PM for physmap.c ?

PM for physmap.c ?

[Steven Scholz]

Hi all,

for quite some time physmap.c uses platform_{device,driver}.

I wonder why it does not contain any (generic) code for power management
yet, i.e. .suspend/.resume functions.

Is it correct that all I would need to survive a suspend/resume cycle is
something like

int physmap_flash_suspend(struct platform_device *dev, pm_message_t state)
{
	struct sa_info *info = platform_get_drvdata(dev);
	int ret = 0;
	if (info)
		ret = info->mtd->suspend(info->mtd);
	return ret;
}

int physmap_flash_resume(struct platform_device *dev)
{
	struct sa_info *info = platform_get_drvdata(dev);
	if (info)
		info->mtd->resume(info->mtd);
	return 0;
}

as stolen from sa1100-flash.c? Or is PM done at some other/higher layer of
the MTD stuff?

Cheers,

-- 
Steven

Re: PM for physmap.c ?

[Lennert Buytenhek]

On Wed, Aug 23, 2006 at 05:07:27PM +0200, Steven Scholz wrote:

> Hi all,

Hello,


> for quite some time physmap.c uses platform_{device,driver}.
> 
> I wonder why it does not contain any (generic) code for power management
> yet, i.e. .suspend/.resume functions.
> 
> Is it correct that all I would need to survive a suspend/resume cycle is
> something like
> 
> int physmap_flash_suspend(struct platform_device *dev, pm_message_t state)
> {
> 	struct sa_info *info = platform_get_drvdata(dev);
> 	int ret = 0;
> 	if (info)
> 		ret = info->mtd->suspend(info->mtd);
> 	return ret;
> }
> 
> int physmap_flash_resume(struct platform_device *dev)
> {
> 	struct sa_info *info = platform_get_drvdata(dev);
> 	if (info)
> 		info->mtd->resume(info->mtd);
> 	return 0;
> }
> 
> as stolen from sa1100-flash.c?

Looks OK to me, but that doesn't say much.


cheers,
Lennert

Re: PM for physmap.c ?

[Steven Scholz]

Lennert,

>> for quite some time physmap.c uses platform_{device,driver}.
>>
>> I wonder why it does not contain any (generic) code for power management
>> yet, i.e. .suspend/.resume functions.
>>
>> Is it correct that all I would need to survive a suspend/resume cycle is
>> something like
>>
>> int physmap_flash_suspend(struct platform_device *dev, pm_message_t state)
>> {
>> 	struct sa_info *info = platform_get_drvdata(dev);
>> 	int ret = 0;
>> 	if (info)
>> 		ret = info->mtd->suspend(info->mtd);
>> 	return ret;
>> }
>>
>> int physmap_flash_resume(struct platform_device *dev)
>> {
>> 	struct sa_info *info = platform_get_drvdata(dev);
>> 	if (info)
>> 		info->mtd->resume(info->mtd);
>> 	return 0;
>> }
>>
>> as stolen from sa1100-flash.c?
> 
> Looks OK to me, but that doesn't say much.

;-) Thanks for your reply anyway. Thought I am getting ignored for asking
stupid things...

However could one of the MTD gurus please state on the following:
- Would the above be enough?
- Is it needed at all? For normal NOR flash (that's what physmap.c is for?).
- What could happen without proper PM handling?
- Is it worth it to provide a proper patch?

Thanks a million!

--
Steven