From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v5] ARM hibernation / suspend-to-disk (fwd)
Date: Mon, 13 Jun 2011 17:44:52 +0100 [thread overview]
Message-ID: <20110613164452.GE13643@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <alpine.DEB.2.00.1106131400090.25153@localhost6.localdomain6>
On Mon, Jun 13, 2011 at 02:20:12PM +0100, Frank Hofmann wrote:
>
>
> On Mon, 13 Jun 2011, Russell King - ARM Linux wrote:
>
>> On Mon, Jun 13, 2011 at 01:04:02PM +0100, Frank Hofmann wrote:
>>> To make it clear: IF AND ONLY IF your suspend(-to-ram) func looks like:
>>>
>>> ENTRY(acmeSoC_cpu_suspend)
>>> stmfd sp!, {r4-r12,lr}
>>> ldr r3, resume_mmu_done
>>> bl cpu_suspend
>>> resume_mmu_done:
>>> ldmfd sp!, {r3-r12,pc}
>>> ENDPROC(acmeSoC_cpu_suspend)
>>
>> Nothing has that - because you can't execute that ldmfd after the call
>> to cpu_suspend returns. I don't think you've understood what I said on
>> that subject in the previous thread.
>>
>
> Ok, to illustrate a bit more, what is ok and what not.
Actually, we can do something about cpu_suspend.
Currently cpu_suspend is not like a normal C function - when it's called
it returns normally to a bunch of code which is not expected to return.
The return path is via code pointed to by 'r3'.
It also corrupts a bunch of registers in ways which make it non-compliant
with a C API.
If we do make this complaint as a normal C-like function, it eliminates
this register saving. We also swap 'lr' and 'r3', so cpu_suspend
effectively only returns to following code on resume - and r3 points
to the suspend code.
So, this becomes:
ENTRY(acmeSoC_cpu_suspend)
stmfd sp!, {lr}
adr r3, soc_finish_suspend
bl cpu_suspend
ldmfd sp!, {pc}
ENDPROC(acmeSoC_cpu_suspend)
soc_finish_suspend:
blah
blah
put soc to sleep
never return
or even:
static void soc_suspend(void)
{
[soc specific preparation]
cpu_suspend(0, PLAT_PHYS_OFFSET - PAGE_OFFSET,
soc_suspend_arg, soc_suspend_fn);
[soc specific cleanup ]
}
where soc_suspend_fn can be either assembly or C code - but must never
return. Patches will follow this evening.
next prev parent reply other threads:[~2011-06-13 16:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-13 12:04 [RFC PATCH v5] ARM hibernation / suspend-to-disk (fwd) Frank Hofmann
2011-06-13 12:26 ` Russell King - ARM Linux
2011-06-13 12:40 ` Frank Hofmann
2011-06-13 13:20 ` Frank Hofmann
2011-06-13 13:56 ` Dave Martin
2011-06-13 13:56 ` Dave Martin
2011-06-13 15:34 ` Frank Hofmann
2011-06-13 15:34 ` Frank Hofmann
2011-06-13 16:11 ` Frank Hofmann
2011-06-13 16:11 ` Frank Hofmann
2011-06-13 16:44 ` Russell King - ARM Linux [this message]
2011-06-15 13:35 ` Frank Hofmann
2011-06-16 21:31 ` Russell King - ARM Linux
2011-06-20 12:32 ` Frank Hofmann
2011-06-21 14:35 ` Russell King - ARM Linux
2011-06-29 14:52 ` Matthieu CASTET
2011-06-29 15:14 ` Frank Hofmann
2011-06-29 20:08 ` Will Deacon
2011-07-05 12:37 ` Matthieu CASTET
[not found] ` <2C577202CB5719438D4E9608C565CB2C01B69D7F@NL-EXC-07.intra.local>
2011-07-05 17:09 ` Matthieu CASTET
2011-09-30 7:48 ` Barry Song
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=20110613164452.GE13643@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.