From: Rob Herring <robherring2@gmail.com>
To: Afzal Mohammed <afzal@ti.com>
Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree-discuss@lists.ozlabs.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
Russell King <linux@arm.linux.org.uk>,
Nicolas Pitre <nico@linaro.org>, Sekhar Nori <nsekhar@ti.com>,
Will Deacon <will.deacon@arm.com>,
Rob Herring <rob.herring@calxeda.com>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
Syed Mohammed Khasim <khasim@ti.com>
Subject: Re: [RFC 2/8] ARM: twd: register clock event for 1 core SMP
Date: Mon, 18 Feb 2013 07:47:29 -0600 [thread overview]
Message-ID: <512230F1.8020208@gmail.com> (raw)
In-Reply-To: <a7f62b8580aa4b33d5658f4f03371a453adaea9b.1361166003.git.afzal@ti.com>
On 02/18/2013 12:30 AM, Afzal Mohammed wrote:
> Register percpu local timer for scheduler tick in the case of one core
> SMP configuration. In other cases - secondary cpu's as well as boot
> cpu's having more than one core, this is being registered as per
> existing boot flow, with a difference that they happens after delay
> calibration. Registering the clock for tick in case of one core should
> be done before Kernel calibrates delay (this is required to boot,
> unless local timer is the only one registered for tick). Registering
> twd local timer at init_time (which platforms are doing now) helps
> achieve that with the proposed change.
>
> This helps in an almost booting Kernel (minimal) by only relying on
> ARM parts for an A9 one core SMP.
>
> Signed-off-by: Afzal Mohammed <afzal@ti.com>
> ---
> arch/arm/kernel/smp_twd.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
> index 616268c..118f4f2 100644
> --- a/arch/arm/kernel/smp_twd.c
> +++ b/arch/arm/kernel/smp_twd.c
> @@ -335,6 +335,9 @@ static int __init twd_local_timer_common_register(struct device_node *np)
>
> twd_get_clock(np);
>
> + if (num_possible_cpus() == 1)
> + twd_timer_setup(evt);
> +
Shouldn't this be fixed in the core code, so the same issue is fixed for
all timers?
Rob
> return 0;
>
> out_irq:
>
next prev parent reply other threads:[~2013-02-18 13:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-18 6:28 [RFC 0/8] ARM: AM43 (OMAP2+) boot support Afzal Mohammed
2013-02-18 6:30 ` [RFC 1/8] ARM: localtimer: return percpu clkevt on register Afzal Mohammed
2013-02-18 6:30 ` [RFC 2/8] ARM: twd: register clock event for 1 core SMP Afzal Mohammed
2013-02-18 13:47 ` Rob Herring [this message]
2013-02-19 8:00 ` Mohammed, Afzal
2013-02-18 6:30 ` [RFC 3/8] ARM: twd: clock rate from DT (if no DT clk tree) Afzal Mohammed
2013-02-18 6:30 ` [RFC 4/8] ARM: am33xx: ll debug config help Afzal Mohammed
2013-02-18 6:30 ` [RFC 5/8] ARM: OMAP2+: am43: Kconfig Afzal Mohammed
2013-02-18 6:30 ` [RFC 6/8] ARM: OMAP2+: am43: basic dt support Afzal Mohammed
2013-02-18 6:30 ` [RFC 7/8] ARM: dts: am4372: initial support Afzal Mohammed
2013-02-18 6:30 ` [RFC 8/8] ARM: dts: am43-pre-silicon support Afzal Mohammed
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