cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mii_timestamper.c (3638B)

      1// SPDX-License-Identifier: GPL-2.0
      2//
      3// Support for generic time stamping devices on MII buses.
      4// Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
      5//
      6
      7#include <linux/mii_timestamper.h>
      8
      9static LIST_HEAD(mii_timestamping_devices);
     10static DEFINE_MUTEX(tstamping_devices_lock);
     11
     12struct mii_timestamping_desc {
     13	struct list_head list;
     14	struct mii_timestamping_ctrl *ctrl;
     15	struct device *device;
     16};
     17
     18/**
     19 * register_mii_tstamp_controller() - registers an MII time stamping device.
     20 *
     21 * @device:	The device to be registered.
     22 * @ctrl:	Pointer to device's control interface.
     23 *
     24 * Returns zero on success or non-zero on failure.
     25 */
     26int register_mii_tstamp_controller(struct device *device,
     27				   struct mii_timestamping_ctrl *ctrl)
     28{
     29	struct mii_timestamping_desc *desc;
     30
     31	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
     32	if (!desc)
     33		return -ENOMEM;
     34
     35	INIT_LIST_HEAD(&desc->list);
     36	desc->ctrl = ctrl;
     37	desc->device = device;
     38
     39	mutex_lock(&tstamping_devices_lock);
     40	list_add_tail(&mii_timestamping_devices, &desc->list);
     41	mutex_unlock(&tstamping_devices_lock);
     42
     43	return 0;
     44}
     45EXPORT_SYMBOL(register_mii_tstamp_controller);
     46
     47/**
     48 * unregister_mii_tstamp_controller() - unregisters an MII time stamping device.
     49 *
     50 * @device:	A device previously passed to register_mii_tstamp_controller().
     51 */
     52void unregister_mii_tstamp_controller(struct device *device)
     53{
     54	struct mii_timestamping_desc *desc;
     55	struct list_head *this, *next;
     56
     57	mutex_lock(&tstamping_devices_lock);
     58	list_for_each_safe(this, next, &mii_timestamping_devices) {
     59		desc = list_entry(this, struct mii_timestamping_desc, list);
     60		if (desc->device == device) {
     61			list_del_init(&desc->list);
     62			kfree(desc);
     63			break;
     64		}
     65	}
     66	mutex_unlock(&tstamping_devices_lock);
     67}
     68EXPORT_SYMBOL(unregister_mii_tstamp_controller);
     69
     70/**
     71 * register_mii_timestamper - Enables a given port of an MII time stamper.
     72 *
     73 * @node:	The device tree node of the MII time stamp controller.
     74 * @port:	The index of the port to be enabled.
     75 *
     76 * Returns a valid interface on success or ERR_PTR otherwise.
     77 */
     78struct mii_timestamper *register_mii_timestamper(struct device_node *node,
     79						 unsigned int port)
     80{
     81	struct mii_timestamper *mii_ts = NULL;
     82	struct mii_timestamping_desc *desc;
     83	struct list_head *this;
     84
     85	mutex_lock(&tstamping_devices_lock);
     86	list_for_each(this, &mii_timestamping_devices) {
     87		desc = list_entry(this, struct mii_timestamping_desc, list);
     88		if (desc->device->of_node == node) {
     89			mii_ts = desc->ctrl->probe_channel(desc->device, port);
     90			if (!IS_ERR(mii_ts)) {
     91				mii_ts->device = desc->device;
     92				get_device(desc->device);
     93			}
     94			break;
     95		}
     96	}
     97	mutex_unlock(&tstamping_devices_lock);
     98
     99	return mii_ts ? mii_ts : ERR_PTR(-EPROBE_DEFER);
    100}
    101EXPORT_SYMBOL(register_mii_timestamper);
    102
    103/**
    104 * unregister_mii_timestamper - Disables a given MII time stamper.
    105 *
    106 * @mii_ts:	An interface obtained via register_mii_timestamper().
    107 *
    108 */
    109void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
    110{
    111	struct mii_timestamping_desc *desc;
    112	struct list_head *this;
    113
    114	if (!mii_ts)
    115		return;
    116
    117	/* mii_timestamper statically registered by the PHY driver won't use the
    118	 * register_mii_timestamper() and thus don't have ->device set. Don't
    119	 * try to unregister these.
    120	 */
    121	if (!mii_ts->device)
    122		return;
    123
    124	mutex_lock(&tstamping_devices_lock);
    125	list_for_each(this, &mii_timestamping_devices) {
    126		desc = list_entry(this, struct mii_timestamping_desc, list);
    127		if (desc->device == mii_ts->device) {
    128			desc->ctrl->release_channel(desc->device, mii_ts);
    129			put_device(desc->device);
    130			break;
    131		}
    132	}
    133	mutex_unlock(&tstamping_devices_lock);
    134}
    135EXPORT_SYMBOL(unregister_mii_timestamper);