1 files changed, 329 insertions, 0 deletions

diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
new file mode 100644
index 000000000000..35a0b192d768
--- /dev/null
+++ b/drivers/pps/kapi.c
@@ -0,0 +1,329 @@
+/*
+ * kernel API
+ *
+ *
+ * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/fs.h>
+#include <linux/pps_kernel.h>
+
+/*
+ * Global variables
+ */
+
+DEFINE_SPINLOCK(pps_idr_lock);
+DEFINE_IDR(pps_idr);
+
+/*
+ * Local functions
+ */
+
+static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
+{
+        ts->nsec += offset->nsec;
+        while (ts->nsec >= NSEC_PER_SEC) {
+                ts->nsec -= NSEC_PER_SEC;
+                ts->sec++;
+        }
+        while (ts->nsec < 0) {
+                ts->nsec += NSEC_PER_SEC;
+                ts->sec--;
+        }
+        ts->sec += offset->sec;
+}
+
+/*
+ * Exported functions
+ */
+
+/* pps_get_source - find a PPS source
+ * @source: the PPS source ID.
+ *
+ * This function is used to find an already registered PPS source into the
+ * system.
+ *
+ * The function returns NULL if found nothing, otherwise it returns a pointer
+ * to the PPS source data struct (the refcounter is incremented by 1).
+ */
+
+struct pps_device *pps_get_source(int source)
+{
+        struct pps_device *pps;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pps_idr_lock, flags);
+
+        pps = idr_find(&pps_idr, source);
+        if (pps != NULL)
+                atomic_inc(&pps->usage);
+
+        spin_unlock_irqrestore(&pps_idr_lock, flags);
+
+        return pps;
+}
+
+/* pps_put_source - free the PPS source data
+ * @pps: a pointer to the PPS source.
+ *
+ * This function is used to free a PPS data struct if its refcount is 0.
+ */
+
+void pps_put_source(struct pps_device *pps)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&pps_idr_lock, flags);
+        BUG_ON(atomic_read(&pps->usage) == 0);
+
+        if (!atomic_dec_and_test(&pps->usage)) {
+                pps = NULL;
+                goto exit;
+        }
+
+        /* No more reference to the PPS source. We can safely remove the
+         * PPS data struct.
+         */
+        idr_remove(&pps_idr, pps->id);
+
+exit:
+        spin_unlock_irqrestore(&pps_idr_lock, flags);
+        kfree(pps);
+}
+
+/* pps_register_source - add a PPS source in the system
+ * @info: the PPS info struct
+ * @default_params: the default PPS parameters of the new source
+ *
+ * This function is used to add a new PPS source in the system. The new
+ * source is described by info's fields and it will have, as default PPS
+ * parameters, the ones specified into default_params.
+ *
+ * The function returns, in case of success, the PPS source ID.
+ */
+
+int pps_register_source(struct pps_source_info *info, int default_params)
+{
+        struct pps_device *pps;
+        int id;
+        int err;
+
+        /* Sanity checks */
+        if ((info->mode & default_params) != default_params) {
+                printk(KERN_ERR "pps: %s: unsupported default parameters\n",
+                                        info->name);
+                err = -EINVAL;
+                goto pps_register_source_exit;
+        }
+        if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 &&
+                        info->echo == NULL) {
+                printk(KERN_ERR "pps: %s: echo function is not defined\n",
+                                        info->name);
+                err = -EINVAL;
+                goto pps_register_source_exit;
+        }
+        if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
+                printk(KERN_ERR "pps: %s: unspecified time format\n",
+                                        info->name);
+                err = -EINVAL;
+                goto pps_register_source_exit;
+        }
+
+        /* Allocate memory for the new PPS source struct */
+        pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
+        if (pps == NULL) {
+                err = -ENOMEM;
+                goto pps_register_source_exit;
+        }
+
+        /* These initializations must be done before calling idr_get_new()
+         * in order to avoid reces into pps_event().
+         */
+        pps->params.api_version = PPS_API_VERS;
+        pps->params.mode = default_params;
+        pps->info = *info;
+
+        init_waitqueue_head(&pps->queue);
+        spin_lock_init(&pps->lock);
+        atomic_set(&pps->usage, 1);
+
+        /* Get new ID for the new PPS source */
+        if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
+                err = -ENOMEM;
+                goto kfree_pps;
+        }
+
+        spin_lock_irq(&pps_idr_lock);
+
+        /* Now really allocate the PPS source.
