Add a platform clocksource by adapting the existing arch_gettimeoffset
implementation.
Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
Acked-by: Linus Walleij <linus.wall...@linaro.org>
---
Changed since v1:
- Moved clk_total access to within the irq lock.
- Use type u32 for tick counter.
---
arch/m68k/hp300/time.c | 37 ++++++++++++++++++++++++++++++-------
1 file changed, 30 insertions(+), 7 deletions(-)
diff --git a/arch/m68k/hp300/time.c b/arch/m68k/hp300/time.c
index d30b03ea93a2..90982803a629 100644
--- a/arch/m68k/hp300/time.c
+++ b/arch/m68k/hp300/time.c
@@ -8,6 +8,7 @@
*/
#include <asm/ptrace.h>
+#include <linux/clocksource.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
@@ -19,6 +20,18 @@
#include <asm/traps.h>
#include <asm/blinken.h>
+static u64 hp300_read_clk(struct clocksource *cs);
+
+static struct clocksource hp300_clk = {
+ .name = "timer",
+ .rating = 250,
+ .read = hp300_read_clk,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 clk_total;
+
/* Clock hardware definitions */
#define CLOCKBASE 0xf05f8000
@@ -32,9 +45,10 @@
#define CLKMSB3 0xD
/* This is for machines which generate the exact clock. */
-#define USECS_PER_JIFFY (1000000/HZ)
-#define INTVAL ((10000 / 4) - 1)
+#define HP300_TIMER_CLOCK_FREQ 250000
+#define HP300_TIMER_CYCLES (HP300_TIMER_CLOCK_FREQ / HZ)
+#define INTVAL (HP300_TIMER_CYCLES - 1)
static irqreturn_t hp300_tick(int irq, void *dev_id)
{
@@ -45,6 +59,7 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
local_irq_save(flags);
in_8(CLOCKBASE + CLKSR);
asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
+ clk_total += INTVAL;
timer_routine(0, NULL);
local_irq_restore(flags);
@@ -53,20 +68,26 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
return IRQ_HANDLED;
}
-u32 hp300_gettimeoffset(void)
+static u64 hp300_read_clk(struct clocksource *cs)
{
- /* Read current timer 1 value */
+ unsigned long flags;
unsigned char lsb, msb1, msb2;
- unsigned short ticks;
+ u32 ticks;
+ local_irq_save(flags);
+ /* Read current timer 1 value */
msb1 = in_8(CLOCKBASE + 5);
lsb = in_8(CLOCKBASE + 7);
msb2 = in_8(CLOCKBASE + 5);
if (msb1 != msb2)
/* A carry happened while we were reading. Read it again */
lsb = in_8(CLOCKBASE + 7);
+
ticks = INTVAL - ((msb2 << 8) | lsb);
- return ((USECS_PER_JIFFY * ticks) / INTVAL) * 1000;
+ ticks += clk_total;
+ local_irq_restore(flags);
+
+ return ticks;
}
void __init hp300_sched_init(irq_handler_t vector)
@@ -76,9 +97,11 @@ void __init hp300_sched_init(irq_handler_t vector)
asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
- if (request_irq(IRQ_AUTO_6, hp300_tick, 0, "timer tick", vector))
+ if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", vector))
pr_err("Couldn't register timer interrupt\n");
out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
+
+ clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);
}
--
2.18.1
