mISDN: Add ISDN sample clock API to mISDN core

Add ISDN sample clock API to mISDN core (new file clock.c)
hfcmulti and mISDNdsp use clock API.

Signed-off-by: Andreas Eversberg <andreas@eversberg.eu>
Signed-off-by: Karsten Keil <kkeil@suse.de>

5 files changed, 236 insertions, 25 deletions

diff --git a/drivers/isdn/mISDN/Makefile b/drivers/isdn/mISDN/Makefile
index 1cb5e633cf75..0a6bd2a9e730 100644
--- a/drivers/isdn/mISDN/Makefile
+++ b/drivers/isdn/mISDN/Makefile
@@ -8,6 +8,6 @@ obj-$(CONFIG_MISDN_L1OIP) += l1oip.o
 
 # multi objects
 
-mISDN_core-objs := core.o fsm.o socket.o hwchannel.o stack.o layer1.o layer2.o tei.o timerdev.o
+mISDN_core-objs := core.o fsm.o socket.o clock.o hwchannel.o stack.o layer1.o layer2.o tei.o timerdev.o
 mISDN_dsp-objs := dsp_core.o dsp_cmx.o dsp_tones.o dsp_dtmf.o dsp_audio.o dsp_blowfish.o dsp_pipeline.o dsp_hwec.o
 l1oip-objs := l1oip_core.o l1oip_codec.o
diff --git a/drivers/isdn/mISDN/clock.c b/drivers/isdn/mISDN/clock.c
new file mode 100644
index 000000000000..44d9c3d5d33d
--- /dev/null
+++ b/drivers/isdn/mISDN/clock.c
@@ -0,0 +1,216 @@
+/*
+ * Copyright 2008  by Andreas Eversberg <andreas@eversberg.eu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * Quick API description:
+ *
+ * A clock source registers using mISDN_register_clock:
+ *      name = text string to name clock source
+ *      priority = value to priorize clock sources (0 = default)
+ *      ctl = callback function to enable/disable clock source
+ *      priv = private pointer of clock source
+ *      return = pointer to clock source structure;
+ *
+ * Note: Callback 'ctl' can be called before mISDN_register_clock returns!
+ *       Also it can be called during mISDN_unregister_clock.
+ *
+ * A clock source calls mISDN_clock_update with given samples elapsed, if
+ * enabled. If function call is delayed, tv must be set with the timestamp
+ * of the actual event.
+ *
+ * A clock source unregisters using mISDN_unregister_clock.
+ *
+ * To get current clock, call mISDN_clock_get. The signed short value
+ * counts the number of samples since. Time since last clock event is added.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/spinlock.h>
+#include <linux/mISDNif.h>
+#include "core.h"
+
+static u_int *debug;
+static LIST_HEAD(iclock_list);
+DEFINE_RWLOCK(iclock_lock);
+u16     iclock_count;           /* counter of last clock */
+struct  timeval iclock_tv;      /* time stamp of last clock */
+int     iclock_tv_valid;        /* already received one timestamp */
+struct  mISDNclock *iclock_current;
+
+void
+mISDN_init_clock(u_int *dp)
+{
+        debug = dp;
+        do_gettimeofday(&iclock_tv);
+}
+
+static void
+select_iclock(void)
+{
+        struct mISDNclock *iclock, *bestclock = NULL, *lastclock = NULL;
+        int pri = -128;
+
+        list_for_each_entry(iclock, &iclock_list, list) {
+                if (iclock->pri > pri) {
+                        pri = iclock->pri;
+                        bestclock = iclock;
+                }
+                if (iclock_current == iclock)
+                        lastclock = iclock;
+        }
+        if (lastclock && bestclock != lastclock) {
+                /* last used clock source still exists but changes, disable */
+                if (*debug & DEBUG_CLOCK)
+                        printk(KERN_DEBUG "Old clock source '%s' disable.\n",
+                                lastclock->name);
+                lastclock->ctl(lastclock->priv, 0);
+        }
+        if (bestclock && bestclock != iclock_current) {
+                /* new clock source selected, enable */
+                if (*debug & DEBUG_CLOCK)
+                        printk(KERN_DEBUG "New clock source '%s' enable.\n",
+                                bestclock->name);
+                bestclock->ctl(bestclock->priv, 1);
+        }
+        if (bestclock != iclock_current) {
+                /* no clock received yet */
+                iclock_tv_valid = 0;
+        }
+        iclock_current = bestclock;
+}
+
+struct mISDNclock
+*mISDN_register_clock(char *name, int pri, clockctl_func_t *ctl, void *priv)
+{
+        u_long                  flags;
+        struct mISDNclock       *iclock;
+
+        if (*debug & (DEBUG_CORE | DEBUG_CLOCK))
+                printk(KERN_DEBUG "%s: %s %d\n", __func__, name, pri);
+        iclock = kzalloc(sizeof(struct mISDNclock), GFP_ATOMIC);
+        if (!iclock) {
+                printk(KERN_ERR "%s: No memory for clock entry.\n", __func__);
+                return NULL;
+        }
+        strncpy(iclock->name, name, sizeof(iclock->name)-1);
+        iclock->pri = pri;
+        iclock->priv = priv;
+        iclock->ctl = ctl;
+        write_lock_irqsave(&iclock_lock, flags);
+        list_add_tail(&iclock->list, &iclock_list);
+        select_iclock();
+        write_unlock_irqrestore(&iclock_lock, flags);
+        return iclock;
+}
+EXPORT_SYMBOL(mISDN_register_clock);
+
+void
+mISDN_unregister_clock(struct mISDNclock *iclock)
+{
+        u_long  flags;
+
+        if (*debug & (DEBUG_CORE | DEBUG_CLOCK))
+                printk(KERN_DEBUG "%s: %s %d\n", __func__, iclock->name,
+                        iclock->pri);
+        write_lock_irqsave(&iclock_lock, flags);
+        if (iclock_current == iclock) {
+                if (*debug & DEBUG_CLOCK)
+                        printk(KERN_DEBUG
+                                "Current clock source '%s' unregisters.\n",
+                                iclock->name);
+                iclock->ctl(iclock->priv, 0);
+        }
+        list_del(&iclock->list);
+        select_iclock();
+        write_unlock_irqrestore(&iclock_lock, flags);
+}
+EXPORT_SYMBOL(mISDN_unregister_clock);
+
+void
+mISDN_clock_update(struct mISDNclock *iclock, int samples, struct timeval *tv)
+{
+        u_long          flags;
+        struct timeval  tv_now;
+        time_t          elapsed_sec;
+        int             elapsed_8000th;
+
+        write_lock_irqsave(&iclock_lock, flags);
+        if (iclock_current != iclock) {
+                printk(KERN_ERR "%s: '%s' sends us clock updates, but we do "
+                        "listen to '%s'. This is a bug!\n", __func__,
+                        iclock->name,
+                        iclock_current ? iclock_current->name : "nothing");
+                iclock->ctl(iclock->priv, 0);
+                write_unlock_irqrestore(&iclock_lock, flags);
+                return;
+        }
+        if (iclock_tv_valid) {
+                /* increment sample counter by given samples */
+                iclock_count += samples;
+                if (tv) { /* tv must be set, if function call is delayed */
+                        iclock_tv.tv_sec = tv->tv_sec;
+                        iclock_tv.tv_usec = tv->tv_usec;
+                } else
+                        do_gettimeofday(&iclock_tv);
+        } else {
+                /* calc elapsed time by system clock */
+                if (tv) { /* tv must be set, if function call is delayed */
+                        tv_now.tv_sec = tv->tv_sec;
+                        tv_now.tv_usec = tv->tv_usec;
+                } else
+                        do_gettimeofday(&tv_now);
+                elapsed_sec = tv_now.tv_sec - iclock_tv.tv_sec;
+                elapsed_8000th = (tv_now.tv_usec / 125)
+                        - (iclock_tv.tv_usec / 125);
+                if (elapsed_8000th < 0) {
+                        elapsed_sec -= 1;
+                        elapsed_8000th += 8000;
+                }
+                /* add elapsed time to counter and set new timestamp */
+                iclock_count += elapsed_sec * 8000 + elapsed_8000th;
+                iclock_tv.tv_sec = tv_now.tv_sec;
+                iclock_tv.tv_usec = tv_now.tv_usec;
+                iclock_tv_valid = 1;
+                if (*debug & DEBUG_CLOCK)
+                        printk("Received first clock from source '%s'.\n",
+                            iclock_current ? iclock_current->name : "nothing");
+        }
+        write_unlock_irqrestore(&iclock_lock, flags);
+}
+EXPORT_SYMBOL(mISDN_clock_update);
+
+unsigned short
+mISDN_clock_get(void)
+{
+        u_long          flags;
+        struct timeval  tv_now;
+        time_t          elapsed_sec;
+        int             elapsed_8000th;
+        u16             count;
+
+        read_lock_irqsave(&iclock_lock, flags);
+        /* calc elapsed time by system clock */
+        do_gettimeofday(&tv_now);
+        elapsed_sec = tv_now.tv_sec - iclock_tv.tv_sec;
+        elapsed_8000th = (tv_now.tv_usec / 125) - (iclock_tv.tv_usec / 125);
+        if (elapsed_8000th < 0) {
+                elapsed_sec -= 1;
+                elapsed_8000th += 8000;
+        }
+        /* add elapsed time to counter */
+        count = iclock_count + elapsed_sec * 8000 + elapsed_8000th;
+        read_unlock_irqrestore(&iclock_lock, flags);
+        return count;
+}
+EXPORT_SYMBOL(mISDN_clock_get);
+
diff --git a/drivers/isdn/mISDN/core.c b/drivers/isdn/mISDN/core.c
index 43fd97b0fe42..9116f54def2c 100644
--- a/drivers/isdn/mISDN/core.c
+++ b/drivers/isdn/mISDN/core.c
@@ -199,6 +199,7 @@ mISDNInit(void)
 
         printk(KERN_INFO "Modular ISDN core version %d.%d.%d\n",
                 MISDN_MAJOR_VERSION, MISDN_MINOR_VERSION, MISDN_RELEASE);
+        mISDN_init_clock(&debug);
         mISDN_initstack(&debug);
         err = mISDN_inittimer(&debug);
         if (err)
diff --git a/drivers/isdn/mISDN/core.h b/drivers/isdn/mISDN/core.h
index 7da7233b4c1a..7ac2f81a812b 100644
--- a/drivers/isdn/mISDN/core.h
+++ b/drivers/isdn/mISDN/core.h
@@ -74,4 +74,6 @@ extern void	l1_cleanup(void);
 extern int      Isdnl2_Init(u_int *);
 extern void     Isdnl2_cleanup(void);
 
+extern void     mISDN_init_clock(u_int *);
+
 #endif
diff --git a/drivers/isdn/mISDN/dsp_cmx.c b/drivers/isdn/mISDN/dsp_cmx.c
index 04dbb407f7a0..efe4c7430e6d 100644
--- a/drivers/isdn/mISDN/dsp_cmx.c
+++ b/drivers/isdn/mISDN/dsp_cmx.c
@@ -1557,13 +1557,11 @@ send_packet:
         schedule_work(&dsp->workq);
 }
 
-static u32      samplecount;
+static u32      jittercount; /* counter for jitter check */;
 struct timer_list dsp_spl_tl;
 u32     dsp_spl_jiffies; /* calculate the next time to fire */
-#ifdef UNUSED
-static u32      dsp_start_jiffies; /* jiffies at the time, the calculation begins */
-#endif /* UNUSED */
-static struct timeval dsp_start_tv; /* time at start of calculation */
+static u16      dsp_count; /* last sample count */
+static int      dsp_count_valid ; /* if we have last sample count */
 
 void
 dsp_cmx_send(void *arg)
@@ -1577,38 +1575,32 @@ dsp_cmx_send(void *arg)
         int r, rr;
         int jittercheck = 0, delay, i;
         u_long flags;
-        struct timeval tv;
-        u32 elapsed;
-        s16 length;
+        u16 length, count;
 
         /* lock */
         spin_lock_irqsave(&dsp_lock, flags);
 
-        if (!dsp_start_tv.tv_sec) {
-                do_gettimeofday(&dsp_start_tv);
+        if (!dsp_count_valid) {
+                dsp_count = mISDN_clock_get();
                 length = dsp_poll;
+                dsp_count_valid = 1;
         } else {
-                do_gettimeofday(&tv);
-                elapsed = ((tv.tv_sec - dsp_start_tv.tv_sec) * 8000)
-                    + ((s32)(tv.tv_usec / 125) - (dsp_start_tv.tv_usec / 125));
-                dsp_start_tv.tv_sec = tv.tv_sec;
-                dsp_start_tv.tv_usec = tv.tv_usec;
-                length = elapsed;
+                count = mISDN_clock_get();
+                length = count - dsp_count;
+                dsp_count = count;
         }
         if (length > MAX_POLL + 100)
                 length = MAX_POLL + 100;
-/* printk(KERN_DEBUG "len=%d dsp_count=0x%x.%04x dsp_poll_diff=0x%x.%04x\n",
- length, dsp_count >> 16, dsp_count & 0xffff, dsp_poll_diff >> 16,
- dsp_poll_diff & 0xffff);
- */
+        /* printk(KERN_DEBUG "len=%d dsp_count=0x%x\n", length, dsp_count); */
 
         /*
-         * check if jitter needs to be checked
-         * (this is about every second = 8192 samples)
+         * check if jitter needs to be checked (this is every second)
          */
-        samplecount += length;
-        if ((samplecount & 8191) < length)
+        jittercount += length;
+        if (jittercount >= 8000) {
+                jittercount -= 8000;
                 jittercheck = 1;
+        }
 
         /* loop all members that do not require conference mixing */
         list_for_each_entry(dsp, &dsp_ilist, list) {