m68k: mac: Convert to clocksource API

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>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index 8b88489..3c2cfcb 100644 (file)
--- a/arch/m68k/mac/via.c
+++ b/arch/m68k/mac/via.c
@@ -23,6 +23,7 @@
  *
  */
 
+#include <linux/clocksource.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
@@ -577,16 +578,39 @@ EXPORT_SYMBOL(via2_scsi_drq_pending);
 /* timer and clock source */
 
 #define VIA_CLOCK_FREQ     783360                /* VIA "phase 2" clock in Hz */
-#define VIA_TIMER_INTERVAL (1000000 / HZ)        /* microseconds per jiffy */
 #define VIA_TIMER_CYCLES   (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */
 
 #define VIA_TC             (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */
 #define VIA_TC_LOW         (VIA_TC & 0xFF)
 #define VIA_TC_HIGH        (VIA_TC >> 8)
 
+static u64 mac_read_clk(struct clocksource *cs);
+
+static struct clocksource mac_clk = {
+       .name   = "via1",
+       .rating = 250,
+       .read   = mac_read_clk,
+       .mask   = CLOCKSOURCE_MASK(32),
+       .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 clk_total, clk_offset;
+
+static irqreturn_t via_timer_handler(int irq, void *dev_id)
+{
+       irq_handler_t timer_routine = dev_id;
+
+       clk_total += VIA_TIMER_CYCLES;
+       clk_offset = 0;
+       timer_routine(0, NULL);
+
+       return IRQ_HANDLED;
+}
+
 void __init via_init_clock(irq_handler_t timer_routine)
 {
-       if (request_irq(IRQ_MAC_TIMER_1, timer_routine, 0, "timer", NULL)) {
+       if (request_irq(IRQ_MAC_TIMER_1, via_timer_handler, IRQF_TIMER, "timer",
+                       timer_routine)) {
                pr_err("Couldn't register %s interrupt\n", "timer");
                return;
        }
@@ -596,13 +620,16 @@ void __init via_init_clock(irq_handler_t timer_routine)
        via1[vT1CL] = VIA_TC_LOW;
        via1[vT1CH] = VIA_TC_HIGH;
        via1[vACR] |= 0x40;
+
+       clocksource_register_hz(&mac_clk, VIA_CLOCK_FREQ);
 }
 
-u32 mac_gettimeoffset(void)
+static u64 mac_read_clk(struct clocksource *cs)
 {
        unsigned long flags;
        u8 count_high;
-       u16 count, offset = 0;
+       u16 count;
+       u32 ticks;
 
        /*
         * Timer counter wrap-around is detected with the timer interrupt flag
@@ -618,11 +645,11 @@ u32 mac_gettimeoffset(void)
        if (count_high == 0xFF)
                count_high = 0;
        if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT))
-               offset = VIA_TIMER_CYCLES;
-       local_irq_restore(flags);
-
+               clk_offset = VIA_TIMER_CYCLES;
        count = count_high << 8;
-       count = VIA_TIMER_CYCLES - count + offset;
+       ticks = VIA_TIMER_CYCLES - count;
+       ticks += clk_offset + clk_total;
+       local_irq_restore(flags);
 
-       return ((count * VIA_TIMER_INTERVAL) / VIA_TIMER_CYCLES) * 1000;
+       return ticks;
 }