The DSM 'DSM_PAPR_SCM_HEALTH' should return a 'struct
nd_papr_scm_dimm_health_stat' containing information in dimm health back
to user space in response to ND_CMD_CALL. We implement this DSM by
implementing a new function papr_scm_get_health() that queries the
DIMM health information and then copies these bitmaps to the package
payload whose layout is defined by 'struct papr_scm_ndctl_health'.
The patch also handle cases where in future versions of 'struct
papr_scm_ndctl_health' may want to return more health
information. Such payload envelops will contain appropriate version
information in 'struct nd_papr_scm_cmd_pkg.payload_version'. The patch
takes care of only returning the sub-data corresponding to the payload
version requested. Please see the comments in papr_scm_get_health()
for how this is done.
Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
---
arch/powerpc/platforms/pseries/papr_scm.c | 73 +++++++++++++++++++++++
1 file changed, 73 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index 29f38246c59f..bf81acb0bf3f 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -415,6 +415,74 @@ static int cmd_to_func(struct nvdimm *nvdimm, unsigned int
cmd, void *buf,
return pkg->hdr.nd_command;
}
+/*
+ * Fetch the DIMM health info and populate it in provided papr_scm package.
+ * Since the caller can request a different version of payload and each new
+ * version of struct nd_papr_scm_dimm_health_stat is a proper-subset of
+ * previous version hence we return a subset of the cached 'struct
+ * nd_papr_scm_dimm_health_stat' depending on the payload version requested.
+ */
+static int papr_scm_get_health(struct papr_scm_priv *p,
+ struct nd_papr_scm_cmd_pkg *pkg)
+{
+ int rc;
+ size_t copysize;
+ /* Map version to number of bytes to be copied to payload */
+ const size_t copysizes[] = {
+ [1] =
+ sizeof(struct nd_papr_scm_dimm_health_stat_v1),
+
+ /* This should always be preset */
+ [ND_PAPR_SCM_DIMM_HEALTH_VERSION] =
+ sizeof(struct nd_papr_scm_dimm_health_stat),
+ };
+
+ rc = drc_pmem_query_health(p);
+ if (rc)
+ goto out;
+ /*
+ * If the requested payload version is greater than one we know
+ * aboute, return the payload version we know about and let
+ * caller/userspace handle the mess.
+ */
+ if (pkg->payload_version > ND_PAPR_SCM_DIMM_HEALTH_VERSION)
+ pkg->payload_version = ND_PAPR_SCM_DIMM_HEALTH_VERSION;
+
+ copysize = copysizes[pkg->payload_version];
+ if (!copysize) {
+ dev_dbg(&p->pdev->dev, "%s Unsupported payload version=0x%x\n",
+ __func__, pkg->payload_version);
+ rc = -ENOSPC;
+ goto out;
+ }
+
+ if (pkg->hdr.nd_size_out < copysize) {
+ dev_dbg(&p->pdev->dev, "%s Payload not large enough\n",
+ __func__);
+ dev_dbg(&p->pdev->dev, "%s Expected %lu, available %u\n",
+ __func__, copysize, pkg->hdr.nd_size_out);
+ rc = -ENOSPC;
+ goto out;
+ }
+
+ dev_dbg(&p->pdev->dev, "%s Copying payload size=%lu version=0x%x\n",
+ __func__, copysize, pkg->payload_version);
+
+ /* Copy a subset of health struct based on copysize */
+ memcpy(papr_scm_pcmd_to_payload(pkg), &p->health, copysize);
+ pkg->hdr.nd_fw_size = copysize;
+
+out:
+ /*
+ * Put the error in out package and return success from function
+ * so that errors if any are propogated back to userspace.
+ */
+ pkg->cmd_status = rc;
+ dev_dbg(&p->pdev->dev, "%s completion code = %d\n", __func__, rc);
+
+ return 0;
+}
+
int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm
*nvdimm,
unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
{
@@ -460,6 +528,11 @@ int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
struct nvdimm *nvdimm,
*cmd_rc = 0;
break;
+ case DSM_PAPR_SCM_HEALTH:
+ call_pkg = nd_to_papr_cmd_pkg(buf);
+ *cmd_rc = papr_scm_get_health(p, call_pkg);
+ break;
+
default:
dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd_in);
*cmd_rc = -EINVAL;
--
2.24.1
