Implement support for fetching dimm performance metrics via H_SCM_PERFORMANCE_HEALTH hcall as documented in Ref[1]. The hcall returns a structure as described in Ref[1] and defined as newly introduced 'struct papr_scm_perf_stats'. The struct has a header followed by key-value pairs of performance attributes.
The module 'papr_scm' however doesn't interpret or parses these performance attributes as it will be returning this buffer as it is to user-space for further parsing. For now we only implement a dimm specific sysfs attribute named 'papr_stats_version' that returns the version of the structure returned from H_SCM_PERFORMANCE_HEALTH hcall. Hence this patch implements a new function drc_pmem_query_stats() that issues hcall H_SCM_PERFORMANCE_HEALTH ,requesting PHYP to store performance stats in pre-allocated 'struct papr_scm_perf_stats' buffer 'stats'. References: [1]: https://patchwork.ozlabs.org/patch/1154292/ Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> --- arch/powerpc/platforms/pseries/papr_scm.c | 56 +++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 1a0cc66f3dc9..deaece6e4d18 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -22,6 +22,16 @@ (1ul << ND_CMD_GET_CONFIG_DATA) | \ (1ul << ND_CMD_SET_CONFIG_DATA)) +#define PAPR_SCM_MAX_PERF_STAT 4096 + +/* Buffer layout returned by phyp when reporting drc perf stats */ +struct papr_scm_perf_stats { + uint8_t version; /* Should be 0x01 */ + uint8_t reserved1; + __be16 size; /* Size of this struct in bytes */ + uint8_t buffer[]; /* Performance matrics */ +} __packed; + struct papr_scm_priv { struct platform_device *pdev; struct device_node *dn; @@ -148,6 +158,25 @@ static int drc_pmem_query_n_bind(struct papr_scm_priv *p) return drc_pmem_bind(p); } +static int drc_pmem_query_stats(struct papr_scm_priv *p, + struct papr_scm_perf_stats *stats) +{ + unsigned long ret[PLPAR_HCALL_BUFSIZE]; + int64_t rc; + + if (!stats) + return -EINVAL; + + rc = plpar_hcall(H_SCM_PERFORMANCE_STATS, ret, p->drc_index, + __pa(stats)); + if (rc != H_SUCCESS) { + dev_err(&p->pdev->dev, + "Failed to query performance stats, Err:%lld\n", rc); + return -ENXIO; + } else + return 0; +} + static int drc_pmem_query_health(struct papr_scm_priv *p) { unsigned long ret[PLPAR_HCALL_BUFSIZE]; @@ -332,6 +361,32 @@ static inline int papr_scm_node(int node) return min_node; } +static ssize_t papr_stats_version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct nvdimm *dimm = to_nvdimm(dev); + struct papr_scm_priv *p = nvdimm_provider_data(dimm); + struct papr_scm_perf_stats *retbuffer; + int rc; + + /* Return buffer for phyp where stats are written */ + retbuffer = kzalloc(PAPR_SCM_MAX_PERF_STAT, GFP_KERNEL); + if (!retbuffer) + return -ENOMEM; + + rc = drc_pmem_query_stats(p, retbuffer); + if (rc) + goto out; + else + rc = sprintf(buf, "%d\n", retbuffer->version); + +out: + kfree(retbuffer); + return rc; + +} +DEVICE_ATTR_RO(papr_stats_version); + static ssize_t papr_health_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -353,6 +408,7 @@ DEVICE_ATTR_RO(papr_health); /* papr_scm specific dimm attributes */ static struct attribute *papr_scm_nd_attributes[] = { &dev_attr_papr_health.attr, + &dev_attr_papr_stats_version.attr, NULL, }; -- 2.24.1
