[patch 1/1 17-rc3-mm1] generic-time: add macro to simplify/hide maskconstants

[Jim Cromie]

This patch compiles clean, and is running and maintaining ntp lock
(across ethernet to a laptop).  I've verified (with objdump) that
macro reduces to constant at compile-time. Also compile-tested with 
allnoconfig.  Please consider for -mm.

---

From: Jim Cromie <jim.cromie@xxxxxxxxx>
Date: Wed May  3 10:59:00 EDT 2006


Add a CLOCKSOURCE_MASK macro to simplify initializing the mask for 
a struct clocksource, and use it to replace literal mask constants
in the various clocksource drivers.

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>

---

arch/i386/kernel/hpet.c       |    4 ++--

arch/i386/kernel/i8253.c      |    2 +-
arch/i386/kernel/tsc.c        |    2 +-
drivers/clocksource/acpi_pm.c |    2 +-
drivers/clocksource/cyclone.c |    4 ++--
include/linux/clocksource.h   |    2 ++
localversion-clk              |    1 +		(trimmed out)
8 files changed, 10 insertions(+), 7 deletions(-)


diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/arch/i386/kernel/hpet.c clksrc-mask/arch/i386/kernel/hpet.c
--- linux-2.6.17-rc3-mm1/arch/i386/kernel/hpet.c        2006-05-03 08:29:48.000000000 -0400
+++ clksrc-mask/arch/i386/kernel/hpet.c 2006-05-03 09:43:03.000000000 -0400
@@ -6,7 +6,7 @@
#include <asm/hpet.h>
#include <asm/io.h>

-#define HPET_MASK      0xFFFFFFFF
+#define HPET_MASK      CLOCKSOURCE_MASK(32)
#define HPET_SHIFT     22

/* FSEC = 10^-15 NSEC = 10^-9 */
@@ -23,7 +23,7 @@ static struct clocksource clocksource_hp
       .name           = "hpet",
       .rating         = 250,
       .read           = read_hpet,
-       .mask           = (cycle_t)HPET_MASK,
+       .mask           = HPET_MASK,
       .mult           = 0, /* set below */
       .shift          = HPET_SHIFT,
       .is_continuous  = 1,
diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/arch/i386/kernel/i8253.c clksrc-mask/arch/i386/kernel/i8253.c
--- linux-2.6.17-rc3-mm1/arch/i386/kernel/i8253.c       2006-05-03 08:29:48.000000000 -0400
+++ clksrc-mask/arch/i386/kernel/i8253.c        2006-05-03 09:45:33.000000000 -0400
@@ -69,7 +69,7 @@ static struct clocksource clocksource_pi
       .name   = "pit",
       .rating = 110,
       .read   = pit_read,
-       .mask   = (cycle_t)-1,
+       .mask   = CLOCKSOURCE_MASK(64),
       .mult   = 0,
       .shift  = 20,
};
diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/arch/i386/kernel/tsc.c clksrc-mask/arch/i386/kernel/tsc.c
--- linux-2.6.17-rc3-mm1/arch/i386/kernel/tsc.c 2006-05-03 08:29:48.000000000 -0400
+++ clksrc-mask/arch/i386/kernel/tsc.c  2006-05-03 09:42:22.000000000 -0400
@@ -337,7 +337,7 @@ static struct clocksource clocksource_ts
       .name                   = "tsc",
       .rating                 = 300,
       .read                   = read_tsc,
-       .mask                   = (cycle_t)-1,
+       .mask                   = CLOCKSOURCE_MASK(64),
       .mult                   = 0, /* to be set */
       .shift                  = 22,
       .update_callback        = tsc_update_callback,
diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/drivers/clocksource/acpi_pm.c clksrc-mask/drivers/clocksource/acpi_pm.c
--- linux-2.6.17-rc3-mm1/drivers/clocksource/acpi_pm.c  2006-05-03 08:29:58.000000000 -0400
+++ clksrc-mask/drivers/clocksource/acpi_pm.c   2006-05-03 08:58:53.000000000 -0400
@@ -32,7 +32,7 @@
 */
u32 pmtmr_ioport __read_mostly;

-#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
+#define ACPI_PM_MASK CLOCKSOURCE_MASK(24) /* limit it to 24 bits */

static inline u32 read_pmtmr(void)
{
diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/drivers/clocksource/cyclone.c clksrc-mask/drivers/clocksource/cyclone.c
--- linux-2.6.17-rc3-mm1/drivers/clocksource/cyclone.c  2006-05-03 08:29:58.000000000 -0400
+++ clksrc-mask/drivers/clocksource/cyclone.c   2006-05-03 08:58:53.000000000 -0400
@@ -14,7 +14,7 @@
#define CYCLONE_MPCS_OFFSET    0x51A8          /* offset to select register */
#define CYCLONE_MPMC_OFFSET    0x51D0          /* offset to count register */
#define CYCLONE_TIMER_FREQ     99780000        /* 100Mhz, but not really */
-#define CYCLONE_TIMER_MASK     0xFFFFFFFF      /* 32 bit mask */
+#define CYCLONE_TIMER_MASK     CLOCKSOURCE_MASK(32) /* 32 bit mask */

int use_cyclone = 0;
static void __iomem *cyclone_ptr;
@@ -28,7 +28,7 @@ static struct clocksource clocksource_cy
       .name           = "cyclone",
       .rating         = 250,
       .read           = read_cyclone,
-       .mask           = (cycle_t)CYCLONE_TIMER_MASK,
+       .mask           = CYCLONE_TIMER_MASK,
       .mult           = 10,
       .shift          = 0,
       .is_continuous  = 1,
diff -ruNp -X dontdiff -X exclude-diffs linux-2.6.17-rc3-mm1/include/linux/clocksource.h clksrc-mask/include/linux/clocksource.h
--- linux-2.6.17-rc3-mm1/include/linux/clocksource.h    2006-05-03 08:30:25.000000000 -0400
+++ clksrc-mask/include/linux/clocksource.h     2006-05-03 10:35:40.000000000 -0400
@@ -65,6 +65,8 @@ struct clocksource {
       u64 interval_snsecs;
};

+/* simplify initialization of mask field */
+#define CLOCKSOURCE_MASK(bits) (cycle_t)(bits<64 ? ((1ULL<<bits)-1) : -1)

/**
 * clocksource_khz2mult - calculates mult from khz and shift


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