Subject: [RFC PATCH 8/8] powerpc/papr_scm: Use FORM2 associativity details

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 14 Jun 2021 22:10:03 +0530

FORM2 introduce a concept of secondary domain which is identical to the
conceept of FORM1 primary domain. Use secondary domain as the numa node
when using persistent memory device. For DAX kmem use the logical domain
id introduced in FORM2. This new numa node

Signed-off-by: Aneesh Kumar K.V <[email-masked]>
---
 arch/powerpc/mm/numa.c                    | 28 +++++++++++++++++++++++
 arch/powerpc/platforms/pseries/papr_scm.c | 26 +++++++++++++--------
 arch/powerpc/platforms/pseries/pseries.h  |  1 +
 3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 86cd2af014f7..b9ac6d02e944 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -265,6 +265,34 @@ static int associativity_to_nid(const __be32 *associativity)
 	return nid;
 }
 
+int get_primary_and_secondary_domain(struct device_node *node, int *primary, int *secondary)
+{
+	int secondary_index;
+	const __be32 *associativity;
+
+	if (!numa_enabled) {
+		*primary = NUMA_NO_NODE;
+		*secondary = NUMA_NO_NODE;
+		return 0;
+	}
+
+	associativity = of_get_associativity(node);
+	if (!associativity)
+		return -ENODEV;
+
+	if (of_read_number(associativity, 1) >= primary_domain_index) {
+		*primary = of_read_number(&associativity[primary_domain_index], 1);
+		secondary_index = of_read_number(&distance_ref_points[1], 1);
+		*secondary = of_read_number(&associativity[secondary_index], 1);
+	}
+	if (*primary == 0xffff || *primary >= nr_node_ids)
+		*primary = NUMA_NO_NODE;
+
+	if (*secondary == 0xffff || *secondary >= nr_node_ids)
+		*secondary = NUMA_NO_NODE;
+	return 0;
+}
+
 /* Returns the nid associated with the given device tree node,
  * or -1 if not found.
  */
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index ef26fe40efb0..9bf2f1f3ddc5 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -18,6 +18,7 @@
 #include <asm/plpar_wrappers.h>
 #include <asm/papr_pdsm.h>
 #include <asm/mce.h>
+#include "pseries.h"
 
 #define BIND_ANY_ADDR (~0ul)
 
@@ -88,6 +89,8 @@ struct papr_scm_perf_stats {
 struct papr_scm_priv {
 	struct platform_device *pdev;
 	struct device_node *dn;
+	int numa_node;
+	int target_node;
 	uint32_t drc_index;
 	uint64_t blocks;
 	uint64_t block_size;
@@ -923,7 +926,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	struct nd_mapping_desc mapping;
 	struct nd_region_desc ndr_desc;
 	unsigned long dimm_flags;
-	int target_nid, online_nid;
 	ssize_t stat_size;
 
 	p->bus_desc.ndctl = papr_scm_ndctl;
@@ -974,10 +976,8 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	mapping.size = p->blocks * p->block_size; // XXX: potential overflow?
 
 	memset(&ndr_desc, 0, sizeof(ndr_desc));
-	target_nid = dev_to_node(&p->pdev->dev);
-	online_nid = numa_map_to_online_node(target_nid);
-	ndr_desc.numa_node = online_nid;
-	ndr_desc.target_node = target_nid;
+	ndr_desc.numa_node = p->numa_node;
+	ndr_desc.target_node = p->target_node;
 	ndr_desc.res = &p->res;
 	ndr_desc.of_node = p->dn;
 	ndr_desc.provider_data = p;
@@ -1001,9 +1001,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 				ndr_desc.res, p->dn);
 		goto err;
 	}
-	if (target_nid != online_nid)
-		dev_info(dev, "Region registered with target node %d and online node %d",
-			 target_nid, online_nid);
 
 	mutex_lock(&papr_ndr_lock);
 	list_add_tail(&p->region_list, &papr_nd_regions);
@@ -1096,7 +1093,7 @@ static int papr_scm_probe(struct platform_device *pdev)
 	struct papr_scm_priv *p;
 	const char *uuid_str;
 	u64 uuid[2];
-	int rc;
+	int rc, numa_node;
 
 	/* check we have all the required DT properties */
 	if (of_property_read_u32(dn, "ibm,my-drc-index", &drc_index)) {
@@ -1119,11 +1116,20 @@ static int papr_scm_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
 		return -ENOMEM;
 
+	if (get_primary_and_secondary_domain(dn, &p->target_node, &numa_node)) {
+		dev_err(&pdev->dev, "%pOF: missing NUMA attributes!\n", dn);
+		rc = -ENODEV;
+		goto err;
+	}
+	p->numa_node = numa_map_to_online_node(numa_node);
+	if (numa_node != p->numa_node)
+		dev_info(&pdev->dev, "Region registered with online node %d and device tree node %d",
+			 p->numa_node, numa_node);
+
 	/* Initialize the dimm mutex */
 	mutex_init(&p->health_mutex);
 
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 663a0859cf13..9c2a1fc9ded1 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -114,4 +114,5 @@ void pseries_setup_security_mitigations(void);
 void pseries_lpar_read_hblkrm_characteristics(void);
 
 void update_numa_distance(struct device_node *node);
+int get_primary_and_secondary_domain(struct device_node *node, int *primary, int *secondary);
 #endif /* _PSERIES_PSERIES_H */
-- 
2.31.1