sb_edac: correctly fetch DIMM width on Ivy Bridge and Haswell

dimm_dev_type has been incorrectly determined in sb_edac. This patch fixes it
for Ivy Bridge and Haswell only since nothing like exists for Sandy Bridge.
We tested this patch in multiple systems matching the results with the
installed memory modules.
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/edac/sb_edac.c

@@ -280,6 +280,7 @@ struct sbridge_info {
 	u8		max_interleave;
 	u8		(*get_node_id)(struct sbridge_pvt *pvt);
 	enum mem_type	(*get_memory_type)(struct sbridge_pvt *pvt);
+	enum dev_type	(*get_width)(struct sbridge_pvt *pvt, u32 mtr);
 	struct pci_dev	*pci_vtd;
 };
 
@@ -768,6 +769,49 @@ static enum mem_type haswell_get_memory_type(struct sbridge_pvt *pvt)
 	return mtype;
 }
 
+static enum dev_type sbridge_get_width(struct sbridge_pvt *pvt, u32 mtr)
+{
+	/* there's no way to figure out */
+	return DEV_UNKNOWN;
+}
+
+static enum dev_type __ibridge_get_width(u32 mtr)
+{
+	enum dev_type type;
+
+	switch (mtr) {
+	case 3:
+		type = DEV_UNKNOWN;
+		break;
+	case 2:
+		type = DEV_X16;
+		break;
+	case 1:
+		type = DEV_X8;
+		break;
+	case 0:
+		type = DEV_X4;
+		break;
+	}
+
+	return type;
+}
+
+static enum dev_type ibridge_get_width(struct sbridge_pvt *pvt, u32 mtr)
+{
+	/*
+	 * ddr3_width on the documentation but also valid for DDR4 on
+	 * Haswell
+	 */
+	return __ibridge_get_width(GET_BITFIELD(mtr, 7, 8));
+}
+
+static enum dev_type broadwell_get_width(struct sbridge_pvt *pvt, u32 mtr)
+{
+	/* ddr3_width on the documentation but also valid for DDR4 */
+	return __ibridge_get_width(GET_BITFIELD(mtr, 8, 9));
+}
+
 static u8 get_node_id(struct sbridge_pvt *pvt)
 {
 	u32 reg;
@@ -972,17 +1016,7 @@ static int get_dimm_config(struct mem_ctl_info *mci)
 
 				dimm->nr_pages = npages;
 				dimm->grain = 32;
-				switch (banks) {
-				case 16:
-					dimm->dtype = DEV_X16;
-					break;
-				case 8:
-					dimm->dtype = DEV_X8;
-					break;
-				case 4:
-					dimm->dtype = DEV_X4;
-					break;
-				}
+				dimm->dtype = pvt->info.get_width(pvt, mtr);
 				dimm->mtype = mtype;
 				dimm->edac_mode = mode;
 				snprintf(dimm->label, sizeof(dimm->label),
@@ -2371,6 +2405,7 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev, enum type type)
 		pvt->info.interleave_list = ibridge_interleave_list;
 		pvt->info.max_interleave = ARRAY_SIZE(ibridge_interleave_list);
 		pvt->info.interleave_pkg = ibridge_interleave_pkg;
+		pvt->info.get_width = ibridge_get_width;
 		mci->ctl_name = kasprintf(GFP_KERNEL, "Ivy Bridge Socket#%d", mci->mc_idx);
 
 		/* Store pci devices at mci for faster access */
@@ -2390,6 +2425,7 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev, enum type type)
 		pvt->info.interleave_list = sbridge_interleave_list;
 		pvt->info.max_interleave = ARRAY_SIZE(sbridge_interleave_list);
 		pvt->info.interleave_pkg = sbridge_interleave_pkg;
+		pvt->info.get_width = sbridge_get_width;
 		mci->ctl_name = kasprintf(GFP_KERNEL, "Sandy Bridge Socket#%d", mci->mc_idx);
 
 		/* Store pci devices at mci for faster access */
@@ -2409,6 +2445,7 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev, enum type type)
 		pvt->info.interleave_list = ibridge_interleave_list;
 		pvt->info.max_interleave = ARRAY_SIZE(ibridge_interleave_list);
 		pvt->info.interleave_pkg = ibridge_interleave_pkg;
+		pvt->info.get_width = ibridge_get_width;
 		mci->ctl_name = kasprintf(GFP_KERNEL, "Haswell Socket#%d", mci->mc_idx);
 
 		/* Store pci devices at mci for faster access */
@@ -2428,6 +2465,7 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev, enum type type)
 		pvt->info.interleave_list = ibridge_interleave_list;
 		pvt->info.max_interleave = ARRAY_SIZE(ibridge_interleave_list);
 		pvt->info.interleave_pkg = ibridge_interleave_pkg;
+		pvt->info.get_width = broadwell_get_width;
 		mci->ctl_name = kasprintf(GFP_KERNEL, "Broadwell Socket#%d", mci->mc_idx);
 
 		/* Store pci devices at mci for faster access */