Re: [PATCH v2 4/9] powerpc/powernv: Make power7_powersave_common more generic

Shreyas B Prabhu
2016-05-18T06:51:32Z

On 05/18/2016 12:07 PM, Gautham R Shenoy wrote:
> Hi Shreyas,
>
> On Tue, May 03, 2016 at 01:54:33PM +0530, Shreyas B. Prabhu wrote:
>> power7_powersave_common does common steps needed before entering idle
>> state and eventually changes MSR to MSR_IDLE and does rfid to
>> power7_enter_nap_mode.
>>
>> Make it more generic by passing the rfid address as a function parameter.
>> Also make function name more generic.
>
> [..snip..]
>
>>
>> _GLOBAL(power7_winkle)
>> - li r3,3
>> + li r3,PNV_THREAD_WINKLE
>
> This particular change above can go as an independent patch.

Okay.
>
>>
>> _GLOBAL(power7_wakeup_tb_loss)
>> diff --git a/arch/powerpc/kernel/idle_power_common.S b/arch/powerpc/kernel/idle_power_common.S
>> index 05954ae..ff7a541 100644
>> --- a/arch/powerpc/kernel/idle_power_common.S
>> +++ b/arch/powerpc/kernel/idle_power_common.S
>> @@ -21,8 +21,10 @@
>> * To check IRQ_HAPPENED in r4
>> * 0 - don't check
>> * 1 - check
>> + *
>> + * Address to 'rfid' to in r5
>> */
>> -_GLOBAL(power7_powersave_common)
>> +_GLOBAL(power_powersave_common)
>> /* Use r3 to pass state nap/sleep/winkle */
>> /* NAP is a state loss, we create a regs frame on the
>> * stack, fill it up with the state we care about and
>> @@ -79,13 +81,12 @@ _GLOBAL(power7_powersave_common)
>> * because as soon as we do that, another thread can switch
>> * the MMU context to the guest.
>> */
>> - LOAD_REG_IMMEDIATE(r5, MSR_IDLE)
>> + LOAD_REG_IMMEDIATE(r7, MSR_IDLE)
>> li r6, MSR_RI
>> andc r6, r9, r6
>> - LOAD_REG_ADDR(r7, power7_enter_nap_mode)
>> mtmsrd r6, 1 /* clear RI before setting SRR0/1 */
>> - mtspr SPRN_SRR0, r7
>> - mtspr SPRN_SRR1, r5
>> + mtspr SPRN_SRR0, r5
>> + mtspr SPRN_SRR1, r7
>> rfid
>> /* No return */
>
> Any particular reason why you swapped the roles of r5 and r7 ?
>

With this patch, r5 which is the third parameter to
power_powersave_common contains the return address that needs to be
written to SRR0. So here I'm keeping r5 unaltered and using r7 for the MSR.

Thanks,
Shreyas