EDAC/amd64: Set maximum channel layer size depending on family

The AMD64 EDAC module currently hardcodes the EDAC channel layer size
count to two. Future AMD systems may have more channels than this.

Set the EDAC channel layer size equal to the maximum number of channels
possible for the system. On Family 17h and later, this is set in the
num_umcs variable. Older systems will continue to use two as the
default.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190325203319.7603-1-Yazen.Ghannam@amd.com

drivers/edac/amd64_edac.c

@@ -3326,8 +3326,14 @@ static int init_one_instance(unsigned int nid)
 	 * Always allocate two channels since we can have setups with DIMMs on
 	 * only one channel. Also, this simplifies handling later for the price
 	 * of a couple of KBs tops.
+	 *
+	 * On Fam17h+, the number of controllers may be greater than two. So set
+	 * the size equal to the maximum number of UMCs.
 	 */
-	layers[1].size = 2;
+	if (pvt->fam >= 0x17)
+		layers[1].size = num_umcs;
+	else
+		layers[1].size = 2;
 	layers[1].is_virt_csrow = false;
 
 	mci = edac_mc_alloc(nid, ARRAY_SIZE(layers), layers, 0);