[PATCH 18/21] EDAC, mc: Introduce edac_mc_alloc_by_dimm() for per dimm allocation

[Robert Richter]

Systems using ACPI GHES for error detection do not have exact
knowledge of the memory hierarchy. Compared to other memory controller
drivers the total size of each layer is unknown (card/module,
channel/slot, etc.). But there is the total number of dimms. So add a
function to allocate an mc device this way. The edac's driver uses
internally a dimm index already for data access.

Signed-off-by: Robert Richter <rrichter@xxxxxxxxxxx>
---
 drivers/edac/edac_mc.c   | 83 ++++++++++++++++++++++++++++------------
 drivers/edac/edac_mc.h   | 17 ++++++--
 drivers/edac/ghes_edac.c |  7 ++--
 3 files changed, 76 insertions(+), 31 deletions(-)

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index f7e6a751f309..bdeb9fd08249 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -303,10 +303,11 @@ static void _edac_mc_free(struct mem_ctl_info *mci)
 	kfree(mci);
 }
 
-struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
-				   unsigned n_layers,
-				   struct edac_mc_layer *layers,
-				   unsigned sz_pvt)
+struct mem_ctl_info *__edac_mc_alloc(unsigned mc_num,
+				unsigned dimm_num,
+				unsigned n_layers,
+				struct edac_mc_layer *layers,
+				unsigned sz_pvt)
 {
 	struct mem_ctl_info *mci;
 	struct edac_mc_layer *layer;
@@ -321,6 +322,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 	bool per_rank = false;
 
 	BUG_ON(n_layers > EDAC_MAX_LAYERS || n_layers == 0);
+
 	/*
 	 * Calculate the total amount of dimms and csrows/cschannels while
 	 * in the old API emulation mode
@@ -336,6 +338,26 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 			per_rank = true;
 	}
 
+	/* allocate dimm_num DIMMS, layer size must be zero */
+	if (dimm_num) {
+		if (dimm_num <= 0 ||
+			layers[0].size ||
+			(n_layers > 1 && layers[1].size) ||
+			(n_layers > 2 && layers[2].size)) {
+			edac_printk(KERN_WARNING, EDAC_MC,
+				"invalid layer data\n");
+			return NULL;
+		}
+
+		/*
+		 * Assume 1 csrow per dimm which also means 1 channel
+		 * per csrow.
+		 */
+		tot_dimms	= dimm_num;
+		tot_csrows	= dimm_num;
+		tot_channels	= 1;
+	}
+
 	/* Figure out the offsets of the various items from the start of an mc
 	 * structure.  We want the alignment of each item to be at least as
 	 * stringent as what the compiler would provide if we could simply
@@ -422,25 +444,10 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 		dimm->mci = mci;
 		dimm->idx = idx;
 
-		/*
-		 * Copy DIMM location and initialize it.
-		 */
-		len = sizeof(dimm->label);
-		p = dimm->label;
-		n = snprintf(p, len, "mc#%u", mc_num);
-		p += n;
-		len -= n;
-		for (j = 0; j < n_layers; j++) {
-			n = snprintf(p, len, "%s#%u",
-				     edac_layer_name[layers[j].type],
-				     pos[j]);
-			p += n;
-			len -= n;
-			dimm->location[j] = pos[j];
-
-			if (len <= 0)
-				break;
-		}
+		/* unknown location */
+		dimm->location[0] = -1;
+		dimm->location[1] = -1;
+		dimm->location[2] = -1;
 
 		/* Link it to the csrows old API data */
 		chan->dimm = dimm;
@@ -462,6 +469,34 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 			}
 		}
 
+		/*
+		 * Copy DIMM location and initialize it.
+		 */
+		len = sizeof(dimm->label);
+		p = dimm->label;
+		n = snprintf(p, len, "mc#%u", mc_num);
+		p += n;
+		len -= n;
+
+		if (dimm_num) {
+			n = snprintf(p, len, "dimm#%u", idx);
+			p += n;
+			len -= n;
+			continue;
+		}
+
+		for (j = 0; j < n_layers; j++) {
+			n = snprintf(p, len, "%s#%u",
+				     edac_layer_name[layers[j].type],
+				     pos[j]);
+			p += n;
+			len -= n;
+			dimm->location[j] = pos[j];
+
+			if (len <= 0)
+				break;
+		}
+
 		/* Increment dimm location */
 		for (j = n_layers - 1; j >= 0; j--) {
 			pos[j]++;
@@ -480,7 +515,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(edac_mc_alloc);
+EXPORT_SYMBOL_GPL(__edac_mc_alloc);
 
 void edac_mc_free(struct mem_ctl_info *mci)
 {
diff --git a/drivers/edac/edac_mc.h b/drivers/edac/edac_mc.h
index c4ddd5c1e24c..e8215847f853 100644
--- a/drivers/edac/edac_mc.h
+++ b/drivers/edac/edac_mc.h
@@ -99,6 +99,10 @@ do {									\
  * edac_mc_alloc() - Allocate and partially fill a struct &mem_ctl_info.
  *
  * @mc_num:		Memory controller number
+ * @dimm_num:		Number of DIMMs to allocate. If non-zero the
+ *			@layers' size parameter must be zero. Useful
+ *			if the MC hierarchy is unknown but the number
+ *			of DIMMs is known.
  * @n_layers:		Number of MC hierarchy layers
  * @layers:		Describes each layer as seen by the Memory Controller
  * @sz_pvt:		size of private storage needed
@@ -122,10 +126,15 @@ do {									\
  *	On success, return a pointer to struct mem_ctl_info pointer;
  *	%NULL otherwise
  */
-struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
-				   unsigned n_layers,
-				   struct edac_mc_layer *layers,
-				   unsigned sz_pvt);
+struct mem_ctl_info *__edac_mc_alloc(unsigned mc_num,
+				unsigned dimm_num,
+				unsigned n_layers,
+				struct edac_mc_layer *layers,
+				unsigned sz_pvt);
+#define edac_mc_alloc(mc_num, n_layers, layers, sz_pvt) \
+	__edac_mc_alloc(mc_num, 0, n_layers, layers, sz_pvt)
+#define edac_mc_alloc_by_dimm(mc_num, dimm_num, n_layers, layers, sz_pvt) \
+	__edac_mc_alloc(mc_num, dimm_num, n_layers, layers, sz_pvt)
 
 /**
  * edac_get_owner - Return the owner's mod_name of EDAC MC
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index b8878ff498d1..4bac643d3404 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -707,11 +707,12 @@ ghes_edac_register_one(int nid, struct ghes *ghes, struct device *parent)
 	struct edac_mc_layer layers[1];
 
 	layers[0].type = EDAC_MC_LAYER_ALL_MEM;
-	layers[0].size = mem_info.num_per_node[nid];
+	layers[0].size = 0;
 	layers[0].is_virt_csrow = true;
 
-	mci = edac_mc_alloc(nid, ARRAY_SIZE(layers), layers,
-			sizeof(struct ghes_edac_pvt));
+	mci = edac_mc_alloc_by_dimm(nid, mem_info.num_per_node[nid],
+				ARRAY_SIZE(layers), layers,
+				sizeof(struct ghes_edac_pvt));
 	if (!mci) {
 		pr_err("Can't allocate memory for EDAC data\n");
 		return -ENOMEM;
-- 
2.20.1