Commit af0870c4 authored by Vaibhav Jain's avatar Vaibhav Jain Committed by Michael Ellerman
Browse files

powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric 



We add support for reporting 'fuel-gauge' NVDIMM metric via
PAPR_PDSM_HEALTH pdsm payload. 'fuel-gauge' metric indicates the usage
life remaining of a papr-scm compatible NVDIMM. PHYP exposes this
metric via the H_SCM_PERFORMANCE_STATS.

The metric value is returned from the pdsm by extending the return
payload 'struct nd_papr_pdsm_health' without breaking the ABI. A new
field 'dimm_fuel_gauge' to hold the metric value is introduced at the
end of the payload struct and its presence is indicated by by
extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID.

The patch introduces a new function papr_pdsm_fuel_gauge() that is
called from papr_pdsm_health(). If fetching NVDIMM performance stats
is supported then 'papr_pdsm_fuel_gauge()' allocated an output buffer
large enough to hold the performance stat and passes it to
drc_pmem_query_stats() that issues the HCALL to PHYP. The return value
of the stat is then populated in the 'struct
nd_papr_pdsm_health.dimm_fuel_gauge' field with extension flag
'PDSM_DIMM_HEALTH_RUN_GAUGE_VALID' set in 'struct
nd_papr_pdsm_health.extension_flags'

Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200731064153.182203-3-vaibhav@linux.ibm.com
parent 2d02bf83

arch/powerpc/include/uapi/asm/papr_pdsm.h

+9 −0
Original line number Diff line number Diff line
@@ -72,6 +72,11 @@ 
#define PAPR_PDSM_DIMM_CRITICAL      2

#define PAPR_PDSM_DIMM_FATAL         3



/* struct nd_papr_pdsm_health.extension_flags field flags */



/* Indicate that the 'dimm_fuel_gauge' field is valid */

#define PDSM_DIMM_HEALTH_RUN_GAUGE_VALID 1



/*

 * Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH

 * Various flags indicate the health status of the dimm.
@@ -84,6 +89,7 @@ 
 * dimm_locked		: Contents of the dimm cant be modified until CEC reboot

 * dimm_encrypted	: Contents of dimm are encrypted.

 * dimm_health		: Dimm health indicator. One of PAPR_PDSM_DIMM_XXXX

 * dimm_fuel_gauge	: Life remaining of DIMM as a percentage from 0-100

 */

struct nd_papr_pdsm_health {

	union {
@@ -96,6 +102,9 @@ struct nd_papr_pdsm_health { 
			__u8 dimm_locked;

			__u8 dimm_encrypted;

			__u16 dimm_health;



			/* Extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID */

			__u16 dimm_fuel_gauge;

		};

		__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];

	};

arch/powerpc/platforms/pseries/papr_scm.c

+49 −0
Original line number Diff line number Diff line
@@ -518,6 +518,51 @@ static int is_cmd_valid(struct nvdimm *nvdimm, unsigned int cmd, void *buf, 
	return 0;

}



static int papr_pdsm_fuel_gauge(struct papr_scm_priv *p,

				union nd_pdsm_payload *payload)

{

	int rc, size;

	u64 statval;

	struct papr_scm_perf_stat *stat;

	struct papr_scm_perf_stats *stats;



	/* Silently fail if fetching performance metrics isn't  supported */

	if (!p->stat_buffer_len)

		return 0;



	/* Allocate request buffer enough to hold single performance stat */

	size = sizeof(struct papr_scm_perf_stats) +

		sizeof(struct papr_scm_perf_stat);



	stats = kzalloc(size, GFP_KERNEL);

	if (!stats)

		return -ENOMEM;



	stat = &stats->scm_statistic[0];

	memcpy(&stat->stat_id, "MemLife ", sizeof(stat->stat_id));

	stat->stat_val = 0;



	/* Fetch the fuel gauge and populate it in payload */

	rc = drc_pmem_query_stats(p, stats, 1);

	if (rc < 0) {

		dev_dbg(&p->pdev->dev, "Err(%d) fetching fuel gauge\n", rc);

		goto free_stats;

	}



	statval = be64_to_cpu(stat->stat_val);

	dev_dbg(&p->pdev->dev,

		"Fetched fuel-gauge %llu", statval);

	payload->health.extension_flags |=

		PDSM_DIMM_HEALTH_RUN_GAUGE_VALID;

	payload->health.dimm_fuel_gauge = statval;



	rc = sizeof(struct nd_papr_pdsm_health);



free_stats:

	kfree(stats);

	return rc;

}



/* Fetch the DIMM health info and populate it in provided package. */

static int papr_pdsm_health(struct papr_scm_priv *p,

			    union nd_pdsm_payload *payload)
@@ -558,6 +603,10 @@ static int papr_pdsm_health(struct papr_scm_priv *p, 


	/* struct populated hence can release the mutex now */

	mutex_unlock(&p->health_mutex);



	/* Populate the fuel gauge meter in the payload */

	papr_pdsm_fuel_gauge(p, payload);



	rc = sizeof(struct nd_papr_pdsm_health);



out:

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