edac: add a sysfs node to report the maximum location for the system

The userspace tools need to know what's the maximum location on each
system, as it helps to create nice maps showing how the memory was
filled at the system.

Reviewed-by: Aristeu Rozanski <arozansk@redhat.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/edac/edac_mc_sysfs.c

@@ -766,6 +766,23 @@ static ssize_t mci_size_mb_show(struct device *dev,
 	return sprintf(data, "%u\n", PAGES_TO_MiB(total_pages));
 }
 
+static ssize_t mci_max_location_show(struct device *dev,
+				     struct device_attribute *mattr,
+				     char *data)
+{
+	struct mem_ctl_info *mci = to_mci(dev);
+	int i;
+	char *p = data;
+
+	for (i = 0; i < mci->n_layers; i++) {
+		p += sprintf(p, "%s %d ",
+			     edac_layer_name[mci->layers[i].type],
+			     mci->layers[i].size - 1);
+	}
+
+	return p - data;
+}
+
 /* default Control file */
 DEVICE_ATTR(reset_counters, S_IWUSR, NULL, mci_reset_counters_store);
 
@@ -777,6 +794,7 @@ DEVICE_ATTR(ue_noinfo_count, S_IRUGO, mci_ue_noinfo_show, NULL);
 DEVICE_ATTR(ce_noinfo_count, S_IRUGO, mci_ce_noinfo_show, NULL);
 DEVICE_ATTR(ue_count, S_IRUGO, mci_ue_count_show, NULL);
 DEVICE_ATTR(ce_count, S_IRUGO, mci_ce_count_show, NULL);
+DEVICE_ATTR(max_location, S_IRUGO, mci_max_location_show, NULL);
 
 /* memory scrubber attribute file */
 DEVICE_ATTR(sdram_scrub_rate, S_IRUGO | S_IWUSR, mci_sdram_scrub_rate_show,
@@ -792,6 +810,7 @@ static struct attribute *mci_attrs[] = {
 	&dev_attr_ue_count.attr,
 	&dev_attr_ce_count.attr,
 	&dev_attr_sdram_scrub_rate.attr,
+	&dev_attr_max_location.attr,
 	NULL
 };