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From: jon-hunter@ti•com (Jon Hunter)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 09/12] ARM: OMAP2+: powerdomain: skip register reads for powerdomains known to be on
Date: Wed, 19 Dec 2012 15:09:31 -0600	[thread overview]
Message-ID: <50D22D0B.3050502@ti.com> (raw)
In-Reply-To: <20121209200327.3196.27686.stgit@dusk.lan>

Hi Paul,

On 12/09/2012 02:03 PM, Paul Walmsley wrote:
> There's no need to determine the current power state for powerdomains
> that must be on while the kernel is running.  We mark these
> powerdomains with a new flag, PWRDM_ACTIVE_WITH_KERNEL.  Any
> powerdomain marked with that flag is reported as being in the ON power
> state while the kernel is running.
> 
> Signed-off-by: Paul Walmsley <paul@pwsan•com>
> Cc: Beno?t Cousson <b-cousson@ti•com>
> ---
>  arch/arm/mach-omap2/powerdomain.c           |    9 ++++++---
>  arch/arm/mach-omap2/powerdomain.h           |    4 ++++
>  arch/arm/mach-omap2/powerdomains2xxx_data.c |    2 ++
>  arch/arm/mach-omap2/powerdomains33xx_data.c |    3 ++-
>  arch/arm/mach-omap2/powerdomains3xxx_data.c |    9 ++++++---
>  arch/arm/mach-omap2/powerdomains44xx_data.c |    5 ++++-
>  6 files changed, 24 insertions(+), 8 deletions(-)

[snip]

> diff --git a/arch/arm/mach-omap2/powerdomains44xx_data.c b/arch/arm/mach-omap2/powerdomains44xx_data.c
> index 704664c..b64213c 100644
> --- a/arch/arm/mach-omap2/powerdomains44xx_data.c
> +++ b/arch/arm/mach-omap2/powerdomains44xx_data.c
> @@ -53,7 +53,8 @@ static struct powerdomain core_44xx_pwrdm = {
>  		[3] = PWRSTS_ON,	/* ducati_l2ram */
>  		[4] = PWRSTS_ON,	/* ducati_unicache */
>  	},
> -	.flags		  = PWRDM_HAS_LOWPOWERSTATECHANGE,
> +	.flags		  = (PWRDM_HAS_LOWPOWERSTATECHANGE |
> +			     PWRDM_ACTIVE_WITH_KERNEL),
>  };

My understanding is that for OMAP4 devices, the core power domain may
not be active the same time as the MPU power domain. The Cortex-A9 has
the ability to access some peripherals (such as timer, McBSP) via a
private bus that does not require the core domain to be active. This is
a difference from OMAP3 devices, where the core would always be on with
the MPU power domain.

Hopefully, Benoit will chime in if I have gotten this wrong ;-)

Cheers
Jon

  parent reply	other threads:[~2012-12-19 21:09 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-09 20:02 [PATCH 00/12] ARM: OMAP2+: powerdomain updates after the functional power state conversion Paul Walmsley
2012-12-09 20:02 ` [PATCH 01/12] ARM: OMAP2+: powerdomain: consolidate arch_pwrdm check code Paul Walmsley
2012-12-09 20:03 ` [PATCH 02/12] ARM: OMAP2+: PM/powerdomain: move the power state time tracking into the powerdomain code Paul Walmsley
2012-12-09 20:03 ` [PATCH 03/12] ARM: OMAP2+: powerdomain: split pwrdm_state_switch() Paul Walmsley
2012-12-09 20:03 ` [PATCH 04/12] ARM: OMAP2+: PM: clean up some debugfs functions Paul Walmsley
2012-12-09 20:03 ` [PATCH 06/12] ARM: OMAP2+: CM: use the cached copy of the clockdomain's hwsup state Paul Walmsley
2012-12-09 20:03 ` [PATCH 07/12] ARM: OMAP2+: powerdomain: cache the powerdomain next power state Paul Walmsley
2012-12-09 20:03 ` [PATCH 08/12] ARM: OMAP2+: powerdomain: cache the powerdomain's previous " Paul Walmsley
2012-12-09 20:03 ` [PATCH 09/12] ARM: OMAP2+: powerdomain: skip register reads for powerdomains known to be on Paul Walmsley
2012-12-12 10:22   ` Vaibhav Hiremath
2012-12-19 21:09   ` Jon Hunter [this message]
2012-12-20 17:22     ` Paul Walmsley
2012-12-21  6:33       ` Santosh Shilimkar
2012-12-26  6:21   ` Bedia, Vaibhav
2012-12-26  6:31     ` Bedia, Vaibhav
2012-12-26 20:49     ` Paul Walmsley
2012-12-09 20:03 ` [PATCH 10/12] ARM: OMAP2+: powerdomain: skip previous-power-state read if next_pwrst is ON Paul Walmsley
2012-12-09 20:03 ` [PATCH 11/12] ARM: OMAP2xxx: powerdomain: add previous power state tracking Paul Walmsley
2012-12-09 20:03 ` [PATCH 12/12] ARM: OMAP2xxx: PM: add pwrdm_(pre|post)_transition() calls to the 2xxx PM code Paul Walmsley
2013-01-04 14:26 ` [PATCH 00/12] ARM: OMAP2+: powerdomain updates after the functional power state conversion Tero Kristo

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