* - mark-tsc-on-geodelx-reliable.patch removed from -mm tree
@ 2007-02-17 7:14 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2007-02-17 7:14 UTC (permalink / raw)
To: marcelo, johnstul, mingo, tglx, zippel, mm-commits
The patch titled
Mark TSC on GeodeLX reliable
has been removed from the -mm tree. Its filename was
mark-tsc-on-geodelx-reliable.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: Mark TSC on GeodeLX reliable
From: Marcelo Tosatti <marcelo@kvack.org>
The Geode can safely use the TSC for highres, since:
1) Does not support frequency scaling,
2) The TSC _does_ count when the CPU is halted. Furthermore, the Geode
supports a mode called "suspension on halt", where Suspend mode (which
interacts with the power management states) is entered. TSC counting
during suspend mode is controlled by bit 8 of the Bus Controller
Configuration Register #0 (thanks Tom!).
3) no SMP :)
Check if "RTSC counts during suspension" and remove the requirement for
verification, so the clocksource code can safely select it as an timesource
for the highres timers subsystem.
Signed-off-by: Marcelo Tosatti <marcelo@kvack.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/i386/kernel/tsc.c | 20 ++++++++++++++++++++
include/asm-i386/msr.h | 3 +++
2 files changed, 23 insertions(+)
diff -puN arch/i386/kernel/tsc.c~mark-tsc-on-geodelx-reliable arch/i386/kernel/tsc.c
--- a/arch/i386/kernel/tsc.c~mark-tsc-on-geodelx-reliable
+++ a/arch/i386/kernel/tsc.c
@@ -364,6 +364,25 @@ __cpuinit int unsynchronized_tsc(void)
return tsc_unstable;
}
+/*
+ * Geode_LX - the OLPC CPU has a possibly a very reliable TSC
+ */
+#ifdef CONFIG_MGEODE_LX
+/* RTSC counts during suspend */
+#define RTSC_SUSP 0x100
+
+static void __init check_geode_tsc_reliable(void)
+{
+ unsigned long val;
+
+ rdmsrl(MSR_GEODE_BUSCONT_CONF0, val);
+ if ((val & RTSC_SUSP))
+ clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
+}
+#else
+static inline void check_geode_tsc_reliable(void) { }
+#endif
+
static int __init init_tsc_clocksource(void)
{
@@ -372,6 +391,7 @@ static int __init init_tsc_clocksource(v
dmi_check_system(bad_tsc_dmi_table);
unsynchronized_tsc();
+ check_geode_tsc_reliable();
current_tsc_khz = tsc_khz;
clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
clocksource_tsc.shift);
diff -puN include/asm-i386/msr.h~mark-tsc-on-geodelx-reliable include/asm-i386/msr.h
--- a/include/asm-i386/msr.h~mark-tsc-on-geodelx-reliable
+++ a/include/asm-i386/msr.h
@@ -307,4 +307,7 @@ static inline void wrmsrl (unsigned long
#define MSR_CORE_PERF_GLOBAL_CTRL 0x38f
#define MSR_CORE_PERF_GLOBAL_OVF_CTRL 0x390
+/* Geode defined MSRs */
+#define MSR_GEODE_BUSCONT_CONF0 0x1900
+
#endif /* __ASM_MSR_H */
_
Patches currently in -mm which might be from marcelo@kvack.org are
origin.patch
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2007-02-17 7:14 - mark-tsc-on-geodelx-reliable.patch removed from -mm tree akpm
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