ptp: Added a brand new class driver for ptp clocks.

This patch adds an infrastructure for hardware clocks that implement
IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a
registration method to particular hardware clock drivers. Each clock is
presented as a standard POSIX clock.

The ancillary clock features are exposed in two different ways, via
the sysfs and by a character device.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 159 insertions, 0 deletions

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
new file mode 100644
index 000000000000..a8d03aeb4051
--- /dev/null
+++ b/drivers/ptp/ptp_chardev.c
@@ -0,0 +1,159 @@
+/*
+ * PTP 1588 clock support - character device implementation.
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ *  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/module.h>
+#include <linux/posix-clock.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+
+#include "ptp_private.h"
+
+int ptp_open(struct posix_clock *pc, fmode_t fmode)
+{
+        return 0;
+}
+
+long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
+{
+        struct ptp_clock_caps caps;
+        struct ptp_clock_request req;
+        struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+        struct ptp_clock_info *ops = ptp->info;
+        int enable, err = 0;
+
+        switch (cmd) {
+
+        case PTP_CLOCK_GETCAPS:
+                memset(&caps, 0, sizeof(caps));
+                caps.max_adj = ptp->info->max_adj;
+                caps.n_alarm = ptp->info->n_alarm;
+                caps.n_ext_ts = ptp->info->n_ext_ts;
+                caps.n_per_out = ptp->info->n_per_out;
+                caps.pps = ptp->info->pps;
+                err = copy_to_user((void __user *)arg, &caps, sizeof(caps));
+                break;
+
+        case PTP_EXTTS_REQUEST:
+                if (copy_from_user(&req.extts, (void __user *)arg,
+                                   sizeof(req.extts))) {
+                        err = -EFAULT;
+                        break;
+                }
+                if (req.extts.index >= ops->n_ext_ts) {
+                        err = -EINVAL;
+                        break;
+                }
+                req.type = PTP_CLK_REQ_EXTTS;
+                enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
+                err = ops->enable(ops, &req, enable);
+                break;
+
+        case PTP_PEROUT_REQUEST:
+                if (copy_from_user(&req.perout, (void __user *)arg,
+                                   sizeof(req.perout))) {
+                        err = -EFAULT;
+                        break;
+                }
+                if (req.perout.index >= ops->n_per_out) {
+                        err = -EINVAL;
+                        break;
+                }
+                req.type = PTP_CLK_REQ_PEROUT;
+                enable = req.perout.period.sec || req.perout.period.nsec;
+                err = ops->enable(ops, &req, enable);
+                break;
+
+        case PTP_ENABLE_PPS:
+                if (!capable(CAP_SYS_TIME))
+                        return -EPERM;
+                req.type = PTP_CLK_REQ_PPS;
+                enable = arg ? 1 : 0;
+                err = ops->enable(ops, &req, enable);
+                break;
+
+        default:
+                err = -ENOTTY;
+                break;
+        }
+        return err;
+}
+
+unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
+{
+        struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+
+        poll_wait(fp, &ptp->tsev_wq, wait);
+
+        return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
+}
+
+ssize_t ptp_read(struct posix_clock *pc,
+                 uint rdflags, char __user *buf, size_t cnt)
+{
+        struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+        struct timestamp_event_queue *queue = &ptp->tsevq;
+        struct ptp_extts_event event[PTP_BUF_TIMESTAMPS];
+        unsigned long flags;
+        size_t qcnt, i;
+
+        if (cnt % sizeof(struct ptp_extts_event) != 0)
+                return -EINVAL;
+
+        if (cnt > sizeof(event))
+                cnt = sizeof(event);
+
+        cnt = cnt / sizeof(struct ptp_extts_event);
+
+        if (mutex_lock_interruptible(&ptp->tsevq_mux))
+                return -ERESTARTSYS;
+
+        if (wait_event_interruptible(ptp->tsev_wq,
+                                     ptp->defunct || queue_cnt(queue))) {
+                mutex_unlock(&ptp->tsevq_mux);
+                return -ERESTARTSYS;
+        }
+
+        if (ptp->defunct)
+                return -ENODEV;
+
+        spin_lock_irqsave(&queue->lock, flags);
+
+        qcnt = queue_cnt(queue);
+
+        if (cnt > qcnt)
+                cnt = qcnt;
+
+        for (i = 0; i < cnt; i++) {
+                event[i] = queue->buf[queue->head];
+                queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
+        }
+
+        spin_unlock_irqrestore(&queue->lock, flags);
+
+        cnt = cnt * sizeof(struct ptp_extts_event);
+
+        mutex_unlock(&ptp->tsevq_mux);
+
+        if (copy_to_user(buf, event, cnt)) {
+                mutex_unlock(&ptp->tsevq_mux);
+                return -EFAULT;
+        }
+
+        return cnt;
+}