94 lines
2.7 KiB
C
94 lines
2.7 KiB
C
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/*
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* drivers/platform/tegra/ptp-notifier.c
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*
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* Copyright (c) 2016-2019, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/notifier.h>
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#include <linux/module.h>
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static u64 (*get_systime)(void *);
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static void *param;
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static DEFINE_RAW_SPINLOCK(ptp_notifier_lock);
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static ATOMIC_NOTIFIER_HEAD(tegra_hwtime_chain_head);
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/* Clients register for notification of hwtime change events */
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int tegra_register_hwtime_notifier(struct notifier_block *nb)
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{
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return atomic_notifier_chain_register(&tegra_hwtime_chain_head, nb);
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}
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EXPORT_SYMBOL(tegra_register_hwtime_notifier);
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/* Clients unregister for notification of hwtime change events */
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int tegra_unregister_hwtime_notifier(struct notifier_block *nb)
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{
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return atomic_notifier_chain_unregister(&tegra_hwtime_chain_head, nb);
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}
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EXPORT_SYMBOL(tegra_unregister_hwtime_notifier);
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/* Trigger notification of hwtime change to all registered clients */
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int tegra_hwtime_notifier_call_chain(unsigned int val, void *v)
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{
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int ret = atomic_notifier_call_chain(&tegra_hwtime_chain_head, val, v);
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return notifier_to_errno(ret);
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}
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void tegra_register_hwtime_source(u64 (*func)(void *), void *data)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&ptp_notifier_lock, flags);
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get_systime = func;
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param = data;
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raw_spin_unlock_irqrestore(&ptp_notifier_lock, flags);
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/* Notify HW time stamp update to registered clients.
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* NULL callback parameter. We use a separate timestamp
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* function to peek MAC time.
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*/
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tegra_hwtime_notifier_call_chain(0, NULL);
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}
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EXPORT_SYMBOL(tegra_register_hwtime_source);
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void tegra_unregister_hwtime_source(void)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&ptp_notifier_lock, flags);
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get_systime = NULL;
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param = NULL;
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raw_spin_unlock_irqrestore(&ptp_notifier_lock, flags);
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}
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EXPORT_SYMBOL(tegra_unregister_hwtime_source);
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int get_ptp_hwtime(u64 *ns)
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{
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unsigned long flags;
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int ret = 0;
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raw_spin_lock_irqsave(&ptp_notifier_lock, flags);
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if (get_systime)
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*ns = get_systime(param);
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else
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ret = -EINVAL;
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raw_spin_unlock_irqrestore(&ptp_notifier_lock, flags);
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return ret;
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}
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EXPORT_SYMBOL(get_ptp_hwtime);
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MODULE_LICENSE("GPL");
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