717c033669
Add an optional feature of PPSAPI, kernel consumer support, which uses the added hardpps() function. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
122 lines
3.8 KiB
C
122 lines
3.8 KiB
C
/*
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* PPS kernel consumer API
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*
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* Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for 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, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/pps_kernel.h>
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#include "kc.h"
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/*
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* Global variables
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*/
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/* state variables to bind kernel consumer */
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DEFINE_SPINLOCK(pps_kc_hardpps_lock);
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/* PPS API (RFC 2783): current source and mode for kernel consumer */
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struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */
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int pps_kc_hardpps_mode; /* mode bits for kernel consumer */
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/* pps_kc_bind - control PPS kernel consumer binding
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* @pps: the PPS source
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* @bind_args: kernel consumer bind parameters
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*
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* This function is used to bind or unbind PPS kernel consumer according to
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* supplied parameters. Should not be called in interrupt context.
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*/
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int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args)
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{
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/* Check if another consumer is already bound */
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spin_lock_irq(&pps_kc_hardpps_lock);
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if (bind_args->edge == 0)
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if (pps_kc_hardpps_dev == pps) {
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pps_kc_hardpps_mode = 0;
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pps_kc_hardpps_dev = NULL;
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spin_unlock_irq(&pps_kc_hardpps_lock);
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dev_info(pps->dev, "unbound kernel"
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" consumer\n");
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} else {
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spin_unlock_irq(&pps_kc_hardpps_lock);
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dev_err(pps->dev, "selected kernel consumer"
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" is not bound\n");
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return -EINVAL;
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}
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else
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if (pps_kc_hardpps_dev == NULL ||
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pps_kc_hardpps_dev == pps) {
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pps_kc_hardpps_mode = bind_args->edge;
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pps_kc_hardpps_dev = pps;
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spin_unlock_irq(&pps_kc_hardpps_lock);
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dev_info(pps->dev, "bound kernel consumer: "
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"edge=0x%x\n", bind_args->edge);
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} else {
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spin_unlock_irq(&pps_kc_hardpps_lock);
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dev_err(pps->dev, "another kernel consumer"
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" is already bound\n");
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return -EINVAL;
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}
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return 0;
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}
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/* pps_kc_remove - unbind kernel consumer on PPS source removal
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* @pps: the PPS source
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*
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* This function is used to disable kernel consumer on PPS source removal
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* if this source was bound to PPS kernel consumer. Can be called on any
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* source safely. Should not be called in interrupt context.
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*/
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void pps_kc_remove(struct pps_device *pps)
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{
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spin_lock_irq(&pps_kc_hardpps_lock);
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if (pps == pps_kc_hardpps_dev) {
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pps_kc_hardpps_mode = 0;
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pps_kc_hardpps_dev = NULL;
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spin_unlock_irq(&pps_kc_hardpps_lock);
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dev_info(pps->dev, "unbound kernel consumer"
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" on device removal\n");
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} else
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spin_unlock_irq(&pps_kc_hardpps_lock);
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}
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/* pps_kc_event - call hardpps() on PPS event
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* @pps: the PPS source
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* @ts: PPS event timestamp
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* @event: PPS event edge
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*
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* This function calls hardpps() when an event from bound PPS source occurs.
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*/
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void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts,
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int event)
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{
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unsigned long flags;
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/* Pass some events to kernel consumer if activated */
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spin_lock_irqsave(&pps_kc_hardpps_lock, flags);
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if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
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hardpps(&ts->ts_real, &ts->ts_raw);
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spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags);
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}
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