[Skiboot] [PATCH] core/direct-controls: increase special wakeup timeout on POWER9

[Vaidyanathan Srinivasan]

* Nicholas Piggin <npiggin at gmail.com> [2017-10-17 15:23:39]:

> Some instances have been observed where the special wakeup assert
> times out. The current timeout is too short for deeper sleep states.
> Hostboot uses 100ms, so match that.

Good to match hostboot's values since there are many corner cases with
a lower timeout.
 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>

Acked-by: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>


> ---
>  core/direct-controls.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/core/direct-controls.c b/core/direct-controls.c
> index 9acdab5e..c6834d77 100644
> --- a/core/direct-controls.c
> +++ b/core/direct-controls.c
> @@ -36,7 +36,10 @@
>  
>  #define P9_EC_PPM_SSHHYP		0x0114
>  #define P9_SPECIAL_WKUP_DONE		PPC_BIT(1)
> -#define P9_SPWKUP_TIMEOUT		10
> +
> +/* Waking may take up to 5ms for deepest sleep states. Set timeout to 100ms */
> +#define P9_SPWKUP_POLL_INTERVAL		100
> +#define P9_SPWKUP_TIMEOUT		100000
>  
>  /*
>   * This implements direct control facilities of processor cores and threads
> @@ -62,7 +65,7 @@ static int p9_core_set_special_wakeup(struct cpu_thread *cpu)
>  		return OPAL_HARDWARE;
>  	}
>  
> -	for (i = 0; i < P9_SPWKUP_TIMEOUT; i++) {
> +	for (i = 0; i < P9_SPWKUP_TIMEOUT/P9_SPWKUP_POLL_INTERVAL; i++) {
>  		if (xscom_read(chip_id, sshhyp_addr, &val)) {
>  			prlog(PR_ERR, "Could not set special wakeup on %u:%u:"
>  					" Unable to read PPM_SSHHYP.\n",
> @@ -72,7 +75,7 @@ static int p9_core_set_special_wakeup(struct cpu_thread *cpu)
>  		if (val & P9_SPECIAL_WKUP_DONE)
>  			return 0;
>  
> -		time_wait_us(1);
> +		time_wait_us(P9_SPWKUP_POLL_INTERVAL);
>  	}
>  
>  	prlog(PR_ERR, "Could not set special wakeup on %u:%u:"
> -- 
> 2.13.3
> 
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