Re: [PATCH] soc: ti: pm33xx: Enable DS0 for the platforms on which it is functional

["J, KEERTHY" <j-keerthy@ti.com>]

On 8/22/2018 2:13 PM, Johan Hovold wrote:
> On Wed, Aug 22, 2018 at 01:50:29PM +0530, J, KEERTHY wrote:
>>
>>
>> On 8/22/2018 1:07 PM, Johan Hovold wrote:
>>> On Wed, Aug 22, 2018 at 09:34:09AM +0200, Johan Hovold wrote:
>>>> On Wed, Aug 22, 2018 at 11:02:31AM +0530, Keerthy wrote:
>>>>> Enable DS0 for only those platforms on which it is functional
>>>>>
>>>>> Signed-off-by: Keerthy <j-keerthy@ti.com>
>>>>> ---
>>>>>    arch/arm/mach-omap2/pm33xx-core.c    | 5 +++++
>>>>>    drivers/soc/ti/pm33xx.c              | 9 +++++++++
>>>>>    include/linux/platform_data/pm33xx.h | 2 ++
>>>>>    3 files changed, 16 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm/mach-omap2/pm33xx-core.c b/arch/arm/mach-omap2/pm33xx-core.c
>>>>> index f4971e4..f0f6e8e 100644
>>>>> --- a/arch/arm/mach-omap2/pm33xx-core.c
>>>>> +++ b/arch/arm/mach-omap2/pm33xx-core.c
>>>>> @@ -135,6 +135,11 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
>>>>>    {
>>>>>    	int ret = 0;
>>>>>    
>>>>> +	if (!(args & WFI_FLAG_DEEP_SLEEP0)) {
>>>>> +		pr_err("DS0 mode not supported\n");
>>>>> +		return -ENOTSUPP;
>>>>> +	}
>>>>> +
>>>>>    	amx3_pre_suspend_common();
>>>>>    	scu_power_mode(scu_base, SCU_PM_POWEROFF);
>>>>>    	ret = cpu_suspend(args, fn);
>>>>> diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c
>>>>> index d0dab32..53238d7 100644
>>>>> --- a/drivers/soc/ti/pm33xx.c
>>>>> +++ b/drivers/soc/ti/pm33xx.c
>>>>> @@ -324,6 +324,15 @@ static int am33xx_pm_probe(struct platform_device *pdev)
>>>>>    	suspend_wfi_flags |= WFI_FLAG_SAVE_EMIF;
>>>>>    	suspend_wfi_flags |= WFI_FLAG_WAKE_M3;
>>>>>    
>>>>> +	/*
>>>>> +	 * Deep Sleep0 mode is currently functional only on am437x-gp-evm,
>>>>> +	 * am33xx-evm and boneblack family. Hence set the DS0 flag
>>>>> +	 */
>>>>> +	if (of_machine_is_compatible("ti,am437x-gp-evm") ||
>>>>> +	    of_machine_is_compatible("ti,am335x-bone-black") ||
>>>>> +	    of_machine_is_compatible("ti,am335x-evm"))
>>>>> +		suspend_wfi_flags |= WFI_FLAG_DEEP_SLEEP0;
>>>>
>>>> What about other (out-of-tree) machines which supports DS0 and which
>>>> this change would break?
>>>>
>>>> I think this needs to be a blacklist if anything.
>>>>
>>>> Please also expand in the commit message why you think this is needed.
>>
>> Currently when one does echo mem > /sys/power/state on unsuppored
>> machines there can be a crash or a hang. So bail out with a message.
> 
> Yes, but why is this unsupported on some machines? Which machines, and
> why? Your commit messages should be self-contained and hold the
> information needed to determine whether your patch makes sense in the
> first place.

Okay

> 
>>>> Last, what tree is this against? There's no am43xx_suspend() in
>>>> linux-next (and you add compatibles above for am33xx too).
>>>
>>> Sorry, there is indeed an am43xx_suspend(), but you are adding
>>> compatibles for am33xx which use am33xx_suspend().
>>
>> am33xx_pm_probe is a common probe function for both am33 and am43.
> 
> Yes, but you add a check for your new flag only to am43xx_suspend(), not
> to am33xx_suspend() which is used by the am33xx compatibles you add.

Got it. I will add a check there as well.

> 
>> AFAIK for am33 family am335x-evm and am335x-bone-black support Deep
>> Sleep mode. For am43 family am43tx-gp-evm alone supports at the moment.
> 
> But these are development boards (EVKs), not SOC families (or
> chip revisions). What about all the products that customers to TI who
> have bought these SoCs have built?
> 
>> Can you let me know of other am33 machines that support DS0 mode?
> 
> I have a customer who use DS0, whose DTS is not yet in mainline, and
> whose setup this patch would break for example.

okay

> 
>> I could have simply used ti,am33xx compatible which covers entire am33
>> family but then am33xx-bone (bone white) does not support this mode.
> 
> Yes, and a blacklist would make much more sense for something like this
> if where talking about specific boards.
> 
> Also note that your patch doesn't even handle bone-white as you didn't
> add a check to am33xx_suspend() as I pointed out above.

Tony,

Black list is easier here?

Regards,
Keerthy
> 
> Johan
>