the physical timer Doug Anderson
2014-09-11 15:58 ` Christopher Covington
2014-09-11 16:04 ` Doug Anderson
2014-09-11 16:09 ` Will Deacon [this message]
2014-09-11 16:20 ` Christopher Covington
2014-09-11 16:07 ` Nathan Lynch
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