[Skiboot] [RFC PATCH 3/5] hdat: parse and export STOP levels

[Vasant Hegde]

On 09/16/2016 12:15 PM, Oliver O'Halloran wrote:
> ISAv3 added the STOP instruction to act as a front end to the various
> power saving modes. The exact function of the stop instruction is
> implementation dependent and the firmware must advertise which "stop
> levels" are supported.
>
> This patch adds the required HDAT parsing and exports the
> "ibm,enabled-stop-levels" devicetree node for use inside of skiboot.

Patch looks good. But probably its better to fold patch 3 & 4. Otherwise we may 
hit issues during git bisect...

Reviewed-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>


-Vasant

>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
>   hdata/spira.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 58 insertions(+)
>
> diff --git a/hdata/spira.c b/hdata/spira.c
> index e4e6b2d5830c..ed918a376adf 100644
> --- a/hdata/spira.c
> +++ b/hdata/spira.c
> @@ -1049,6 +1049,62 @@ static void hostservices_parse(void)
>   	hservices_from_hdat(dt_blob, size);
>   }
>
> +static void add_stop_levels(void)
> +{
> +	struct spira_ntuple *t = &spira.ntuples.proc_chip;
> +	struct HDIF_common_hdr *hdif;
> +	u32 stop_levels = ~0;
> +	bool valid = false;
> +	int i;
> +
> +	if (proc_gen < proc_gen_p9)
> +		return;
> +
> +	/*
> +	 * OPAL only exports a single set of flags to indicate the supported
> +	 * STOP modes while the HDAT descibes the support top levels *per chip*
> +	 * We parse the list of chips to find a common set of STOP levels to
> +	 * export.
> +	 */
> +	for_each_ntuple_idx(t, hdif, i, SPPCRD_HDIF_SIG) {
> +		const struct sppcrd_chip_info *cinfo =
> +			HDIF_get_idata(hdif, SPPCRD_IDATA_CHIP_INFO, NULL);
> +		u32 ve, chip_levels;
> +
> +		if (!cinfo)
> +			continue;
> +
> +		/*
> +		 * If the HDAT is too old contain the support STOP level then
> +		 * assume we have none.
> +		 */
> +		if (be16_to_cpu(hdif->version) < 0x20) {
> +			stop_levels = 0;
> +			break;
> +		}
> +
> +		ve = be32_to_cpu(cinfo->verif_exist_flags) & CPU_ID_VERIFY_MASK;
> +		ve >>= CPU_ID_VERIFY_SHIFT;
> +		if (ve == CHIP_VERIFY_NOT_INSTALLED ||
> +		    ve == CHIP_VERIFY_UNUSABLE)
> +			continue;
> +
> +		chip_levels = be32_to_cpu(cinfo->stop_levels);
> +
> +		prlog(PR_INSANE, "CHIP[%x] supported STOP mask 0x%.8x\n",
> +			be32_to_cpu(cinfo->proc_chip_id), chip_levels);
> +
> +		stop_levels &= chip_levels;
> +		valid = true;
> +	}
> +
> +	if (!valid)
> +		stop_levels = 0;
> +
> +	dt_add_property_cells(dt_new_check(opal_node, "power-mgt"),
> +		"ibm,enabled-stop-levels", stop_levels);
> +}
> +
>   /*
>    * Legacy SPIRA is being deprecated and we have new SPIRA-H/S structures.
>    * But on older system (p7?) we will continue to get legacy SPIRA.
> @@ -1151,6 +1207,8 @@ int parse_hdat(bool is_opal, uint32_t master_cpu)
>   	/* Parse System Attention Indicator inforamtion */
>   	slca_dt_add_sai_node();
>
> +	add_stop_levels();
> +
>   	prlog(PR_INFO, "Parsing HDAT...done\n");
>
>   	return 0;
>