[RFC PATCH 07/13] m68k: amiga: Convert to clocksource API

[Finn Thain]

Add a platform clocksource by adapting the existing arch_gettimeoffset
implementation.

Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
---
 arch/m68k/amiga/config.c | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index a575ad419b23..40ebd471cc3c 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 +462,30 @@ 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 *data)
+{
+       irq_handler_t timer_routine = data;
+       unsigned long flags;
+
+       local_irq_save(flags);
+       clk_total += jiffy_ticks;
+       local_irq_restore(flags);
+
+       return timer_routine(irq, data);
+}
 
 static void __init amiga_sched_init(irq_handler_t timer_routine)
 {
@@ -481,15 +505,16 @@ 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);
+}
 
-static u32 amiga_gettimeoffset(void)
+static u64 amiga_read_clk(struct clocksource *cs)
 {
        unsigned long flags;
        unsigned short hi, lo, hi2;
@@ -512,14 +537,13 @@ static u32 amiga_gettimeoffset(void)
        if (ticks > jiffy_ticks / 2)
                /* check for pending interrupt */
                if (cia_set_irq(&ciab_base, 0) & CIA_ICR_TA)
-                       offset = 10000;
+                       offset = jiffy_ticks;
 
        local_irq_restore(flags);
 
        ticks = jiffy_ticks - ticks;
-       ticks = (10000 * ticks) / jiffy_ticks;
 
-       return (ticks + offset) * 1000;
+       return clk_total + ticks + offset;
 }
 
 static void amiga_reset(void)  __noreturn;
-- 
2.18.1