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Subject[RFC PATCH v2 11/14] m68k: mvme147: Convert to clocksource API
Date
Add a platform clocksource by adapting the existing arch_gettimeoffset
implementation.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
Changed since v1:
- Moved clk_total access to within the irq lock.
- Use type u32 for tick counter.
---
arch/m68k/include/asm/mvme147hw.h | 1 -
arch/m68k/mvme147/config.c | 38 ++++++++++++++++++++++++++-----
2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/m68k/include/asm/mvme147hw.h b/arch/m68k/include/asm/mvme147hw.h
index 9c7ff67c5ffd..7c3dd513128e 100644
--- a/arch/m68k/include/asm/mvme147hw.h
+++ b/arch/m68k/include/asm/mvme147hw.h
@@ -66,7 +66,6 @@ struct pcc_regs {
#define PCC_INT_ENAB 0x08

#define PCC_TIMER_INT_CLR 0x80
-#define PCC_TIMER_PRELOAD 63936l

#define PCC_LEVEL_ABORT 0x07
#define PCC_LEVEL_SERIAL 0x04
diff --git a/arch/m68k/mvme147/config.c b/arch/m68k/mvme147/config.c
index 4ef4faa5ed8b..82b53b5ca82b 100644
--- a/arch/m68k/mvme147/config.c
+++ b/arch/m68k/mvme147/config.c
@@ -17,6 +17,7 @@
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/tty.h>
+#include <linux/clocksource.h>
#include <linux/console.h>
#include <linux/linkage.h>
#include <linux/init.h>
@@ -92,6 +93,21 @@ void __init config_mvme147(void)
vme_brdtype = VME_TYPE_MVME147;
}

+static u64 mvme147_read_clk(struct clocksource *cs);
+
+static struct clocksource mvme147_clk = {
+ .name = "pcc",
+ .rating = 250,
+ .read = mvme147_read_clk,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 clk_total;
+
+#define PCC_TIMER_CLOCK_FREQ 160000
+#define PCC_TIMER_CYCLES (PCC_TIMER_CLOCK_FREQ / HZ)
+#define PCC_TIMER_PRELOAD (0x10000 - PCC_TIMER_CYCLES)

/* Using pcc tick timer 1 */

@@ -103,6 +119,7 @@ static irqreturn_t mvme147_timer_int (int irq, void *dev_id)
local_irq_save(flags);
m147_pcc->t1_int_cntrl = PCC_TIMER_INT_CLR;
m147_pcc->t1_int_cntrl = PCC_INT_ENAB|PCC_LEVEL_TIMER1;
+ clk_total += PCC_TIMER_CYCLES;
timer_routine(0, NULL);
local_irq_restore(flags);

@@ -112,32 +129,41 @@ static irqreturn_t mvme147_timer_int (int irq, void *dev_id)

void mvme147_sched_init (irq_handler_t timer_routine)
{
- if (request_irq(PCC_IRQ_TIMER1, mvme147_timer_int, 0, "timer 1",
- timer_routine))
+ if (request_irq(PCC_IRQ_TIMER1, mvme147_timer_int, IRQF_TIMER,
+ "timer 1", timer_routine))
pr_err("Couldn't register timer interrupt\n");

/* Init the clock with a value */
- /* our clock goes off every 6.25us */
+ /* The clock counter increments until 0xFFFF then reloads */
m147_pcc->t1_preload = PCC_TIMER_PRELOAD;
m147_pcc->t1_cntrl = 0x0; /* clear timer */
m147_pcc->t1_cntrl = 0x3; /* start timer */
m147_pcc->t1_int_cntrl = PCC_TIMER_INT_CLR; /* clear pending ints */
m147_pcc->t1_int_cntrl = PCC_INT_ENAB|PCC_LEVEL_TIMER1;
+
+ clocksource_register_hz(&mvme147_clk, PCC_TIMER_CLOCK_FREQ);
}

-/* This is always executed with interrupts disabled. */
/* XXX There are race hazards in this code XXX */
-u32 mvme147_gettimeoffset(void)
+static u64 mvme147_read_clk(struct clocksource *cs)
{
+ unsigned long flags;
volatile unsigned short *cp = (volatile unsigned short *)0xfffe1012;
unsigned short n;
+ u32 ticks;
+
+ local_irq_save(flags);

n = *cp;
while (n != *cp)
n = *cp;

n -= PCC_TIMER_PRELOAD;
- return ((unsigned long)n * 25 / 4) * 1000;
+ ticks = clk_total + n;
+
+ local_irq_restore(flags);
+
+ return ticks;
}

static int bcd2int (unsigned char b)
--
2.18.1
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