[RFC PATCH 2/2] ARM: CSR: add PM sleep entry for SiRFprimaII

[Barry Song]

2011/8/15 Russell King - ARM Linux <linux at arm.linux.org.uk>:
> On Mon, Aug 15, 2011 at 03:43:13PM +0800, Barry Song wrote:
>> Sorry, my fault. i simply picked these lines which have been verified
>> to be working in local old 2.6.38.8 kernel and really didn't think and
>> refine more carefully.
>> in deep sleep mode, SiRFprimaII will powerdown CPU core.
>
> ... just like everyone else.
>
>> due to this,
>> i just ignored to delete the codes saving registers of all kinds of
>> CPU modes. but it is not the real situation in kernel. For example,
>> IRQ mode used the stack of corrupted thread, and kernel was not in
>> interrupt while going to pm_ops->enter(), then it is unnecessary to
>> enter IRQ and save sp of IRQ:
>
> No.  There is _no_ need to save and restore these registers.  They
> can simply be re-setup.  The generic cpu_suspend stuff already
> takes care of that.

i did have saied it is not necessary to save and restore if you read
my reply carefully :-)

>
>> Ok. agree. then the work flow for SiRFprimaII suspend can be:
>> pm.enter()->
>>     sirfsoc_cpu_sleep(v:p offset)
>>     1. save registers on stack
>>     2. load sirfsoc_cpu_resume to r3
>>     3. bl cpu_suspend
>>     4. make sdram self-refresh
>>     5. write force DEEPSLEEP by rtciobrg
>>
>> One issue is L2
>
> That's why I did not include it in the list of code which could be
> eliminated.