dmaengine: idxd: expose general capabilities register in sysfs

There are some capabilities for the device that are interesting to user
apps that are interacting directly with the device. Expose gencap register
in sysfs to allow that information.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/158256729399.55526.10842505054968710547.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/sysfs.c

@@ -1160,6 +1160,16 @@ static ssize_t op_cap_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(op_cap);
 
+static ssize_t gen_cap_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct idxd_device *idxd =
+		container_of(dev, struct idxd_device, conf_dev);
+
+	return sprintf(buf, "%#llx\n", idxd->hw.gen_cap.bits);
+}
+static DEVICE_ATTR_RO(gen_cap);
+
 static ssize_t configurable_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
@@ -1297,6 +1307,7 @@ static struct attribute *idxd_device_attributes[] = {
 	&dev_attr_max_batch_size.attr,
 	&dev_attr_max_transfer_size.attr,
 	&dev_attr_op_cap.attr,
+	&dev_attr_gen_cap.attr,
 	&dev_attr_configurable.attr,
 	&dev_attr_clients.attr,
 	&dev_attr_state.attr,