Hi,
here comes my patch for user space tsc emulation for decrementing counters. I
had to extend the __xn_tscinfo structure because the counter value from the
last tsc update is needed to calculate the new tsc value.
I will post a second patch for Adeos which implements the kernel side for
s3c24xx platforms on adeos-main.
--
Sebastian
Index: include/asm-arm/syscall.h
===================================================================
--- include/asm-arm/syscall.h (Revision 2768)
+++ include/asm-arm/syscall.h (Arbeitskopie)
@@ -4,6 +4,9 @@
* ARM port
* Copyright (C) 2005 Stelian Pop
*
+ * Copyright (C) 2007 Sebastian Smolorz <[EMAIL PROTECTED]>
+ * Support for TSC emulation in user space for decrementing counters
+ *
* Xenomai 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,
@@ -202,6 +205,7 @@
struct {
volatile unsigned *counter;
unsigned mask;
+ volatile unsigned *last_cnt;
volatile unsigned long long *tsc;
} fr;
struct {
@@ -248,6 +252,28 @@
if ((counter & mask) < (before & mask))
before += mask + 1;
return (before & ~mask) | (counter & mask);
+
+#elif CONFIG_XENO_ARM_HW_DIRECT_TSC == __XN_TSC_TYPE_DECREMENTER
+ const unsigned long long mask = __xn_tscinfo.u.fr.mask;
+ unsigned long long after, before;
+ unsigned counter, last_cnt;
+
+ do {
+ before = *__xn_tscinfo.u.fr.tsc;
+ counter = *__xn_tscinfo.u.fr.counter;
+ last_cnt = *__xn_tscinfo.u.fr.last_cnt;
+ /* compiler barrier. */
+ asm("" : /* */ : /* */ : "memory");
+
+ after = *__xn_tscinfo.u.fr.tsc;
+ } while (after != before);
+
+ counter &= mask;
+ last_cnt &= mask;
+ if (counter > last_cnt)
+ before += mask + 1;
+ return (before + last_cnt - counter);
+
#endif /* CONFIG_XENO_HW_DIRECT_TSC == __XN_TSC_TYPE_FREERUNNING */
}
@@ -279,8 +305,8 @@
page_size = sysconf(_SC_PAGESIZE);
switch(__xn_tscinfo.type) {
-#if CONFIG_XENO_ARM_HW_DIRECT_TSC == __XN_TSC_TYPE_FREERUNNING
- case __XN_TSC_TYPE_FREERUNNING:{
+ case __XN_TSC_TYPE_FREERUNNING:
+ case __XN_TSC_TYPE_DECREMENTER: {
unsigned long phys_addr;
phys_addr = (unsigned long) __xn_tscinfo.u.fr.counter;
@@ -296,7 +322,6 @@
((char *) addr + (phys_addr & (page_size - 1))));
break;
}
-#endif /* CONFIG_XENO_ARM_HW_DIRECT_TSC == __XN_TSC_TYPE_FREERUNNING */
case __XN_TSC_TYPE_NONE:
goto error;
Index: include/asm-arm/bits/shadow.h
===================================================================
--- include/asm-arm/bits/shadow.h (Revision 2768)
+++ include/asm-arm/bits/shadow.h (Arbeitskopie)
@@ -176,6 +176,12 @@
info.u.fr.tsc = ipipe_info.archdep.tsc.u.fr.tsc;
break;
case IPIPE_TSC_TYPE_DECREMENTER:
+ info.type = __XN_TSC_TYPE_DECREMENTER,
+ info.u.fr.counter = ipipe_info.archdep.tsc.u.fr.counter;
+ info.u.fr.mask = ipipe_info.archdep.tsc.u.fr.mask;
+ info.u.fr.last_cnt = ipipe_info.archdep.tsc.u.fr.last_cnt;
+ info.u.fr.tsc = ipipe_info.archdep.tsc.u.fr.tsc;
+ break;
case IPIPE_TSC_TYPE_NONE:
return -ENOSYS;
Index: configure.in
===================================================================
--- configure.in (Revision 2768)
+++ configure.in (Arbeitskopie)
@@ -182,7 +182,8 @@
ixp4xx|pxa) arch=5
tsc_type=__XN_TSC_TYPE_FREERUNNING;;
- s3c2410) arch=4;;
+ s3c2410) arch=4
+ tsc_type=__XN_TSC_TYPE_DECREMENTER;;
sa1100) arch=4
CONFIG_XENO_ARM_SA1100=y
Index: ChangeLog
===================================================================
--- ChangeLog (Revision 2768)
+++ ChangeLog (Arbeitskopie)
@@ -1,3 +1,8 @@
+2007-07-19 Sebastian Smolorz <[EMAIL PROTECTED]>
+
+ * include/asm-arm/syscall.h: Add user-space access to
+ tsc emulation for decrementing counters.
+
2007-07-19 Jan Kiszka <[EMAIL PROTECTED]>
* ksrc/nucleus/timer.c (xntimer_tick_aperiodic): Keep processing
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