This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / include / asm-x86_64 / mach-xen / mach_timer.h

diff --git a/include/asm-x86_64/mach-xen/mach_timer.h b/include/asm-x86_64/mach-xen/mach_timer.h
new file mode 100644 (file)
index 0000000..4b9703b
--- /dev/null
+++ b/include/asm-x86_64/mach-xen/mach_timer.h
@@ -0,0 +1,48 @@
+/*
+ *  include/asm-i386/mach-default/mach_timer.h
+ *
+ *  Machine specific calibrate_tsc() for generic.
+ *  Split out from timer_tsc.c by Osamu Tomita <tomita@cinet.co.jp>
+ */
+/* ------ Calibrate the TSC ------- 
+ * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset().
+ * Too much 64-bit arithmetic here to do this cleanly in C, and for
+ * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2)
+ * output busy loop as low as possible. We avoid reading the CTC registers
+ * directly because of the awkward 8-bit access mechanism of the 82C54
+ * device.
+ */
+#ifndef _MACH_TIMER_H
+#define _MACH_TIMER_H
+
+#define CALIBRATE_LATCH        (5 * LATCH)
+
+static inline void mach_prepare_counter(void)
+{
+       /* Set the Gate high, disable speaker */
+       outb((inb(0x61) & ~0x02) | 0x01, 0x61);
+
+       /*
+        * Now let's take care of CTC channel 2
+        *
+        * Set the Gate high, program CTC channel 2 for mode 0,
+        * (interrupt on terminal count mode), binary count,
+        * load 5 * LATCH count, (LSB and MSB) to begin countdown.
+        *
+        * Some devices need a delay here.
+        */
+       outb(0xb0, 0x43);                       /* binary, mode 0, LSB/MSB, Ch 2 */
+       outb_p(CALIBRATE_LATCH & 0xff, 0x42);   /* LSB of count */
+       outb_p(CALIBRATE_LATCH >> 8, 0x42);       /* MSB of count */
+}
+
+static inline void mach_countup(unsigned long *count_p)
+{
+       unsigned long count = 0;
+       do {
+               count++;
+       } while ((inb_p(0x61) & 0x20) == 0);
+       *count_p = count;
+}
+
+#endif /* !_MACH_TIMER_H */