[PATCH] Time: Clocksource Infrastructure

This introduces the clocksource management infrastructure.  A clocksource is a
driver-like architecture generic abstraction of a free-running counter.  This
code defines the clocksource structure, and provides management code for
registering, selecting, accessing and scaling clocksources.

Additionally, this includes the trivial jiffies clocksource, a lowest common
denominator clocksource, provided mainly for use as an example.

[hirofumi@mail.parknet.co.jp: Don't enable IRQ too early]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bca6f389da66..968631678d4a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -61,6 +61,7 @@ parameter is applicable:
         MTD     MTD support is enabled.
         NET     Appropriate network support is enabled.
         NUMA    NUMA support is enabled.
+        GENERIC_TIME The generic timeofday code is enabled.
         NFS     Appropriate NFS support is enabled.
         OSS     OSS sound support is enabled.
         PARIDE  The ParIDE subsystem is enabled.
@@ -341,10 +342,11 @@ running once the system is up.
                         Value can be changed at runtime via
                                 /selinux/checkreqprot.
 
-        clock=          [BUGS=IA-32,HW] gettimeofday timesource override.
-                        Forces specified timesource (if avaliable) to be used
-                        when calculating gettimeofday(). If specicified
-                        timesource is not avalible, it defaults to PIT.
+        clock=          [BUGS=IA-32, HW] gettimeofday clocksource override.
+                        [Deprecated]
+                        Forces specified clocksource (if avaliable) to be used
+                        when calculating gettimeofday(). If specified
+                        clocksource is not avalible, it defaults to PIT.
                         Format: { pit | tsc | cyclone | pmtmr }
 
         disable_8254_timer
@@ -1617,6 +1619,10 @@ running once the system is up.
 
         time            Show timing data prefixed to each printk message line
 
+        clocksource=    [GENERIC_TIME] Override the default clocksource
+                        Override the default clocksource and use the clocksource
+                        with the name specified.
+
         tipar.timeout=  [HW,PPT]
                         Set communications timeout in tenths of a second
                         (default 15).