[Skiboot] [PATCH] Tie tm-suspend fw-feature and opal_reinit_cpus() together

[Cyril Bur]

On Fri, 2018-03-02 at 14:08 +1100, Michael Neuling wrote:
> Currently opal_reinit_cpus(OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED)
> always returns OPAL_UNSUPPORTED.

I wonder if more of a mention of how the mode is set by hostboot on IPL
. I seem unable to actually come up with that I feel is missing.

> 
> This ties the tm suspend fw-feature to the
> opal_reinit_cpus(OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED) so that when tm
> suspend is disabled, we correctly report it to the kernel.  For
> backwards compatibility, it's assumed tm suspend is available if the
> fw-feature is not present.
> 
> Signed-off-by: Michael Neuling <mikey at neuling.org>

Reviewed-by: Cyril Bur <cyril.bur at au1.ibm.com>

> ---
>  core/cpu.c | 27 ++++++++++++++++++++++-----
>  1 file changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/core/cpu.c b/core/cpu.c
> index 2eab522553..7a9dbe5d70 100644
> --- a/core/cpu.c
> +++ b/core/cpu.c
> @@ -57,6 +57,7 @@ static bool ipi_enabled;
>  static bool pm_enabled;
>  static bool current_hile_mode;
>  static bool current_radix_mode;
> +static bool tm_suspend_enabled;
>  
>  unsigned long cpu_secondary_start __force_data = 0;
>  
> @@ -1012,6 +1013,21 @@ static int find_dec_bits(void)
>  	return bits;
>  }
>  
> +static void init_tm_suspend_mode_property(void)
> +{
> +	struct dt_node *node;
> +
> +	/* If we don't find anything, assume TM suspend is enabled */
> +	tm_suspend_enabled = true;
> +
> +	node = dt_find_by_path(dt_root, "/ibm,opal/fw-features/tm-suspend-mode");
> +	if (!node)
> +		return;
> +
> +	if (dt_find_property(node, "disabled"))
> +		tm_suspend_enabled = false;
> +}
> +
>  void init_all_cpus(void)
>  {
>  	struct dt_node *cpus, *cpu;
> @@ -1021,6 +1037,8 @@ void init_all_cpus(void)
>  	cpus = dt_find_by_path(dt_root, "/cpus");
>  	assert(cpus);
>  
> +	init_tm_suspend_mode_property();
> +
>  	/* Iterate all CPUs in the device-tree */
>  	dt_for_each_child(cpus, cpu) {
>  		unsigned int pir, server_no, chip_id;
> @@ -1436,11 +1454,10 @@ static int64_t opal_reinit_cpus(uint64_t flags)
>  	if (flags & OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED) {
>  		flags &= ~OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED;
>  
> -		/*
> -		 * Pending a hostboot change we can't determine the status of
> -		 * this, so it always fails.
> -		 */
> -		rc = OPAL_UNSUPPORTED;
> +		if (tm_suspend_enabled)
> +			rc = OPAL_UNSUPPORTED;
> +		else
> +			rc = OPAL_SUCCESS;
>  	}
>  
>  	/* Handle P8 DD1 SLW reinit */