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