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 v2:
- Don't check for timer interrupt in amiga_read_clk() when the timer is
about to be reloaded.
Changed since v1:
- Moved clk_total access to within the irq lock.
---
arch/m68k/amiga/config.c | 64 +++++++++++++++++++++++++++-------------
1 file changed, 43 insertions(+), 21 deletions(-)
diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index d4976c1aa0cc..0c2c07318f6c 100644
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -17,6 +17,7 @@
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <linux/tty.h>
+#include <linux/clocksource.h>
#include <linux/console.h>
#include <linux/rtc.h>
#include <linux/init.h>
@@ -461,7 +462,28 @@ void __init config_amiga(void)
*(unsigned char *)ZTWO_VADDR(0xde0002) |= 0x80;
}
+static u64 amiga_read_clk(struct clocksource *cs);
+
+static struct clocksource amiga_clk = {
+ .name = "ciab",
+ .rating = 250,
+ .read = amiga_read_clk,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
static unsigned short jiffy_ticks;
+static u32 clk_total;
+
+static irqreturn_t ciab_timer_handler(int irq, void *dev_id)
+{
+ irq_handler_t timer_routine = dev_id;
+
+ clk_total += jiffy_ticks;
+ timer_routine(0, NULL);
+
+ return IRQ_HANDLED;
+}
static void __init amiga_sched_init(irq_handler_t timer_routine)
{
@@ -481,41 +503,41 @@ static void __init amiga_sched_init(irq_handler_t
timer_routine)
* Please don't change this to use ciaa, as it interferes with the
* SCSI code. We'll have to take a look at this later
*/
- if (request_irq(IRQ_AMIGA_CIAB_TA, timer_routine, 0, "timer", NULL))
+ if (request_irq(IRQ_AMIGA_CIAB_TA, ciab_timer_handler, IRQF_TIMER,
+ "timer", timer_routine))
pr_err("Couldn't register timer interrupt\n");
/* start timer */
ciab.cra |= 0x11;
-}
-#define TICK_SIZE 10000
+ clocksource_register_hz(&amiga_clk, amiga_eclock);
+}
-/* This is always executed with interrupts disabled. */
-static u32 amiga_gettimeoffset(void)
+static u64 amiga_read_clk(struct clocksource *cs)
{
- unsigned short hi, lo, hi2;
+ unsigned long flags;
+ u8 msb, lsb, tmp;
u32 ticks, offset = 0;
- /* read CIA B timer A current value */
- hi = ciab.tahi;
- lo = ciab.talo;
- hi2 = ciab.tahi;
+ local_irq_save(flags);
- if (hi != hi2) {
- lo = ciab.talo;
- hi = hi2;
- }
-
- ticks = hi << 8 | lo;
+ /* read CIA B timer A current value */
+ tmp = ciab.tahi;
+ lsb = ciab.talo;
+ msb = ciab.tahi;
+ if (msb != tmp)
+ lsb = ciab.talo;
- if (ticks > jiffy_ticks / 2)
+ if (msb > 0)
/* check for pending interrupt */
if (cia_set_irq(&ciab_base, 0) & CIA_ICR_TA)
- offset = 10000;
+ offset = jiffy_ticks;
+
+ ticks = jiffy_ticks - (msb << 8 | lsb);
+ ticks += offset + clk_total;
- ticks = jiffy_ticks - ticks;
- ticks = (10000 * ticks) / jiffy_ticks;
+ local_irq_restore(flags);
- return (ticks + offset) * 1000;
+ return ticks;
}
static void amiga_reset(void) __noreturn;
--
2.18.1