+         * After idr_get_new() calling the new source will be freely available
+         * into the kernel.
+         */
+        err = idr_get_new(&pps_idr, pps, &id);
+        if (err < 0) {
+                spin_unlock_irq(&pps_idr_lock);
+                goto kfree_pps;
+        }
+
+        id = id & MAX_ID_MASK;
+        if (id >= PPS_MAX_SOURCES) {
+                spin_unlock_irq(&pps_idr_lock);
+
+                printk(KERN_ERR "pps: %s: too many PPS sources in the system\n",
+                                        info->name);
+                err = -EBUSY;
+                goto free_idr;
+        }
+        pps->id = id;
+
+        spin_unlock_irq(&pps_idr_lock);
+
+        /* Create the char device */
+        err = pps_register_cdev(pps);
+        if (err < 0) {
+                printk(KERN_ERR "pps: %s: unable to create char device\n",
+                                        info->name);
+                goto free_idr;
+        }
+
+        pr_info("new PPS source %s at ID %d\n", info->name, id);
+
+        return id;
+
+free_idr:
+        spin_lock_irq(&pps_idr_lock);
+        idr_remove(&pps_idr, id);
+        spin_unlock_irq(&pps_idr_lock);
+
+kfree_pps:
+        kfree(pps);
+
+pps_register_source_exit:
+        printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
+
+        return err;
+}
+EXPORT_SYMBOL(pps_register_source);
+
+/* pps_unregister_source - remove a PPS source from the system
+ * @source: the PPS source ID
+ *
+ * This function is used to remove a previously registered PPS source from
+ * the system.
+ */
+
+void pps_unregister_source(int source)
+{
+        struct pps_device *pps;
+
+        spin_lock_irq(&pps_idr_lock);
+        pps = idr_find(&pps_idr, source);
+
+        if (!pps) {
+                BUG();
+                spin_unlock_irq(&pps_idr_lock);
+                return;
+        }
+        spin_unlock_irq(&pps_idr_lock);
+
+        pps_unregister_cdev(pps);
+        pps_put_source(pps);
+}
+EXPORT_SYMBOL(pps_unregister_source);
+
+/* pps_event - register a PPS event into the system
+ * @source: the PPS source ID
+ * @ts: the event timestamp
+ * @event: the event type
+ * @data: userdef pointer
+ *
+ * This function is used by each PPS client in order to register a new
+ * PPS event into the system (it's usually called inside an IRQ handler).
+ *
+ * If an echo function is associated with the PPS source it will be called
+ * as:
+ *      pps->info.echo(source, event, data);
+ */
+
+void pps_event(int source, struct pps_ktime *ts, int event, void *data)
+{
+        struct pps_device *pps;
+        unsigned long flags;
+
+        if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
+                printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
+                        event, source);
+                return;
+        }
+
+        pps = pps_get_source(source);
+        if (!pps)
+                return;
+
+        pr_debug("PPS event on source %d at %llu.%06u\n",
+                        pps->id, (unsigned long long) ts->sec, ts->nsec);
+
+        spin_lock_irqsave(&pps->lock, flags);
+
+        /* Must call the echo function? */
+        if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
+                pps->info.echo(source, event, data);
+
+        /* Check the event */
+        pps->current_mode = pps->params.mode;
+        if (event & PPS_CAPTUREASSERT) {
+                /* We have to add an offset? */
+                if (pps->params.mode & PPS_OFFSETASSERT)
+                        pps_add_offset(ts, &pps->params.assert_off_tu);
+
+                /* Save the time stamp */
+                pps->assert_tu = *ts;
+                pps->assert_sequence++;
+                pr_debug("capture assert seq #%u for source %d\n",
+                        pps->assert_sequence, source);
+        }
+        if (event & PPS_CAPTURECLEAR) {
+                /* We have to add an offset? */
+                if (pps->params.mode & PPS_OFFSETCLEAR)
+                        pps_add_offset(ts, &pps->params.clear_off_tu);
+
+                /* Save the time stamp */
+                pps->clear_tu = *ts;
+                pps->clear_sequence++;
+                pr_debug("capture clear seq #%u for source %d\n",
+                        pps->clear_sequence, source);
+        }
+
+        pps->go = ~0;
+        wake_up_interruptible(&pps->queue);
+
+        kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+
+        spin_unlock_irqrestore(&pps->lock, flags);
+
+        /* Now we can release the PPS source for (possible) deregistration */
+        pps_put_source(pps);
+}
+EXPORT_SYMBOL(pps_event);