From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V2 1/6] ARM: tegra: add pending SGI checking API
Date: Thu, 06 Dec 2012 11:52:53 -0700 [thread overview]
Message-ID: <50C0E985.2020604@wwwdotorg.org> (raw)
In-Reply-To: <1354777471.13857.9.camel@jlo-ubuntu-64.nvidia.com>
On 12/06/2012 12:04 AM, Joseph Lo wrote:
> On Thu, 2012-12-06 at 06:09 +0800, Stephen Warren wrote:
>> On 12/05/2012 03:01 AM, Joseph Lo wrote:
>>> The "powered-down" CPU idle mode of Tegra cut off the vdd_cpu rail, it
>>> include the power of GIC. That caused the SGI (Software Generated
>>> Interrupt) been lost. Because the SGI can't wake up the CPU that in
>>> the "powered-down" CPU idle mode. We need to check if there is any
>>> pending SGI when go into "powered-down" CPU idle mode. This is important
>>> especially when applying the coupled cpuidle framework into "power-down"
>>> cpuidle dirver. Because the coupled cpuidle framework may have the
>>> chance that misses IPI_SINGLE_FUNC handling sometimes.
>>>
>>> For the PPI or SPI, something like the legacy peripheral interrupt. It
>>> still can be maintained by Tegra legacy interrupt controller. If there
>>> is any pending PPI or SPI when CPU in "powered-down" CPU idle mode. The
>>> CPU can be woken up immediately. So we don't need to take care the same
>>> situation for PPI or SPI.
>>
>> Is this feature something that can/should be added to the core GIC
>> driver, rather than something custom in the Tegra code?
>>
> This function is SoC specific code not a generic common code even I
> modify it to more generic for checking the pending irq (SGI, PPI and
> SPI). Different SoC had different design about it. For ex, some SoC only
> put CPU core to power saving mode not include GIC, or there is another
> irq controller can handle the case when CPU go into power saving mode.
> Differenc SoC had different usage here (some need to check all pending
> irq, some need to check SGI only and some even no need to consider
> this).
Hmmm. OK.
>> Part of the reason I ask is that I'd like to avoid any more:
>>
>> static void __iomem *distbase = IO_ADDRESS(TEGRA_ARM_INT_DIST_BASE);
>>
>> since that requires static page tables to be set up, whereas I'd like to
>> reduce, as much as possible, the set of pages Tegra maps statically.
>
> I can move this into the function as a temp variable.
Well, the issue here is use of the IO_ADDRESS() macro at all; ioremap()
at run-time would be better, which I imagine is what the core GIC driver
does when intialized from DT. Still, I suppose there are many instance
of IO_ADDRESS() in the mach-tegra directory right now, so adding one
more won't hurt too much; we still need to do a big pass to get rid of
them sometime if possible.
next prev parent reply other threads:[~2012-12-06 18:52 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-05 10:01 [PATCH V2 0/6] ARM: tegra20: cpuidle: add power-down state Joseph Lo
2012-12-05 10:01 ` [PATCH V2 1/6] ARM: tegra: add pending SGI checking API Joseph Lo
2012-12-05 22:09 ` Stephen Warren
2012-12-06 7:04 ` Joseph Lo
2012-12-06 18:52 ` Stephen Warren [this message]
2012-12-05 10:01 ` [PATCH V2 2/6] ARM: tegra20: cpuidle: add powered-down state for secondary CPU Joseph Lo
2012-12-05 10:50 ` Lorenzo Pieralisi
2012-12-06 8:25 ` Joseph Lo
2012-12-06 18:56 ` Stephen Warren
2013-01-11 7:20 ` Joseph Lo
2013-01-11 12:24 ` Lorenzo Pieralisi
2013-01-15 3:00 ` Joseph Lo
2013-01-15 11:34 ` Lorenzo Pieralisi
2013-01-16 3:17 ` Joseph Lo
2013-01-12 17:33 ` Nicolas Pitre
2012-12-05 22:18 ` Stephen Warren
2012-12-06 7:22 ` Joseph Lo
2012-12-06 18:59 ` Stephen Warren
2012-12-05 10:01 ` [PATCH V2 3/6] ARM: tegra20: clocks: add CPU low-power function into tegra_cpu_car_ops Joseph Lo
2012-12-05 10:01 ` [PATCH V2 4/6] ARM: tegra20: flowctrl: add support for cpu_suspend_enter/exit Joseph Lo
2012-12-05 10:01 ` [PATCH V2 5/6] ARM: tegra20: cpuidle: add powered-down state for CPU0 Joseph Lo
2012-12-05 10:01 ` [PATCH V2 6/6] ARM: tegra20: cpuidle: apply coupled cpuidle for powered-down mode Joseph Lo
2012-12-05 10:01 ` Joseph Lo
2012-12-05 10:10 ` Joseph Lo
2012-12-06 11:03 ` Grant Likely
2012-12-05 10:01 ` Joseph Lo
2012-12-05 10:11 ` Joseph Lo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=50C0E985.2020604@wwwdotorg.org \
--to=swarren@wwwdotorg$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox