Bug#317297: zaptel-source: ztdummy accuracy improvements on kernel 2.6 (patch)

[Christian Luijten]

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Package: zaptel-source
Version: 1:1.0.9-2
Severity: normal
Tags: patch

Following http://bugs.digium.com/view.php?id=4301 this patch gravely
improves the accuracy of the ztdummy driver (and thus resolves many
delay-issues).

-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.11-1-686
Locale: LANG=C, LC_CTYPE=nl_NL.utf8 (charmap=UTF-8)

Versions of packages zaptel-source depends on:
ii  bzip2                         1.0.2-7    high-quality block-sorting file co
ii  debhelper                     4.9.3      helper programs for debian/rules
ii  dpatch                        2.0.13     patch maintenance system for Debia
ii  module-assistant              0.9.3      tool to make module package creati

Versions of packages zaptel-source recommends:
pn  zaptel                        <none>     (no description available)

-- no debconf information

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Index: ztdummy.c
===================================================================
RCS file: /usr/cvsroot/zaptel/ztdummy.c,v
retrieving revision 1.4.2.4
diff -u -r1.4.2.4 ztdummy.c
--- ztdummy.c	21 Jan 2005 05:05:18 -0000	1.4.2.4
+++ ztdummy.c	21 May 2005 21:53:28 -0000
@@ -6,6 +6,7 @@
  * Written by Robert Pleh <robert.pleh@hermes.si>
  * 2.6 version by Tony Hoyle
  * Unified by Mark Spencer <markster@digium.com>
+ * Converted to use RTC on i386 by Tony Mountifield <tony@softins.co.uk>
  *
  * Copyright (C) 2002, Hermes Softlab
  * Copyright (C) 2004, Digium, Inc.
@@ -38,6 +39,15 @@
 #  error "This kernel is too old: not supported by this file"
 #endif
 
+/*
+ * NOTE: (only applies to kernel 2.6)
+ * If using an i386 architecture without a PC real-time clock,
+ * the #define USE_RTC should be commented out.
+ */
+#if defined(__i386__)
+#define USE_RTC
+#endif
+
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/module.h>
@@ -54,6 +64,9 @@
 #include <asm/io.h>
 #endif
 #ifdef LINUX26
+#ifdef USE_RTC
+#include <linux/rtc.h>
+#endif
 #include <linux/moduleparam.h>
 #endif
 #include "ztdummy.h"
@@ -77,8 +90,10 @@
 static int debug = 0;
 
 #ifdef LINUX26
+#ifndef USE_RTC
 /* New 2.6 kernel timer stuff */
 static struct timer_list timer;
+#endif
 #else
 #if LINUX_VERSION_CODE < VERSION_CODE(2,4,5)
 #  error "This kernel is too old: not supported by this file"
@@ -103,6 +118,28 @@
 
 
 #ifdef LINUX26
+#ifdef USE_RTC
+/* rtc_interrupt - called at 1024Hz from hook in RTC handler */
+static void rtc_interrupt(void *private_data)
+{
+	struct ztdummy *ztd = private_data;
+	unsigned int ticks;
+
+	atomic_inc(&ztd->ticks);
+	ticks = atomic_read(&ztd->ticks);
+	if (ticks == 42 || ticks == 85) {
+		/* skip it */
+	} else if (ticks >= 128) {
+		/* skip and restart count */
+		atomic_set(&ztd->ticks, 0);
+	} else {
+		/* zaptel timing - called in 125 of every 128 interrupts = 1000Hz */
+		zt_receive(&ztd->span);
+		zt_transmit(&ztd->span);
+	}
+}
+#else
+/* use kernel system tick timer if PC architecture RTC is not available */
 static void ztdummy_timer(unsigned long param)
 {
     zt_receive(&ztd->span);
@@ -110,6 +147,7 @@
     timer.expires = jiffies + 1;
     add_timer(&timer);
 }
+#endif
 #else
 static void ztdummy_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
@@ -150,7 +188,11 @@
 
 int init_module(void)
 {
-#ifndef LINUX26
+#ifdef LINUX26
+#ifdef USE_RTC
+    int err;
+#endif
+#else
     int irq;
     spinlock_t mylock = SPIN_LOCK_UNLOCKED;
 	
@@ -180,10 +222,25 @@
     }
 
 #ifdef LINUX26
+#ifdef USE_RTC
+    atomic_set(&ztd->ticks, 0);
+    ztd->rtc_task.func = rtc_interrupt;
+    ztd->rtc_task.private_data = ztd;
+    err = rtc_register(&ztd->rtc_task);
+    if (err < 0) {
+	printk("ztdummy: Unable to register zaptel rtc driver\n");
+        zt_unregister(&ztd->span);
+	kfree(ztd);
+	return err;
+    }
+    rtc_control(&ztd->rtc_task, RTC_IRQP_SET, 1024);	/* 1024 Hz */
+    rtc_control(&ztd->rtc_task, RTC_PIE_ON, 0);
+#else
     init_timer(&timer);
     timer.function = ztdummy_timer;
     timer.expires = jiffies + 1;
     add_timer(&timer);
+#endif
 #else
     irq=s->irq;
     spin_lock_irq(&mylock);
@@ -214,7 +271,12 @@
 void cleanup_module(void)
 {
 #ifdef LINUX26
+#ifdef USE_RTC
+    rtc_control(&ztd->rtc_task, RTC_PIE_OFF, 0);
+    rtc_unregister(&ztd->rtc_task);
+#else
     del_timer(&timer);
+#endif
 #else
     free_irq(s->irq, ztd);  /* disable interrupts */
 #endif
Index: ztdummy.h
===================================================================
RCS file: /usr/cvsroot/zaptel/ztdummy.h,v
retrieving revision 1.2
diff -u -r1.2 ztdummy.h
--- ztdummy.h	24 Feb 2003 06:00:31 -0000	1.2
+++ ztdummy.h	21 May 2005 21:53:28 -0000
@@ -32,9 +32,16 @@
 struct ztdummy {
 	struct zt_span span;
 	struct zt_chan chan;
+#ifdef LINUX26
+#ifdef USE_RTC
+	atomic_t ticks;
+	rtc_task_t rtc_task;
+#endif
+#endif
 };
 
 
+#ifndef LINUX26
 /* Uhci definitions and structures - from file usb-uhci.h */
 #define TD_CTRL_IOC		(1 << 24)	/* Interrupt on Complete */
 #define USBSTS 2
@@ -141,3 +148,4 @@
 	struct pci_pool *desc_pool;
 	long last_error_time;          // last error output in uhci_interrupt()
 } uhci_t, *puhci_t;
+#endif

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