1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/net/phy/mii_timestamper.c b/drivers/net/phy/mii_timestamper.c
new file mode 100644
index 000000000..51ae0593a
--- /dev/null
+++ b/drivers/net/phy/mii_timestamper.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Support for generic time stamping devices on MII buses.
+// Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
+//
+
+#include <linux/mii_timestamper.h>
+
+static LIST_HEAD(mii_timestamping_devices);
+static DEFINE_MUTEX(tstamping_devices_lock);
+
+struct mii_timestamping_desc {
+	struct list_head list;
+	struct mii_timestamping_ctrl *ctrl;
+	struct device *device;
+};
+
+/**
+ * register_mii_tstamp_controller() - registers an MII time stamping device.
+ *
+ * @device:	The device to be registered.
+ * @ctrl:	Pointer to device's control interface.
+ *
+ * Returns zero on success or non-zero on failure.
+ */
+int register_mii_tstamp_controller(struct device *device,
+				   struct mii_timestamping_ctrl *ctrl)
+{
+	struct mii_timestamping_desc *desc;
+
+	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&desc->list);
+	desc->ctrl = ctrl;
+	desc->device = device;
+
+	mutex_lock(&tstamping_devices_lock);
+	list_add_tail(&mii_timestamping_devices, &desc->list);
+	mutex_unlock(&tstamping_devices_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(register_mii_tstamp_controller);
+
+/**
+ * unregister_mii_tstamp_controller() - unregisters an MII time stamping device.
+ *
+ * @device:	A device previously passed to register_mii_tstamp_controller().
+ */
+void unregister_mii_tstamp_controller(struct device *device)
+{
+	struct mii_timestamping_desc *desc;
+	struct list_head *this, *next;
+
+	mutex_lock(&tstamping_devices_lock);
+	list_for_each_safe(this, next, &mii_timestamping_devices) {
+		desc = list_entry(this, struct mii_timestamping_desc, list);
+		if (desc->device == device) {
+			list_del_init(&desc->list);
+			kfree(desc);
+			break;
+		}
+	}
+	mutex_unlock(&tstamping_devices_lock);
+}
+EXPORT_SYMBOL(unregister_mii_tstamp_controller);
+
+/**
+ * register_mii_timestamper - Enables a given port of an MII time stamper.
+ *
+ * @node:	The device tree node of the MII time stamp controller.
+ * @port:	The index of the port to be enabled.
+ *
+ * Returns a valid interface on success or ERR_PTR otherwise.
+ */
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+						 unsigned int port)
+{
+	struct mii_timestamper *mii_ts = NULL;
+	struct mii_timestamping_desc *desc;
+	struct list_head *this;
+
+	mutex_lock(&tstamping_devices_lock);
+	list_for_each(this, &mii_timestamping_devices) {
+		desc = list_entry(this, struct mii_timestamping_desc, list);
+		if (desc->device->of_node == node) {
+			mii_ts = desc->ctrl->probe_channel(desc->device, port);
+			if (!IS_ERR(mii_ts)) {
+				mii_ts->device = desc->device;
+				get_device(desc->device);
+			}
+			break;
+		}
+	}
+	mutex_unlock(&tstamping_devices_lock);
+
+	return mii_ts ? mii_ts : ERR_PTR(-EPROBE_DEFER);
+}
+EXPORT_SYMBOL(register_mii_timestamper);
+
+/**
+ * unregister_mii_timestamper - Disables a given MII time stamper.
+ *
+ * @mii_ts:	An interface obtained via register_mii_timestamper().
+ *
+ */
+void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
+{
+	struct mii_timestamping_desc *desc;
+	struct list_head *this;
+
+	if (!mii_ts)
+		return;
+
+	/* mii_timestamper statically registered by the PHY driver won't use the
+	 * register_mii_timestamper() and thus don't have ->device set. Don't
+	 * try to unregister these.
+	 */
+	if (!mii_ts->device)
+		return;
+
+	mutex_lock(&tstamping_devices_lock);
+	list_for_each(this, &mii_timestamping_devices) {
+		desc = list_entry(this, struct mii_timestamping_desc, list);
+		if (desc->device == mii_ts->device) {
+			desc->ctrl->release_channel(desc->device, mii_ts);
+			put_device(desc->device);
+			break;
+		}
+	}
+	mutex_unlock(&tstamping_devices_lock);
+}
+EXPORT_SYMBOL(unregister_mii_timestamper);