[ndctl PATCH 7/8] libndctl,papr_scm: Implement support for DSM_PAPR_SCM_HEALTH

[Vaibhav Jain <vaibhav@linux.ibm.com>]

Add support for reporting DIMM health by issuing DSM_PAPR_SCM_HEALTH
DSM. It returns an instance of '
struct nd_papr_scm_dimm_health_stat' as defined in
'papr_scm_dsm.h'. The patch provides support for dimm-ops 'new_smart' &
'smart_get_health' as papr_new_smart_health() &
papr_smart_get_health() respectively. This callbacks should enable
ndctl to report DIMM health.

Also a new member 'struct dimm_priv.health' is introduced which holds
the current health status of the dimm. This member is set inside newly
added function 'update_dimm_health_v1()' which parses the v1 payload
returned by the kernel after servicing DSM_PAPR_SCM_HEALTH. The
function will also update dimm-flags viz 'struct ndctl_dimm.flags.f_*'
based on the flags set in the returned payload.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
 ndctl/lib/papr_scm.c | 80 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 3 deletions(-)

diff --git a/ndctl/lib/papr_scm.c b/ndctl/lib/papr_scm.c
index 0a3857e2a4c4..a01649d3a9fe 100644
--- a/ndctl/lib/papr_scm.c
+++ b/ndctl/lib/papr_scm.c
@@ -40,7 +40,9 @@
 
 /* Per dimm data. Holds per-dimm data parsed from the cmd_pkgs */
 struct dimm_priv {
-	/* Empty for now */
+
+	/* Cache the dimm health status */
+	struct nd_papr_scm_dimm_health_stat health;
 };
 
 static bool papr_cmd_is_supported(struct ndctl_dimm *dimm, int cmd)
@@ -88,6 +90,43 @@ static bool cmd_is_valid(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
 	return true;
 }
 
+/*
+ * Parse the nd_papr_scm_dimm_health_stat_v1 payload embedded in ndctl_cmd and
+ * update dimm health/flags
+ */
+static int update_dimm_health_v1(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
+{
+	struct nd_papr_scm_cmd_pkg *pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
+	struct dimm_priv *p = dimm->dimm_user_data;
+	const struct nd_papr_scm_dimm_health_stat_v1 *health =
+		papr_scm_pcmd_to_payload(pcmd);
+
+	/* Update the dimm flags */
+	dimm->flags.f_arm = health->dimm_unarmed;
+	dimm->flags.f_flush = health->dimm_bad_shutdown;
+	dimm->flags.f_restore = health->dimm_bad_restore;
+	dimm->flags.f_smart = (health->dimm_health != 0);
+
+	/* Cache the dimm health information */
+	memcpy(&p->health, health, sizeof(*health));
+	return 0;
+}
+
+/* Check payload version returned and pass the packet to appropriate handler */
+static int update_dimm_health(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
+{
+	const struct nd_papr_scm_cmd_pkg *pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
+
+	if (pcmd->payload_version == 1)
+		return update_dimm_health_v1(dimm, cmd);
+
+	/* unknown version */
+	PAPR_ERR(dimm, "Unknown payload version for dimm_health."
+		 "Ver=%d, Supported=%d\n", pcmd->payload_version,
+		 ND_PAPR_SCM_DIMM_HEALTH_VERSION);
+	return -EINVAL;
+}
+
 /* Parse a command payload and update dimm flags/private data */
 static int update_dimm_stats(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
 {
@@ -113,6 +152,8 @@ static int update_dimm_stats(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
 	/* Get the command dsm and handle it */
 	pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
 	switch (pcmd_to_dsm(pcmd)) {
+	case DSM_PAPR_SCM_HEALTH:
+		return update_dimm_health(dimm, cmd);
 	default:
 		PAPR_ERR(dimm, "Unhandled dsm-command 0x%016llx\n",
 			 pcmd_to_dsm(pcmd));
@@ -158,14 +199,45 @@ static struct ndctl_cmd *allocate_cmd(struct ndctl_dimm *dimm,
 	return cmd;
 }
 
+static struct ndctl_cmd *papr_new_smart_health(struct ndctl_dimm *dimm)
+{
+	struct ndctl_cmd *cmd_ret;
+
+	cmd_ret = allocate_cmd(dimm, DSM_PAPR_SCM_HEALTH,
+			       sizeof(struct nd_papr_scm_dimm_health_stat),
+			       ND_PAPR_SCM_DIMM_HEALTH_VERSION);
+	if (!cmd_ret) {
+		PAPR_ERR(dimm, "Unable to allocate smart_health command\n");
+		return NULL;
+	}
+
+	cmd_ret->pkg[0].nd_size_out = ND_PAPR_SCM_ENVELOPE_CONTENT_SIZE(
+		struct nd_papr_scm_dimm_health_stat);
+
+	return cmd_ret;
+}
+
+static unsigned int papr_smart_get_health(struct ndctl_cmd *cmd)
+{
+	struct dimm_priv *p = cmd->dimm->dimm_user_data;
+
+	/*
+	 * Update the dimm stats and use some math to return one of
+	 * defined ND_SMART_*_HEALTH values
+	 */
+	if (update_dimm_stats(cmd->dimm, cmd) || !p->health.dimm_health)
+		return 0;
+	else
+		return 1 << (p->health.dimm_health - 1);
+}
+
 static unsigned int papr_smart_get_flags(struct ndctl_cmd *cmd)
 {
 	/* In case of error return empty flags * */
 	if (update_dimm_stats(cmd->dimm, cmd))
 		return 0;
 
-	/* Return empty flags for now as no DSM support */
-	return 0;
+	return ND_SMART_HEALTH_VALID;
 }
 
 static int papr_dimm_init(struct ndctl_dimm *dimm)
@@ -205,4 +277,6 @@ struct ndctl_dimm_ops * const papr_scm_dimm_ops = &(struct ndctl_dimm_ops) {
 	.dimm_init = papr_dimm_init,
 	.dimm_uninit = papr_dimm_uninit,
 	.smart_get_flags = papr_smart_get_flags,
+	.new_smart = papr_new_smart_health,
+	.smart_get_health = papr_smart_get_health,
 };
-- 
2.24.1
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